    [From the U.S. Government Printing Office, www.gpo.gov]

              UPPER BAY SURVEY

                      Final Report to the
            Maryland Department of Natural Resources
                  Annapolis, Maryland 21401

                         VOLUME II

                    Property of Csc Library

                     November 30, 1975

                         T. O. Munson
                     Project Chief Scientist

       D. K. Ela                              Carleton Rutledge, Jr.
    Project Manager                            Project Engineer and
                                            Coordinating Editor

               U. S. DEPARTMENT OF COMMERCE NOAA
              COASTAL SERVICES CENTER
               2234 SOUTH HOESON AVENUE
              r hARLESTON , SC 29405-2413

            WESTINGHOUSE ELECTRIC CORPORATION
                      OCEANIC DIVISION
                 ANNAPOLIS, MARYLAND 21404

    PREFACE

           Volume II of the Upper Bay Survey final report contains the contributions of the principal in-
    vestigators in the biological, geological, and physical science fields. Each chapter reports the details and
    data summations which substantiate the findings. Each chapter is the product of a particular in-
    vestigator; the words, the thoughts, and the responsibility for the content are his. However, Chapter 1 is
    an exception.
           Chapter 1 was written as an integrating overview. For example, Chapter 6 discusses the
    biochemistry work, but in Chapter 1, the biochemistry findings and conclusions are integrated as ap-
    propriate into the marine biology, microbiology, sedimentology, and hydrology results. Chapter 1
    provides the consolidated, multidisciplinary understanding of the entire program, including the objec-
    tives of the survey, the rationale in the technical approach,the execution of the project, and a summary of
    the findings.
           In this summary, the pattern of integration is seen clearly to be the pathways of the pollutants
    through the systems of the upper Chesapeake Bay. The pathways are the key to a clear understanding
    and ultimate management of the bay. That these pathways are defined more completely and described as
    never before is the outstanding contribution of this project. It is recommended that this part be read and
    studied carefully for the best appreciation of the entire major work.
           Volume III, Automated Data Processing Operations and Supplementary Data contains the com-
    plete set of fundamental data acquired during the survey as well as description and instructions for use of
    the data base. Volume IV, Numerical Modeling, contains the description and discussion of the upper bay
    mathematical model developed during the project. As the reader has seen, Volume I, Executive Sum-
    mary, is an introduction and digest of the entire project including conclusions and recommendations.
           At first glance, Chapter 1 of Volume II seems to be largely redundant with Volume I. The reader
    must recognize that they have distinctly different purposes. Volume I is intended to be the essence of the
    information contained in the other volumes expressed in uncomplicated language. It is for the busy ex-
    ecutive to read; it is for the government administrator and the natural resource manager especially.
    Chapter 1 of Volume II summarizes the scientific chapters of this volume only, and it is written for the
    scientist and the project manager.
            It is expected that the public official who reads Volume I may make informed judgments based
    upon its content, but that he will consult with his technical staff for precise definitions. His scientists will
    have the access to and the ability to digest and interpret Volumes II, III, and IV.

                TABLE OF CONTENTS

                      PREFACE

                     CHAPTER 1
              Multidisciplinary Overview
                    (T. 0. Munson)

                     CHAPTER 2
                   Marine Biology
                     (J. M. Forns)

                     CHAPTER 3
                     Microbiology
    (R. R. Colwell, G. S. Sayler, and J. D. Nelson, Jr.)

                     CHAPTER 4
               Estuarine Sedimentology
     (H. D. Palmer, J. R. Schubel, and W. B. Cronin)

                     CHAPTER 5
              Hydrology and Meteorology
                    (K. T. S. Tzou)

                     CHAPTER 6
                     Biochemistry
                    (T. 0. Munson)

              CHAPTER 1

    MULTIDISCIPLINARY OVERVIEW

             T.O. Munson
           Oceanic Division
    Westinghouse Electric Corporation

                                      TABLE OF CONTENTS

    Section                                                                                          Page

    1.0  INTRODUCTION...............................................................1-1
    1.1ocpt...........................................................................1-
    11.becie2..........................................................................1-
    22OEVEW..........................................................1.............3-
    22.negain1..............................................................1..........3-
    22.ahwy2.........................................................1................3-
    33TESUVY.......................................................................7-

    4.1  Hydrology and Meteorology ....................................................1-15

    4.2.1 Bottom Sediments............................................................1-16
    4.2.2 Suspended Sediments ........................................................1-16
    4.3  Marine Biology ..............................................................1-17

    4.5  Numerical Modeling ..........................................................1-19

                                        LIST OF FIGURES

    Figure                                                                                           Page

    1 -1    The Principal Sampling Stations of the Upper Bay Survey...........................1-10
    1 -2  Work Organization of the Disciplinary Tasks...................................... 1-11

    1. INTRODUCTION

      1.1 Concept
           The concept of the Upper Bay Survey grew directly from the Chester River Study, a program of
    more limited scope which was completed in the fall of 1972. An objective of that program was to provide
    the Maryland Department of Natural Resources with environmental and resource management informa-
    tion essential to the local shellfish industry. These studies were directed toward determining the source
    and fate of chlorinated hydrocarbons and selected trace metals (i.e., Zn, Pb, Cd, Cu, Cr, and Fe) in es-
    tuarine waters and sediments. The approach was multidisciplinary. The project as a whole was con-
    sidered experimental, since it was to encompass many aspects of an estuarine ecosystem with the
    declared purpose of supporting the practical needs of natural resource managers. Thus, the Chester
    River Study was a program of focused, applied research rather than a more basic program to extend
    knowledge in estuarine sciences.
           As a result of this program, the probability became clear that the upper Chesapeake Baywasthe
    source of sediment-borne materials considered potentially harmful to the living resources of the Chester
    River. An extension of the Chester River project encompassing the bay between the Severn and Sus-
    quehanna Rivers, became the next logical step in assessing the impacts of man-made substances in the
    bay's ecosystem. The Upper Bay Survey was begun in December 1973, fortified by incorporating
    bacteriological studies.

      1.2 Objectives
           On the basis of knowledge gained during the more limited Chester River Study, a 12-month field
    program was implemented to assess the nature of the sources, routes, and sinks of chlorinated hydrocar-
    bons and bacteria damaging to aquatic species. Five definitive objectives for the Upper Bay Survey were
    to:

           (1) Determine concentrations, distributions, and sources for chlorinated hydrocarbons (CHC),
                including pesticides and polychlorinated biphenyls (PCB), and to determine the nature of
                transport paths, mechanisms, and rates in the Chesapeake Bay's waters, sediments, and
                organisms.

    (2)  Determine immediate and longer-term biological consequences of chlorinated hydrocar-
         bons and PCB's on commercially important species.
    (3)  Determine the distribution of bacteria on sediments and suspended particles of the upper
         bay, and to perform toxicological studies of the combined effects of pesticides and bacteria
         on oysters.
    (4)  Institute numerical models for projecting contaminant distribution relative to the sources
         and to develop interrelations to biological impacts resulting from changes in the upper
         Chesapeake Bay's input stresses.
    (5)  Report results in a format convenient for resource management and in a format for com-
         puter storage, retrieval, and augmentation.

                                               1-2

     ZOVERVIEW

      2.1 Integration
           Each contributor to the Upper Bay Survey has presented his or her findings in the separate
    chapters which follow in Volumes II, III, and IV. These are summarized in this chapter under Section 4,
    Results. The purpose of this section, Overview, is to draw upon these findings for an overall discussion of
    the rates, routes, sources, sinks, and reservoirs of the chlorinated hydrocarbons and bacteria in the up-
    per Chesapeake Bay. The emphasis in this chapter is to be on a multidisciplinary approach as opposed to
    the specific science approaches of each of the following chapters. The thread of the approach is the
    pathways through the upper bay, including:

           *   Suspended sediment deposition
           *   Suspended sediments and zooplankton
           *  Suspended sediments and bacteria
           *  Suspended sediments and shellfish
           *   Bottom sediments and infaunal processes
           *   Baltimore harbor circulation with the upper Chesapeake Bay.
           *   Predictive model of the process

      2.2 Pathways
           The Upper Bay Survey, the Chester River Study, and several similar estuarine or marine in-
    vestigations have shown that the finer grained sediments are enriched in cations, synthetic organic
    molecules, and bacteria which are adsorbed to the relatively large surface area of the finer particles
    generally carried in suspension in bay waters. It is, therefore, important to evaluate the transport of fine
    sediment through the upper bay.

                                                    1-3

    *  The major path for the movement of CHC's from the suspended sediment reservoir involves
        at least one phase of sediment deposition. Total Viable Count (TVC) of bacteria also is higher
        in the bottom sediments than in the water. The suspended sediment load appears to be
        generally constant, a factor which on a budget basis requires that an amount equivalent to
        the annual fresh load from the Susquehanna be deposited. The areas of deposition of fine-
        grain sediments can be visualized as sinks where the CHC's and bacteria attached to
        suspended sediments are deposited.
    *  Over most of the upper bay, the principal route for movement of these materials from the
        sinks would be through resuspension of the fine-grains by tidal scour. Resuspension may
        return large numbers of coliforms and fecal I streptococci from the sink to the suspended sedi-
        ment reservoir. In some areas such as Baltimore harbor, the movement out of the sediment
        sink is slow and there is a resulting accumulation of fine-grain sediments and their
        associated contaminants. Where these areas of accumulation coincide with navigational
        channels, maintenance dredging represents a major mechanism for removal of sediments
        bearing relatively high concentrations of chlorinated hydrocarbons. Both overboard disposal
        and hopper barge dredging techniques involve resuspension of large quantities of sediments
        enriched in CHC's, trace metals and bacteria. The impact of such an influx is currently under
        study by several groups active in Chesapeake Bay studies.
    � A pathway for movement of CHC's out of the seston reservoir is via the zooplankton. At any
       given time, only a small part (less than one percent) of the total CHC's present in the water-
        column are detectable in the zooplankton standing stock. The movement, therefore, of CHC's
        into the biological system from the non-biological system is influenced by changes in the
        concentration of CHC's adsorbed to suspended sediment. The suspended sediment could be
        considered a reservoir of CHC's with movement into the biological system from this reservoir
        when the zooplankton blooms occur. The zooplankton concentrated the CHC's five to eight
        times over the levels found in the suspended sediment fraction. Whatever the details of this
        pathway, in order to quantify the rate of movement of CHC's via this route, one would need
        information regarding turnover rates in the plankton community. (Most likely, phytoplankton
        also would be involved.) A change in Chesapeake Bay conditions increasing the zooplankton
        population would probably have the effect of increasing the exchange of CHC's from the
        suspended sediment reservoir into the biological system with potential adverse conse-
        quences.
    *  Higher counts of bacteria associated with suspended sediments were observed at the
        stations near the Susquehanna River, but the counts decreased southward to Kent Island.
        Transport gradients are indicated although a sharp correlation between concentrations of
        bacteria and suspended sediment was not observed.
    *  Filtering of bay water by shellfish represents another direct route for the passage of CHC's
        from the suspended sediment reservoir into the biological system. The shellfish concen-
        trated the CHC's many thousands of times higher than the levels in the water column (e.g.,
        PCB, 4,000; chlordane, 30,000; and DDTR, 45,000). Although shellfish clearly are ac-
        cumulating CHC's, efforts to quantify this route would require more information on the stan-
        ding crop of shellfish and the population cycles in the shellfish community of the upper bay.
        Also, an important consideration is the potential transmission of pathogenic micro-
        organisms to human beings via shellfish, as shellfish are known to concentrate bacteria.
    *  Another route for CHC movement from the sediment sinks into the biological system is
        through the deposit-feeding infaunal organisms which inhabit the fine-grain sediments. In
        particular, certain polychaetes are the most abundant macrofauna in silt-clay habitats, in-
        cluding grossly polluted areas in Baltimore harbor. These organisms form a major part of the
        diet of crabs and certain species of fish in some areas. This pathway is of particular interest
        because of the direct route to human beings via crabs and fish in commercial and
        recreational catches.

                                              1-4

    *   Chemical breakdown of CHC's by non-biological processes and by microbial metabolism con-
        stitutes a pathway for the movement of CHC's from the bay's system. However, bacterial
        metabolism studies show that the microbial degradation of the PCB, Aroclor* 1 254, is ex-
       tremely slow.
    0 Baltimore harbor appears to provide local sources of PCB and chlordane which cause some of
        the very high values found in the sediments. The entry of CHC's from aerial fallout and runoff
        also cause localized high concentrations in the harbor itself. The major route for CHC's out of
        the harbor would be removal via dredging and via the stratified flow of water containing
        suspended sediments. But, the levels in the harbor are the same as those in the reservoir of
        suspended sediments in the bay, except for some elevation in the chlordane.
    � A numerical model has been developed which provides a significant forward stride in the
        capability to examine the source-sink process. The model describes contaminant sources if
        they also are sediment sources, which is the dominant case in the upper bay. Although ten-
        tative at this stage, the model correctly shows the Susquehanna to be a source of sediments,
        given sediment concentration data over the upper Chesapeake Bay. It further shows areas of
        deposition and resuspension and a net southward flow. These positive results are based on
        limited data and interpolative procedures which will require much more ground truth infor-
        mation to refine them. Nonetheless, the difficult problem of modeling vertical transport has
        been partially solved.

    * A registered trade name of Monsanto Company, St. Louis, Mo.

    3. THE SURVEY

      3.1 The Setting
           The Chesapeake Bay, and particularly that part within Maryland's borders, isa familiar region ad-
    jacent to the southern end of the Washington - Boston metropolitan corridor. It consists of a great many
    areas that are extremely valuable in terms of industrial, recreational, and agricultural land use. Extensive
    discussion of the related details is beyond the scope of this volume, so the interested reader is referred to
    two excellent documents: The Integrity of the Chesapeake Bay, Publication Number 184 of the Maryland
    Department of State Planning and the U. S. Army Corps of Engineers publication, Chesapeake Bay.' Ex-
    isting Conditions Report of December 1973 (7 Volumes).
           The latter report discussed a series of significant aspects of which some of the most pertinent are
    extracted and presented below as a cameo of the Chesapeake Bay region:

           *   "Chesapeake Bay is one of the largest estuaries in the world, having a surface area of about
               4,400 square miles and a length of nearly 200 miles. Like many coastal plain estuaries, the
                Bay is a broad, shallow expanse of water varying from 4 to 30 miles in width, but having an
               average depth of less than 28 feet.
           *   "Approximately 7.9 million people inhabited the Bay Area in 1970. This total is more than
               double the 1940 figure and is expected to double again by the year 2020, reaching ap-
                proximately 1 6.3 million people.
           *   "About 80 percent of the people in the Bay Area live in urban areas. In the last several
               decades, people have tended to move out of the inner cities and rural counties and into the
               suburban counties.
           *   "Over 50 percent of the total growth in the Bay Area between 1970 and 2020 is expected to
               take place in the Washington, D. C., subregion.
           *   "Approximately 3.3 million people were employed in the Bay Area in 1970, and the un-
                employment rate was significantly lower than the national average. The per capita income in
                1 970 for residents of the Bay Area was $3,690 as compared to $3,390 for the United States
                as a whole.

                                                      1-7

    *   "The four major categories of employers in the Bay Area are the Service Sector (26 percent of
       total employment), the Wholesale and Retail Trade Sector (17 percent), the Manufacturing
        Sector (16 percent), and the Public Administration Sector (14 percent). The Bay Area percen-
        tage for manufacturing is low, though, when compared to a national average of 25 percent.
        The public administration sector is almostthreetimesthe national percentage, primarily due
       to large numbers of Federal employees in the Washington, D. C. area.
    *   "Only a little over one-third of the land around the Bay is considered developed and most, or
        about 87 percent, of this developed land is in agricultural use. The concentration of people
        and economic activity is further illustrated by the fact that all land used for residential, com-
        mercial, and industrial purposes is less than 5 percent of the total land around the Bay.
    *   "About 5 percent of the land around the Bay is classified as wetlands. Wetlands which are
        very important to the productivity of the Bay are being lost or threatened by development at
        an alarming rate.
    *   "The Bay receives fresh water from a drainage area of 64,160 square miles. The five major
        rivers, the Susquehanna, Potomac, Rappahannock, York, and James, provide almost 90 per-
        cent of the total fresh water flow into the Bay with the Susquehanna alone providing about
        50 percent.
    *   "The physical composition and structure of the earth in the BayArea variesfrom the basically
        flat, sedimentary Atlantic Coastal Plain Province to the more rugged topography of the Pied-
        mont Plateau Province. The Coastal Plain, includes the Eastern Shore of Maryland and
        Virginia, most of Delaware, and a portion of the Western Shore to the Fall Line where it ad-
        joins the Piedmont Plateau. The Piedmont Plateau then extends westward past the limits of
        the study area.
    *   "The Bay Area is underlain by a wedge of sedimentary deposits which contain several ex-
        cellent water-bearing sands and gravels that serve as a major source of both public and
        private fresh water throughout much of the Coastal Plain.
    *   "Industry is by far the largest water user in the Bay Area with a daily use of approximately
        1,600 million gallons as compared to 860 and 100 million gallons per day for public and
        agricultural use, respectively. The major sources of water are the fresh water tributaries of
        the Bay, ground water and the brackish water of the estuary itself which is used for cooling.
    *   "The Chesapeake Bay Region offers a wide variety of water-oriented recreational oppor-
        tunities. In some parts of the region, though, the supply of facilities is not adequate to meet
        the increasing public demand. The Washington-Baltimore area especially has a shortage of
        picnicking, camping, and swimming facilities.
    *   "The Bay Area is served by five major electric utilities plus a number of small companies
        which together provide about two-thirds of the power consumed in the Region. The
        generating facilities within the Bay Area include 21 fossil-fueled, three nuclear, and two
        hydroelectric plants.
    *  "Water quality conditions in the Bayvarywidelydue to a variety of factors; proximity to urban
        areas, type and extent of industrial and agricultural activity, stream-flow characteristics, and
        the amount and type of upstream land and water usage. Most of the water quality problems
        occur in the estauries of the Bay's tributaries and not in the Bay proper.
    *   "Erosion (caused mainly by the daily tidal process, storm-induced waves, and the wakes of
        passing ships) and the rising of the sea level cause a loss of approximately 450 acres of
        shoreline land each year.
    *   "The economic development of the Bay Area has been largely based on the natural transpor-
        tation network provided by the Bay and its tributaries. A total of about 150 million tons of
        cargo was shipped on the Bay in 1970 with the majority passing through the major deep
        water ports of Baltimore and Hampton Roads. Baltimore is basically an importing port with
        iron ore, automobiles, and heavy metals the primary commodities. Hampton Roads, on the
        other hand, is an exporting port with coal being the prime export.

                                               1-8

           *   "Certain aquatic plants have become known as "noxious weeds" because they often in-
               terfere with man's use and enjoyment of the Bay. The three most common of these are
               watermilfoil, sea lettuce, and the water chestnut. The extent of these weeds in the Bay has
               been reduced in recent years by disease and various controls.
           *   "Because of the variations in salinity levels, the Chesapeake Estuary supports a wide variety
               of fish life. Generally, finfish reproduce in the low saline waters of the Upper Bay and the up-
               stream portions of the tributaries. On the other hand, the famous blue crab reproduces in the
               saltier waters at the mouth of the Bay. In addition, some species use the Bay as a spawning
               area and nursery, then migrate to the ocean for their adult life.
           *   "In 1970, Chesapeake Bay landings of a wide variety of shellfish and finfish totaled 630
               million pounds valued at $41 million. The most important species from a value standpoint are
               oysters, crabs, clams, menhaden, and striped bass.
           *   "The marshes, woodlands, and the Bay itself, provide an extremely productive natural
               habitat for over 2,700 different species. The sheer number of species alone forecasts the
               complexity of Bay biota in terms of partitioning species to communities and determining
               functional relationships that will aid in understanding the Bay as an ecosystem."

      3.2 The Approach
           The Survey objectives have been noted, and the approaches which address these objectives are
    listed below. It was essential to perform:

           *   Multidisciplinary work because of the complex scientific interrelationships involved;
           *  Near-synoptic observations in order to acquire a picture dominated by longer transients such
               as high and low flows and seasonal effects;
           *   Bimonthly sampling and measurements of most parameters to achieve the highest data fre-
               quency commensurate with cost;
           *  Sampling at stations where spacing and positions were suitable to the modeling effort (See
               Figure 1-1);
           *  Supporting efforts in laboratory analysis to support the synoptic and seasonal sample
               regime, and;
           *   Modeling development to support predictive capabilities in resource management.

           The above elements are sufficiently self-explanatory to define the scope of the program, but they
    do not include other aspects which might be considered for a fully comprehensive effort. For example,
    there are many boundary conditions for which only spot checks could be made. Examples include air-
    borne particulate fallout sources, runoff analysis, and shoreline erosion. Investigation of pathways
    through higher trophic levels is needed. Although these are of interest, the clear domination of the Sus-
    quehanna led to practical limitations in setting program scope. Another boundary is the number of data
    points; it was obvious that conclusions would have to be drawn from statistics with large standard
    deviations.
           Because of the dynamic nature of the estuarine system, especially in the case of the shallow up-
    per Chesapeake Bay, it is imprudent to employ merely average values of given parameters in describing
    background conditions. Broad excursions in temperature, salinity, dissolved oxygen, and other water-
    mass properties occur in very short periods of time, and they may vary dramatically on a seasonal or an
    annual basis. Similarly, the biomass is characterized by patchiness and instabilities. Thus, investigators
    should examine the component data points as well as the statistical summaries which generally appear
    in graphs and tables. These data are provided in Volume IIIl.
           The task breakdown shown in Figure 1 -2 illustrates the division of effort in executing the above
    approach. More detailed task descriptions are evident in each of the principal investigator's reports.

                                                     1-9

      UPPER CHESAPEAKE BAY               I            CONOWDAM
                                          SUISQUEHANNA R.

                                                   HAVRE
                                                    DE GRACE

           NAUTICAL MILES                                     b~

                            GUNpOW,

                                                        34a         GOEP
                                                         *b

                                                        b         ~~~SASSAFRAS R

    BALTIMORE   1POOLES IS 5a
                                    - ~     ~~ 0~
                                       b

               41                   ~~~~~~~~~C

                              10a~

                       S~SA~r~/pr   .0 LOVE P3,     -

         ANNAPOLIS    jiia~       KENTS

                                                                                 75151A220
                       Figure 1-i1. The Principal Sampling Stations of the Upper Bay Survey

                                              1-10

                                                                  UPPER BAY
                                                                    SURVEY

    MARINE                  MICRO-                   BIO0-                  ESTUARINE             HYDRODYNAMICS             METEOROLOGY
    BIOLOGY                 BIOLOGY                CHEMISTRY              SEDIMENTOLOGY            & HYDROLOGY              & HYDROLOGY

       FIELD                   FIELD                  LABORATORY                FIELD                   DATA                      FIELD
       PROGRAM                 PROGRAM                ANALYSES                  PROGRAM                 COLLECTION                PROGRAM

    * PLANKTON                                       � FIELD SAMPLES         0 SUSPENDED              0 SEDIMENT               * AIR-DUST

      LABORATORY              PROGRAM                  - SUSPENDED               SEDIMENT                                        GROUDWATER
      PROGRAM                                              SEDIMENTS
                            * ANALYSES                 - PLANKTON
                            *XNM    ASSOCIATION        -BENTHOS                LABORATORY              MODEL
      * TAXANOMY                W/PARTICULATES         - OTHER                 PROGRAM                  DEVELOPMENT
    * ZOOPLANKTON           0 DISPOSITION               DATA
        COMMUNITY               OF PATHOGENS
         COMMUNITY              OF PATHOGEN0� CONCENTRATIONS                                          0 FORMULATION              AQUISITION
      * CHC CONC                & INDICATORS          SUPPORT OF             � SIZE                   � VERIFICATION
      TRANSFERIBUTION         ACCUMULATION             EXPERIMENTS               DISTRIBUTION                                 HMETEOROLOGY
           � TRANSFER           BY SHELLFISH �                                                                                   HYDROLOGY
        MECHANISMS          0 CHC ASSOCIATION        * SHELLFISH                                                              * CHC
                               W/BACTERIA               LABORATORY
     SHELLFISH                                      * SHELLFISH
      EXPERIMENTS I                                      IN-SITU
                              SHELLFISH             � BACTERIA
     LABORATORY               EXPERIMENTS            � OTHER
        DOSING
    � IN-SITU              * CHC & PATHOGEN
        DOSING                 SYNERGISMS

                                                                                                                                    75151A221
                                          Figure 1-2. Work Organization of the Disciplinary Tasks

      3.3 Participants
           The principal investigators were drawn from the Chesapeake Bay Institute (CBI) of The Johns
    Hopkins University, the Department of Microbiology of the University of Maryland, and the staff of
    Westinghouse Ocean Research Laboratory. Program and data management were provided by
    Westinghouse's Oceanic Division, into which Ocean Research Laboratory subsequently merged.

           Westinghouse:

                Dr. T. 0. Munson                            Biochemistry
                Project Chief Scientist

                Dr. H. D. Palmer                            Estuarine Sedimentology (Bottom)

                Dr. K. T. S. Tzou                           Hydrology and Meteorology

                Mr. J. M. Forns                             Marine Biology

                Mr. D. K. Ela                               Program Manager

                Mr. Carleton Rutledge Jr.                   Program Engineer

                Mr. A. R. Barskis                           Data Operations

           Chesapeake Bay Institute:

                Dr. D. W. Pritchard                         Circulation and Modeling

                Dr. J. R. Schubel *                         Estuarine Sedimentology (Suspended)

                Dr. J. R. Hunter                            Numerical Modeling

           University of Maryland:

                Dr. R. R. Colwell                           Microbiology

                Dr. J. D. Nelson                            Microbiology

                Dr. G. S. Saylor                            Microbiology

           The project benefited by the continuing guidance and advice of the Board of Scientific Direction, a
    peer group formed by the Maryland Department of Natural Resources. Dr. T. Chamberlain, Director of the
    Chesapeake Research Consortium, was elected chairman of this board to supervise the continuous
    review of the project on an interactive basis. Thus, the technical progress of the project benefited from
    the assembled expertise of the board's members, all of whom have extensive experience in Chesapeake
    Bay research. Members of the Board included:

                   Chairman:
                   Dr. Theodore Chamberlain, Director
                   Chesapeake Research Consortium
                   The Johns Hopkins University

    *Presently at the State University of New York, Stoney Brook, N.Y.

                                                   1-12

    Dr. Rita R. Colwell
    Department of Microbiology
    University of Maryland

    Dr. Eugene Cronin, Director
    Natural Resources Institute
    University of Maryland

    Dr. Max Eisenberg
    Maryland Department of Health and
      Mental Hygiene

    Mr. D. K. Ela, Project Manager
    Upper Bay Survey
    Westinghouse Oceanic Division

    Mr. Frank Hamons, Project Manager
    Maryland Department of Natural Resources

    Dr. John C. R. Kelly, Jr., Director
    Atmospheric, Terrestrial & Marine Research
    Westinghouse Ocean Research Laboratory

    Dr. Donald W. Lear
    Annapolis Field Office
    Environmental Protection Agency

    Dr. T. 0. Munson
    Manager, Aquatic Biology
    Westinghouse Ocean Research Laboratory

    Dr. Donald W. Pritchard
    Chesapeake Bay Institute
    The Johns Hopkins University

    Mr. William Trischman, Chief
    Planning Division, Baltimore District
    Department of the Army, Corps of Engineers

    Dr. Peter E. Wagner, Director
    Center for Environmental & Estuarine Studies
    University of Maryland

    Dr. F. Prescott Ward, Director
    Ecological Studies
    Edgewood Arsenal

                                1-13/1-14

    4. RESULTS

      4.1 Hydrology and Meteorology
           Climatologically, during the study-period December 1973 to December 1974, the upper
    Chesapeake Bay area experienced a mild wet winter, a cool dry summer, and winds less than normal.
    The Susquehanna River, which contributed 97 percent of the fresh water and suspended sediments to
    the upper bay, delivered an annual mean flow of 39,911 cfs in 1974. The average yearly flow pattern is
    typified by a period of overwhelmingly high flow, the spring freshet, usually occuring in March or April.
    However, in 1974, winter flows were relatively high, and the spring freshet was not the dominant high-
    flow period because much of the precipitation fell as rain rather than snow.
           Air samples collected at a station in the Baltimore harbor area were found to contain chlorinated
    hydrocarbons-apparently primarily in the vapor phase. In the six air samples analyzed for chlorinated
    hydrocarbons, including AroclorO 1254, chlordane (sum of the alpha and gamma isomers), dieldrin, and
    DDT were found to occur in the ratios (average of all samples) of 4.0: 1.0: 0.08: 0.03. The average PCB
    (Aroclor� 1254) concentration was five nanograms (10-9 grams) per cubic meter of air.
           Rainwater samples were collected at two stations in the Baltimore harbor area: (1) Fort
    Smallwood, a public recreational area away from the heavily industrialized areas, and (2) Sollers Point, a
    residential area close to a heavily industrialized zone of Baltimore. PCB and the chlorinated pesticides
    chlordane, toxaphene, DDT, and benzene hexachloride (BHC) were found in the rainwater at both
    stations. The average PCB for five samples at Fort Smallwood was 0.4 ppt (parts per trillion; i.e.,
    nanograms per liter) and for three samples at Sollers Point was 125 ppt. The average ratio of PCB to
    chlordane to toxaphene to DDT to BHC (sum of the alpha and gamma isomers) at Fort Smallwood was 0.4
    : 0.5 : 30 : 0.3 : 5. The ratio at Sollers Point was 1 : 1 : 0.9 : 0.1 : 0.07.
           Six samples of storm runoff were collected from a storm sewer in Morrell Park. Traces of tox-
    aphene were found in one sample, and traces of BHC were found in two samples.

                                                                                           K. T. S. Tzou

                                                   1-15

      4.2 Sedimentology

           4.2.1 Bottom Sediments
                   Much of the bottom sediment of the upper bay consists of fine grained materials of the
    size of silt and clay particles (less than 62 microns in their longest dimension). Previous studies have
    shown an inverse relationship between grain size and concentrations of chlorinated hydrocarbons and
    trace metals; a suite of bottom samples from various sites within the upper Chesapeake Bay have con-
    firmed this relationship. Experiments with bulk samples of bottom sediments in which various size frac-
    tions were removed for analyses have proved that: (1) the finer fractions are enriched in PCB's, DDT
    residues (DDTR), and chlordane and (2) that the Baltimore harbor mud has a significantly higher concen-
    tration of chlorinated hydrocarbons than that from other locations sampled during this study.
                   Deposits of finer-grained materials are concentrated: (1)in areaswhere currents and tur-
    bulence are minimal and (2) in the turbidity maximum where finer materials are re-cycled and deposited
    through the action of currents associated with tidal scour and net nontidal estuarine flow in a stratified
    water column. In view of (1) the sustained high levels of chlorinated hydrocarbons on suspended
    sediments from Station 1A at the mouth of the Susquehanna River and (2)from estimates that deposition
    is occurring at a rate of at least five to eight millimeters per year, it is concluded that chlorinated
    hydrocarbons are accumulating in the fine-grained bottom sediments of the upper bay. The chlorinated
    hydrocarbon levels found in the upper bay sediments were two to three times higher than those observed
    in the sediments of the Chester River. The sediments from Baltimore harbor were found to contain the
    greatest amounts of the CHC contaminants with values as high as 3.7 ppm (parts per million) for PCB,
    0.082 ppm for chlordane, and 0.19 ppm for DDTR, but it appears that these accumulations are not carried
    to the Bay through the weak flushing which occurs in the Patapsco River mouth and the harbor.

           4.2.2 Suspended Sediments
                   According to measurements taken at Conowingo Dam during the course of this study, 0.8
    million metric tons of suspended sediment passed this point on the lower Susquehanna River. This
    amount was approximately two-thirds that of the previous year (1973), and an average of about one
    million metric tons per year may be assumed to enter the upper bay from this source.
                   The movement of suspended sediments is controlled by two processes. The normal net
    non-tidal flow regime in effect during most of the year coupled with tidal scour establishes a turbidity
    maximum near the head of the bay, and suspended sediments are trapped by a re-cycling of bay waters in
    this area. However, a second flow regime is established during the freshet period when the Susquehan-
    na River flow (net non-tidal) is increased by spring flooding. In this case, the head of the bay isflushed as
    the river flow overpowers the weak tidal circulation and all materials move seaward.
                   In general, the size of the materials averages between 1.2 and 2.6 microns, with 65 per-
    cent lying in the range 1.2 to 1.6 microns. On the basis of water temperatures and salinities
    characteristic of the upper bay waters, the settling velocity for these particles is less than 10-3 cm/
    second. Natural background turbulence in the shallow waters of the bay generally exceed this velocity;
    thus, the bulk of the finest particulate matter is maintained in suspension, and in the event it is deposited,
    it is susceptible to resuspension by tidal currents. Thus the fine fraction of upper bay sediment, which
    has been shown to act as the vehicle for transport of chlorinated hydrocarbons materials, remains in a
    state of flux.
                   Centers of deposition in the turbidity maximum, in the Baltimore harbor area, and in the
    wide bay floor between the mouth of the harbor and the Chester River show elevated concentrations of
    chlorinated hydrocarbons. Values are generally lower at the mouth of the Susquehanna River, a result of
    the coarse nature of the bottom materials in that area. The finer suspended matter carried by the river
    water bypasses this site, finally coming to rest in the upper Chesapeake Bay either through direct settling
    from suspension or, more likely, through organic agglomeration (e.g., metabolic byproducts of
    zooplankton and benthos). There is no clearly defined longitudinal gradient in mean grain size along the
    axis of the bay; although, the distribution of the background particle population has been found to be
    similar from year to year.

                                                    1-16

                   In light of: (1) the contribution of suspended matter from the Susquehanna River (and
    lesser amounts from the tributaries to the upper bay) and (2) the fact that concentrations of sediment re-
    main essentially the same, the suspended sediment budget demands that an equivalent amount be lost
    from the waters of the upper bay. Thus, the flux is thus either downward by sedimentation or seaward by
    longitudinal transport. Previous work has revealed that by far the greatest amount is lostto the bayfloor;
    thus, the fine fractions bearing the highest concentrations of chlorinated hydrocarbons are ac-
    cumulating as bottom deposits.
                   The average concentrations of PCB, chlordane, and DDTR were highest in suspended
    sediments filtered from the water in Baltimore harbor, with high individual values of 3.8 ppm for PCB,
    0.34 ppm for chlordane, and 0.30 ppm for DDTR being recorded. When these data are presented as the
    amount of CHC present in the water column on suspended sediment, the average CHC values show a
    decreasing trend southward down the baywith the harbor station not as high in the case of PCB or, about
    the same in DDTR and chlordane as the upper stations. A positive correlation was found between the
    concentration of suspended sediments in the water and the concentrations of CHC's in the water column
    on suspended sediments, a factor which reflects the adsorbtive capacity of the finer fractions of Bay
    sediments.
                                                                                       - H. D. Palmer

      4.3 Marine Biology
           In zooplankton larger than 202 microns, standing stocks were highest in the late winter months
    and minimal in early summer and early fall. The average standing stocks increased from Station 1 Adown
    the bay. Baltimore harbor was distinct from the other stations in that the average standing stocks exceed-
    ed other bay localities by a factor of four to five. The biomass calculations indicated that the collections
    from the more northerly stations contained more organic debris than did the other stations.
           The species diversity showed a decreasing trend from Station 1A down the bay. Of the 90
    different forms identified and counted, the most dominant groups were the copepods (27 species) and
    the cladocerans (20 species). Oak leaf hairs were found to be the second most abundant form in terms of
    frequency of occurrence. The largest numbers of oak leaf hairs were collected at the more northern
    stations.
           The community correlation coefficients suggest four basic zooplankton communities in the study
    area: (1) a basically freshwater community extending from Havre de Grace to Turkey Point, (2) a com-
    munity in the vicinity of Pooles Island, (3) a distinct community in Baltimore harbor dominated by the
    copepod Eurytemora affinis, and (4) another community extending from below the Patapsco River to
    about the Severn River.
           The CHC residue concentrations found in zooplankton samples varied tremendously in time and
    space-so much, that the sampling frequency probably was not sufficient (temporally or spatially)for the
    average values to be entirely representive. The concentrations of PCB and DDTR in the zooplankton were
    highest at Station 1 A at the head of the bay (maximum values of 7.5 ppm PCB and 4.2 ppm for DDTR). The
    most consistently high chlordane values in zooplankton were found in Baltimore harbor, the highest be-
    ing 0.14 ppm. When the amount of CHC present in the water column but contained in the zooplankton
    biomass was calculated, a positive correlation was found with the zooplankton biomass.
           The shellfish in the upper bay were found to have about the same levels of PCB, chlordane, and
    DDTR as the shellfish in the Chester River. The shellfish concentrated the CHC's many thousands of
    times higher than the levels in the water column (e.g., PCB, 4,000; chlordane, 30,000; and DDTR,
    45,000).
           Toxaphene was observed in only one biological sample in the upper bay-a zooplankton sample
    from Baltimore harbor.
           The laboratory experiments with the Aroclor� 1254 PCB formulation, demonstrated that PCB is
    rapidly adsorbed from the water by suspended clay particles. Data from the in situ experiment show that
    when PCB was added to Chesapeake Bay water containing only 10 to 20 mg/I suspended sediment, es-
    sentially all of the recovered PCB is contained on the suspended sediment rather than free in the water.

                                                   1-17

           The clams and oysters in the in situ experiments were able to take up the PCB from the suspend-
    ed sediments, in some cases accumulating concentrations 1,000 times higher than the concentration
    administered. Raising the water temperature increased the PCB uptake dramatically-perhaps by in-
    creasing the shellfish pumping rates, thereby increasing the amount of PCB-containing suspended
    sediments passing through the animals. As in previous experiments with chlordane, the clams ac-
    cumulated the PCB even at th'e very low ambient water temperature (4.70C). The oysters accumulated
    the PCB very slowly at water temperatures below 1 00C. As in the chlordane experiments, from a given
    level administered, the oysters were able to accumulate higher levels in their tissues than were clams.
                                                                                        --J. M. Forns

      4.4 Microbiology
           The microbiology of suspended particulates, bottom sediments, and water of the upper
    Chesapeake Bay was examined. Co-transportation of chlorinated hydrocarbons, bacterial indicator
    organisms, and potential pathogensvia suspended sediment wasfound to occur. The highesttotal viable
    counts (TVC) of bacteria in bottom water samples were observed during the winter and spring months;
    the lowest were observed in July, September, and October. Total viable counts of bottom sediment
    samples followed essentially the same distribution. The highest recorded counts over the year, obtained
    at Station 1A, were ten to a hundred times greater than at Stations 5A and 10 B.
           Most probable number (MPN) levels of total coliforms, fecal coliforms, and fecal streptococci fluc-
    tuated seasonally and spatially from Stations 1A to 1 1A. In general, MPN values decreased from winter
    t:o summer, with a gradual increase in the number of indicator organisms in the fall, except that higher
    MPN values occurred at Station 1 1 A in June through September. Total coliform levels were higher than
    feral coliforms and fecal streptococci levels, with the highest MPN values being found in water samples
    from Station 1 A. The entry of total coliforms to the upper Chesapeake Bay via the Susquehanna River
    appears to be significant. MPN values at all of the sampling stations were lower in bottom sediments
    than in the water, with relatively less of a seasonal fluctuation occuring in the sediments. Fecal strep-
    tococci levels were generally higher than total and fecal coliform levels in bottom sediment.
           Approximately 80 percent of the fecal coliforms were Escherichia coli, Type I. Station 1 OB more
    commonly gave false positive coliform MPN's. More than 80 percent of the fecal streptococci were enter-
    cocci.
            More than 33 percent of the FC:FS ratios were greater than 4.0 for Station 1 A samples, including
    suspended sediment samples.
           The relative proportions of fecal coliforms and fecal streptococci in the total viable counts
    decreased southwards from Station 1 Ato 11 A during the winter months, were uniform during the spring
    months, and rose starting in June at Station 11A.
           A highly significant proportion of both total viable bacteria and selected indicators of fecal pollu-
    tion were found associated with particulate matter in the water column. Up to 53 percent of the total
    viable bacteria in Station 11 A water samples was found to be associated with particulate matter.
            By means of a non-selective enrichment, Salmonella enteritidis was isolated from samples
    collected during this study. Clostridium botulinum Types B and E, Vibrioparahaemolyticus, and Yersinia
    sp. also were isolated.
            Approximately one to ten percent of the total viable bacterial population was found to be resistant
    to and potentially capable of metabolizing PCB 1254. These bacteria were present at all stations.
            Greater amounts of humic acid were found in samples collected at Station 1A, and the humic
    acid concentration decreased from Station 1A to Station 11A.
                                                                                       --R. R. Colwell

                                                     1-18

      4.5 Numerical Modeling
           A numerical model has been developed to predict the source field from the concentration field of
    a passive contaminant subject to advection, diffusion, and vertical settling velocity (Volume IV). The
    model is three-dimensional and in this case is applied to the upper Chesapeake Bay. However, it can be
    adapted readily to any other body of water.
           The complete model consists of ten discrete programs. The reasons for this segmentation are
    twofold:

           (1) All the programs were designed to be run on computers of relatively low storage capacity
                 (less than 20,000 numbers) such as the IBM 7094 at Johns Hopkins. For a three-
                 dimensional model, this imposes a very strong constraint, and multiple programs are
                 necessary.
           (2) Segmentation increases the versatility of the model as a whole. In the future, sections of the
                 model may be modified readily in response to changes in input data quality and quantity,
                 output requirements, and computer capabilities. Furthermore, certain aspects of the pre-
                sent modeling sequence are far from ideal. For example, an intrinsic requirement of a
                transport process model for a contaminant in a fluid is the velocity field of that fluid. This
                could be derived: (1) from a great quantity of current meter observations quite beyond the
                capabilities of the Upper Bay Survey or (2) a three-dimensional dynamic model of the water
                 motions in the upper bay. Such a model does not exist at present; hence, a pseudo-dynamic
                 model was developed that predicts in a grossly simplified manner a plausible velocity field,
                based on observations of currents at the boundaries. This section of the total model, no
                doubt, can be replaced when present two and three-dimensional dynamic estuarine models
                 have been adequately verified and developed into useable tools. (Examples of such models
                are those of Leendertze et al., 1973, and Caponi, 1973).

           The best estimates of sources and sinks so far show the fluxes of sediment through the northern
    and southern open boundaries. The variations in source field across the southern boundary in the low
    flow case may be due to errors in the input data in this region or an artifact of the model. An interesting
    and probably real feature of the source fields, especially in the southern and middle areas of the model, is
    the way in which many regions are shown as a source in one season and a partially-compensating sink in
    the other. The source field thus shows a strong variation from season to season, many regions alter-
    nating between sedimentation and resuspension during the year.
           It is important to note that some regions of the model have little or no suspended sediment data;
    hence, the predicted source fields in these regions are a function of the interpolation procedures used
    rather than of any real phenomena. Such regions are the Chester River and the mouths of the Gun-
    powder, Middle, and Back Rivers.
           It must be emphasized that the vertically integrated sediment source fields derived here are only
    tentative. They are a function of: (1)the velocity field, (2)the suspended sediment concentration field and
    the interpolation procedure used to derive it, and (3) the fact that horizontal diffusive exchange is
    neglected. Ideally, investigations should be carried out as to the sensitivity of the predicted source field to
    these input parameters and to the factors upon which they depend.
           Based on the availability of current velocity and suspended sediment data at the present time, it
    would appear that the most reasonable predictions of suspended sediment sources can be obtained by
    the following combination of models:

           (1) A pseudo-dynamic model of the velocity field in three dimensions or, better, a full dynamic
                model (which does not at present exist).
           (2) A prediction model for the vertically integrated source field of suspended sediment, based
                initially on a zero horizontal exchange coefficient and later on a finite one if it appears
                necessary.

                                                    1-I 9

           Data requirements for one run of the model are:

           (1)  The discharge of the Susquehanna River at Conowingo Dam.
           (2)  Current meter records at the southern open boundary of the model (roughlythree moorings
                with three meters per mooring-these data to be used as the boundary condition for the
                 pseudo-dynamic model)and in the interior of the model (roughlythree moorings with three
                 meters per mooring-these data to be used as a means of choosing the optimum value of K
                 in the pseudo-dynamic model). The duration of these records should be at least 30 days and
                the recording interval 30 minutes or less.
           (3)  Vertical profiles of the suspended sediment concentration (and, if applicable, the concen-
                tration of sediment-borne contaminant) at roughly 30 stations in the Upper Bay.
                                                                                        --J. D. Hunter

      4.6 Data Base
           The Upper Bay Survey Data Base system was a useful and efficienttool for managing, analyzing,
    and presenting the many kinds of data collected during the survey, the laboratory analyses, the report
    writing, and the culmination of the project (Volume Ill). It met with a high degree of success in achieving
    the objectives as stated in the proposal and incorporated in the contract. These objectives for the pro-
    ject's automated data processing operations were to:

           *   Plan, design, and operate an automated data handling system.
           *   Coordinate and conduct the collection and assembly of all data to be stored and/or processed
               by computers.
           *   Provide for storage and rapid retrieval of data for study participants.
           *   Provide data manipulation, statistical analyses and correlation capability for study par-
               ticipants.

           The data base's management feature facilitates the quick retrieval of any portion of the data and
    provides an inexpensive method of storing these data when not in use. The data base is easily updated
    with new data and expanded to provide for new data parameters. In the course of the project, it was
    demonstrated that it was possible to enter new data items into the system with ease as soon as they
    become available and to retrieve any part of the archived data for examination, comparison, or analysis.
           It was particularly gratifying to demonstrate that these things can be accomplished regularly by
    the principal investigators and, in many cases, by their assistants and clerical personnel after a minimal
    period of instruction.
           Special data manipulation subroutines were established and stored in the system for report
    writing, simple statistical calculations, and some elementary multidisciplinary correlations. The success
    of these demonstrated the capability of the system to produce answers to special questions or to prepare
    special data tables and reports in response to particular needs and requirements of public agencies and
    officials concerned with natural resources management. The flexibility of the Upper Bay Survey Data
    Base in creating data reports in response to ad hoc requests for information from various users makes
    the system highly suited for a wide scope of applications.
           The limitations experienced were typical to electronic data processing systems. The lag time
    between a sampling or measurement event and entry of the values into the system makes concurrent
    analysis very difficult. Errors in formatting, incorrect data, key punch errors, and procedural errors were
    all experienced, but they were overcome with a reasonable amount of persistence.
                                                                                        --A. R. Barskis

                                                     1-20

              CHAPTER 2

           MARINE BIOLOGY

              J. M.. Forns
            Oceanic Division
    Westinghouse Electric Corporation

    ABSTRACT

           A one-year field sampling and experimentation program was undertaken in the upper
    Chesapeake Bay as part of an interdisciplinary evaluation of the mechanisms, rates, and routes of
    chlorinated hydrocarbon transport through aquatic biota. The biota investigated included the fraction of
    the zooplankton community greater than 200/A and the sessile benthic shellfish including clams (Mya
    arenaria) oysters (Crassostrea virginica), and brackish water clams (Rangia cuneata).
           Field collections were made nine times during one calendar year from approximately 18 stations
    distributed throughout the upper Chesapeake Bay from Annapolis to Harve de Grace. Biomass, tax-
    onomic, and biochemical evaluations were performed on the resulting samples. Quantifications were
    made of the abundance, distribution, and chlorinated hydrocarbon content for the zooplankton.
    Chlorophyll-a was measured; physical parameter profiles of temperature, salinity, pH, and dissolved ox-
    ygen also were taken.
           Experiments were performed in the laboratory to identify possible mechanisms by which quan-
    titated fractions of chlorinated hydrocarbons became available to aquatic biota, particularly
    commercially-sought shellfish. Combining the results of the interdisciplinary field sampling survey with
    the initial laboratory tests, a series of in situ shellfish experiments were conducted. Clams and oysters
    were subjected to chlorinated hydrocarbon (Aroclot�1 254) stresses under realistic conditions at various
    temperatures, and accumulations within whole body tissue were measured.
           Results of this program indicate that zooplankton communities are controlled and distributed
    throughout the upper bay by the estuarine mixing characteristics regulated by temperature and salinity
    regimes. Although distinctly different communities of zooplankton were observed, organism diversity or
    abundance was not related to sources or levels of chlorinated hydrocarbons in the aquatic environment.
           Chlorinated hydrocarbon accumulations by shellfish are regulated to a great extent by their
    pumping rate which, in turn, is dependent on the environmental parameters. Oysters appear to remove
    chlorinated hydrocarbons effectively from non-viable suspended sediments at ambient temperatures
    above 100C. Clams, however, seem to accumulate chlorinated hydrocarbons irrespective of
    temperature, and their total body burdens of chlorinated hydrocarbons fluctuate. Comparison of oysters
    and clams from the same experiment indicates that each species behaves differently, and projections of
    biological effects based solely on source water characteristics cannot be made.

                                       TAB3LE OF CONTENTS

    Section                                                                                                     Page

    2.  MARINE BIOLOGY .............................................................2-1
    22.ntoutin..........................................................................1-
    2.2  Plankton Investigations .........................................................2-2
    2.2.1 Sampling and Analytical Methodology.............................................2-4
    2.2.2 Results and Discussion.........................................................2-5
    2.3  Benthic Investigations ........................................................2-15
    2.3.1 Field Investigations ...........................................................2-20
    2.3.2 Laboratory Experiments........................................................2-20
    2.3.3 In Situ Experiments ...........................................................2-23
    22.oclsos4..........................................................2.............23
    2.5  Acknowledgements ...........................................................2-35

                                         LIST OF FIGURES

    Figure                                                                                                      Page

    2-1       Net Plankton Sampling Station in the Upper Chesapeake Bay,
            December 1973 through December 1974.........................................2-3
    2-2       >2O2bt Net Plankton Standing Stock, Annual Average Concentrations by Month . . .....2-10
    2-3    >202,u Net Plankton Average Annual Standing Stock by Station.....................2-1 1
    2-4       Frequency Distributions of Biomass Values for Upper Chesapeake Bay Zooplankton.....2-12
    2-5   Biomass Ratios of Average Monthly Data........................................2-13
    2-6       Biomass Ratios for Principal Stations Sampled Throughout the
            Upper Chesapeake Bay .......................................................2-14
    2-7       2O2M~ Net Plankton Investigations Taxonomic Data Analysis:
            Community Correlations ......................................................2-19
    2-8   Low Percentage Organic Clay Adsorption with PCB3 1254 ..........................2-22
    2-9  In Situ Experimental Laboratory System.........................................2-24
    2-1 OA  Laboratory Module on R/V SEARCHSTAR Being Towed to Station...................2-25
    2-1lOB High Pressure Particle Separator...............................................2-25
    2-1 C  Organism Test Chambers Having a Two-Liter per Minute Flow Rate..................2-25
    2-1 1  Regressions on Biomass Animal Sorting Evaluations ..............................2-28
    2-12  PCB-1 254 Uptake by Oysters During/In Situ Test .................................2-32
    2-13  PCB Uptake by Clams During/In Situ Test........................................2-33

                                          LIST OF TABLES

    Table                                                                                 Page

    2-1     Plankton Biomass for the Upper Chesapeake Bay:
            A Sample of the Data.........................................................2-6
    2-2     Plankton Taxa from the Upper Chesapeake Bay:
            A Sample of the Data.........................................................2-7
    2-3     Zooplankton Biomass Annual Average Concentrations by Month at all Stations.........2-8
    2-4     Zooplankton Biomass Annual Average Concentrations by Station ....................2-9
    2-5     Biomass Ratios Based on Monthly Average Concentrations at All Stations.............2-9
    2-6     Dominant Forms from Upper Chesapeake Bay ...................................2-16
    2-7     >2O2p Net Plankton Species Diversity by Station for Upper Bay ....................2-17
    2-8     >202p Net Plankton Species Diversity by Station for Upper Bay ....................2-17
    2-9     Average Number of Species per Station from Upper Chesapeake Bay ................2-18
    2-10    Results of Low Percentage Organic Clay Absorption Experiment ....................2-21
    2-11    PCB 1254 Absorbed to Suspended Sediments During In Situ Experiment.............2-26
    2-1 2    Oyster Biomass Sorting Evaluations for In Situ Experimentations ...................2-26
    2-1 3    Clam Biomass Sorting Evaluations for In Situ Experimentations.....................2-27
    2-14    Physical Parameter Measurements During/In Situ Dose Experiment,
            Station 1 1 A................................................................2-30
    2-1 5    Data from/In Situ Experiment at Station h1A ....................................2-31

                                                  iv

     2. MARINE BIOLOGY

       2.1 Introduction
           The aquatic biology task of the Upper Bay Survey was planned to include essentially two es-
    tuarine communities of organisms, the zooplankton and the benthos. With respect to the overall objec-
    tives of the Upper Bay Survey to determine rates, routes, sources, sinks of chlorinated hydrocarbons
    (CHC) - the organisms investigated were to provide a means of understanding the areal distribution and
    abundances of chlorinated hydrocarbons, potential localized sources of these compounds to the
    waterways, and initial identification of potential biological transfer mechanismsforthese nondegrading
    chemicals. Consideration of these objectives led to selecting for investigation the fraction of the plankton
    community retained in a 202-micron mesh sampling net and the sessile benthic community.
           The selection of this > 202-ju fraction of the zooplankton was based on several factors. From the
    recent literature, there seems to be reasonably adequate knowledge of the abundance, distribution, and
    productivity of the smaller fraction (< 202/4) zooplankton and phytoplankton populations. Also, it was felt
    that there was a definite lack of detail for the larger zooplankton, especially such meroplanktonic forms
    as fish eggs and larvae. The fact that no definitive effort was planned in this program to address fish pop-
    ulations also influenced the decision to choose the > 202-/ fraction of zooplankton. Because it would be
    quite difficult to document the source of chlorinated hydrocarbons measured in relatively transitory fish
    stocks, the obvious alternative was to investigate from upper bay waters the potential food sources
    which might contain these chemicals.
           Selection of the molluscan fraction of the benthos from the upper Chesapeake Bay was based on
    several considerations. It was felt that these organisms, which are primarily sedentary filter feeders,
    would provide a means of utilizing stationary benthic populations as biological samplers of chlorinated
    hydrocarbons. From previous studies in the Chester River, it was believed that a principal mechanism for
    CHC availability comes from the suspensoid material within the water column. More definitively, the in-
    organic suspended sediments act as a site for adsorption of these insoluble chemical compounds which
    can then be passed through the benthic organisms. During certain times of the year when organic
    production is at a minimum, the filter feeding molluscs actually can ingest detritus as part of their diet,
    especially when winter water temperatures are around or above 100C.
           Another reason for selecting the molluscs for this investigation was their ubiquity throughout the
    upper bay. From previous assessments by the Maryland Department of Natural Resources, the brackish
    water clam, Rangia cuneata, was distributed throughout the upper Chesapeake Bay except in Baltimore
    harbor.

                                                     2-1

           Finally, utilizing the molluscs as investigative organisms provided a means of making direct
    assessments of potential environmental impacts to commercially important species in Chesapeake Bay.
    By working with oysters (Crassostrea virginica) and soft-shelled clams (Mya arenaria), it was felt that a
    valuable insight could be gained with respect to the management of these renewable natural resources.
           The survey program was divided into two discrete phases: the first to include a one-year field
    sampling effort throughout the upper bay and the second to involve experimental investigations with
    chlorinated hydrocarbons and shellfish. Conducting field sampling in conjunction with the other scien-
    tific disciplines gave insight to the background levels and sources of CHC's in plankton and benthos.
    From this baseline of data, experimental designs were established, and low level toxicity testing was
    conducted.
           The results of evaluations in both phases of the marine biological task led to definite conclusions.
    While the conclusions are by no means complete, they do provide a means of understanding the levels
    and concentrations of CHC in zooplankton and benthic organisms. With reasonable interpretation, the
    resultant information can be used to forecast chlorinated hydrocarbon conditions in plankton and
    benthos of the upper Chesapeake Bay.

      2.2 Plankton Investigations
           Zooplankton populations throughout the upper Chesapeake Bay were examined during
    December 1973 through December 1974. During that time, ten series of samplings were made from the
    R/V MAURY, R/V WARFIELD or R/V NORTHSTAR. Eighteen stationswere visited, resulting in 95 pair-
    ed net plankton samples (Figure 2-1). Volume III contains a complete inventory of the data described
    here. The objectives for which the samples were collected were to:

           (1)  Determine the seasonal biomass abundances for the > 202-/z net plankton fraction of the
                upper Chesapeake Bay.

           (2)  Identify and quantitate the species distribution for these upper bay fauna.

           (3)  Analyze for background levels of chlorinated hydrocarbons within these organisms.

           (4)  Compare the resultant plankton data with chlorinated hydrocarbon levels in water,
                suspended sediments, and bottom sediments.

           The rationale for this program was based on several premises gained from reported literature in
    similar estuarine waters and from initial observations made during the Chester River Study in 1972.
    Plankton serve as biological samplers of chlorinated hydrocarbons within the water column and, since
    these organisms rely on hydrographic whims for their mass transport and distribution, their movements
    may serve as a means of detecting CHC trajectories, distribution, and possible source areas. Also, this -
    > 202-/ fraction of the plankton community serves as an intermediate level of the aquatic food web and
    may indicate a role in bioaccumulation processes. Finally, it has been well documented that the more
    sensitive stages of many aquatic organisms occur during their life cycle when they lead a meroplanktonic
    existence and are within the > 202-/z fraction of water column biota.

                                                     2-2

    ;IS'~~~~

                                                                             #w

                                                                              3A

                                              05A

                                                      6A 69 ~    ;A                          ,

                               8   se10                   sRW
                                           dP  8C~~~~~~~~~~'
                                                p~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~o 4<4.

                                        '~;' ~.                  ~' ':~  tI STATIONS SAMPLED
                                                                                    EACH CRUISE
                                                              9B
                                                           Q
                                                                             lo *                        i.<2~~<4"-' *

                          ,,~' ,,~                     ~_ ~,~.~   ~la     STATIONS SAMPLED DURING
                            ~   I1C                                       MOS-T  10 LOG I CAL SEASONS

                                                                  100                 7

                                                                                                           75151A132

                Figure 2-1. Net Plankton Sampling Stations in the Upper Chesapeake Bay,
                             December 1973 Through December 1974

                                                       2-3

           2.2.1 Sampling and Analytical Methodology
                   The collection of these plankton samples was made with paired half-meter standard
    oceanographic nets using hexane-rinsed 202-p/ Nitex netting. A calibrated T.S.K.-type mechanical
    flowmeter was placed in the mouth of each of the two nets to record the volume of water passing
    through. A third was placed equidistant above the nets to record the unobstructed waterflow during tow-
    ing. From the timed flow values measured by the three flowmeters, were calculated the volumes of water
    filtered in each net, net filtering rate, and a measure of each net's filtration efficiency. The reduced
    calculations from the 95 paired samples showed that the average filtration rate was 14.6 m3 per minute
    at an average towing speed of 1.4 meters/second (+0.6). The average net filtration efficiency for the 95
    collections was 73 percent with the lower efficiencies occurring during the June, July, and September
    cruises.
                   Each net haul consisted of towing obliquely from surface to near-bottom to surface for
    2.5 to 5 minutes. Upon completion of each tow, the nets were carefully washed to concentrate the
    plankton in the cod end. The cod end was then removed, and the sample was washed through a 4-mm
    PVC-stainless steel sieve to separate out the larger gelatinous material. The large organism fraction,
    consisting mostly of medusae and comb jellies, was counted; the volumes were recorded, and the
    gelatinous forms were discarded. All large non-gelatinousformswere recorded and placed in the sample
    fraction which passed through the 4-mm sieve. The samples were then concentrated through a 202-j/
    sieve and brought to a volume of approximately one pint. From each pair of net samples, the net collection
    for taxonomy and biomass was preserved with buffered formaldehyde at a final concentration of five per-
    cent. The net collection used for biochemical analysis was further concentrated on hexane-extracted 47-
    mm Gelman glass filters. The resultant sample pad was wrapped in aluminum foil and frozen for
    laboratory analysis ashore. During the summer cruises, several individual parts of samples were remov-
    ed, and individual species were isolated for micro-extraction and biochemical analysis. A total of 12
    micro-samples were isolated for individual analysis. Unfortunately, this particular effort proved to be
    fruitless - the first few sets of samples were found to contain insufficient biological material to yield
    chlorinated hydrocarbon values above the detection limits, and adequate time was not available for
    analysis of the larger samples isolated later.
                   Profiles of physical parameters (including temperature, salinity, dissolved oxygen, and
    pH) were collected at each sampling station. Total seston mass was measured on millipore filters, and
    chlorophyll-a extractions in acetone also were accomplished for each plankton sampling station.
                   The frozen samples were thawed in the laboratory, and prepared for chemical extractions
    according to the procedures described in Section 6. The formalin-preserved samples were washed with
    distilled water and split in a modified Folsom splitter to a manageable aliquot not less than one thirty-
    second of the whole sample. The working aliquotswere kept in distilled water, and the remaining sample
    was transferred sequentially to a 10 percent ethyl alcohol solution for final preservation and archiving.
    Experience shows that initial buffered-formalin fixing followed by alcohol preservation is the least
    deleterious to the samples, and this procedure reduces the amount of solution which takes place when
    organic acids reduce pH in buffered-formalin preserved samples. Also, it appears that natural pigments
    are better retained by this method.
                   The taxonomic analysis of the net plankton collections consisted of placing the split ali-
    quot in a graduate, bringing the sub-sample to 1 00 ml and removing 10 ml by Stemple pipet. This fraction
    was then placed in a gridded sorting tray, and two series of identification and counts were undertaken.
    Initially, a 10 percent count was made for the dominating forms, followed by a 100 percent count for all
    other organisms. Efforts were made to identify the dominating organisms to the species level and less
    abundant forms at least to the group level. Normally, by this method about 500to 2,000 organismswere
    examined from each sample aliquot, and counting reproducibility was greater than 75 percent. All data
    were transferred then to the initial format sheets for numerical computation to reduce the tray counts to
    numbers of organisms per cubic meter and relative percent composition. These data then were
    transferred to the standardized formats for entry into the data base (Volume Ill).

                                                     2-4

                   Five measures of biomass were made on the 95 samples analyzed: wet weight, displace-
    ment volume, dry weight, ash weight, and ash-free dry weight. From experience with previous estuarine
    investigations, it was found necessary to perform these analyses to discriminate the truly planktonic
    organisms from the sometimes substantial quantities of debris collected in the nets. Detailed procedures
    described in the Chester River Study (1972) and Forns (1973) were used for the biomass evaluations.
    Wet weights were determined by (1) washing the sample matter into a precalibrated, fritted glass cruci-
    ble, (2) applying slight pressure to force out interstitial water, and (3) weighing on a Mettler H20
    analytical balance. Displacement volumes were measured by the Gooch crucible mercury immersion
    method described by Yentsch and Hebard (1957). Dry weights were determined by the procedures of
    Lovegrove (1966), and ash weights were determined by furnace combustion to 5000C over a two-hour
    period. The data from these analyses, chlorophyll-a, and seston measurements can be found in Volume
    III, Section 4.

            2.2.2 Results and Discussion
                   Biomass analysis has been completed for all 95 samples. Taxonomic evaluations have
    been accomplished for 51 samples, and approximately 70 chlorinated hydrocarbon analyses have been
    completed on the frozen plankton samples. The resultant biomass data were expressed as microliters per
    cubic meter (,uI/m3) for displacement volumes and as milligrams per cubic meter for all other
    measurements (Table 2-1 ). The taxonomic data have been expressed as numbers of organisms per cubic
    meter and as relative percent composition in each sample (Table 2-2). The species distributions for the
    taxa have been computed according to Margalef (1951) and Shannon and Weaver (1963) for each sam-
    ple, and community correlation coefficients have been calculated according to Jaccard (1961). The
    chlorinated hydrocarbon data have been presented first as micrograms (1 0-6 grams) of CHC found divided
    by the gramswetweight of zooplankton extracted (parts per million, ppm), and additionally as nanograms
    (1 0-9 grams) of CHC found in the sample divided by the liters of bay water filtered to obtain the sample
    (parts per trillion, ppt). These varied means of expressing biomass standing stock, taxonomic composi-
    tion, and CHC data make this material compatible with similar investigations conducted at Woods Hole
    (Harvey, 1973), the Southern California (SCWRRP) area (Young, 1975) and other estuarine studies.
                   Net zooplankton biomass data have been reduced in Tables 2-3 and 2-4 to show: (1) an-
    nual average concentrations expressed by month throughout the entire upper bay and (2) annual
    average biomass concentrations displayed by station for the principle stations sampled throughout the
    year. Graphically, Figure 2-2 indicates that highest overall net plankton standing stock occurs during the
    late winter months with seasonal low concentrations in early summer and early fall. This slightly
    bimodal distribution coincides well with productivity values when higher biomass and primary produc-
    tion blooms occur prior to the increases in secondary trophic levels (which comprise the bulk of the -
    > 200-, plankton fraction). Comparison of the biomass values from Table 2-4 and Figure 2-3 indicates
    increasing average plankton standing stocks from the mouth of the Susquehanna River (Station 1A)
    down the bay to Annapolis (Stations 1 1A and 11 C). The obvious exception lies in the samples from the
    Baltimore harbor area (Stations 7A and 7B) where biomasses were generally four to five times greater
    than any other station. This occurrence is also seen in Figure 2-4 where the frequency distribution of
    biomasses are skewed to the left toward lower values, except for those from Stations 7A and 7B. Op-
    posite sampling stations across the bay (Stations 5A vs 5B, 8B vs 8C, and 11 A vs 11 C) reveal higher
    average concentrations on the eastern side of the bay. While these values coincide quite well with the
    STD profiles taken at the plankton sampling stations (Volume III), it seems somewhat contrary to the
    classical axiom of higher productivity in the shallower waters of the estuary.
                   Biomass ratios from monthly average concentrations (Table 2-5)were computed in an ef-
    fort to differentiate the non-viable detrita I material (> 202 ,) from the actual planktonic organisms. From
    the ten monthly observations, the biomass ratios are found generally similar to those reported previously
    (Forns, 1975). However, comparison of the dryweight to wet weight ratios and of the ash-free dry weight
    to wet weight ratios indicate unusually high values for the October series of samples (Figure 2-5). Com-
    parison of these ratios from Table 2-4 on a station basis indicates very little change in biomass ratios for
    the 11 principal stations sampled throughout the upper bay (Figure 2-6). The somewhat higher values
    found at Station 1 A are due undoubtably to the usually high amounts of debris collected in the nets from
    the Susquehanna River.

                                                     2-5

               TABLE 2-1. PLANKTON BIOMASS FOR THE UPPER CHESAPEAKE BAY FROM
                         DECEMBER 1973 TO DECEMBER 1974: A SAMPLE OF THE DATA,
                         CONTAINED IN VOLUME III.

                           BIOMASS DATA
                             75/07/18.

    SAMPLE  STAT  DATE          TIME  BIOMAS   BIOM WET   BIOM DRY   RIO- ASH   ASH-F. n
    NUMBER  ION   MM DD YY    MRS   MG  M3   MG M3           MG M3       MG M3       M6, M3
    C703    C702  C705          C706  C713       C714        C715        C716        C717

         1  11A   12/12/1973  1100  158.29        128.34      17.135      15.879       1.236
         2  10B   12/12/1973  1300  133.81         99.59      13.094      11,756       1,338
         3  05A   12/13/1973  1025  110.66         80.32       9.501         .000        .000
         4  01A   12/13/1973  1410  126.98         50.98      20,499       5,986      14.513
         5  09A   12/14/1973  1110  243.06        115.14      16.528      15,417       1.111
         6  08A   12/14/1973  1350  173.29         65.42      89.531      82.455       7.n81
         7  07A   12/14/1973  1515  999,99        990099      99.999      99.999      21.471
         8  09A   01/17/1974   928  121.56        118.06      15.651      13.751       1.P09
         9  09B   01/17/1974  1037  491.68        434.73      66.786      61.050       5.736
        10  09C   01/17/1974  1132  109.16        248.42      41.637      37.739       3.299
        11  11A   01/23/1974   842  120.22        121.02      15.009      13.260       1,749
        12  11C   01/23/1974  1000  200.58        164.47      23.607      20.675       2.q32
        13  07A   01/23/L974  1305  467.11        476.93      59.601      53.806       5.795
        14  10B   01/23/1974  1635   69.26         59.70       8.797       7.273       1.524
        15  08B   01/24/1974   925   36.23         39.41       5.631      11,094      -5.463
        16  05A   01/24/1974  1100   14.34         11.89       1,706       1.276         .430
        17  01A   01/24/1974  1400  123.84        137,09      47.183      17.833      29.350
        18  038   01/24/1974  1610   38.43         33.97       7.480       4.228       3.252
        19  058   01/24/1974  1655    8.09          7.91        .956        .706        .250
        20  OBC   01/24/1974  1745   26.32         21.28       2.807       1.028       1.780
        21  07A   03/19/1974  1105  877.91        838.90      97.546      90.474       7.072
        22  11D   03/19/1974  1413  999.99        999.99      99.999      99.999      -2.138
        23  11A   03/20/1974   820  479.93        492.85      67.559      60.545       7.n14
        24  11C   03/20/1974   945  999.99        999.99      99.999      99.999       8.901
        25  10B   03/20/1974  1110  290.49        284.39      38.635      37.473       1.162
        26  08C   03/20/1974  1200  899.76        999.99      99.999      99,999      13.301
        27  088   03/20/1974  1215  371.88        349,33      40,442      33.469       6.q73
        28  05A   03/21/1974   845   97.56         84.93       9.073       7,659       1.415
        29  01A   03/21/1974  1310   18.30         21.13       2,745       1.372       1.372
        30  036   03/21/1974  1430   33.83         29.21       6.653       5.300       1,353
        31  056   03/21/1974  1515  433.18        36b.05      40.955      34.851       6.104
        32  07B   05/01/1974   850   97.72         55.70       8.404       5.537       2.867
        33  liD   05/01/1974  1340  198.90         86.41      12.155      10.387       1.768
        34  11C   05/02/1974   755   18.52          9.11       1.148        .889        .?59
        35  11A   05/02/1974   830   25.71          7.56        .771        .000
        36  10B   05/02/1974   954    6.05          1.60        .182        .000
        37  08C   05/02/1974  1110    6.70           .80        .067        .045        .022
        38  088   05/02/1974  1152    9.02          1.92        .195        .165        .030

                                               2-6

             TABLE 2-2. PLANKTON TAXA FROM THE UPPER CHESAPEAKE BAY SAMPLED

                             FROM DECEMBER 1973 TO DECEMBER 1974: A SAMPLE OF THE

                             DATA, CONTAINED IN VOLUME III.

                         MARINE BIOLOGY DATA REPORT PART-B
                                       75/04/16.

    SAMP   STAT    DATE            TOTAL-LIP    CHL A    TOXONOMY                -PUPULAT.  PELT                                 SF70
    NUMA    ION     mm DO YY       NG"M13        UGL        OR0ANIZM TYPE        GENUS SPECIES              NUMBER      PCMP    N;'jmr
    C703    CTG2   C70B            C718          C719       C726                 C72T                        MeS        CTT9     C730

                                                          ORYOZOA              BRYOZOAN STATORLAST              .05     .00      17
                                                          PLANT                GLOBULAR SEED                    .05     .0)      19A
                                                          PLANT                3 SIDED SEED                     .05     .00      1~'
                                                          PLA NT               OAK LEAF HAIRS                   .15     .01      2u
      29    GIA  03/21/1974                      6.80      COPEPOD               ACARTIA TONSA                    .37     .49)       1
                                                          COPEPOD              EURtT*EMORA AFFINXS          60.36  80.78
                                                          COPEPOD              CYCLOPOID A                     2.20    2,94        3
                                                          COPEP0D              NALICYCLOPS 8                  1.65   2.20        4
                                                          COPEPOD              CYCtOPOID C                      .00     .1?
                                                          COPEPOD              tUC.YCLOPS                       .73     .98
                                                          COPEPOD              IMMATURE CYCLOPOIDS            2.56    3.42        7
                                                          COPEPOD              CALANOIIF NAUPLII                .09     * :2       p
                                                          CLADOCERA            AOS*OONA LONGIROSYRIS          3.57    4.78
                                                          CLAOOCERA            OAPHNIA                          .09     .12      IA1
                                                          ANNELID              ANNELID                         1.10    1.47      11
                                                          INSECT               INSECT                           .09     .12      12
                                                          USTRAC D      I      OSTRACOO                         .27     :36      13
                                                          TAROIGRADE           TARDIURADE                       .09     .12      14
                                                         ROTIFER              ROTIFER                          .46     .62     115
                                                          PLANT                OAK LEAF HAIRS                  1.01    1.35      14
                                                         DEBRIS               ORGANIC                                           17
      30   03B    013/~I/1974                    6.10
      31    058    03/21/0974                    12.60
      32   070      05/01/1974                             COPEPOD              ACARTIA TONSA                    .72      .02I
                                                          COPEPOO              EUkYTEMORA AFFINIS          1693.16  44.42         p
                                                          COPEPOD              CYCLOPOID A                      .26     .1        3
                                                         COPEPOD              HiA ICYCLOPS B                 2.02      .09       4
                                                         COPEPOD              CYCLOI-CIII *AUPLI~           17.46      .41
                                                         COPEPOD              HA,,PACTICOID A                  .39    .81
                                                         COPEPOO             JiAPPACTICOID 0                   * a?7    .80
                                                         COPEPOO              ERGASILUS CHAUTAUONS             .26      01i
                                                         COPEPOD              CALANOID NAUPLII-                .13     .00
                                                         CLADOCERA            BOSe4INA LONGIROSTRIS            .07     .00      10
                                                         ANNELID              ANNELID                          .07     .00   it
                                                         BRYC1ODA             ANTOZOAN FLOATOBLAST           0.0'.     .02,  le
                                                          INSECT               INSECT                          .13      .00      1
                                                         OSTRACOD             PRIONOrTPRIS LIINJOFMA           .7      .00      1-.
                                                         ROTIFER              AOTIFER                          .s9     .Oi   I.,
                                                         PLANT     '~        OAK LEAF HAIRS               23445.26  55.03       11'
      33    lID     0S/I1/1974                   4.41
      34   IIC      05/02/1974                   22.30)
      35    110     05/02/1974                             COPEPOD              ACANTIA TONSA                  54.016   8.28        I
                                                         COPEPOD              EUNTTE'ORA AFFINIS            34.45   5.04         2
                                                         COPEPOO              INMATUHE CYCLOPU005              .46     .07
                                                         CLADOCERA            BOSMINA LONGIRU1STRIS            .10     .02.      4
                                                         CLAOOCE4A            DAPHNIA                          .20     .03
                                                         CLADOCERA            POrjoN                        35.94   5.27         4
                                                         BARNACLC             NAIJPLII                      22.26    3.?A        7
                                                         CRUSTACEAN           UNrNOWN LARVAE                 .05     .01
                                                         OSTRACOG             USTRACOD                       2.'.?      34

                                                                  2-7

     TABLE  2-3.  >202,u NET ZOOPLANKTON  BIOMASS ANNUAL  AVERAGE  CONCENTRATIONS  IN
                        THE UPPER CHESAPEAKE BAY BY MONTH AT ALL STATIONS

                     Displacement        Wet                  Dry                 Ash            Ash-Free Dry
    Date             Volume              Weight               Weight              Weight         Weight
                     (ul/m3)            (mg/m3)             (mg/m3)              (mg/m3 )       (mg/m3)

    12/73              278.011              218.683             38.041               33.070         6.679
                     (+321.296)          (�341.634)           (+39.018)           (�40.429)      (+ 8.308)

     1/74              140.525              144.222             22.835               18.748         4.080
                     (�160.336)          (�155.221)           (+23.091)           (+40.030)      (+ 8.102)

     3/74              500.256             496.887              54.873               51.922         4.775
                     (�384.585)          (�396.914)           (�39.871)           (�40.030)      (+ 4.495)

     5/75               45.005               25.013              3.340                2.512         0.906
                     (+ 57.586)          (+ 29.329)           (+ 4.105)           (+ 3.471)      (+ 0.926)

     6/74               20.888               12.696              1.397                1.349         0.158
                     (+ 16.753)          (+ 17.016)           (+ 1.986)           (+ 1.929)      (+ 0.130)

     7/74               41.252               34.269              4.150                3.742         0.409
                     (+ 45.147)          (  41.664)           (+ 4.630)           (+ 4.158)      (+ 0.514)

     9/74              110.137               88.758             10.041                9.204         0.837
                     (+167.727)          (+138.086)           (�14.619)           (�13.140)      (+ 1.567)

    10/74               10.410                7.175              3.899                0.423         3.476
                     (+  6.644)          (+  3.875)          (+ 1.734)            (+ 0.388)      (+ 1.569)

    11/74              127.462               99.338             24.291              20.928         12.706
                    (+149.521)          (+127.704)           (�26.151)           (�32.439)      (�12.859)

    12/74               80.026               68.119             16.000                8.120         7.788
                    (+ 81.916)          (+ 70.541)          (+13.205)            (+ 7.788)      (+ 5.605)

                                                         2-8

          TABLE 2-4. >202/u NET ZOOPLANKTON BIOMASS ANNUAL AVERAGE CONCENTRATIONS IN
                                  THE UPPER CHESAPEAKE BAY BY STATION

    Station          Displacement        Wet                 Dry                  Ash           Ash-Free Dry
    Numbers          Volume              Weight              Weight              Weight         Weight
                    (PI /m3)            (mg/m )             (mg/m )             (mg/m )        (mg/mi)

    1A                  50.501              43.862             11.247                4.620         6.626
                    (+ 45.443)          (+ 41.392)          (�15.841)           (+ 5.617)      (+10.431)

    3B                  48.529              38.819               6.596               4.978          1.618
                    (+ 65.798)          (+ 49.597)          (+ 6.312)           (+ 6.411)      (+ 1.564)

    5A&B                63.661              50.479               6.969               4.499         2.149
                    (+107.285)          (+ 90.941)          (+10.203)           (+ 8.710)      (+ 2.701)

    7A&B               320.316             304.411             34.826               32.693         4.818
                    (+410.949)          (�410.029)          (�43.905)           (�42.449)      (+ 7.248)

    8A&C               129.388             117.823              19.966              23.911         2.460
                    (�243.594)          (�269.631)          (�33.887)           (�38.971)      (+ 4.799)

    10OB                68.806              58.848               9.478               7.069         2.656
                    (+ 87.462)          (+ 85.042)          (+11.883)           (+11.378)      (+ 3.511)

    11A&C              142.722             133.305             18.332               14.833         4.391
                    (�237.750)          (�239.521)          (�25.871)           (�25.009)      (+ 4.932)

      TABLE 2-5. UPPER BAY BIOMASS RATIOS BASED ON MONTHLY AVERAGE CONCENTRATIONS
                                          AT ALL STATIONS SAMPLED

                    Wet/
    Date             Displacement        Dry/Wet              Ash/Wet            Ash-Free/      Ash-Free Dry/
                    Volume                                                      Wet            Dry

    12/73              78.66               17.39                15.12                3.05         17.55

     1/74             102.63               15.83               12.99                 2.83         17.86

     3/74              99.32               11.04                10.44                0.96          8.70

     5/74              55.57               13.35                10.04                3.62         27.12

     6/74              60.78               11.00                10.63                1.24           1.13

     7/74              83.07               12.11                10.92                1.19          9.85

     9/74              80.58               11.31                10.36                0.94          8.33

    10/74              68.92               54.34                 5.89               48.44         89.15

    11/74              77.93               24.45                21.06               12.79         52.30

    12/74              85.12               23.48                11.92               11.43         48.67

                                                         2-9

         600 -

         500 -                                         50 -
    o
         400-         /\' 40-
    z                                                E
           300-                                   >- E 30-
    ,.LU

    <~   V200-                                          20-
    a,
         100 -                                         10-

                IJAN       MAYIJUL    OCTIDEC               IJIN   I  MAYIJUL 0       OCTIDEC
              DEC    MAR    JUN    SEPT NOV                DEC   MAR    JUN    SEPT NOV

              1973            1974                         1973            1974

         500-           \                            12.5-

         .400-                                     - 10.0-

         300-                                      c  7.5-

      w- 200. V.-.

         100-                                         2.5 -

                IJAN       MAYIJUL   IOCTIDEC                IJN        MAYIJUL   IOCT IDEC
              DEC    MAR    JUN    SEPT NOV                DEC    MAR      JUN    SEPT NOV

              1973            1974                         1973            1974

                                                                                75151A101
           Figure 2-2. >202t4 Net Plankton Standing Stock Annual Average Concentrations By Month

                                             2-10

         160-

         140-

    LU   120 -

    -j10                                                  50

       zE80- 40

         20-                                              10-

                    38 I 7A&BI  16B I                    A7A&BI   B1
              IA    5A&B. 8A&C  1 1A&C                         1A    5A&B   8A&C   1 1A&C

        140-

        120-

                  100 -~~~~~~~~~~~~I
    UpE  80 -
                                                   (J 10.0

                                                 U-
         230-                   7                         .5 -

                       138    I 7A&Bl   1081                   138    I  7A&BI   lElOBI

            Figur 2-3  E22  Ne  lntn vrg  nua  tnigStc  ySaio                         55A

                                              2-1

         70 - __70 -

    o    60 -                                                        z  60.
    z                                                                0
    In
    cc 50-                                                           < 50-
                   n~~~~~~~~~~~
    U    40-                                                         Lu 40

    LL   30 -                                                        0
                   0                                                LL~~~~~~~~~~~ 30-
                   Er ~~~~~~~~~0
        20-                                                          m  20-

      10-                                                               10-

                 In  CD)  0C   0~ ICa  LO) LO)   In LO                    LOU)L                                       )L
                     - N    M~  'I*  LO)  (0  r-. co
               (A)      WET WEIGHT          3)g/                              (B)    ASH WEIGHT  (mg/rn3)

         70 -

    U    60--                                                         /)60-
    z                                                                LU
    EC 50  -                                                             50

      U 40-                                                          Z) 40-
    LL                                                               C.
    o    30-                                                         0 30 -
                   M                                                U_~~~~~~~~~~~~~~~~~~~~~L
    Uj                                                               0
    co 20-                                                           M  20 -
                                                                  LU
    z    10-                                                             10 -

              RI  Ll)  LI)   LI)  CC  LI)  Un   U    LI)  Lqn                LO   Lo)  in   i    Lo)  Lo)  LI)  U   LO)
              to~ aL oin  OLo)  Lo)                                         rl        I'   " r-" rl                 ,
                     C14 r  ~         LI)  co  F, co    03                        U)  co   N   LO) a)   l to)  0)  i)
                                                                                                     - N    C1 co    r
               (C)     DRY WEIGHT   (mg/rn3)                            ID)    ASH-FREE DRY WEIGHT (mg/rn3)

                                                                                                                 75151A 103

        Figure 2-4. Frequency Distributions of Biomass Values for Upper Chesapeake Bay Zooplankton

                                                            2-12

        50-

        40-

    z  30-

    o_ 20-

        10-

              DEC JAN      MAR       MAY JUN JUL       SEPT OCT NOV DEC

                          (A) DRY WEIGHT VS WET WEIGHT

       50 -

       40-

    "u 30 -

      20-

       10-
                                                          I

             DEC JAN       MAR      MAY JUN JUL       SEPT OCT NOV DEC

                      (B) ASH-FREE DRY WEIGHT VS WET WEIGHT

                                                                        75151A104
                    Figure 2-5. Biomass Ratios of Average Monthly Data

                                      2-13

       30-

    Z-
       20-

                lA     3B          5A&B         7A&B  8A&C        16B  11A&C
                                          STATIONS
                              (A) DRY WEIGHT VS WET WEIGHT

       30-

    Uj
    20_

        10-

                11A    3B          5A&B         7A&B  8A&C           10B  11A&C
                                          STATIONS
                            (B) ASH-FREE DRY WEIGHT VS WET WEIGHT
        60-

        50-

        40-
    z

    LU
    i30/

        20-

        10-

                 lA    3B         5A&B          7A&B  8A&C           1 B  1 1 A&C
                                          STATIONS
                          (C) ASH-FREE DRY WEIGHT VS DRY WEIGHT

    Figure 2-6. Biomass Ratios for Principal Stations Sampled Throughout The Upper Chesapeake Bay

                                         2-14
                                         2-14

                  A total of 90 different specific forms were identified and counted from the 51 samples
    analyzed for taxonomy. By far the most dominant groups were the copepods (27 species) and the
    cladocerans (20 species). All recognizable forms were categorized and counted during the procedure,
    resulting in sometimes significant contributions by non-planktonic forms. The second most dominant
    form isolated in the 202-/t net tows were oak leaf hairs which sometimes accounted for more than 50
    percent of the total count from the upper bay samples (Table 2-6). Interestingly, this plant debris is found
    mostly in the northern bay (Stations 1A and 5A). Numerically, the total number of organisms per cubic
    meter coincides with the trend of increasing biomass from the head of Chesapeake Bay down to An-
    napolis and an average of 4,633 organisms per cubic meter recorded in the Baltimore harborwaters.
                   Species diversity was computed by two methods (Tables 2-7 and 2-8). The highest
    average diversity occurs in December throughout the upper bay, and the lowest diversity occurs in March
    when biomasses are at maximum concentrations. On a station basis, the highest species diversity oc-
    curs at Station 1A, and the lowest diversity is at the lowermost stations (Stations 10B and 11A). The
    average numbers of species at each station indicate a similar trend (Table 2-9). While these observations
    are fairly predictable by making comparisons of salinity profiles throughout the upper bay, numbers of
    species and individual organisms are almost inversely related to the biomass standing stocks.
                   Data from stations in the upper bay were compared for organism community
    relationships (Figure 2-7). These community correlation coefficients show four basic communities of
    planktonic organisms in the upper Chesapeake Bay. The first, basically a fresh water community, ex-
    tends from Havre de Grace (Station 1A) to Turkey Point (Station 3B). The second community is in the
    vicinity of Pooles Island (Station 5A), and the third community seems restricted to the Baltimore harbor
    area, where salinities average 50/oo and Eurytemora affinis overwhelmingly dominates. The fourth
    community seems to be located below the Patapsco influence and down to the Severn River area (Station
    11A).
                   Presentation and discussion of the chlorinated hydrocarbon levels found in the
    zooplankton samples will be found in Chapter 6, Biochemistry.

       2.3 Benthic Investigations
           Evaluation of the benthos with respect to chlorinated hydrocarbons from upper Chesapeake Bay
    waters was to meet three basic objectives:

           (1) Through selective field sampling, determine the quantitative residual chlorinated hydrocar-
               bon content within indigenous benthic molluscs.

           (2) Based on the results of field investigations, experimentally evaluate potential mechanisms of
               biological uptake.

           (3) Working from laboratory tests, conduct in situ experimentation atop a productive shellfish
               bar to verify hypothetical paths of chlorinated hydrocarbon transfer to shellfish.

           These objectives were carried out in three phases. The first consisted of field sampling for
    chlorinated hydrocarbon analysis of upper bay populations of benthic organisms, mainly molluscs. After
    the analyses of the field samples, laboratory experimentations were designed and undertaken. The final
    phase of the benthic investigation involved in situtests with commercially-sought shellfish, utilizing as
    design parameters the results of the field and laboratory work.

                                                    2-15

    TABLE 2-6. DOMINANT FORMS FROM UPPER CHESAPEAKE BAY

                   TAXA                            Percentage
                                                  of Occurence

                Acartia tonsa                            98.03

                 Oak Leaf Hairs                           84.31

                 Barnacle Nauplii                         82.35

                Podon leucarti                           76.47

                 Eurytemora affinis                       74.50

                 Polychaete Larvae                        74.50

                 Prionocypris longiforma                  72.54

                 Daphnia spp                              50.98

                 Bryozoan Floatoblast                     49.01

                 Cyclops spp (A)                          45.09

                 Bosmina longirostris                     45.09

                 Insects                                  45.09

                 Cyclopoid Nauplii                        41.17

                 Harpacticus spp (B)                      41.17

                                     2-16

         TABLE 2-7. >202# NET PLANKTON SPECIES DIVERSITY* BY STATION FOR UPPER BAY

                                                   STATIONS

    Month           1A            5A            7A&B            8A&C             10B           11A

    12/73           5.6008        3.1038          --               --         1.5135        1.9339

     1/74             --            --            --              --          1.9959        2.0807

     3/74           3.4769        2.4769        1.3309          1.2024        1.2513        0.7526

     5/74           3.8649        3.3574        1.7948           --           2.2694        1.5320

     6/74           4.1626        3.2761        3.0980             --         3.0106        1.7644

     7/74           4.0255        1.9274        3.8228             --         2.3564        1.3092

     9/74           3.2755        2.5390        2.0203             --         0.8889        2.0372

    10/74             --          3.7371          --               --         4.1357        2.0487

    11/74             --          2.8001          --               --         1.8546        1.6833

    12/74           7.2473        4.7905          --               --         2.5492        2.5045

    *See Margalef, 1956.

         TABLE 2-8. >202ji NET PLANKTON SPECIES DIVERSITY** BY STATION FOR UPPER BAY

                                                    STATIONS

    Month           1A            5A            7A&B            8A&B          10B           11A

    12/73           0.8570        0.2219          --               --         0.4837        0.1094

     1/74             --            --            --              --          0.2832        0.3672

     3/74           0.3928        0.0533        0.0523          0.2082        0.1958        0.2791

     5/74           0.4549        0.6944          --              --          0.3773        0.3805

     6/74           0.6277        0.2945        0.3980             --         0.2929        0.3314

     7/74           0.2612        0.2171       0.5393             --          0.1108

     9/74           0.4878        0.0662       0.0288             --          0.0814        0.0262

    10/74             --          0.0806          --              --          0.3674        0.04383

    11/74             --          0.2185          --              --          0.0816        0.02387

    12/74           0.7792        0.4394          --              --          0.3919        0.3271

    **See Shannon and Weaver, 1949..

                                                       2-17

    TABLE 2-9. AVERAGE NUMBER OF SPECIES PER STATION FROM UPPER CHESAPEAKE BAY

                                                                                 Average
                    Station                                                     Number  of Species

                    1A                                                               29.57
                                                                              (+ 8.69)

                    5A&B                                                             22.00
                                                                              (+ 5.17)

                    7A&B                                                             19.83
                                                                              (+ 5.38)

                    10OB                                                             13.90
                                                                              (+ 4.74)

                    11A                                                              13.30
                                                                              (- 4.52)

                                                     2-18

             Stations                  73 74' . .............
                                    D J FM AM J J A SON  D
           Compared   ,

                           .7000-           ,

                          .5000- ,/*
             1 1A+10B
                           .3000 -

                           .1000     ,           ,                  , ,     ,

                           .5000-                             *

             11A+5A   .3000   -\I

                           .1000  ,      ,   ,  ,   ,  ,       ,       ,  ,   ,

             11A+1A    .3000                             *

                          .5000
             1OB+5A                - **.*
                           .3000 -

                           .1000-   I    i  i,      I,   I  , 1

             1B+1A           .3000   *
                           .1000             I  I  I
                           .5000-

             5A+1A   .3000-                           /

                           .1000      ,,       ,

                                                                                75151A133

    Figure 2-7. 202J1 Net Plankton Investigations Taxonomic Data Analysis: Community Correlations

                                          2-19

           2.3.1  Field Investigations
                   Field samples were taken selectively throughout the upper bay during the first phase of
    the program to collect representative quantities of benthic organisms for evaluation of CHC content.
    Eight suites of samples were undertaken at stations coincidentally with the plankton and hydrographic
    measurements (see Figure 2-1 ) over a period of one calendar year. Approximately 56 individual samples
    were collected with a modified bottom trawl and a Ponar dredge. The data are recorded in Volume Ill, Sec-
    tion 4 under the biochemistry section, and the reduced values are given in Table 6-1 in Chapter 6. Section
    6.3.4 of that chapter contains further elaboration on the field samples.

           2.3.2 Laboratory Experiments
                   The second phase of the benthic investigations focused on a series of experiments aimed
    to understand better the natural processes bywhich chlorinated hydrocarbons become available to com-
    mercially important shellfish. The polychlorinated biphenyl (PCB) formulation, Aroclor 1254, was
    chosen as the test chemical because of its ubiquity throughout the upper bay field samples. From
    previous experiments of the Chester River Study (1972), it was believed that substantial amounts of the
    CHC's present were adsorbed to the fine-grain suspended sediments from which they could be ac-
    cumulated by shellfish. Work by Huang and Liao (1970) suggested that insoluble, extremely hydrophobic
    chlorinated hydrocarbons rapidly attach to fine-fraction clay particles. However, their pesticide ex-
    periments were conducted with processed (dried)kaolinite, illite, and montmorillonite. While these tests
    reflected the spectrum of clay composition in suspended sediments, they did not realistically represent
    the actual conditions under which naturally-existing, fine-fraction suspensoid material is present in an
    estuarine environment. Therefore, the first series of tests undertaken in the laboratory were to evaluate
    the capability of PCB 1254 to adsorb on naturally occurring suspended sediments from the upper
    Chesapeake Bay.
                   Samples of natural clay sediments taken off Windmill Point in the Chester River were
    brought to the laboratory wet, where tests were made for percent organic composition and analyses
    were made for grain-size fraction. Combustion tests on the clays revealed that they contained less than
    15 percent organic matter, and the sizes of most particles were found to be in the 0.6 to 1.5 p range by
    Coulter counter analysis. To test the ability of this clay sediment to bind PCB 1254, experiments were
    performed as described below.
                   The clay experiments consisted of pipetting a fewtenths of a milliliter of an acetone solu-
    tion of PCB 1254 (of sufficient strength to give a resultant concentration of 100 pg/I in the test chamber)
    into one liter of filtered bay water containing added clay while mixing the water vigorouslywith a teflon-
    coated magnetic stirring bar. After immediately withdrawing a 100-ml sample (200-ml sample in the
    1,000 mg/1 test), the system was sealed; it was reopened periodically during the ensuing five hours to
    remove additional subsamples. The 100-ml (or 200-mi) aliquots were immediately filtered through a
    glass-fiber filter, and both the filters and filtrates were reserved for PCB analysis. Five tests were con-
    ducted using suspended sediment concentrations of 50, 100, 500, and 1,000 mg/1 and the control con-
    taining no added suspended sediment. The filters containing the suspended sediments and the filtrates
    were extracted, and the extracts were analyzed for PCB 1254 using gas-liquid chromatography (Chapter
    6).
                   Results of these tests are shown in Table 2-10 and in Figure 2-8. In the first series of
    tests, it was observed that 44.7 percent of the total 100 pg of PCB was lost when it was injected directly
    into filtered bay water and mixed for approximately 20 hours (Figure 2-8a).
                    Repeated tests documented this high loss of PCB. After systematic examination of the
    probable losses which might be incurring at each step in the procedure, it was concluded that a major
    part of the loss might be a result of irreversible adsorption of the PCB to the walls of the glass test
    chamber.
                    Table 2-10 presents the materials balance for the clay-PCB binding tests in which the
     amounts of PCB recovered from the clay and the water samples are recorded separately and then as a
     total. The 200 ml of clay-containing water remaining in each chamber at the end of each test was ex-
     tracted in the chamber, thereby extracting the walls of the chamber also. The amounts of recovered PCB
     were added arithmetically to the amounts from the time series samples to derive the percent error, (i.e.,
     the percent of the total PCB remaining unaccounted).

                                                     2-20

    TABLE 2-10. RESULTS OF LOW PERCENTAGE ORGANIC CLAY ADSORPTION EXPERIMENT
                                               WITH PCB-1254

           Clay                                      PCB-1254 RECOVERED
           Concentration                                                                              Percent
           (mg/I)                      Water                 Clay               Total                 Error*

           Control                     33.6                    2.0              35.6                  42.8

             50                        14.6                  18.2              32.8                   44.3

            100                       31.3                   16.8               48.1                  23.3

            500                        17.8                  30.9               48.7                  29.4

          1,000                         6.5                  43.4               49.9                  31.7

     *Includes Jar Water Recoveries.

                                                        2-21

               IAI 0.0 mg/I CLAY
    10.0 -                                                                       7.0~        (0I)  500 mg/I CLAY

                    42.8%/ ERROR
     8.0 -                                                                       6.0 -             ERROR 29.4%

     6.0-                                                                       5.0-

    (24.0-                                                                       4.0

     2.0-                                                                   3(2

                            WATER                                                            1N

               50     100    150    200    250    360               3      6      0-       S

                           TIME IN MINUTES

             (B)   50.0 mg/I CLAY
                       3. ~ ~ ~~~ ~  ~ ~ ~0 .t'                                                   .
                                             ADS~~~~~~~f? ~~~50                                100    150    200    250    300    350

                            2.0  -  ~~~~~~~~~~~~~~~~~~~TIME IN MINUTES

     1.0 -          ERROR 44.3%

                           0               14.0 -    ~~~~~~~~~~~~~~~(El    1,000 mg/I CLAY
               so ido    150    200    250    300    350
          6.0  A   ~~TIME IN MINUTES                                                                    'E
                       6.0-  A                                                ~~~~~~~~~~~~~~~~~~~12.0-

                     (C)   1 00 mg/I CLAY
     5.0.                                                                      10.0-
                          ERROR  23%ERROR  62.8%

                       4.0                                                     ~~~~~~~~~~~~~~~~~~~~8.0.

                      3.0.~~~~~~~~~~~~~~~ 6.0-

                       2.0 -                            ~~~~~~~~~~~~~~~~~4.0 -

     1.0                                                                        2.0-

                                                                                             ---- WATE
       0                                                                          0 .  7
               50     100    150    200    250    300    350                              50     100    150    200       250    300    350

                             TIME IN MINUTES
                                                                                                   TIME IN MINUTES

                                                                                                                             75151 A222

                      Figure 2-8. Low Percentage Organic Clay Adsorption With PCB 1254

                                                                 2-22

    TABLE 2-10. RESULTS OF LOW PERCENTAGE ORGANIC CLAY ADSORPTION EXPERIMENT
                                               WITH PCB-1254

           Clay                                      PCB-1254 RECOVERED
           Concentration                                                                              Percent
           (mg/I)                      Water                 Clay               Total                 Error*

           Control                     33.6                    2.0              35.6                  42.8

             50                        14.6                  18.2              32.8                   44.3

            100                       31.3                   16.8               48.1                  23.3

            500                        17.8                  30.9               48.7                  29.4

          1,000                         6.5                  43.4               49.9                  31.7

     *Includes Jar Water Recoveries.

                                                        2-21

               IAI 0.0 mg/I CLAY
      10.0 -                                                                      7.0  (0)   500 mg/l CLAY

                    42.8% ERROR

      8.0 -                                                                      6.0 -              ERROR 29.4%

       5 G.0-                                                                     5.0

    Q4.0-

       2.0-                                                                       3.0-

                           WATER

               50     160    150    260    250    360    350                    2.0 -
                           TIME IN MINUTES                                     1.0

             (B)   50.0 mg/I CLAY
      3.0                   CLA y                                                  0
                                           3.0 A~ 0 /~ ~50                                   100    150    200    250    300    350

            �e; 2.0       _....                                                                          TIME IN MINUTES
      2.0'

    0 1.0            ERROR 44.3%

                                                                                 (E)    1,000mg/I CLAY
        0:                                                                       14.0 �
                50     100    150    200    250    360    350
                          TIME IN MINUTES
       6.0      A                                                                 12.0-

                     (C)  100 mg/I CLAY
       5.0.  10.0-
            |     \         ERROR  23.3%           _                                                  ERROR  62.8%

       4.0G                                                                       8.0 ,
           N      \N

       C_3.0.                                                                �    6.0-

                               O/       ,_WATER

        2.0 -4.0-

        1.0                                                   -                   2.0-
                                                                              v _ _ _   __ _ _. WATE.

                50     100    150    200    250    360    350                              50     100    150    200    250    300    350
                            TIME IN MINUTES                                                           TIME IN MINUTES

                                                                                                                    75151A222

                      Figure 2-8.  Low Percentage Organic Clay Adsorption With PCB 1254

                                                              2-22

                    It is important to note that when no clay was added to the water, very little of the PCB was
     recovered on the filter (Figure 2-8A). This point is critical to the experiment, because it suggests that the
     PCB retained on the filters from the tests in which clay was added was really adsorbed to the clay par-
    ticles rather than the glass-fiber filter.
                    The plots of the data in Figures 2-8A through 2-8E do not depict smooth curves one might
    expect from such experiments-possibly indicating random errors in the analytical procedures. A few
    tentative observations can be made, however. The clay-suspended sediments appear to bind a large part
    of the added PCB. Apparently, a major part of the adsorption takes place almost immediately, all of the
    clay samples taken just after addition of the PCB are well on the way to the maximum adsorption observ-
    ed. Except for the earliest sample in the lowest clay test (which maybe an incorrect value), the amount of
    this initial adsorption increases as the concentration of clay increases. The adsorption process as a
    whole does not appear instantaneous, however; at this high PCB level, a considerable amount of PCB
    appears to be free in the water even after five hours of exposure to the clay. As will be seen later from the
    in situ experimental data, the adsorption of PCB by the naturally occurring suspended sediments in bay
    water appears somewhat different.
                   In all of the exposures, whether claywas present or not, 23 to 44 percent of the PCB 1254
    was lost-more than can be accounted through analytical errors. A part of the PCB seems (1) to become
    irreversibly attached to the clay, (2) to become irreversibly attached to the glass walls of the test
    chambers, (3) to volatilize, or (4) perhaps experience a combination of all three.

            2.3.3 In Situ Experiments:
                   As a climax tothe program of field and laboratory biological experiments with chlorinated
    hydrocarbons, a series of inlsitu tests were designed to assess the reality of background environmental
    measurements from the field collections and to examine the hypothesized predications of the laboratory
    experiments. The in:situ work was designed to conduct realistic dosing experiments using bottom waters
    taken directly from an active oyster bar and adjusting specific physical parameters to optimize and
    enhance shellfish pumping characteristics.
                   The in situ experimental apparatus consisted of an open-cycle, once-through seawater
    circulation system (Figure 2-9) installed in a laboratory module placed on the R/VSEARCHSTAR (Figure
    2-10A). A high pressure particle separator (Figure 2-10B) in the system was capable of removing par-
    ticles greater than 20u from the water at 24 psi. Two modified impervious graphite shell and tube heat
    exchangers were constructed for raising ambient water temperatures by increments of 40C and 80C to
    increase the pumping rates of the test animals. This variable open-flow, closed-chamber system (Figure
    2-1 OC) was stepped down to produce a flow rate of approximately two liters of water per minute through
    each test chamber with a residence time of approximately 26 minutes. Using previous calculations by
    Pratt (1933) and others, it is estimated that the system will circulate more than ten times the volume of
    water required by the organisms at the maximum operating temperatures. It also provides sufficient time
    for the chlorinated hydrocarbons to react with ambient suspended sediments and to produce a
    measurable adsorption to suspended particulates.
                   Table 2-1 1 shows the adsorption of PCB 1254 to the suspended sediments during the in
    situ dosing experiments.
                   Twenty parts per billion (ppb) was selected as a PCB 1254 dose concentration, based on
    the biochemical results of the field samplings and laboratory experimental tests. Four chambers each
    containing 1 2 oysters and 1 2 clams were prepared for exposure. Selection of organisms for testing was
    based on comparing data from several series of biomass analyses including displacement volume, dis-
    placement wet weights, wet weights, and pseudofeces measurements. Tables 2-12 and 2-13 show the
    results of this sorting procedure and Figure 2-1 1 shows the linear regressions for the oysters and clams
    selected for experimentation.
                   The clams were water-injected into a sand substrate in 250-ml breakers to reduce the
    hydrostatic stresses on these infaunal organisms. The test animals were then placed in their respective
    tubes for in situ experimentation. After a 48-hour period for acclimation of the test animals to the tube
    chambers and elevated temperatures, the laboratory module was towed to Station 11 A off Hacketts' bnr.

                                                    2:23

            I--- fo          T2

              I          150CAT D"&

                  ~~~~~~~~~~~I  If,

            ,   I                    i

            I            1                                              CONSTANT HEAD

                             I
                 I   +               C1  C2      C3      C4

    ,,       L_  HEAT

                                 LI    ED                   1

           SEA LEVEL

                                    P1 - CIRCULATING WATER PUMP

                                    P2-' PERISTALTIC DOSE DELIVERY PUMP
                                     S - PARTICLE SEPARATOR (<201i @ 24 PSI)

                                    T1 - 50C AT HEAT EXCHANGER
                                                                  100�F HEAT SOURCE
                                   T2 - 100C AT HEAT EXCHANGER

                                    D - CHEMICAL DELIVERY RESERVOIR

                                C1...4 - ANIMAL TEST CHAMBERS
                                   ED - EFFLUENT DISCIIARGE POINT

                                     F - FILTRATION CLEANUP

                                   P3- HOT WATER CIRCULATION PUMP

                                                                                 75151A134

                  Figure 2-9. In Situ Experimental Laboratory System

                                        2-24

                                                                        75151A135
                      Figure 2-1OA. Laboratory Module on RNV SEARCHSTAR
                            being Towed to Station by R/V NORTHSTAR

     A,.+

                                  755A375151A135                                          75151A135
    Figure 2- 10B.  High Pressure Particle Seperator           Figure 2-10C. Organism Test Chambers Having a
       Used in the In Situ Dosing Experiments                    Two-Liter per Minute Flow Rate as Used
                                                         in the In Situ Dosing Experiments

                                               2-25

    TABLE  2-11. PCB-1254 ADSORBED  TO SUSPENDED SEDIMENTS  DURING  IN SITU EXPERIMENT

                                 Time
             Tank                 (Hours)                     ug/l PCB-1254
             No.                                      Filter                  Water

               2                   24                 3.6614                 0.4649

               2                   48                 5.2834                 0.0877

               2                   96                 1.7805                 0.1986

               2                  144                 5.0721                 0.0001

               3                   24                 2.9164                 0.9351

               3                   48                 2.9270                 0.1558

               3                   96                 1.0461                  0.0760

               3                  144                 2.2560                  0.0389

               4                   24                 3.1383                 0.2377

               4                   48                 4.9558                 0.8030

               4                   96                 0.8559                 0.0861

               4                  144                 8.0308                 0.2958

     TABLE 2-12. OYSTER BIOMASS SORTING EVAULATIONS FOR IN SITU EXPERIMENTATIONS

                                                      TUBE NUMBER
                                         1                   2                 3                 4
             Displacement                54.53                51.29             45.67             35.18
             Volume                    (�12.32)             (+ 9.58)          (� 9.03)          (+11.90)

             Displacement                45.87                45.92             40.58             29.91
             Weight                    (� 9.18)             (+10.46)          (�11.24)          (+11.09)

             Wet                        101.75                95.93             85.54             64.23
             Weight                    (+16.51)             (+18.87)          (+19.52)          (+22.31)

             Composite Meat              29.75                27.83             21.67             14.80
             Weight                    (+ 7.73)             (+ 7.05)          (+ 3.14)          (+ 3.72)

                                                       2-26

    TABLE 2-13. CLAM BIOMASS SORTING EVALUATIONS FOR IN SITU EXPERIMENTATIONS

                                                    TUBE NUMBER

                                      1                    2                 3                 4

          Displacement                  54.53               51.29             45.67             35.18
          Volume                     (+ 12.32)            (+ 9.58)          (+ 9.03)          (+11.90)

          Displacement                  45.87               45.92             40.50             29.91
          Weight                     (+  9.18)            (�10.46)          (�+11.24)         (�11.09)

          Wet                          101.75               95.93             85.54             64;23
          Weight                     (+ 16.51)            (+18.87)          (+19.52)          (�22.31)

          Composite Meat                29.75               27.83             21.67              14.80
          Weight                     (+  7.73)            (+ 7.05)          (+ 3.14)          (+ 3.72)

                                                    2-27

                                           LL
         60-                               D   60-

                                           -

    c(   40-                                z 40-
                                           F-           7     0
    ~- C2          R� 0.987                 w                  R= 0.984
    wL   20-                                5   20-
                                           a.

           50    70i   90  110                          2  40  60
                 DISPLACEMENT                           DISPLACEMENT
                     WEIGHT                                 WEIGHT
                      (gms)                                  (gins)

                                    (a) OYSTERS

                                                LU
         45-                   /                r    45-
                                                .-J

    40-                                                40-
    L- 40-zi

                                                w
    - 35-               R0.993                   U    35-
                                                     a             s i:~R 0.991

         30              .     .                      30
            3     4      5     6      73                        4      5     6      7

                   DISPLACEMENT                                 DISPLACEMENT
                      WEIGHT                                       WEIGHT
                       (gms)                                        (gms)

                                       (b) CLAMS

                                                                            75151A106

                   Figure 2-11. Regressions on Biomass Animal Sorting Evaluations

                                           2-28

                   The PCB 1254 dosing was initiated then at a calculated concentration of 20 ppb with a
    bay water flow rate of two liters per minute. One milliliter per minute of 40 ppm solution of PCB 1254 in
    20-percent acetone in water was pumped into the inlet water lines of exposure Tubes 2, 3 and 4. (The
    control tube, Tube 1, received 1.0 ml per minute of 20-percent acetone in water.)Afourth channel of the
    pump delivered 1.0 ml per minute of the PCB solution to a holding bottle for later analysis. Temperatures,
    flow rates, and PCB dose rate were monitored every two hours, and the reduced results were recorded in
    Table 2-14.
                   From examining these data, one observes the daily average temperature varied only
    0.650C, and the flow rates were within �64 ml/min during the entire 144 hours of dosing. Measured
    concentrations of PCB in the holding bottle were within 10 percent of the calculated dose rate. Sequen-
    tial measurements were made by analyzing organisms, suspended sediments, and filtrate waters (Table
    2-15). The time sequences arbitrarily chosen for measurement were: (1) just before dosing began, (2) at
    24, 48, and 96 hours after initiation of dosing, and (3) a final measurement 48 hours after cessation of
    dosing at 144 hours.
                   In view of the high levels of PCB used in this experiment, the analyses were not carried to
    such extremely low levels as with the environmental samples. The values reported for PCB in the filtrate
    water and filtered suspensoids below the 0.2 gg/1 level probably are not significant and do not
    necessarily represent positive confirmations of the presence of PCB 1254. The PCB was equal to or less
    than those values, if it was present at all. For this reason, one should not conclude that the bay water
    passing through the control tube contained more PCB free in the water than on the suspended
    sediments.
                   Referring to Table 2-15, one can notice several interesting things about the administered
    PCB. In most cases, the values for PCB free in the water (i.e., passing through the filter)fall belowthe 0.2
    ;,g/l significance level. The lack of any trend or apparent relationship between the values which rise
    above this level cause one to suspect random analytical errors for these positive values. At any rate, one
    seems justified in concluding that very little and perhaps none of the PCB 1254 present was free in the
    water, but it was adsorbed on the suspended sediments in the water instead.
                   These data also indicate that the adsorption of PCB 1254 by the suspended sediments
    was more complete and more rapid than by the clay sediments employed in the laboratory tests. Perhaps
    having the PCB concentration closer to its water solubility (about 10 ppb) accelerated the adsorption
    although less suspended sediment was available. Whatever the case, most of the 20 ppb PCB 1254 add-
    ed was not found in the water and suspended sediments leaving the exposure tubes. Although analytical
    errors may be responsible for some of the irregularity, whythe recovered amounts of PCB varied so wide-
    ly and usually represented less than 25 percent of the amounts added remains a mystery.
                   It seems, however, that the PCB available during dosing was adsorbed to fine-fraction
    particulate matter and that the resulting uptake by organisms must come from ingestion of fine par-
    ticulates, although they may not be viable organic matter. The oyster data suggest that, although these
    organisms can scrub PCB from suspended sediments effectively, they accumulate very little PCB when
    water temperatures are below 10�C (Figure 2-12). However, when water temperatures exceed 100C,
    oysters can accumulate five to ten times more PCB. Further, these animals at temperatures above 1 0�C
    were able to purge 44 percent of the PCB within 48 hours after cessation of exposure, but the oysters ex-
    posed to temperatures below 10�C did not show any significant changes in PCB level.
                   The results from exposing clams did not show the same trends as the results from ex-
    posing oysters; although, conditions were exactly the same (Figure 2-13). The clams seemed to ac-
    cumulate PCB even when ambient temperatures were around 4.70C. However, at this temperature their
    body burden stabilized at about 2 ppm within 48 hours of dosing and dropped to only 1 ppm 48 hours
    after dosing was terminated. The organisms exposed at elevated temperatures generally accumulated
    higher concentrations of PCB, but no definite pattern of uptake was observed. From these results, it is dif-
    ficult to identify any trend with regard to PCB uptake by clams. However, there appears to be a significant
    accumulation of PCB within the first 48 hours of exposure, followed by fluctuations on the order of 7 ppm
    in PCB levels in the clams.

                                                     2-29

     TABLE 2-14. PHYSICAL PARAMETER MEASUREMENTS DURING IN SITU DOSE EXPERIMENT
                          CONDUCTED MARCH 3 THRU 17, 1974 AT STATION 11A

                                                                DATE
                       3/11           3/12            3/13           3/14            3/15           3/16            3/17

          No. 1         4.71            4.60           4.92            4.70           4.74            4.89            5.12
                      (�0.31)        (-0.11)         (�0.25)        (+0.12)        (-�0.28)        (-0.47)         (-0.19)

          No. 2         4.77            4.65           4.95            4.73           4.76            4.92           5.16
                      (-+0.32)       (+0.10)         (�0.24)        (:0.11)         (�0.28)        (-�0.47)        (�0.17)

          No. 3        12.57           12.26          12.47           12.51          12.50           12.63          12.86
                      (+0.57)        (�0.40)         (�0.23)        (+0.42)         (�0.21)        (�0.54)         (�0.16)

    a.O  No. 4          8.74            8.60           8.91            8.72            8.73           8.91            9.13
    E -               (+-0.25)        (+0.07)        (�0.23)         (M0.18)        (�0.15)         (+0.48)        (-0.20)

          Air           4.64            4.79           6.96            2.56           4.07            5.24            5.07
                      (+0.69)        (�0.72)         (+1.78)        (�1.42)         (+1.74)        (�2.62)         (�1.92)

          Surface       4.47            4.29           4.56            4.49           4.50            4.56            4.84
                      (-+0.40)       (�0.14)         (�0.22)        (+0.11)         (+0.27)        (�0.39)         (+0.15)

          No. 1         1.990           2.040          2.003           1.953           1.949          1.963           1.924
                      (�0.062)       (�0.061)        (�0.049)       (�0.011)        (�0.020)       (�0.010)        (-0.025)

    co No. 2            1.997           2.046          2.021           1.942          1.942           2.097          2.058
                       c  (�0.067)   (�0.014)        (�0.020)       (-+0.008)       (+-0.059)      (+0.018)       (-+0.024)

    ,-  No. 3            1.962          2.059           2.088          1.953           1.979          2.003           1.995
                      (�0.017)       (�0.064)        (�0.024)       (�0.029)       (-+0.033)       (-+0.021)       (+0.008)

          No. 4         1.976           1.970          1.955           1.932          1.943           1.971           1.986
                      (-0.012)       (+0.012)        (�0.013)       (�0.009)        (�0.009)       (+0.017)        (-0.008)

                                                         2-30

        TABLE 2-15. DATA FROM IN SITU EXPERIMENT CONDUCTED MARCH 3 THRU 17, 1974
                                               AT STATION 11A

                                    Suspended    PCB in         PCB on        PCB in        PCB in
           Tube       Time          Sediments    Water          Filters       Clams         Oysters
            No.        (Hours)       (mg/I)        (9g/l)        (pg/l)        (ppm)         (ppm)

            1            0           19.47         0.174         0.000         0.072         0.084
      -    1           24           10.53         0.171         0.004         0.006         0.009
            1           48            8.27         0.030         0.010         0.021         0.012
      o    1           96           11.40         0.006         0.119         0.054         0.042
            1          144           12.43         0.005         0.072         0.103         0.030
            1          192           10.93         0.000         0.005         0.048         0.028

            2            0           18.04          --           0.010         0.045         0.085
      c    2           24           12.77         0.465         3.661         0.419         0.049
    z  X    2           48            8.43         0.088         5.283         1.920         0.026
    E Q    2            96            9.30         0.199         1.781         1.850         0.089
    E<E    2           144           13.63         0.001         5.072         1.910         0.186
      ' 2              192           11.83        0.001         0.003          1.100         0.050

            3            0           19.60         0.137         0.009         0.199         0.100
            3           24            8.60         0.935         2.916         1.770         0.128
      o    3           48            11.83        0.156         2.927          5.520         0.462
      +C    3           96           11.33        0.075          1.046       11.500         4.800
            3          144           13.27         0.039         2.256         4.810        22.700
            3          192           13.70         0.000         0.001         5.300         9.000

            4            0           18.04         0.063         0.004         0.169         0.063
            4           24            7.50         0.238         3.138         2.330         0.414
            4           48            7.70         0.803         4.956         7.780         0.389
            4           96            7.93         0.086         0.856         3.040         1.720
      - 4             144           11.17         0.296         8.031         9.970         0.889
       +    4          192           10.80         0.001         0.001         4.100         2.400

                                                       2-31

        20.0-

                                          (+8-C)
     15.0-                                   12.50C

     0~
    CCT

         5.0-

                                                             (+40C)
                                                            i= 8.70C

                                     (-~-cAMQ _TEM P.)    _X=4.70C
                     0  2'4    4'8  1     996            144            142

                                        TIME
                                       (HOURS)

              L.--...PCB DOSING PERIOD-------a
                             (20 btg/Q)

                                                                             75151A107

             Figure 2-12. PCB 1254 Uptake by Oysters During In Situ Test

                                      2-32

           10.0-

                      (+80C)
               1t     x12.50C
    LOT
     a_

                          /       \   (+40C)
            5.0-          IX' 8.70C/

                              AMBIENTTEMP. X=4.70C

               0     24    48             96            144         192
                                     TIME
                                    (HOURS)

               L    �,,,- - PCB DOSING PERIOD   --
                                (20 mg/Q)

                                                                        75151A108

               Figure 2-13. PCB Uptake by Clams During In Situ Test

                                     2-33

                   Several conclusions can be drawn from the oyster and clam in situexposures to PCB.
    First, it appears that filter-feeding oysters can scrub PCB from suspended particulates, and the amount of
    uptake is directly related to their pumping rate. Secondly, oysters can purge themselves of PCB within 48
    hours if their pumping rate is high. Thirdly, clams, will accumulate PCB through siphon pumping even
    under winter conditions when temperatures are below 50C as was demonstrated with chlordane in the
    Chester River Study. Fourthly, after the clams initially (within 48 hours) accumulate PCB to a concentra-
    tion of approximately 5 to 6 ppm, there is no identifiable body burden, and levels tend to fluctuate. This
    does seem consistent with their feeding behavior, and similar observations involving other chemicals
    have been made.

      2.4 Conclusions
           The results of the work performed led to certain conclusions which merit the attention of
    resource managers. While the data supporting these results may not be absolutely and statistically
    significant, it is the sincere judgment of the principal investigator that the following conclusions can be
    drawn:

           (1)  Although, the zooplankton populations of upper Chesapeake Bay are spatially distributed
                and influenced primarily by seasonal temperature and salinity regimes, zooplankton pop-
                ulations within the Baltimore harbor area are distinct. Based on more than 95
                measurements of biomass, stations sampled from the Baltimore harbor area yielded values
                four to five times greater than those from any other stations in the upper bay.

           (2)  Zooplankton organism diversity decreases from the head at Havre de Grace down the bay
                toward Annapolis; yet biomass abundance increases. This means there are more different
                types of plankton organisms in the upper reaches, but standing stocks there are substan-
                tially lower than at the more southerly stations of the upper bay. An hypothesis to explain
                this phenomenon is that enormous pulses of suspended particulate loads are introduced
                 into the bay from the Susquehanna River and the resulting turbidities depress autotrophic
                production.

           (3)  Compared to similar mid-temperate zone estuaries, the upper Chesapeake Bay supports a
                 healthy diversity of species in an abundant zooplankton community. However, contrary to
                 some published data, the dominant organism throughoutthe upper bay(Acartia tonsa) does
                 not have a winter replacement (Acartia clause). This copepod, Acartia tonsa, functions as
                the single most important holoplanktonic species supporting the secondary level of the
                 aquatic food web.

           (4)  From the data collected during the laboratory experiments, it seems that laboratory results
                 cannot be used to make direct predictions of field situations in estuarine waters with
                 respect to chlorinated hydrocarbon behavior. The behavior of chlorinated hydrocarbons in
                 adsorption to natural sediments in the laboratory is not the same as in situ.

            (5)  The biological effects of chlorinated hydrocarbons on oysters are directly related to their
                 pumping rate and efficiency, which in turn are regulated by the basic environmental
                 parameters of temperature and salinity. For oysters, there appears to be a 1 0�C threshold
                 below which chlorinated hydrocarbon uptake will not occur and above which concen-
                 trations in whole-body tissue can triple within 96 hours of exposure.

            (6)  The behavior of clams subjected to chlorinated hydrocarbon stresses indicates that there is
                 no definite temperature threshold controlling uptake.

                                                     2-34

           (7)  Comparison of oyster and clam in situ exposure data indicates that eachorganism responds
                differently to chlorinated hydrocarbon stresses and that measurements of source water
                characteristics may not be sufficient to identify or extrapolate environmental stresses to
                shellfish by chlorinated hydrocarbons.

      2.5 Acknowledgements
           The author wishes to extend sincere appreciation to the members staff of the Westinghouse
    Ocean Research Laboratory for their valuable support in conducting the program, especially to Mrs. M.
    Crawford for the biological field work, Mrs. D. Woll for the zooplankton taxonomy and data base, Mr. G.
    Lyons for laboratory and in situ experimentation, and Mr. S. Stillwaugh for the benthicfield program.

      2.6 References
    Clarke, W. D., H. D. Palmer, and L. C. Murdock (eds), 1972. Chester River Study, Westinghouse Electric
           Corp., Annapolis, Md.

    Forns, J. M., 1973. Environmental Survey of an Interim Ocean Dumpsite: Mid-Atlantic Bight. EPA 903/
           9-73-001 -A, pp. 54-60.

    Forns, J. M., 1974. Mid-Atlantic Zooplankton: An Overview with Consideration of Potential Impacts of
           Offshore Oil Exploitation. Proc. Est. Res. Fed. Outer Cont. Shelf Workshop. ERF 75-1.

    Harvey, G. R. and I. M. Teal, 1973. PCB and Hydrocarbon Contamination of Plankton by Nets. Bull. Env.
           Cort and Tox., V. 9, No. 5, pp. 287-290.

    Huang, J. and C. Jiao, 1970. Absorption of Pesticides by ClayMinerals. J. San. Eng. Div., ASCE, SA5, pp.
           1057 - 1078.

    Jaccard, P., 1908. Nouvelles Recherches SurLa Distribution Florale. Bull. Soc. Vand Sci Nat., No. 44, pp.
           223 - 270.

    Lovegrove, T., 1966. The Determination of the Dry Weight of Plankton and the Effect of Various Factors
           on the Values Obtained. In: Barnes, H. (ed), Some Contemporary Studies in Marine Science,
           George Allen and Unwin Ltd., London, pp. 429 - 467.

    Margalef, R., 1956. Information andSpecies Diversity in Communities of Organisms. Inv. Pisq V. 3, p. 99.

    Pratt, R., 1933. A Guide to the Common Invertebrates Putman, N.Y.C., N.Y.

    Shannon, C. E. and W. Weaver, 1949. A Mathematical Theory of Communication, Univ. of Ill. Press, Ur-
           bana, Ill.

    Yentsch, C. S. and J. F. Hebard, 1957.A Gauge forDeterminingPlankton Volume by the Mercury Ilmmer-
           sion Method. J. Conseil, No. 22, pp. 184 - 190.

                                                    2-35

                     CHAPTER 3

                   MICROBIOLOGY

    R. R. Colwell, G. S. Sayler, and J. 0). Nelson, Jr.
             Department of Microbiology
                University of Maryland

    ABSTRACT

           The microbiology of suspended particulates, bottom sediments, and water of the upper
    Chesapeake Bay was examined. Co-transportation of chlorinated hydrocarbons, bacterial indicator
    organisms, and potential pathogens via suspended sediment was found to occur. The highest total viable
    counts (TVC) of bacteria in bottom water samples were observed during the winter and spring months;
    the lowest were observed in July, September, and October. Total viable counts of bottom sediment
    samples followed essentially the same distribution. The highest recorded counts over the year, obtained
    at Station 1A, were ten to a hundred times greater than at Stations 5B and 10B.
           Most probable number (MPN) levels of total coliforms, fecal coliforms, and fecal streptococci fluc-
    tuated seasonally and spatially from Stations 1 A to 1 1 A. In general, MPN values decreased from winter
    to summer, with a gradual increase in the number of indicator organisms in the fall, except that higher
    MPN values occurred at Station 11 A in June through September. Total coliform levels were higher than
    fecal coliforms and fecal streptococci levels, with the highest MPN values being found in water samples
    from Station 1 A. The entry of total coliforms to the upper Chesapeake Bay via the Susquehanna River
    appears to be significant. MPN values at all of the sampling stations were lower in bottom sediments
    than in the water, with relatively less of a seasonal fluctuation occurring in the sediments. Fecal strep-
    tococci levels were generally higher than total and fecal coliform levels in bottom sediment.
           Approximately 80 percent of the fecal coliforms were Escherichi coli, Type I. Station 10B more
    commonly gave false positive coliform MPN's. More than 80 percent of the feca I streptococci were enter-
    ococci.
           More than 33 percent of the FC:FS ratios were greater than 4.0for Station 1A samples, including
    suspended sediment samples.
           The relative proportions of fecal coliforms and fecal streptococci in the total viable counts
    decreased southwards from Station 1 Ato 1 1 A during the winter months, were uniform during the spring
    months, and rose starting in June at Station 11A.
           A highly significant proportion of both total viable bacteria and selected indicators of fecal pollu-
    tion were found associated with particulate matter in the water column. Up to 53 percent of the total
    viable bacteria in Station 1 1 A water samples was found to be associated with particulate matter.
           By means of a non-selective enrichment, Salmonella enteritidis was isolated from samples
    collected during this study. Clostridium botulinum Types B and E, Vibrio parahaemolyticus, and
    suspected Yersinia sp. also were isolated.
           Approximately one to ten percent of the total viable bacterial population was found to be resistant
    to, and potentially capable of metabolizing PCB 1254. These bacteria were present at all stations.
           Greater amounts of humic acid were found in samples collected at Station 1A, and the humic
    acid concentration decreased from Station 1 A to Station 1 1 A.
           The oyster, Crassostrea virginica, was found to accumulate Salmonella typhimurium and E. coli
    at similar rates under controlled, PCB-stressed conditions. However, depuration of indicator organisms,
    viz. E. coli, was reduced under PCB stress, resulting in an artificially improved bacteriological quality of
    the oyster.

                                                   TABLE OF CONTENTS

    Paragraph                                                                                                                                Page

    3.    MICROBIOLOGY ..................................................... 3-1
    3.1   Introduction ..................................................... 3-1
    3.2            Media and Methods ..................................................... 3-2
    3.2.1          Total Viable Counts ..................... .......................................................................... 3-2
    3.2.2          Most Probable Number of Selected Indicator Organisms .................................................. 3-2
    3.2.3          Isolation of Pathogenic Bacteria ............................................................................. 3-4
    3.2.4   Suspended Sediment Analyses ............................................................................................. 3-9
    3.2.5    Humic Acid Determination ..................................................................... 3-12
    3.2.6          Nutrient Analyses ................................................................................    ................... ........3-12
    3.2.7          PCB-Metabolizing Bacteria ........................................................................................3-12
    3.2.8    Bacteriological Analyses of Oysters ................................................................................... 3-16
    3.3    Results and Discussion ........................................................................................................ 3-16
    3.3.1          Total Viable Counts ................................................................ 3-16
    3.3.2          Most Probable Number Index of Indicator Organisms ................................................... 3-17
    3.3.3          Effeciency of Identification of Indicator Organisms ...............................3-22
    3.3.4          FC/FS  Ratios ..............................................................................................3-22
    3.3.5          Occurrence of Indicator Organisms Relative to Total Viable Counts ..............................3-22
    3.3.6          Association of Bacteria with Particulates ........................ .................................................3-24
    3.3.7          Isolation of Potentially Pathogenic Bacteria ....................................................................... 3-28
    3.3.8   Bacteriology of Oysters ........................................................................................................ 3-29
    3.3.9          PCB-Metabolizing Bacteria ........................................................... .....3-30
    3.3.10    Effect of PCB-1254 on Bacterial Activity ........................................3-30
    3.4    Conclusions .......................................................................................................................... 3-39
    3.5            Acknowledgements ........................................................................................3-39
    3.6            References ............................................................................................................................3-40
                                                               APPENDIX 3A
    3A1.           Introduction .................................................................................... 3A-1
    3A2.           Materials and Methods ............................................................................................3A-2
    3A2.1   Culture Conditions ........................................3A-2
    3A2.2  Oyster Maintenance .....................................................................................................3A-3
    3A3.           Results and Discussion ........................3A-4..............................................
    3A3.1          PCB  Stress and the Accumulation of E. coli ......... ........................................................... 3A-4
    3A3.2    PCB Stress and the Accumulation of Salmonella Typhimurium .............................                                        3A-8
    3A4.           References .................................................................................................... ........ 3A-13
                                                               APPENDIX 3B
    3B1. Introduction..................................................................................................................... ....3B-1
    3B2.           Materials and  Methods .................................                                                                ..3B-2
    3B2.1          Sampling ...............................................................................................................3B-2
    3B2.2   Bacterial Enumeration ........................................3B-2
    3B2.3          Characterization of Isolates .................................................................3B............3B-5
    3B3.    Results and Discussion ........................................................................................................3B-6
    3B3.1    Recovery of Salmonella .............................S3B................................3B-6
    3B3.2   Evaluation of Enrichment Techniques ..............................3B-10
    3B3.3          Salmonella  Characterization ........................................           ............................................ 3B-10
    3B4.           Acknowledgements .......................................                                                                3B-14
    3B5.           References ........................................................................................3B-15

                                                               iii

                                               LIST OF FIGURES

    Figure                                                                                     Page

    3-1       Bacterial Association with Particulates (Light Microscopy 1,000 X) ............................... 3-13
    3-2       Bacterial Association with Particulates (Light Microscopy 1,000 X) ............................... 3-13
    3-3       Bacterial Association with Particulates (Light Microscopy 1,000 X) ............................... 3-14
    3-4       Bacterial Association with Particulates (Light Microscopy 1,000 X) ............................... 3-14
    3-5       Bacterial Association with Particulates (Light Microscopy 1,000 X) ............................... 3-14
    3-6       Comparison of the Temporal Distribution of Total Viable Bacterial in
               Water and Sediment Among Upper Bay Samples ............................................................. 3-18
    3-7       Comparison of the Temporal Distribution of Fecal Indicator Organisms in the
               Bottom Water Among Upper Bay Samples ...................................................................... 3-19
    3-8       Comparison of the Temporal Distribution of Fecal Indicator Organisms in the
               Sediment Among Upper Bay Stations ................................................................................ 3-20
    3-9       Comparison of Waterborne Indicator Organisms in Relation to the Temporal
               Distribution of Total Viable Bacteria Among Upper Bay Stations ................................3-21
    3-10      Comparison of Sediment-Bound Indicator Organisms in Relation to the Temporal
               Distribution of Total Viable Bacteria in Upper Bay Sediments ........................................ 3-23
    3-11      Comparative Recovery of Bacteria Associated with the Suspended
               Sediment at Stations 1A and 11A ...................................................................................... 3-27
    3-12      Effect of PCB 1254 on the Dissimilation of [U-14C] Glucose by a
               Heterogenous Marine Population ............................................................... 3-34
    3-13      Oxidation of PCB 1254 by an Estuarine Pseudomonas spp ............................................. 3-36
    3-14      Effect of PCB 1254 on Glucose Oxidation by an Estuarine Pseudomonas spp .............. 3-37
    3A-1      Survival of Total Viable Bacteria (TVC) and E. coli in Aquarium Water
               Under PCB-Stress and Unstressed Conditions. ( * E. coli - PCB Stress,
               A E. coli - No Stress, � TVC - PCB Stress, o TVC - No Stress; Oysters
               Were Removed from the Aquaria at Day 12.) .................................................................... 3A-6
    3A-2      Accumulation and Excretion of E. coli by Oysters Following PCB Stressed and
               Unstressed Conditions.  A, E. coli Tissue Accumulation with PCB-Stress;
               A E. coli Tissue Accumulation with No Stress; 0 E. coli Excretion with PCB-Stress;
               o E. coli Excretion with No Stress.) ..................................................................................... 3A-7
    3A-3      Survival of Total Viable Bacteria (TVC) and Salmonella Typhimurium in Aquarium
               Water Under Stressed and Unstressed Conditions. ( * Salmonella with PCB Stress;
               A Salmonella with No Stress; * TVC, with PCB Stress; o TVC
               With No Stress; Oysters Removed at Day 12.) ..................................3A-9
    3A-4      Accumulation of Total Viable Bacteria (TVC) and Salmonella Typhimurium by the
               Oyster, Crassostrea Virginica Following PCB Stress (a TVC with PCB Stress;
               o TVC with No Stress; * Salmonella with PCB Stress;
               A Salmonella with No Stress.) ..........................................................  3A-10
    3B-1      Chesapeake Bay Stations Sampled in the Study of March-June, 1975 .......................3B-3
    3B-2      Procedure for Enumeration and Identification of Salmonella Employing
               Non-Selective Enrichment .........................3B-4

                                                 LIST OF TABLES

    Table                                                                                       Page

    3-1       Identification of Organisms Isolated in the Coliform MPN Determination Procedures .... 3-3
    3-2       Identification of Organisms Isolated from Fecal Streptococcus MPN Determinations ..... 3-5
    3-3       Enumeration of Vibrio Parahaemolyticus ................................................................... 3-6
    3-4       Detection of Salmonella Species .........................................3........................................ 3-10
    3-5       Detection of Clostridium Botulinum ......................................................................3-11
    3-6       Distribution of Micronutrients at Five Upper Bay Stations ................................  3-15
    3-7       FC/FS Ratios Calculated from Samples Collected at the Upper Bay
               Sampling Stations .......................................................................................................  3-25
    3-8       Association of Bacteria with Particulates .......................................................................... 3-26
    3-9       Comparative Bacteriology of Oysters and Bottom Water Collected at
               Tolly Bar, Station 11A ..................................................................... 3-31
    3-10      Concentration of PCB-Metabolizing Bacteria in Selected
               Esturary and Marine Samples .............................................................. 3-32
    3-11      Isolation of PCB-Metabolizing Bacteria from Upper Bay Stations ................................  3-33
    3-12      Concentration of Humic Acid in Upper Chesapeake Bay .....................................  3-38
    3A-1      Experimental Outline for Assay of Enteric Bacteria Accumulated by
               the Oyster, Crassostrea Virginica, Following Acute PCB Stress ............................. 3A-5
    3A-2      Excretion of Total Viable Bacteria (TVC) from Oysters Following
               PCB-Stress and E. coli Dosing ............................................................................................ 3A-5
    3A-3      Accumulation of Salmonella Typhimurium in Oyster Tissue
               Following PCB Stress ................................................................................................... 3A-11
    3A-4      Accumulation of Total Viable Bacteria (TVC) in Oyster Tissue Following PCB
               Stress and Salmonella Dosing ........................................            3A-11
    3B-1      Recovery of Salmonella from Chesapeake Bay Samples Employing
               Non-Selective and Selective Enrichment ...........................................................................3B-7
    3B-2      Physical, Chemical, and Microbiological Characteristics of Chesapeake Bay
               Samples from Which Recovery of Confirmed Salmonella was Obtained ........................3B-8
    3B-3      Recovery of Salmonella Enteritidis From Samples of Water and Sediment
               Collected at Jones Falls Station by the Non-Selective Enrichment Procedure ...............3B-9
    3B-4      Comparative Recovery of Salmonella and Related Enteric Bacteria
                Using the Non-Selective Enrichment Procedures ........................................ 3B-11
    3B-5      Comparison of Biochemical Characteristics of Salmonella Enteritidis Isolated from
               Estuarine Samples with Those of Clinical Isolates ...............................3B-12

    3. MICROBIOLOGY

      3.1 Introduction
           The research work covered in this report was undertaken to assess the microbiology of suspend-
    ed particulates, bottom sediment, and water and to examine correlations of chlorinated hydrocarbon
    (CHC) contamination of the upper Chesapeake Bay with the microbiological data. Primary emphasis was
    placed on assessing co-transportation of bacterial indicator organisms and potential pathogens with the
    chlorinated hydrocarbons via suspended sediment in the upper Chesapeake Bay. The research plan in-
    cluded four paths of inquiry, each dealing with a separate, important and not unrelated, aspect of pollu-
    tion of the upper bay. The four principal tasks were:

           (1)  To determine the association of indicator organisms with suspended particulate matter in
                the water column and the potential transport of such organisms throughout the
                Chesapeake Bay.
           (2)  To assess the deposition of pathogens and indicator organisms in upper Chesapeake Bay
                sediment, and to determine the potential release or re-introduction of bacteria from the
                sediment to the water.
           (3)  To relate shellfish levels of accumulated bacteria to standard or generally accepted indices
                of bacterial contamination (i.e., indicator organisms and pathogens).
           (4)  To assess the association of bacterial populations with chlorinated hydrocarbons in the up-
                per Chesapeake Bay.

           The research work, thus, was designed to provide useful information dealing with these tasks in
    the contractually limited time allowed for the data accumulation and analysis.

                                                    3-1

      3.2 Media and Methods

           3.2.1 Total Viable Counts
                  The total plate count agar medium used was a marine salt water-yeast extract (MSWYE)
    medium prepared with dilute three-salts solution(6.66%/oo)and used routinely in the University of
    Maryland laboratory for culturing estuarine bacteria. Ingredients (per liter) for the Upper Bay Extract
    (UBYE) agar were:

                              NaCI                                  5.0   gm
                              KCI                                   0.16  gm
                              MgSO4 * 7H20                          1.5   gm
                              Difco Bacto-yeast Extract             1.0   gm
                              Difco Proteose Peptone                1.0   gm

    The pH was adjusted to 7.2; 20 gm agar was added, and the extract was sterilized by heating to 1 21 �C at
    15 psi for 15 min.
                   Appropriate dilutions of water, sediment, and suspended sediment samples were spread
    on UBYE agar and incubated at 15�C for four weeks. Counts were made at one, two, three, and four
    weeks.
                   Preparation of dilutions- Serial dilutions of samples for TVC's were made in sterile Up-
    per Bay (UB) salts (i.e., the salt solution used in preparing UBYE agar). Initial one-tenth dilutions of sedi-
    ment were prepared by adding portions of sediment to a sterile polyethylene bottle containing 90 ml of
    UB salts and calibrated to a volume of 100 ml. Sediment TVC's were expressed in units of TVC/ml.
    Dilutions of sediment for determination of total coliform and fecal streptococcus MPN's* were prepared
    by diluting the one-tenth UB salts dilution one tenth in sterile 0.5 percent Difco Proteose Peptone.
    Suspended sediment samples were diluted directly into Difco Proteose Peptone solution for the same
    purpose.

           3.2.2 Most Probable Number of Selected Indicator Organisms
                   Total coliforms - Bacto-Lactose Broth (Difco)** and other media appropriate for es-
    timating presence of coliforms were prepared and used according to American Public Health Association
    (APHA) regulations. Five tube replicates of a minimum of three serial ten-fold dilutionswere used. Tubes
    showing growth and gas formation after 48 hours at 350C were used to inoculate tubes of Bacto-Brilliant
    Green Lactose Bile (BGLB) Broth (Difco). The presence of growth and gas formation in the latter medium
    constituted a confirmed total coliform test. Total coliform MPN values reported and listed in the data bank
    are confirmed values.
                   Fecal coliforms - Tubes of Bacto-EC Broth (Difco) were inoculated from positive lactose
    broth tubes and placed in a 44.50C constanttemperature water bath (with <0.50Ctemperature variation)
    within one-half hour of inoculation after incubation for 24 hours, tubes showing growth and gas forma-
    tion were recorded. IMViC*** tests were run on all cultures, that is, on both gas-producing and non-gas-
    producing cultures and cultures from lactose and BGLB broths after transfer to and isolation from Eosin
    Methylene Blue (EMB) agar (Table 3-1).

    *    Most Probable Number.
    ** Difco Laboratories, Detroit, Michigan.
    ***  Gram negative asporogenous rods fermenting lactose; indole (+), methyl red (+), acetion (-), and
         citrate (-), typically of human fecal origin.

                                                     3-2

              TABLE 3-1. IDENTIFICATION OF ORGANISMS ISOLATED IN THE COLIFORM MPN
                                          DETERMINATION PROCEDURES

          Growth Response*                                Total No.             No. E. Coil            Percent E. Coli
    Lactose            BGLB               EC              Cultures**            Type I***                   Type I

        +                  -                -                 24                      4                       16.7

       +                  +                -                 17****                  1                        5.9

       +                  +                +                 81                     64                       79.0

        +                  +                (+)                 2                     1                       50.0

     *A positive response is growth and gas production. (+) indicates growth without gas production. Lactose =
       lactose broth, BGLB = brilliant green lactose bile broth, and EC = EC broth.

    ** Isolated from colonies appearing on EMB agar which had been streaked onto the EMB agar from positive
       MPN tubes.

     *** Gram negative asporogenous rods fermenting lactose; indole (+), methyl red (-), and citrate (-), typically
       of human fecal origin (IMViC).

     ** Intermediate chemotypes (-+-+).

                                                        3-3

                   Fecal Streptococcus MPN - Presumptive MPN's were obtained following APHA
    regulations by inoculation of BioQuest* Azide Dextrose (AD) Broth. Three 5-ml tube replicates of a
    minimum of three serial ten-fold dilutions were used. Inoculum volumes were multiples of five
    milliliters. Sample volumes greater than five milliliters were filtered through 47-mm sterile 0.45 micron
    Millipore filters which were rolled up and placed in single strength broth. Tubes showing growth after 48
    hours at 350C were inoculated into 10 ml of Ethyl Violet Azide (EV) Broth with a special triple loop. After
    incubation at 350C for 48 hours, tubes of EV broth showing turbidity and a button of purple sediment
    were recorded as positive for the presence of confirmed fecal streptococcus. Fecal streptococcus MPN
    values reported and listed in the data bank are confirmed values. Subsequent testing of isolates from EV
    broth indicated that the majority of these organisms should be more appropriately labelled Enterococci,
    i.e., of probable human origin. (Table 3-2).
                   For further testing, aliquots taken from positive EV broth cultures were streaked on M-
    Enterococcus Agar (BioQuest). Small pink to red colonies appearing after incubation at 350C were sub-
    cultured in Brain Heart Infusion Broth (Difco) and tested further after purification. Each isolate was
    tested for a Gram reaction, morphology, catalase, hippurate hydrolysis, starch hydrolysis, and growth at
    pH 9.6 and in 6.5 percent NaCI. The following scheme was used for the presumptive separation of
    enterococci from fecal streptococci of animal origin:

                                                                  Growth at      Growth at
                                     Hippurate      Starch        pH 9.6         6.5% NaCI

           Enterococci of
              human origin                -                            +               +

           Other fecal
             streptococci                +             +

    Hippurate tests were performed according to the method of Facklam, et al. (1974). Starch hydrolysis was
    tested using 0.2 percent soluble starch incorporated in a Nutrient Agar (Difco) overlay, which was flood-
    ed with Gram's Iodine Solution after visible growth of the cultures. Growth at pH 9.6 and 6.5 percent
    NaCI was tested using nutrient broth as a base. The broth was buffered with 0O.05M Na2CO3 for the former
    test.

           3.2.3 Isolation of Pathogenic Bacteria
                   Vibrio parahaemolyticus -Three methodsfor enumeration of V. parahaemolyticus were
    employed. One method was a direct plate procedure involving placing filters on TCBS Agar after filtration
    of known volumes of the sample and incubating the plates at 250C. Dark green colonies were recorded as
    V. parahaemo/yticus-like organisms (VPLO). The other methods involved an MPN procedure, using a
    three-tube and three-dilution series of Salt Colistin Broth or Salt Water Yeast Extract (SWYE) broth
    enrichments. Following incubation of the tubes at 250C for 24 to 48 hours, the tubes showing growth
    were streaked onto TCBS Agar to test for the presence of VPLO (Table 3-3). The latter two methods were
    discontinued because of the difficulty encountered in obtaining the Salt Colistin Broth medium from
    commercial sources and the insufficient selectivity of the SWYE broth. Glucose-Salt-Teepol broth
    enrichment has been recommended by the Food and Drug Administration (FDA) and should be used in
    future experiments.
                   VPLO cultures were purified and a battery of tests, suggested by Sakazaki and cited by
    Kaneko (T. Kaneko, Ph. D. Thesis, 1973, p. 89), for the presumptive identification of V. parahaemolyticus
    were used. These included Gram stain (-), growth in Peptone Water containing 3 percent NaCI (+),
    cytochrome oxidase (+), fermentation of glucose (TSI and MOF +), gas from glucose (TSI and MOF -),
    acid from sucrose (TSI -), and from lactose (TSI -), Acetoin (-), H2S production (TSI -), and growth at
    430C in SWYE (+).

    *BioQuest Laboratories, Division of Becton-Dickenson, Cockeysville, Maryland.

                                                     3-4

                TABLE 3-2. IDENTIFICATION OF ORGANISMS ISOLATED FROM FECAL STREPTOCOCCUS MPN DETERMINATIONS

                                                                                                      Percent'*
                                                                               Growth
                                      Total No.             Catalase               6.5%                Growth                Starch                    Hippurate
         Source*                        Cultures                (+)                  NaCI                 pH 9.6                Hydrolysis               Hydrolysis

     I.  Direct plating on M
         Enterococcus agar                  14                 7.14                    92.85             78.57                     n.d.***                   7.14

    II.  Ethyl violet azide broth           22                31.82                    77.27              86.36                    n.d.                     13.64

    I II.  Ethyl violet azide broth
         to M Enterococcus agar            123                10.60                    86.90             83.50                   0.02                        0.01

        * Two methods for the isolation of fecal Streptococci were used: direct plating on M Enterococcus agar (I) or the azide dextrose - ethyl violet azide broth
         MPN sequence (II and III). The later two procedures differed in the way cultures were isolated from ethyl violet (+) tubes. In II, cultures were isolated
         by streaking onto a non-selective agar medium, whereas, in Ill, M Enterococcus agar was inoculated by streak plate procedure.

     ** Fecal Streptococci of human origin (enterococci) typically grow in 6.5% NaC1 and pH 9.6 broths, but do not hydrolyze starch or hippuric acid.

    *** Not determined.

                        TABLE 3-3. ENUMERATION OF VIBRIO PARAHAEMOLYTICUS

                                                               Total No. VLPO          No. Positive
    Date            Station              Sample                   Cultures*          V. Parahaemolyticus**

    12/73***         11A            Water                             7                      0
                     11A            Bottom sediment                  3                       1
                     11A           Suspended sediment                5                       0

                     10B           Water                             7                       0
                     10B            Bottom sediment                   1                      0

                      5A           Water                             7                       1
                      5A            Bottom sediment                  6                       1

                      1A           Water                             0                       0
                      1A            Bottom sediment                  2                       0
                      1A           Suspended sediment                5                       1

    3/74t            11A            Water                             5                       1
                     11A            Bottom sediment                  3                       0
                     11A           Suspended sediment                0                       0

                     10B            Water                            5                       0
                     10B            Bottom sediment                   1                      0

                      5A           Water                             0                       0
                      5A            Bottom sediment                  0                       0

                      1A           Water                             0                       0
                      1A           Bottom sediment                   0                       0
                      1A           Suspended sediment                0                       0

    6/74tt           11A            Water                            10                      0
                     11A            Bottom sediment                  0                       0
                     11A           Suspended sediment                0                       0

                     10B           Water                             2                       0
                     10B            Bottom sediment                  0                       0

                      5B           Water                             1                       0
                      5B            Bottom sediment                  0                       0

                      1A           Water                             0                      0
                      1A           Bottom sediment                   0                      0
                      1A           Suspended sediment                0                      0

    7/74ttt          11A            Water                             0                      0
                     11A            Bottom sediment                  0                       0
                     11A           Suspended sediment                0                       0

                     10B           Water                             0                       0
                     10B            Bottom sediment                  0                       0

                                                       3-6

                  TABLE 3-3. ENUMERATION OF VIBRIO PARAHAEMOLYTICUS (Continued)

                                                               Total No. VPLO          No. Positive
    Date            Station               Sample                  Cultures*          V. Parahaemolyticus***

    7/74              5A            Water                             0                       0
                      5A            Bottom sediment                  0                       0

                      1A           Water                             0                       0
                      1A           Bottom sediment                   0                       0
                      1A           Suspended sediment                0                       0

    9/74             11A            Water                             5                       3
                     11A            Bottom sediment                   6                      2
                     11A           Suspended sediment                0                       0

                     10B           Water                              7                      2
                     10B            Bottom sediment                  3                       1

                      5A            Water                             1                      0
                      5A            Bottom sediment                  0                       0

                      1A           Water                             0                       0
                      1A           Bottom sediment                   2                       0
                      1A           Suspended sediment                0                       0

                    Conowingo       Water                             0                      0

    10/74ttt         11A            Water                             2                      0
                     11A            Bottom sediment                  5                       0
                     11A           Suspended sediment                0                       0

                     10B           Water                             4                       0
                     10B            Bottom sediment                  0                       0

                      5A            Water                             1                      0
                      5A            Bottom sediment                   1                      0

                    Conowingo       Water                             0                      0

    11/74ttt         11A            Water                             1                      0
                     11A            Bottom sediment                  2                       0
                     11A           Suspended sediment                0                       O

                     10B           Water                             0                       0
                     10B            Bottom sediment                  0                       0

                      5A           Water                             0                       0
                      5A            Bottom sediment                  0                       0

                   Conowingo       Water                             0                      0

    12/74ttt         11A            Water                             1                      0
                     11A            Bottom sediment                  3                       0
                     11A           Suspended sediment                0                       0

                                                       3-7

                  TABLE 3-3.  ENUMERATION  OF  VIBRIO PARAHAEMOLYTICUS  (Continued)

                                                                Total No. VPLO            No. Positive
    Date             Station                Sample                     Cultures*           V. Parahaemolyticus**

    12/74ttt          10B              Water                               0                        0
                     10B             Bottom sediment                     1                        0

                      5A             Water                               0                        0
                      5A             Bottom sediment                     0                        0

                       1A            Water                                0                        0
                       1A             Bottom sediment                     0                        0
                       1A            Suspended sediment                   0                        0

      * Vibrio parahaemolyticus - like organisms (VPLO) are dark green colonies on TCBS agar.

     ** VPLOcolonies were cultured and tested to confirm their identification.

    *** Salt colistin MPN enrichment procedure used. Positive tubes streaked on TCBS agar after three to
         four days at 250C.

      t Salt colistin MPN enrichment procedure used. Positive tubes streaked on TCBS agar after 24 hours
         at 250C.

     tt  Salt  water-yeast   extract broth (SWYE) MPN  enrichment procedure used. Positive tubes streaked
          on TCBS after 24 hours at 250C.

    ttt Samples plated directly on TCBS agar and incubated at 35�C.

                                                         3-8

                   Salmonella - Various enrichment procedures were used for isolation of Salmonella spp.
    (Table 3-4). Selenite, selenite cystine, and tetrathionate broths were inoculated and incubated for 24 to
    48 hours at 350C or 41.50C. Loopfuls of the enrichment were streaked on several selective differential
    agar media: eosin methylene blue, Salmonella-Shigella, brilliant green, and bismuth suflite. Later efforts
    to improve recovery of Salmonella spp. from Chesapeake Bay water samples included the use of a
    medium with MacConkey Agar as the base and containing 0.03 g/l novobiocin and 0.165 g/I Na2SeO3 to
    inhibit interfering gram negative bacteria. Acontinuous-flow, hollowfiber ultrafiltration system (Amicon
    Model DC 30; Amicon Corp., Lexington, Massachusetts) also was employed to concentrate large
    volumes of bay water to improve recovery and isolation of selected potentially pathogenic organisms
    from the estuarine environment.
                   Presumptive cultures were purified, examined for Gram stain and oxidase reactions, and
    inoculated sequentially into triple sugar iron agar, urea agar, and lysine iron agar. The remaining
    presumptive Salmonella cultures were subjected to further biochemical testing, following the APHA
    diagnostic procedure and were tested for H antigens using standard serological procedures. After one
    passage through a semi-solid growth medium, tube agglutination tests were run, using seven-group
    specific flagellar antisera (BioQuest).
                   Clostridium botulinum-The presence of Cl. botu/inum wasdetermined by indirect means
    by the detection of specific neurotoxin. Cooked meat medium (Difco)was prepared according to the label
    instructions, and a carpet tack was added before autoclaving (L. Smith, VPI Anaerobic Laboratory, per-
    sonal communication). Approximately one gram of freshlycollected sedimentwas added to the medium,
    which had been prepared in screw-cap tubes. A layer of mineral oil was added after inoculation, and the
    culture was incubated at room temperature for five to seven days, at which time the culture, or the cell-
    free culture supernatant solution obtained by centrifugation, wasfrozen at--70�Cfor a minimum of one
    day. To the supernatant solution was added one percent [(W/V)] 1:300 trypsin (BioQuest) to give a final
    concentration of 0.1 percent trypsin, and the mixture was incubated at 370C for 45 minutes. For each
    sample, two white mice were inoculated with 0.4 ml of trypsinized supernatant. One of the pair of mice
    was protected by injection with C. botulinum polyvalent antitoxin (Communicable Disease Center, Atlan-
    ta, Georgia), i.e., by incubating a mixture of 0.4 ml supernatant and 0.1 ml antitoxin in a syringe for 30
    minutes prior to inoculation. Death of the unprotected mouse within 72 hours was a presumptive
    positive indication of the presence of Cl. botulinum. A fresh aliquot of the supernatant was trypsinized,
    and mice were tested with and without protection, using a series of serotype specific antitoxins. When
    polyvalent serum failed to protect the mice, it was presumed that either the toxin titer exceeded that of
    the serum or a non-botulinum toxin was present. Consequently, some sampleswere diluted with sterile
    gel-phosphate (pH 6.5) buffer, and mice were inoculated with 37.5 units of bovine tetanus antitoxin prior
    to inoculation with the supernatant (Table 3-5).

           3.2.4 Suspended Sediment Analyses
                   Collection of suspended sediment - Suspended sediments were harvested from fresh,
    aseptically collected water samples using two methods. In the first procedure, water was filtered through
    an eight-micron Millipore filter until clogging occurred. The filters were shaken with sterile UB salts
    solution* in a wide-mouth, sterile screw-cap jarto dislodge the non-filterable material.This method was
    abandoned after the first cruise as being cumbersome and inefficient. Suspended sediments were ob-
    tained thereafter by centrifugation. Water was placed in sterile screw-cap centrifuge tubes and cen-
    trifuged at a relative centrifugal force of 2100 g for 1 5 minutes. The supernatant solution as aspirated off,
    and the brown flocculent pellets were resuspended in sterile UB salts solution. Total viable counts of
    both water and pellet suspension were determined to estimate the proportion of the total viable popula-
    tion in the pellet.
                   Suspended sediment experiments - To study the association of indicator bacteria with
    suspended sediment, a sterile in vitro system was used. One-liter samples of water were placed in sterile
    graduated cylinders, and suspended sediments were allowed to settle for one hour. Two-hundred
    milliliter samples were aspirated through sterile tubing to sterile vacuum flasks. Total viable count, fecal
    coliform, and fecal streptococci MPN's were determined in each fraction to construct a distribution of
    these bacteria with the particulate fractions.
    * UB salts = NaCI, 5 g; KCL, 0.16 g; MgSO4-7H20, 1.59; H20, 1000 g.
                                                     3-9

                             TABLE 3-4. DETECTION OF SALMONELLA SPECIES*

                                                   Isolation      Salmonella         Salmonella    Fecal coliform
    Date       Station          Sample               Method**      Presumptive***       Positive         MPNt

    12/73        11A      Water                         1                3                 0                7.8
                11A       Bottom sediment               1               1                 0                 1.8
                11A       Suspended sediment            1               2                 0               20.8

                10B       Water                         1               4                 0                2.8
                10B       Bottom sediment               1               1                 0                1.8

                 1A      Water                         1                6                 0             1600.0
                 1A       Bottom sediment              1               11                 0               14.0
                 1A      Suspended sediment            1               13                 itt          9200.0

    3/74         11A       Water                        2                1                 itt              1.8
                11A       Bottom sediment              2                2                 0                2.0

                 1A      Water                         2                1                 0               78.0

    10/74       11A        Dialysis concentrate         4                4                 2tt            680.0

    11/74        5A       Water                         4                1                 0                2.0
                 5A       Bottom sediment              4                2                 0                1.8

    12/74         1A      Water                         4                1                 0               33.0

      *  Only Salmonella presumptive stations reported, other stations yielded samples negative for presumptive
         test results.

         Method 1.   Selenite enrichment streaked to EMB, deoxycholate, SS, and BG agars (350C).
                  2.   Selenite cystine or tetrathionate enrichment streaked to BG or Bismuth Sulfite agars
                       (350C).
                  3.   Tetrathionate (41.50C) enrichment streaked to BG or Bismuth Sulfite (41.50C).
                  4.   Selenite cystine (420C) enrichment streaked to MacConkey-Selenite agar (420C).

         Cytochrome oxidase (-), urease (-) cultures showing red slant (alkaline) and yellow butt (acid) on
         TSI agar.

      t Water, MPN/100 ml; sediment, MPN/ml; suspended sediment, MPN/100 ml.

     tt Biochemically positive Salmonella, but not agglutinated by polyvalent O or H Salmonella antisera.

                                                         3-10

                   TABLE 3-5. DETECTION OF CLOSTRIDIUM BOTULINUM

                                                             Test For
    Date          Station           Sample             Cl. Botulinum Toxin            Type

    3/74           11A             Sediment                    -
                    10OB           Sediment
                     5A            Sediment
                     1A            Sediment                    +                      E

    5/74           11A             Sediment                    -
                    10B            Sediment
                     5A            Sediment
                     lA            Sediment

    6/74           11A             Sediment                    +                      n.d.
                    10B            Sediment
                     5A            Sediment
                     1A            Sediment                    +                      B
                     **            Menhaden                    +                      n.d.***

    7/74           11A             Sediment                    -
                    10B            Sediment                     -
                     5A            Sediment                     -
                     1 A           Sediment                    -

    9/74           11A             Sediment                    -
                    10OB           Sediment                     -
                     5A            Sediment                     -
                     1 A           Sediment                    -

    10/74          11A             Sediment                    -
                    1 1A           Oysters
                    10OB           Sediment
                     5A            Sediment

    11/74          11A             Sediment                    -
                    11A            Oysters
                    10A            Sediment
                     5A            Sediment

    12/74          11A             Sediment                    -
                   10B            Sediment
                     5A            Sediment
                     1A            Sediment

        *  Type not determined. Mixture of B and E or other toxins present. Tetanus toxin also present.

     **  Dead fish specimen  collected from area of fish kill in the vicinity of the Bay Bridge.
         Hemorrhage above eyes observed.

         Type not determined. Tetanus toxin present.

                                                 3-11

                   Microscopy of suspended sediment - Direct microscopic evidence for the association of
    bacteria with suspended sediments was obtained by observing particles of detritus on membrane filters.
    The procedure for fixing and staining the specimens was essentially that of Jannasch and Pritchard
    (1972). Formalin was added to the suspended sediment sample to give a final concentration of 1.6 per-
    cent. Several dilutions of the sample were prepared to give optimal densities on the filters. The samples
    were filtered through 0.45-micron Millipore filters, and the filters were stained with Loeffler's
    methylene blue. An evenness in the staining was obtained by placing the filters on stain-soaked filter
    papers. The membrane filters were decolorized to provide contrast between cells and background by
    soaking the filters in several changes of distilled water. The filters were dried and placed on microscope
    slides. A drop of immersion oil was added on top of thefilter and below, rendering the filter transparentto
    light. The specimens were observed by either bright-field or phase-contrast microscopy (Figures 3-1
    through 3-5).

           3.2.5 Humic Acid Determination
                   Humic substances are known to sequester heavy metals, pesticides, and other organic
    compounds. For this reason it was decided that the Upper Bay Survey samples should be surveyed for
    humic content to delineate a possible role of humic acid in transport of pesticides, nutrients, and
    possibly, bacteria. Humic acids were isolated and assayed according to the methods of Hair and Basset
    (1973) and Zitko et al. (1973). Dissolved, particulate, and sediment humic acid concentrations were
    measured spectrophotometrically, after extraction and purification. A curve was constructed showing
    optical density at 250 nm* plotted against concentration of freshly prepared humic acid standard in 0.5 N
    NaOH. Humic acid standard was isolated from farm soil following the method described by Hair and
    Basset (1973).

           3.2.6 Nutrient Analyses
                   Samples of water, freshly collected using Niskin sterile bag samplers, were filtered
    through Whatman GF/c filters into a vacuum flask. The flask was rinsed with the initial 50 ml of filtrate,
    which was then discarded prior to filtration of the remaining sample. Approximately 250 ml of filtrate
    was transferred to 300 ml 6 N HCI-washed bottles fitted with polyethylene-lined caps. These samples
    were frozen aboard ship and later stored in the laboratory at -700C. Analyses were performed at the
    Chesapeake Bay Institute of The Johns Hopkins University, essentially according to the methods describ-
    ed by Strickland and Parsons (1972). (See Table 3-6).
                   Total dissolved phosphorus and nitrogen were obtained from samples treated by irradia-
    tion with ultraviolet light.

            3.2.7  PCB-Metabolizing Bacteria
                   Isolation of polychlorinated biphenyl-resistant bacteria was accomplished as the
    research progressed. Several species of bacteria have been shown by otherworkers to be resistant to, or
    unaffected by, high concentrations of polychlorinated biphenyls (PCB's) and DDT (Greer and Keil, 1974).
    In addition, an Achromobacter sp. has been shown to metabolize actively several PCB's of various
    chlorine content (Ahmed and Focht, 1973). In the work reported here, bacteria resistant to high concen-
    trations of PCB, or capable of metabolizing PCB, were isolated from various samples using a combined
    enrichment and plating procedure. The polychlorinated biphenyl, Aroclor�0 1254 (Monsanto Co., St.
    Louis, Missouri) was dissolved in acetone and coated on a support of Celite�(J. T. Baker Chemical Co.,
    Philipsburg, New Jersey). Appropriate quantities of coated celite were added to a basal salts broth and
    autoclaved. Dilutions of sediment and water were added to the primary enrichment broth and incubated
    at 250C for twoweeks. Samples of each enrichment broth were then plated on a solid medium containing
    500 mg/1 PCB 1254 as the sole carbon source. Additional water samples were plated directly on PCB
    1 254 agar plates in an effort to determine the quantitative levels of PCB 1 254-metabolizing bacteria pre-
    sent at each of the Chesapeake Bay stations routinely sampled in this study.

    * nm is nanometers or 10-9 meters

                                                    3-12

                                                                             75151A136

    Figure 3-1. Bacterial Association with Particulates (Light Microscopy 1,000 X)

                                                                             75151A137

    Figure 3-2. Bacterial Association with Particulates (Light Microscopy 1,000 X)

                                          3-13

                                                               75t5-tAf38

    Figure 3-3. Bacterial Association with Particulates (Light Microscopy 1,000 X)

                                                              75151A139

    Figure 3-4. Bacterial Association with Particulates (Light Microscopy 1,000 X)

                                                               75151A140

    Figure 3-5. Bacterial Association with Particulates (Light Microscopy 1,000 X)

                                          3-14

        TABLE 3-6. DISTRIBUTION OF MICRONUTRIENTS AT FIVE UPPER BAY STATIONS

                                                                          MiMoles
    Station          Nutrient
                                              July       Sept        Oct         Nov         Dec         Mean

    Conowing         P-PO3                       -           0.7         0.5         0.9                     0.7
                        -1   -2
                     NO +NO                      -         40.0        50.0        50.0                    47.0
                        2    3

    1A               P-PO3                       0.1         0.5         -           -                       0.3
                          4
                        -1   -2
                     NO +NO
                        2    3

    5A               P-PO-3                      0.4         0.7         0.5         0.5         0.2         0.5
                          4
                        -1   -2
                     NO +NO                    45.0        35.0        25.0        40.0        25.0        34.0
                        2    3
    10B              P-PO-3                      0.1         1.7         1.1         0.8         0.6         0.9
                          4
                        -1   -2
                     NO +NO                    < 5.0       25.0        < 5.0       10.0         5.0        10.0
                        2 3
                          -3
    11A              P-PO4                       0.2         0.5         0.3         0.7         0.3         0.4

                        -1   -2
                     NO +NO                    15.0        15.0        25.0        20.0        85.0        32.0
                        2    3

                                                         3-15

                   The PCB 1254 agar plates were incubated at 15�C for two weeks. Individual bacterial
    colonies were isolated and tentatively classified to generic level. Pure cultures of PCB-resistant or
    metabolizing bacteria were then employed in respiration studies to determine the effect of various con-
    centrations of PCB 1 254 on respiratory metabolism.
                   Respiration studies of PCB resistant bacteria - Effects of PCB on respiration were deter-
    mined using a Gilson respirometer, Model GRP 20 (Gilson Medical Electronics, Middleton, Wisconsin).
    Bacteria used in the respiration studies were adapted to PCB 1 254 by incubating cultures in logarithmic
    phase of growth in a basal broth containing 1.0 g/l PCB 1254. Transfers of the PCB adapted cultures
    were made in fresh media containing no PCB 1254, incubated for appropriate time intervals, centrifuged,
    washed with sterile phosphate buffered saline, and added to sterile respirometer flasks containing
    various concentrations of sterile PCB 1 254 coated on celite. Oxygen consumption was monitored for
    several hours and was compared with rates of oxygen consumption of control bacterial cultures in-
    cubated with untreated diatomaceous earth.
                   A [U-'4C] glucose decomposition assay (Kadota, 1972) was employed to examine the
    effect of PCB 1254 on a mixed marine bacterial population. Twenty gram sediment samples were placed
    in duplicate glass dark bottles to which an additional 100 ml of artificial sea salts were added. Another
    pair of dark bottles received 100 ml of surface water. Each sediment and water sample received 2.5 ,Ci*
    of [U-14C] glucose (100 mg/I glucose). One of each pair of sediment and water samples was
    supplemented with 1.56 mg PCB 1254 on Celite (15.6 mg/1 PCB 1254). The dark bottles were stoppered,
    and a flow of air carried '4CO2, (from the decomposition of [U--4C] glucose) to liquid scintillation vials in
    which 14CO2 was trapped in 7.5 ml of scintillation cocktail containing: 27 ml phenylethylamine, 27 ml ab-
    solute ethanol, 0.51 g Omnifluor (New England Nuclear, Boston, Massachusetts), and 100 ml toluene.
    The samples were flushed for an initial hour and then were allowed to incubate undisturbed for 24 hours
    at 20 to 250C. At 24 hours the samples were again flushed with air for one hour, and the 14C02 was
    trapped in the scintillation cocktail. An additional 7.5 ml of a scintillation fluid containing 5.1 g Omnifluor
    in 1,000 ml toluene were added to the scintillation vials. The 14CO2 samples were stored for a period of
    five to seven days and were counted on an Intertechnique SL40 liquid scintillation counter (Teledyne
    Corp., Westwood, New Jersey). A comparison of the effects of PCB 1254 on glucose decomposition was
    then made using a multivariate analysis of variance.

            3.2.8 Bacteriological Analyses of Oysters
                   Benthic filter feeders can effectively concentrate and retain various pathogenic bacteria
    (Janssen, 1973) and viruses (Metcalf and Stiles, 1965). The oyster, Crassostrea virginica, in the
    Chesapeake Bay may concentrate and/or retain fecal indicator organisms or potential pathogens in the
    areas where fecal contamination poses a hazard, (viz., regions of the upper Chesapeake Bay). To deter-
    mine the extent of this problem, oysters were collected from Tolly Bar near Station 11 Aand were cleaned
    and shucked immediately upon sampling. Using procedures prescribed by APHA (American Public
    Health Association, 1970), homogenized oyster tissues were assayed for total and fecal coliforms, fecal
    streptococci, Salmonellae, VPLO, Clostridia and total viable, aerobic, heterotrophic bacterial count. All
    isolation procedures were as described (vide supra) in analyses of water, sediment, and suspended sedi-
    ment samples.

       3.3 Results and Discussion

            3.3.1  Total Viable Counts
                   Total viable bacterial counts (TVC) can be interpreted to reflect input of microorganisms
    from extra-aquatic sources. They may also be employed to described the trophic conditions of a given
     habitat, i.e., availability of growth-supporting organic matter and micronutrients. Fluctuations in TVC
     between sampling stations observed in this study may be a result of either or both conditions.

     * pCi is microcuries

                                                     3-16

                   As shown in Figures 3-6 through 3-9 and as can be seen from the data recorded in
    Volume III, there was a bimodal distribution in total viable counts for bottom water samples for all
    stations sampled. The highest TVC's were obtained during the winter and spring months. The lowest
    TVC's were recorded for the months of July, September, and October. Although not as marked as in the
    case of the bottom water, the TVC's of the sediments at Station 5A, 1 OB, and 11 A followed essentially the
    same distribution (Figure 3-8). TVC's of the sediment at Station 1A followed an anti-coincidental dis-
    tribution, when compared with the other samples (i.e., peak TVC's occurred during June, July, and
    September, with low TVC's occurring in Station 1 A sediment in the winter and early spring). The highest
    recorded counts over the year were obtained at Station 1 A, about 10 to 100 times greater than those at
    Stations 5A and 1 OB. In only three instances, in the case of the March water and sediment samples and
    May water samples, were counts obtained at Station 1 1 A higher than those at Station 1 A. A comparison
    of total viable counts for water samples collected at Station 1A and at Conowingo Dam (Figure 3-6) in-
    dicated a slight influx of organisms from the Susquehanna River at Station 1 A. Total viable counts at
    Conowingo Dam exceeded total viable counts at StationlA by 50 percent in September, while all other
    recorded values for Conowingo water were less than or equal to the values for Station 1A water.

           3.3.2 Most Probable Number Index of Indicator Organisms
                   MPN levels of total col iforms, fecal coliforms, and fecal  streptococci fluctuated seasonal -
    ly and with distance from Station 1A to 11 A (longitudinally) in samples of Chesapeake Bay water examin-
    ed in this study (See Figure 3-7). In general, MPN values decreased from winter to summer, with a
    gradual increase in the number of indicator organisms in the fall. The MPN trend for Station 11A,
    however, was characteristically higher in the summer months, June through September. In most cases,
    total coliform levels (representing both human and non-human sources of coliforms) were higher than
    fecal coliforms and fecal streptococci, as would have been expected. Fecal streptococci in bottom water
    closely paralleled fecal coliform trends except at Station 11 A where fecal streptococci rose dramatically
    during the summer months, whereas fecal coliforms were low. Highest MPN values were obtained for
    water samples from Station 1 A in all cases. The entry of total coliforms to the upper Chesapeake Bay via
    the Susquehanna River appears to be significant, judging from the high total coliform MPN values
    measured at Conowingo Dam. Fecal coliform and fecal streptococci levels at Conowingo Dam were
    relatively high, indicating superimposition of these fecal indicators at Station 1A. The sharp peaks in
    total coliforms and fecal coliforms in December 1974 at Station 5A most likely reflect a point source of
    pollution. (Unfortunately, the R/V RIDGELY WARFIELD sanitary holding tanks are automatically dis-
    charged when full, and this occurred just prior to arrival on station when Station 5Awas sampled. Thus,
    one can conclude that the peak MPN observed at Station 5A attests to the responsiveness of the MPN
    technique to sewage input.)
                   It is interesting to note that the December 1974 peak in fecal coliforms in the water at
    Station 5A was not observed for fecal coliforms in the sediment (See Figure 3-8). It is extremely unlikely
    that adsorption or deposition of coliform bacteria on sediments would occur within the time frame of dis-
    charge and sampling (approximately one hour).
                   An observable irregularity did occur in MPN values for water and sediment (See Figures
    3-7 and 3-8) at Station 1A. A substantial (100-fold) increase in total coliforms and fecal coliforms oc-
    curred in the sediments at Station 1A during the summer of 1974. Fecal streptococci levels held fairly
    steady in the summer months, although a 100-fold fluctuation occurred seasonly. It should be pointed
    out, however, that fecal streptococci levels in December 1973 and December 1 974 were not signif icantly
    different. It is clear from these data that extensive sampling is required for adequate measurement of the
    incidence and distribution of indicator organisms (i.e., their flux within a given aquatic habitat). In
    general, MPN values at all of the sampling stations were lower in sediments than in the water. Also, the
    sediment data indicated somewhat less of a seasonal fluctuation occurring. Fecal streptococci levels
    were frequently higher than total coliform levels in the sediment and were, in general, higher than fecal
    coliform levels in the sediment.

                                                    3-17

           [ Bottom Wate
            Sedlment                                                         Station l
           e   Conowingo wert

      7

       5                                                                           5
       2

       Fu   3                                                                        5o
    -7

                     SdJiN MeAR MAY JUN   JULY   SEP   OCT   NOV   DEC

                                               3-18
                                               3-18

               o  Total  Colforms
               o  hFol  Coliforms
        3     a  Fecol  Streptococci

        2                           0- 13

        o
        2� |   ^/  \a   _ao                   o .                      ~, A

                                                                                  la
       3

    .                                                                      5

    a.
                                                                                 Ia
      1O
                               0                                              El

                       e.D  13-0    .                  0,319

                                             319

               o  Total  Coliforms
               o Fecal Coliforms
          4  �a   Fecal  Streptococci                             Station  la

          3 .

             -o  o  o-o

       w
          4 40b

       W
       L(J

              0                o'0  vO-a   u-9'                     ano
       0
       o
          4                                                                 IOb
          4  -                                                              lob

        3

          2
          o   I                                  o'  A
          o ,-O-9-9--8__"--                                              ~o~

          4                                                                  Ila

          3- "'

                                     MONTHS

                                                               75151A143

    Figure 3-8. Comparison of the Temporal Distribution of Fecal Indicator Organisms in the
                         Sediment Among Upper Bay Stations

                                        3-20

                   n Toal Collforms
                   o Focal Colitforms
                   A Focal Streptococci                       Stotlon  C

                                                             la

              3   '
                                               [3

               2                                 0/A~�D

            0
                                                             50

              4

            Z                                                           lOb
            4I0 b
               40

            , 3

               4
               3.

                                               A

               0                                 .
                    DEC JAN MAR MAY JUN JULY SEP OCT NOV DEC
                                      MONTHS

                                                             75151A144

    Figure 3-9. Comparison of Waterborne Indicator Organisms in Relation to the Temporal
             Distribution of Total Viable Bacteria Among Upper Bay Stations

                                      3-21

                   Several genralizations can be drawn from the data shown in Figures 3-6 through 3-8.
    Higher coliform levels detected during the winter months may result from effects of decreased water
    temperature on the organisms, longer survival times of certain microbial groups, and possible increased
    nutrient flux from decomposition of summer productivity and watershed drainage. Fecal streptococci
    survival appears to be enhanced in the sediments at all stations where the fecal streptococci and fecal
    coliform populations maintained generally low populations.

           3.3.3 Efficiency of Identification of Indicator Organisms
                   Cultures of fecal coliforms and fecal streptococci were routinely characterized to test the
    accuracy of the enumeration methods used (Tables 3-1 and 3-2). Approximately 80 percent of the fecal
    coliforms were phenotypically Escherichia co/iType I, which is considered to be of human origin. Some
    stations produced more false positives than others, and these cultures proved to be a number of in-
    termediate coliform chemotypes as well as non-coliform organisms. Station 1 OB more commonly gave
    false positive coliforms MPN's. This finding underlines the need to characterize MPN's for each environ-
    ment beyond the presumptive level of accuracy. Fecal streptococci isolates were examined using a
    number of selected tests and the results indicated that more than 80 percent were enterococci. Although
    not exclusively of human fecal origin, the majority of these enterococci are considered to originate from
    the human intestinal tract.

           3.3.4 FC/FS Ratios
                   Ratios of fecal coliforms to fecal streptococci are a relative index, describing the propor-
    tion of these fecal indicator organismswithin a given population. Geldreich and Kenner (1969) have cited
    the ratio of fecal coliforms to fecal streptococci (FC:FS) as a characteristic for given types of pollution or
    sources. The ratio itself is not a quantitative indication of pollution but a qualitative pollution index.
    Domestic sewage yields FC:FS ratios greater than 4.0, whereas ratios less than 0.7 are interpreted as in-
    dicating warm blooded animals, other than man, as the source. Lear and Jaworski (1969) reported that
    their data collected for upper Potomac River estuary stations indicted FC:FS ratios in excess of 4.0. FC:FS
    ratios greater than 4.0 were observed at all of the sampling stations included in this study, except Station
    5A. Data for Station 1 A showed more (33 percent) FC:FS ratios greater than 4.0, compared with data for
    samples from Conowingo Dam, Station 1 OB, and Station 1 1 A each of which yielded one sample (less
    than 16 percent of the samples) greater than 4.0. It is notable that suspended sediment samples from
    Station 1 A on three occasions greatly exceeded the 4.0 ratio, whereas none of the suspended sediment
    samples from Station 1 1 A revealed FC:FS ratios greater than 4.0. Sediment samples at Stations 5A, 1 OB,
    and 11A all yielded FC:FS ratios indicating non-human sources of contamination at or near those
    stations. Since differential rates of survival exist among fecal coliforms and fecal streptococci in aged
    samples, lower FC:FS ratios may reflect either time and/or geographical distance factors relative to the
    pollution source.

           3.3.5 Occurrence of Indicator Organisms Relative to Total Viable Counts
                   In order to determine the contribution of indicator organism populations to the total viable
    bacterial population, indicator organism MPN per million TVC was computed (See Figure 3-9). The
    relative proportions of fecal coliforms and fecal streptococci in the total viable counts decreased
    southwards from Station 1 A to 1 1A during the winter months. During the spring months, the proportion
    approached uniformity among sampling stations. However, starting in June at Station 11A, a gradual
    rise in the relative abundance of indicator organisms in the water column occurred (See Figure 3-9). This
    increase was mirrored at the other sampling stations at progressively later dates from Station 1 1A to
    Station 1 A. This pattern of occurrence of indicator organisms was not reflected in the bottom sediments
    (Figure 3-10.) Although Station 11A water and sediments showed coincident peaks in the relative
    proportion of fecal coliforms and fecal streptococci making up the total viable, aerobic, heterotrophic

                                                     3-22

                   o Total Coliforms
                   o Fecal Coliforms
              4.  a  Fecal  Streptococci                              Station  la

              3 -
              2 -
                          Aa~�

          Z                                                                    5a
          W 4

           I-

              3-
              3 -

           2

              2o                8        -        / A
                     2 '

                    DEC JAN MAR MAY JUN JULY SEP OCT NOV DEC
                                         MONTHS

                                                                75151A145

    Figure 3-10. Comparison of Sediment-Bound Indicator Organisms in Relation to the Temporal
                 Distribution of Total Viable Bacteria in Upper Bay Sediments

                                         3-23

    bacterial population, the chronological progression in proportion of indicator organisms per population
    did appear in the sediments at Stations 1 A to 1 1 A. Station 5A and 1 OB sediments showed somewhat
    constant proportions of indicator organisms throughout the year, whereas the abundance of fecal
    coliforms and fecal streptococci showed greater fluctuation in 1A sediments.
                   These results were found to be strongly correlated with results presented in Figures 3-7
    and 3-8. It must be remembered that TVC's are almost always significantly higher in sediments as op-
    posed to bottom water (See Figure 3-6). Thus, the relative abundance of indicator organisms would be
    expected to be lower in sediment samples. However, in several instances a greater proportion of fecal
    streptococci was observed in sediment samples collected at Station 1 OB and 5A. This can be interpreted
    as indicating enhanced survival time of fecal coliforms in sediments or to the distance from and time
    elapsed between the input of fecal contamination and the recovery of the fecal streptococci. It can be
    concluded, from the abundance of fecal indicators observed at Station 1 A, that a source of contamination
    exists in the vicinity of that station. When these data are examined with the FC:FS ratio data for Station
    1 A (Table 3-7) the contamination is concluded to be domestic sewage. The source of contamination at
    Station 1 A is, in part, masked by the dilution of Chesapeake Bay water with Susquehanna River water,
    the latter having high total coliform levels.
                   The progressive increase in numbers of fecal indicator organisms occurring from
    summer to fall at Stations 11A through 1A could also be interpreted as being linked to increased
    summertime activities in Chesapeake Bay related to recreational use. However, this is completely
    speculative, since the pattern of peak occurrence of indicator organisms shows consistently later oc-
    currence during the year, moving in a longitudinal direction southwards from Stations 1 A to 11 A.

           3.3.6 Association of Bacteria with Particulates
                   A potential mechanism of transport for bacteria from water to sediment and vice versa is
    provided by suspended particulate matter. As indicated by data presented in Table 3-8, a highly signifi-
    cant proportion of both total viable bacteria and selected indicators of fecal pollution were found to be
    associated with particulate matter in the water column. Up to 53 percent of the total viable bacteria in
    Station 1 1 A water samples wasfound to be associated with particulate matter collected in 2100 X g cen-
    trifugation pellets. TVC found to be associated with particulates in Station 1A samples exceeded 25 per-
    cent in three of five determinations. Similarly, the centrifugation studies showed a significant proportion
    of the total MPN of the fecal indicators at Station 1 A and a majority of the fecal indicators at Station 1 1 A
    were associated with the suspended particulates. An earlier study, comparing retention of TVC on 8 and
    1 .2-micron membrane filters, revealed that bacteria at Station 1 1 Awere predominantly associated with
    small sized particles than were bacteria at Station 1 A. However, a sharp correlation between concentra-
    tion of suspended sediment at a given station and bacteria associated with particulates was not observ-
    ed.
                   Results of a seasonal comparison of bacteria associated with suspended matter carried
    out at Stations 1A and 11A (Figure 3-11) suggested both TVC's and number of indicator organisms
    decreased from winter to spring at Station 1 A. An identical pattern in TVC distribution was observed at
    Station 1 1 A. However, the distribution of indicator organisms associated with suspended sediment rose
    from December to January and remained stable until September, at which timethe numbers of both total
    coliforms and of fecal coliforms associated with the particulates declined, whereas the number of fecal
    streptococci remained stable until December 1 974. In general, counts of bacteria associated with par-
    ticulates obtained for samples collected at Station 1 A were higher than those at Staion 1 1 A throughout
    the year.
                   Collectively, the above data show that total numbers of fecal coliforms and fecal strep-
    tococci vary temporally and spatially. Further, transport via association with suspended sediments is
    strongly indicated. It must be emphasized that the evidence accumulated in this study point out the dif-
    ficulty and danger in depending on one bacterial group as an indicator of the presence of human
    pathogens in suspended sediment.

                                                      3-24

                   TABLE 3-7. FC/FS RATIOS CALCULATED FROM SAMPLES COLLECTED AT THE UPPER BAY SAMPLING STATIONS

       Station                     Dec.        Jan.         Mar.        May          June        July         Sept.       Oct.         Nov.         Dec.        Average

    Conowingo

       Water                       --          --           --          0.5          2.5         --            0.8         2.2         5.0          1.9            2.3

    1A

       Water                       7.3         1.1           0.9        1.8          1.4         5.0           0.3        --           --           0.2            2.2
       Bottom sediment             0.03        0.4           0.3        1.0          5.4         4.5           5.8        --           --           0.6            2.3
       Suspended sediment          0.04        0.1          11.3        0.3          3.0         8.2          10.8         --          --           1.8            4.4

    5A

       Water                       1.5         1.1           2.8        1.1          1.3         1.3           2.5        2.7          2.7          1.0             1.8
       Bottom sediment             1.9         0.7           0.1        0.3          0.3         0.3           0.5        0.5          3.0          0.3            0.9

    10B

      Water                       2.5         1.1          11.1        1.0          1.0         0.4           3.0        0.8          3.0          1.4            2.3
       Bottom sediment            0.03         0.3           0.04       0.1          0.3         0.3           1.9        0.3          0.3         0.3             0.4

    11A

      Water                       5.2         0.7           1.0        1.0          0.13        0.07          0.02        1.1         3.0          1.5            1.6
      Bottom sediment            0.001        0.8            .04       0.3          0.6         0.1           0.1        0.3          0.08        0.3             0.2
      Suspended sediment          3.3         0.6           0.3        0.3          0.5         0.3           0.2         0.3         0.004        7.5             1.5

      Average                     2.2         0.5           2.8        0.7          1.5         2.0           2.4         1.0         2.1          1.5

                       TABLE 3-8. ASSOCIATION OF BACTERIA WITH PARTICULATES

                                   11A                                                 11A

                           Percent of TVC*                                     Percent of MPN**         Suspended
                   8             1.2         2,100 x g                 Fecal            Fecal           Sediment
    Date        Micron         Micron            Pellet                Coliform          Strep.            (mg/1)

    12/73       54.0           81.8              --                       --  5.6
     1/74      30.5            63.5              17.9                     89.0           < 93.8              7.98
     3/74      80.0            79.4              19.3                     --                --               9.62
     5/74      --              --                53.1                     --             < 83.3             10.48
     6/74      --              --                11.4                     28.4               7.0             3.66
     7/74      --              --                --                       43.8               9.9             7.38
     9/74      --              --                15.9                  <  78.0              74.7             6.34
    10/74       --             --                  3.1                 <   1.4              --
    11/74       --             --                  5.6                    16.0              15.6
    12/74       --             --                --                       --                62.5

                                     1A                                                  1A

    12/73       --             --                --                       --                --             42.42
     1/74      91.5            94.7              25.2                      7.5             --              33.86
     3/74      94.5            94.4                1.4                    76.3               6.1            12.66
     5/74      --              --                26.8                      3.5              22.3           43.34
     6/74      --              --                27.9                     39.4           < 18.0             13.2
     7/74      --              --                 0.22                    93.2           < 57.1            13.52
     9/74      --              --                --                       --               --                7.70
    10/74       --             --
    11/74       --             --                --
    12/74       --

     *   Percentage of the TVC  retained by 8 and 1.2 pore size membrane filters or sedimented by
         centrifugation at 2,100 x g.

         Percentage of MPN  indicator organisms removed by centrifugation of water at 2,100 x g.

                                                          3-26

            o TVC
            o  Total  Colform  MPWN
            a Fecal  Colform  MPN
            a  Fecal  Streptococci MPN               Station  lo

       7.                                                            .7
       6                      o                                        6

          ~~    A~13\   1                                              4 T

       -3.

       0                                                                 0

                                                  <3  Ila   I

        0- 0                                                   0
                  O~~~~~~~~~

        4�- \ 4
                                  0'0~                             0
      o                                                       Ia

        2 CC

            A S- I

           DEC  JAN  MAR MAY JUN JULY SEP  OCT  NOV  DEC
                             MONTHS

                                                      751SIA1146

    Figure3_11i. Cornparative Recovery of Bact,-ria Associated with the Suspended Sedirnent
                          at Stations 1A and I 1A

                                  3-27

                   More direct evidence for the association of bacteria with suspended sediments was ob-
    tained (See Figures 3-1 through 3-5). Rod-shaped bacteria were observed to be associated with
    amorphous clumps of material and, less frequently, with diatoms found in suspended sediment
    preparations from Stations 11 A and 1 A. Preliminary information on the settling of indicator organisms
    suggests a relationship of these bacteria with debris and suspended particulates.

           3.3.7 Isolation of Potentially Pathogenic Bacteria
                   Salmonella - The isolation of Salmonellae from fresh and estuarine waters has been
    reported by a number of investigators. Hendricks (1971) and Van Donsel and Geldreich (1971) have
    demonstrated that greater recoveries of Salmonellae can be made from sediment than from surface
    water samples. The occurrence of Salmonella in the aquatic environment may be indicative of con-
    tamination by fecal material of human and animal origin, from both treated and untreated sewage.
                   Of the 115 samples of water, sediment, and suspended sediment collected from the five
    regularly sampled stations included in this study, none have been found to contain detectable authentic
    Salmonella spp. when examined by the standard methods. (See Table 3-4.) Two isolated, tentatively
    identified as Salmonella spp. and having biochemical characteristics of Salmonella, were isolated.
    However, neither culture was identified serologically as a Salmonella sp. when H-antisera were
    employed. A number of isolates were shown to agglutinate in polyvalent salmonella-O antiserum, but
    they were subsequently found to be H-negative. These findings are consistent with the occurrence of
    cross-reacting biochemical and serological types among the Family Enterobacteriaceae. Among the
    more common isolates that were characterized to genus were Pseudomonas spp. and other
    Enterobacteriaceae, including coliform organisms and Citrobacter spp.
                   The low frequency of isolation of Salmonella in the upper Chesapeake Bay is probably a
    consequence of the low density or frequency of occurrence of these organisms, rather than the methods
    used. Van Donsel and Geldreich (1971) reported that the frequency of isolation of Salmonella was
    related to fecal coliform density, based upon similar survival rates in sediment for these two groups of
    microorganisms. Interestingly, the ratio of Salmonella isolation frequency to fecal coliform MPN in es-
    tuarine water was observed to be less than half that of fresh water, for levels of one to 200fecal coliforms
    per 1 00 ml. The same authors indicated that Salmonella were not isolated very frequently from sediment
    collected at sites with less than 200 fecal coliforms per 100 ml of surface water, or 1,000 to 10,000 per
    milliliter of sediment. Similarly, Spino (1966) showed that no Salmonella were isolated from fresh
    waters with less than 220 fecal coliforms per 100 mi. Lear and Jaworski (1969) reported that no
    Salmonella were isolated from the upper Potomac River estuary, when fecal coliforms were present in
    numbers less than 100 per 100 mi. The data given in Table 3-5 indicate that, using the results of Lear and
    Jaworski (1969), few of the samples examined in this studyyielded levels of fecal coliforms high enough
    to make isolations of Salmonella feasible. Van Donsel and Geldreich (1971) calculated that the average
    ratio of fecal coliforms to Salmonella in sediment was 14,000 to one. On the basis of such a calculation,
    the sample volumes used would have precluded detection of Salmonella.
                   Salmonella, occurring at levels not detectable by the methods initially employed in this
    study, nevertheless, may pose a serious public health threat. Quantities of surface water, up to 100
    gallons, were concentrated using the Amincon hollow-fiber, continuous-flow dialysis concentrator. This
    method allowed for all particle sizes greater than 50,000 MW to be concentrated in a volume as small as
    five liters. This method, when employed at Station 11 A in October 1 974, did not yield isolation of authen-
    tic Salmonella. However, four cultures presumptively identified as Salmonella were isolated. The
    possibility does exist that Salmonella spp. recovered from environmental samples, in which they have
    resided for a very long period of time, may be physiologically and/or serologically distinct from the
    Salmonella spp. in the gut of animals and man. If this turns out to be the case, present methods of
    enumeration of Salmonella are ill-designedfor identifying these pathogens in estuarine samples. Anon-
    selective enrichment procedure proved successful in isolating Salmonella. (See Appendix B.)

                                                     3-28

                   Clostridium botulinum -The incidence of botulism poisoning in man in theUnited States
    is extremely low (Gangarosa et al., 1971). Yet, there exists the capacityfor serious epidemicsthrough im-
    proper preservation of foods or the use of newer, unproven food preservation methods. Furthermore,
    botulism has been the cause of large-scale wildfowl mortalities. The association of botulism with alewife
    mortalities in the Great Lakes has been suggested (Graikoski et al., 1969). The majority of human mor-
    talities in the United States has been associated with types A, B, and E toxins. Types A and B are
    restricted, generally speaking, to the western and eastern sections of this country, respectively, and Type
    E is associated primarily with aquatic habitats (Gangarosa et al., 1971). The Upper Bay Survey provided
    an excellent opportunity to search for this organism and to assess a possible role in the mortalities of
    various species of animals in the Chesapeake Bay (See Table 3-5). The incidence of the organism in
    samples of sediment was found to be sporadic. Of the 41 samples collected, four were found to be
    positive for Clostridium botulinum. Two of six samples from Station 1 A were found to be positive, and
    Type B and E toxin were detected. The simultaneous detection of C/. botulinum in sediment and in the vic-
    tim of a fishkill in June 1974 may prove to be significant. A number of unusual circumstances
    characterized the upper bay in June. The water was unusually clear; the densities of plankton were very
    low and an oxygen depletion was measured below the halocline.
                   In view of the fact that approximately 10 percent of all samples examined were positive
    for lethal toxin production, the assessment of Clostridia in the upper Chesapeake Bay should be con-
    sidered a significant public health problem; further study is clearly warranted. Fully one-third of the
    samples collected at Station 1 A were found to be positive, suggesting the need for a careful study of the
    source of such contamination and its implications to the shellfish industry.
                   Vibrio parahaemolyticus- Vibrio parahaemolyticus is a recognized agentof food borne il-
    Iness (Sakazaki, Personal Communication) and has been shown to be pathogenic for oyster larvae
    (Tubiash et al., 1970). The organism is detected in the waters of mid-Chesapeake Bay when the water
    temperature is above 150C, and it has been shown to be associated with the surfaces of copepods
    (Kaneko and Colwell, 1973). V. parahaemolyticus was enumerated in this study so the distribution of an
    estuarine pathogen could be compared with the distribution of organisms associated with domestic
    sewage.
                   Three different isolation procedures for V. parahaemolyticuswere employed and, in each
    case, numbers of V. parahaemolyticus-like organisms (VPLO) were found to increase from Station 1Ato
    Station 11A (See Table 3-3). This is consistent with the known habitat and salt requirements of this
    organism. That is, V. parahaemolyticus is an estuarine organism with a requirement for salt. Few con-
    firmed V. parahaemolyticus strains were isolated during the winter and spring, a finding in keeping with
    the temperature limits shown for this organism in an earlier study undertaken in the University of
    Maryland laboratory (Kaneko and Colwell, 1973). Direct plating on TCBS* agar was found to be the most
    selective. However, reduced recoveries may result without prior incubation in less selective media (T.
    Kaneko, PH. D. Thesis, Georgetown University, 1973).

           3.3.8 Bacteriology of Oysters
                   Total viable counts of oyster tissue did not exceed State of Maryland limits for shell stock.
    (Maximum permitted is 100,000 TVC per 100 g of oyster meat.) At not time didthefecal  coliform MPN of
    oysters exceed the State recognized standard of 130fecal coliforms per 100 g (Personal communication,
    M. J. Garreis, Maryland Environmental Health Administration). Fecal streptococci were shown to be
    three to ten times higher in oyster tissue than fecal coliforms. However, there are no recognized max-

    *TCBS is thiosulfate citrate bile salts sucrose

                                                     3-29

    imum limits for fecal streptococci in shellfish. Fecal streptocci levels in oyster tissue were comparable to
    those found in sediment samples collected at Station 11 A during the summer (See Figure 3-8 and Table
    3-9). No Salmonella spp. or CI. botulinum were found to be present in oysters from September to
    December 1 974. However, this does not indicate an inabilityto retain these pathogens, since pathogens
    were not found in the overlying water during the same period. One presemptive VPLO was recovered
    from oysters collected during September. This isolation was coincidental with five presumptive VPLO
    isolations from water taken at Station 11 A during the same time. The positive VPLO isolation occurred
    during a time of high coliform and fecal streptococci density in water from Station 11 A. The probability
    exists that pathogen uptake and retention by shellfish may be dependent on a threshold concentration of
    such organisms in their immediate environment. In general, all bacterial counts appeared to decline as
    winter approached (i.e., as the water temperature dropped).

           3.3.9  PCB-Metabolizing Bacteria
                   Significant proportions of the TVC of water and sediment were recovered from media
    containing PCB 1254 as the primary source of carbon for growth (Table 3-10). Approximately one to ten
    percent of the total viable bacterial population may be involved in the potential metabolism of PCB 1254
    in the water of the upper Chesapeake Bay. A somewhat lower proportion (0.1% > 10%) of the TVC of sedi-
    ment samples was capable of growth on PCB 1254. However, in absolute numbers, this represents a
    greater concentration of bacteria, roughly 10 to 100 times more numerous than in the water column. The
    results obtained for upper Chesapeake Baywater and sediment samples corresponded well to similar es-
    timates of PCB-metabolizing bacteria found in the marine environment (Atlantic Ocean). In general, the
    total number of PCB-metabolizing bacteria was lower in the upper baythan in Miami harbor (Station 1 E),
    but higher than in the open ocean (Stations 3E to 9E).
                   Six bacterial genera were identified among isolates from samples collected at the upper
    Chesapeake Bay stations (Table 3-1 1). Of 26 isolates, 11 (42%)were identified as Pseudomonads, 6 ten-
    tatively as Aeromonas spp., 5 as Bacillus, and the remaining 3 organisms tentatively as Streptomyces,
    Micrococcus, and Acinetobacter. There appeared to be a transition from Gram negative PCB-
    metabolizing bacteria in the Conowingo (Havre de Grace) area to a Gram positive population of PCB-
    metabolizing bacteria in samples collected further down the bay. This transition in bacterial genera
    proceeding down the bay may be an indication of the type and composition of various pollutants entering
    the Chesapeake Bay. Further clarification of this point may be possible when upper Chesapeake Bay
    nutrient data and chlorinated hydrocarbon distributions at upper bay stations are compared with the
    results of the microbiological analyses.
                   Evidence of PCB 1254 effect on bacterial activity was obtained using a [U--14C] glucose
    decomposition assay, whereby differences were measured in the metabolic activity between pop-
    ulations of bacteria in marine habitats (Figure 3-12). A multivariate analysis of variance for non-
    replicated samples was performed on the '4C-glucose decomposition assay data obtained during R/V
    EASTWARD Cruise, E-1 613-74. Results of the statistical analysis indicated no significant stimulatoryor
    inhibitory effect in the overall dissimilation of [U-14C] glucose. There was a significant variability
    between sampling stations, attributabletothe populations and proportions of PCB-metabolizing bacteria
    in the individual samples (See Table 3-10).

           3.3.10 Effect of PCB-1254 on Bacterial Activity
                   Initial evidence indicating microbial utilization of the biodegradable PCB 1254 was the
    isolation of bacteria from enrichment broths containing PCB 1254 as the sole carbon source. The ques-
    tion remained as to whether these bacteria were actually metabolically active in breaking down PCB
    1254. Pseudomonas Strain 1008, isolated from enrichment flasks with an inoculum from a Conowingo
    sample, was selected for further study of the effect of PCB 1 254 on bacterial activity. Preliminary results
    showed that Culture 1008 is capable of growth in flasks containing 1,000 mg/1 of PCB 1254 on

                                                    3-30

            TABLE 3-9. COMPARATIVE BACTERIOLOGY OF OYSTERS* AND BOTTOM WATER
                                 COLLECTED AT TOLLY BAR, STATION 11A

                                September                   October             November              December
    Bacteriological
      Parameter              Oysters         Water      Oysters      Water    Oysters   Water        Oysters       Water

    Total viable count**   6.05 x 102    4.5 x 103  7.5 x 103  6.9 x 103           --    1.8 x 104  9.4 x 100  1.2 x104

    Indicator organisms***

      Total coliforms            79.0            22.0    46.0         7.8      <  4.6      4.5          4.0         33.0

       Fecal coliforms         <   1.8        <   1.8       4.0        2.0      <   4.6 <  1.8            4.0         4.5

       Fecal streptococci         15.0           92.0    46.0          1.8         12.4    0.6           14.6         3.0

    Pathogens

      Clostridiat                 0.0             0.0      0.0        0.0          0.0    0.0            0.0         0.0

      Salmonellaett                0.0            0.0      0.0        0.0           0.0    0.0           0.0         0.0

      VPLOttt                      1.0            5.0      0.0        2.0          0.0      1.0          0.0         1.0

      * Ten oysters per sample, 100 to 200 g oyster tissue.

     ** TVC/g oyster tissue or m1-1 bottom water.

    *** MPN/100 g oyster tissue or 100 ml1- bottom water.

      t Clostridia botulinum toxin, mouse bioassay.

     tt Selenite cystein enrichment, MacConkey-Selenite isolation medium.

    ttt  Direct plating on TCBS medium.

                                                          3-31

               TABLE 3-10. CONCENTRATION OF PCB-METABOLIZING BACTERIA IN SELECTED
                                        ESTUARY AND MARINE SAMPLES

                                   PCB-Metabolizina Bacteria oer aram or Milliliter
    Date          Station               Water             % of TVC                 Sediment            %  of TVC

    9/74          1A                 --                   --                      >  102                   0.01
                  5A                --                                               10 2                  1.0
                 10B                -->  102                                                               0.1
                11A                -->  102                                                               1.0

               Conowingo            >  102                   10.0                                         --

    10/74         1A                 -- .
                 5A                3.5 x 101                  6.3               4.5 x 102                 3.6
                10B                4.0 x 101                  8.2               4.5 x 102                 0.4
                11A                6.5 x 101                  0.9                1.3 x 103                0.3

    11/74*        1E                 1.3 x 102                22.8                9.5 x 103                4.5
                 3E**              1.0 x 102                  5.0               3.5 x 102                 2.9
                 5E**              1.0 x 102                  6.3               4.5 x 101                 0.9
                 7E**              1.0 x 102                  2.6               1.2 x 103               46.0
                 8E                1.3 x 101            >  100.0                 1.2 x 102              46.0
                 9E                6.2 x 101            >  100.0                5.4 x 102                13.5
                10E                7.0 x 101                  0.09              3.9 x 103                 3.3

     *Samples obtained from Miami Harbor to Cape Hatteras, N. Carolina along the outer continental shelf.

    ** Surface water counts elevated due to carryover contamination from 1E in continuous flow concentrator.

                                                         3-32

       TABLE 3-11.  ISOLATION OF PCB-METABOLIZING BACTERIA FROM UPPER BAY STATIONS

      Station              Tentative Genera              Sample Type              Isolation Method

    Conowingo               Aeromonas                     Water                    Enrichment
                           Aeromonas                     Water                   Enrichment
                           Pseudomonas                   Water                   Enrichment
                           Pseudomonas                   Water                   Enrichment
                           Pseudomonas                   Water                   Enrichment
                           Micrococcus                  Water                    Enrichment
                           Pseudomonas                   Water                   Enrichment

          1A               Aeromonas                     Sediment                 Enrichment
                           Aeromonas                    Sediment                 Enrichment
                           Aeromonas                    Sediment                 Enrichment
                           Pseudomonas                  Sediment                 Enrichment
                           Pseudomonas                  Sediment                 Enrichment
                           Pseudomonas                  Sediment                 Enrichment
                           Acinetobacter                 Sediment                Enrichment

          5A                Vibrio/Aeromonas             Sediment                 Direct plating
                           Pseudomonas                  Sediment                 Direct plating

         10B                Bacillus                     Sediment                 Enrichment
                           Bacillus                     Sediment                 Enrichment
                           Bacillus                     Sediment                 Enrichment
                           Pseudomonas                  Sediment                 Enrichment
                           Pseudomonas                  Sediment                 Enrichment

         11A                Bacillus                     Water                    Direct plating
                           Streptomyces                 Sediment                 Direct plating
                           Pseudomonas                  Oyster                   Direct plating
                           Bacillus                     Water                    Direct plating

                                                     3-33

                 LI (U-MC) Glucose

                      (U-'C) Giue+ PC   1254

                      Sadim                 War  Sediment           Water  Sediment
                          IE                     3,E                     YE
                                             STATION

                                                                             75151A147

    Figure 3-12 Effect of PCB 1254 on the Dissimilation of [U- 14C] Glucose by a Heterogenous
                                      Marine Population

                                              3-34

    diatomaceous earth. Additional data were obtained showing that other cultures were capable of
    emulsifying droplets of PCB 1254 adherent to the bottom of enrichment flasks. Such emulsification at
    times reached 100 percent, resulting in the formation of an oil film on the surface of the enrichment
    broth.
                   The rate of oxygen consumption of Strain 1008 was found to be enhanced by concen-
    trations of PCB 1254 less than 1,000 mg/lI (Figure 3-13). There was no significant change in oxygen up-
    take for Culture 1008 grown on Celite or on Celite coated with PCB 1254 at 1,000 and 2,000 mg/I.
    Progressively lower concentrations of PCB 1254 significantly increased oxygen consumption. Since ox-
    ygen uptake is a function CO2 evolution in differential respirometry, increased oxygen uptake must result
    from increased C02 evolution. Increased CO02 evolution, in this case, may result from stimulated decom-
    position of organic matter associated with the diatomaceous earth or from active decomposition of PCB
    1254.
                   Further evidence for the stimulation of oxygen uptake by PCB 1 254 or for degradation of
    PCB 1254 was shown in Figure 3-12. A greatly increased rate of oxygen consumption was observed
    when glucose (1,000 mg/1 )was supplemented with PCB 1254 (1,000 mg/). This increased oxygen up-
    take was significantly higherthan that obtained for the Celite control orthe glucose-coated Celite (Figure
    3-14). The lag in oxygen consumption between zero and 12 hours in the glucose-PCB curve was similar
    to the PCB-induced lag in growth rate observed by Bourquin and Cassidy (1974).
                   Humic acid - Humic acids are a group of ill-defined, stable, natural polymeric substances
    thought to be derived from the biodecomposition and biomodification of organic material of primarily
    plant origin. Because of their polyfunctional, polar nature, they are capable of complexing a wide variety
    of inorganic and organic substances, including heavy metals and pesticides (Stevenson, 1972). For this
    reason, it was felt that humic acid (HA) might be involved in the transport of bacteria and nutrients, as
    well as chlorinated hydrocarbons.
                   Humic acids were extracted and measured from samples of water and sediment collected
    during the December and January cruises. The results of this initial survey are presented in Table 3-12.
    Humic acid in both water and sediment increased from Station 11 A to Station 1 A at the head of the bay,
    suggesting that the humic acid is primarily of terrestrial origin. Humic acid in the water samples was
    predominantly particulate in nature. These preliminary results indicate that the potential complexing
    capacity of the water and sediment is greater at the head of the bay. If this is so, the flux of materials
    associated with humic acid should decrease down the bay.

                                                    3-35

      500 -    n Celile                                          200 mfool
                   PCB 1254 on Celite

    FA
    0

    2 400 -                                                      500 mql'g
    E
                                                                 2000 mql-'
    W

      300 -                                                     looo mail
    a-

    w

    X 200
    0

    w

    :D 100

         0
           0           10           20           30          40
                                        HOURS

                                                                    75151A148

       Figure 3-13. Oxidation of PCB 1254 by an Estuarine Pseudomonas spp

                                      3-36

                       13 Celite
                       * Glucose  PCB 1254 on Celite
                       A Glucose  on Celite

         2.400
          E

         a_
         - 300

         z
         w

         0

            200
         w

         H

         D 100

                0            10            20            30            40

                                           HOURS

                                                                        75151A149

    Figure 3-14. Effect of PCB 1254 on Glucose Oxidation by an Estuarine Pseudomonas spp

                                           3-37

      TABLE 3-12. CONCENTRATION OF HUMIC ACID IN UPPER CHESAPEAKE BAY

                                                                Humic Acid Concentration
                                        Sediment                        Water (Micrograms/Liter)
    Date       Station          Micrograms/g Dry Weight                  Particulate      Dissolved

    12/73         11A                        108                             150              70

                  10OB                       639                            229              143

                   5A                      1175                             520             120

                   1A                      2880*                            800             225

    1/74          11A                        450                             --               --

                  10OB                       757                             180

                   5A                       642                             240

                   1A                         15**                          600

     * Silty sediment.

    ** Sand.

                                                3-38

      3.4 Conclusions
           In view of the diversity and volume of data collected on the microbiological parameters of pollu-
    tion in the upper Chesapeake Bay, a summary of the conclusions derived from this study may assist the
    reader in interpreting the results:

           (1)  The high bacterial TVC's observed to occur during winter and early spring would indicate
                that an influx of organisms and/or nutrients occurs in the upper bay at that time.
           (2)  Station 1 A at Havre de Grace appears to vary independently from the other stations, most
                likely a reflection of the impact of the Susquehanna River.
           (3)  Station 1 A, the data for which represented the highest influx of all of the bacterial indicator
                groups studied, receives point source pollution compounded by the contribution of
                organisms from the Susquehanna River.
           (4)  The  Susquehanna  River  below  Conowingo  Dam  contributes  large numbers  of
                allochthonous bacteria from non-human sources to the upper Chesapeake Bay.
           (5)  Judging from high MPN levels and elevated FC/FS ratio, contamination of a domestic
                source enters the upper bay, most likely in the area of Station 1A.
           (6)  Suspended sediment serves as a vehicle of transport for a large proportion of the viable
                aerobic, heterotrophic bacteria in the water column. In addition, many indicator organisms
                are associated with suspended sediment, perhaps originating at the source of pollution.
           (7)  The relative abundance of indicator organisms, which increases in summer months,
                reflects seasonal effects of temperature and nutrients, and possibly, increasing activity on
                the bay during this time.
           (8)  Significant populations of indicator organisms are associated with bottom sediments.
                Resuspension or movement of sediment may result in the exchange of large numbers of
                total coliforms and fecal Streptococci with the surrounding water and suspended sediment.
           (9)  A potential public health problem may exist in Chesapeake Bay since the presence of
                Clostridium botulinum in upper bay sediments has been shown in this study.
           (10) Shellfish at Tolly Bar are acceptable for public consumption by the criteria currently
                employed. There appears to be a less dramatic uptake of indicator organisms from Station
                11 A sediments or water than was expected.
           (11 ) Salmonella and Vibrio parahaemolyticus-like organisms were isolated employing specially
                designated isolation methods. Difficulty encountered in enumeration may mask the
                significance of these organisms in upper Chesapeake Bay water and sediment.
           (12) Bacteria capable of metabolizing PCB's are distributed throughout the Chesapeake Bay. The
                apparent transition of bacterial genera descending down the bay may be indicative of the
                nature of pollution, i.e., industrial vs. domestic pollution.
           (13) The effect of PCB 1254 can be stimulatory for some strains of bacteria; however, only a
                small portion of the total viable bacterial population was capable of growth in the presence
                of PCB 1254.

      3.5 Acknowledgements
           The excellent technical assistance of Andi Hirsch and M. Baldini is gratefully acknowledged. To
    the crew of the R/V RIDGELEY WARFIELD, always helpful and cooperative, we extend our thanks for
    their assistance in collecting samples for this study. Funds for the autoclave, required for laboratory ex-
    periments involving interactions of pathogenic bacteria and CHC in shellfish, were provided by U. S. En-
    vironmental Protection Agency Grant No. R-803300-01-0.

                                                    3-39

              3.6 References

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           Environ. Contam. Toxicol. V. 10, pp. 70-72.

    American Public Health Association, 1970, RecommendedProcedures for the Examination of Sea Water
           and Shellfish, 4th Ed. American Public Health Association, Inc., Washington, D.C.

    Bourquin, A.W. and S. Cassidy, 1974. Effect of Polychlorinated Biphenyl Formulations on the Growth of
           Estuarine Bacteria. Appl. Microbiol. V. 29, pp. 125-127.

    Center for Disease Control, 1973. Morbidity and Mortality Weekly Report, V. 22, pp. 231-232.

    Cherry, W. B. et al., 1972. Salmonellae as an Index of Pollution of Surface Waters. Appl. Microbiol., V. 24,
           pp. 334-339.

    Chun, D., J. K. Chung, and S. Y. Seol, 1974.Enrichmentof VibrioParahaemolyticusinaSimpleMedium.
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    Facklam, et al., 1974. Presumptive Identification of Group A, B, and D Streptococci Appl. Microbiol. V.
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    Fair, J. F. and S. M. Morrison, 1967. Recovery of BacterialPathogens from High Quality Surface Waters.
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    Gabis, D. A. and J. H. Silliken, 1974. ICMSF Methods Studies. II. Comparison of Analytical Schemes for
           the Detection of Salmonella in High Moisture Foods. Can. J. Microbiol. V. 20, pp. 663-669.

    Gangarosa, E. J. et al., 1971. Botulism in the United States. Amer. J. Epidemiology, V. 93, pp. 93-101.

    Geldreich, E. E. and B. A. Kenner, 1969. Concepts of Fecal Streptococci in Stream Pollution. J. Water
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    Graikoski, J. T., E. W. Bowman, R. A. Robohm, and R. A. Koch, 1970. Proceedings of the First U. S. -Japan
            Conference on Toxic Microorganisms.

    Greer, D. E. and J. E. Keil, 1974. The Effect of DDT andPCB onLipidMetabolism inE. ColiandB. Tragilis.
            Bull. Environ. Contam. Toxicol., V. 12, pp. 295-300.

    Hair, M. E. and C. R. Basset, 1973. Dissolved and Particulate Humic Acids in an East Coast Estuary.
            Estuarine and Coastal Marine Science. V. 1, pp. 107-111.

    Hendricks, C. W., 1971, Increased Recovery Rate of Salmonella from Stream Sediments Versus Surface
            Waters. Appl. Microbiol. V. 21, pp. 379-380.

    Hess, E., G. Lott, and C. Breer, 1974. Sewage Sludge and Transmission Cycles ofSalmonellae. Zbl. Bakt.
            Hyg. V. 168, pp. 446-455.

    Jannasch, H. and P. Pritchard, 1972. Proceedings of the IBP-UNESCO Symposium on Detritus and Its
            Role in the Aquatic Ecosystem, Pallanza, Italy.

    Janssen, W. A. 1973. Oysters: Retention and Excretion of Three Types of Human Waterborne Disease
            Bacteria. Health Lab. Sci., V. 11, pp. 20-24.

                                                     3-40

    Kadota, H., 1972. A New Method for Estimating the MineralizationActivity of Lake Water and Sediment.
           In Y. I. Sorokin and H. Kadota (eds.), Microbial Production and Decomposition in Fresh Waters.
           Blackwell Scientific Publications, London. p. 19.

    Ka neko, T., 1 973. Ecology of Vibrio parahaemolyticus and Related Organisms in Chesapeake Bay., Ph. D.
           Dissertation, Georgetown University. p. 89.

    Kaneko, T., and R. R. Colwell, 1973. Ecologyof Vibrioparahaemolyticus in ChesapeakeBay. J. Bacteriol.,
           V. 113, pp. 24-32.

    Lear, D. W. Jr. and N. A. Jaworski, 1969. Sanitary Bacteriology of the Upper Potomac Estuary.
           Chesapeake Technical Support Laboratory, Middle Atlantic Region, Federal Water Pollution Con-
           trol Administration, U. S. Dept. of the Interior. Technical Report No. 6.

    Metcalf, T. G. and W.C. Stiles, 1965. The Accumulation of Enteric Viruses by the Oyster, Crassostrea
           virginica. J. Infect. Dis., V. 115, pp. 63-73.

    Pagon, S., W. Sonnabend, and U. Krech, 1974. Epidemiologic Relationships Between Human and
           Animal Salmonella Carriers and Their Environment in the Swiss Region of the Lake of Con-
           stance. Zbl. Bakt. Hyg., V. 158, pp. 395-411.

    Spino, D. F. 1966. Elevated Temperature Technique for the Isolation of Salmonella from Streams. Appl.
           Microbiol., V. 14, pp. 591-596.

    Stevenson, F. J. 1972. Role and Function of Humus in Soil with Emphasis on Absorption of Herbicides
           and Chelation of Micro-nutrients. BioScience, V. 22, pp. 643-650.

    Strickland, J. D. H. and T. R.Parsons, 1972. A Practical Handbook of Sea WaterAnalysis. Bull. 167 (2nd
           Ed.). Fisheries Research Board of Canada. Ottawa, Canada.

    Tubiash, H. S., R. R. Colwell, and R. Sakazaki, 1970. Marine VibriosAssociated withBacillaryNecrosis, a
           Disease of Larval and Juvenile Bivalve Mollusks. J. Bacteriol., V. 103, pp. 271-272.

    Van Donsel, D. J. and E. E. Geldreich, 1971. Relationships of Salmonellae to FecalColiforms in Bottom
           Sediments. Water Research, V. 5, pp. 1079-1087.

    Zitko, P., W. V. Carson, and W. G. Carson, 1973. Prediction of Incipient Lethal Levels of Copper to
           Juvenile Atlantic Salmon in the Presence of Humic Acidby Cupric Electrode. Bull. Environ. Con-
           tam. Toxicol., V. 10, pp. 265-271.

                                                    3-41

                          APPENDIX 3A

              EFFECT OF POLYCHLORINATED BIPHENYL
    ON THE ACCUMULATION AND RETENTION OF ENTERIC BACTERIA
             BY THE OYSTER ,CRASSOSTREA VIRGINICA

    3A1. INTRODUCTION

             Polychlorinated biphenyls (PCB) are a recognized contaminant of estuarine and coastal marine
    water throughout the world (Duke et al. 1970; Risenbrough et al., 1968; Veith and Lee, 1970). These in-
    dustrial chlorinated hydrocarbons (CHC) have been shown to be acutely and chronically toxic for many
    estuarine and marine fishes and invertebrates (Duke et al., 1970; Hansen et al. 1974; Hansen et al.
    1971). However, little information is available concerning secondary levels of impact of PCB contamina-
    tion on estuarine and marine animals. A secondary level of impact includes PCB-induced stress, altering
    the normal physiology of the animal, and rendering it vulnerable to invading parasites or pathogens.
             The primary objective of this investigation was to determine whether PCB-induced stress on
    the oyster, Crassostrea virginica, caused it to accumulate enteric bacteria. A study was undertaken to
    test the hypothesis that PCB concentrations commonly encountered by estuarine invertebrates may
    result in reduced bacteriological quality of a commercially important shellfish. It has been shown by
    other investigators that the oyster can effectively filter pathogenic bacteria and viruses from overlying
    waters and accumulate significant quantities of these microorganisms in tissue and on gill surfaces
    (Fugate et al., 1975; Janssen, 1974). Retention of enteric or pathogenic bacteria in stressed oysters
    could lead to serious economic, as well as public health situations, if commercial oyster beds should be
    closed as a result of high coliform counts arising from PCB or other stress, and not from sewage con-
    tamination.

                                                    3A-1

    3A2. MATERIALS AND METHODS

      3A2.1 Culture Conditions
               Laboratory investigations were conducted using two bacterial strains, one an indicator of
    contamination by domestic sewage and the other a known pathogen. They were Escherichia coliType I,
    isolated from the upper Chesapeake Bay and a laboratory stock culture of Salmonella typhimurium
    respectively.
               Bacterial  cultures were harvested by centrifugation at 1 6,300 x g after growth for 48 hours in
    nutrient broth. Pelleted cells were resuspended in sterile salts broth. The resuspended cells were divided
    into equal portions and used for inoculation of aquarium water in tanks containing oysters.
               Analysis of oyster tissue, following dosing with the bacteria, was according to American
    Public Health Association procedures (APHA, 1 970). Oyster shell surfaces were disinfected with 2.5 per-
    cent hypochlorite in an ice bath. Oysters were shucked; the tissue was excised, rinsed with phosphate
    buffered saline, weighed, and homogenized with 100 ml 0.5 percent peptone.
               Total viable bacterial counts (TVC) of both the oyster homogenate and the aquarium water
    were performed using UBYE (Sayler et al., 1975) agar and appropriate dilutions of the samples. Quan-
    titative E. co/li determinations were made employing MacConkey agar. Since there was an absence of
    lactose-fermenting organisms prior to E. coli dosing, all lactose-positive cultures growing on Mac-
    Conkey agar were recorded as E. co/li. At high concentrations of E. coli, water or tissue dilutions were
    plated directly on MacConkey agar. As the number of E. col/idropped, membrane filters (Millipore Corp.,
    New Bedford, Mass.) were used to concentrate the bacteria. The filters were placed on the surface of
    MacConkey agar plates and incubated at 370C for 24 to 48 hours.
               A similar procedure was used for estimation of Salmonella typhimurium, except that bismuth
    sulfate agar (BSA) was used for enumeration. Green colonies on BSA, after 24-hour incubation at 41 �C,
    were recorded as Salmonella. Additional confirmatory tests were made on Kliegler iron agar, as
    warranted, to determine if biochemical alteration of the S. typhimurium occurred as a result of exposure
    to PCB.
               PCB stress was simulated using Aroclor 1 254  (Monsanto Industrial Chemicals, St. Louis,
    Mo.), coated on diatomaceous earth (Celite, J. T. Baker Chemical Co., Phillipsburg, N.J.). PCB dosing was
    maintained at 10 mg per liter (100 mg per liter Celite) for all experimental work.

                                                    3A-2

      3A2.2 Oyster Maintenance
               Oysters (Crassostrea virginica) used in this study were dredged from Tolly Bar in the southern-
    most part of upper Chesapeake Bay near Annapolis, Maryland. This area of the Chesapeake
    Bay-including water, sediment, and oysters harvested in this area- has been found free of enteric
    pathogens and is judged fit for shellfish harvesting (Sayler et al., 1 975). Each animal collected received a
    preliminary cleaning aboard ship to remove mussels and associated animals from the shell. All oysters
    were transported to the laboratory and stored at 60C within six hours of collection. Experimental work
    was initiated within 72 hours of collection.
               Oysters were maintained in 60-gallon, custom-designed, recirculating refrigerated aqaria
    (Sea Lake Systems, Inc., Euclid, Ohio). Operating temperature was maintained at 1 50C. Each aquarium
    was sterilized by autoclaving in an AMSCO-steam autoclave (American Sterilizer Corp, Erie, Pa.). Two
    hundred liters of steam-distilled water were filtered through 0.45 pim, 90 mm Millipore membrane filter
    (Millipore Filter Corp., Bedford, Mass.) and added aseptically by gravity flow to each aquarium. Artificial
    sea salt (Sea Lake Systems) was autoclaved in the dry state and was added to each aquarium, to a final
    salinity of 1 2 O/0, approximately equal to the in situ salinity at Tolly Bar. Each aquarium was fitted with
    glass covers to reduce or eliminate potential contamination. Refrigerant coils and air lines were dis-
    infected with 2.5 percent hypochlorite prior to each experiment.
               One hundred randomly-sized oysters were selected from the total set of oysters collected.
    Shell surfaces were thoroughly cleaned with a wire brush, and each animal was surface-disinfected by
    placing it in an ice bath, followed by an iced 2.5 percent hypochlorite bath for three to five minutes. Icing
    was employed to insure that each animal remained tightly closed; hence, disinfectant was prevented
    from reaching the tissue of the animal. In each of two aquaria 50 cleaned and disinfected oysters were
    placed. The oysters were allowed to remain in the aquaria for48 hours in orderto become equilibrated to
    the system.
               Following the equilibration period, one group of oysters received a dose of 10 mg per liter PCB
    1254 coated on 100 mg per liter celite. The duplicate aquarium received a placebo of 100 mg per liter
    celite and, therefore, served as the control for the experiment. Both sets of oysters were held under iden-
    tical conditions except for stress induced by addition of PCB. Ninety-six hours after PCB dosing, five
    oysters were aseptically removed from each tank, disinfected, and assayed for bacterial quality according
    to APHA procedures (APHA, 1 970). After removal of the five control oysters, both tanks received a dose of
    a washed bacterial suspension. Then five oysters were removed from each tank, disinfected, and
    assayed for accumulated bacteria. Sampling of oysters and water from both aquaria proceeded at es-
    tablished time intervals for 12 days. Next, the remaining oysters from both tanks were removed, surface-
    disinfected, and placed in separate sterile aquaria. Excretion of the accumulated bacteria was followed in
    water of the aquaria to which the oysters had been transferred, and purging of bacteria from the animals
    was determined by periodic sampling of the oysters.

                                                     3A-3

    3A3. RESULTS AND DISCUSSION

              Two sets of experiments were completed, each involving accumulation, retention, and survival
    of enteric bacteria. The first set was designed to examine the accumulation, retention, survival, and
    release of E. co/i in the oyster tissue and the removal and survival of E. co/l in aquarium water under con-
    ditions of no stress and under conditions of PCB stress.
              An outline of the experimental procedure is given in Table 3A-1. Due to a faulty aquarium, ex-
    cretion of Salmonella could not be fully assessed in the second group of experiments. However, the ex-
    perimental procedure allowed for the study of accumulation and retention of Salmonella and a partial
    study of the release of Salmonella by Crassostrea virginica.

       3A3.1   PCB Stress and the Accumulation of E. coli
               The effect of Aroclor�1 254 on the survival of E. coli in aquarium water is depicted in Figure
    3A-1. After E. coli addition and four days post-PCB dosing, an E. coli concentration of 106 cells per liter
    was reached in both the PCB dosing aquarium and control aquarium. This concentration was maintained
    for 24 hours in the control tank; however, there was approximately 99 percent reduction in E. coli
    concentration in the PCB-dosed aquarium water.
               Within 48 hours, 90 percent of the E. coli added to the control aquarium was no longer detec-
    table. The bacteria rapidly declined in the water column in both aquaria thereafter; although, the decline
    was slightly less pronounced in the control aquarium. Six days following addition of E. colito the PCB-
    stressed oyster aquarium, E. coli concentrations dropped to undetectable levels (less than 1 per ml). E.
    coli were detectable in the control aquarium for an additional four days, indicating a slightly longer sur-
    vival in the non-PCB-stressed environment.
               Comparison of the survival of E. co/iwith fluctuations in total viable counts (TVC), as shown in
    Figure 3A-1, indicated trends similartothat demonstrated byE. coli, with the exception thatthere was no
    immediate, marked loss of TVC from the water column. Twelve days after dosing, oysters were removed
    from the aquaria (Figure 3A-1). Absence of the oysters apparently had only a negligible effect on E. coli.
    However, the TVC increased after the oysterswere removed from the aquaria, suggesting that there was
    growth of heterotrophic bacteria introduced into the aquaria with the oysters.
                It is impossible to eliminate all bacteria from the oysters without killing the animals.
    Therefore, a background TVC, as indicated in counts at initiation of the experiments, must be accepted for
    all experimental work of this kind.
                Oyster tissues assayed for E. coliat the time the oysters were removed to fresh aquaria (Day
     12) were found to have accumulated large numbers of E. coli(Figure 3A-2). There was no significant
    difference between accumulation of E. coli after exposure for 12 days by the stressed and non-stressed
    oysters. Both groups of oysters accumulated about ten times more E. colithan the concentration of E. coli
                                                      3A-4

     TABLE 3A-1. EXPERIMENTAL OUTLINE FOR ASSAY OF ENTERIC BACTERIA ACCUMULATED BY
                  THE OYSTER, CRASSOSTREA VIRGINICA, FOLLOWING ACUTE PCB STRESS

    Days                                                   A Q U A  R I A
                                  Stressed                                              No Stress

    -2                50  random  oysters  (1)                                   50  random  oysters  (3)
                     48  hr  equilibration                                      48  hr  equilibration

     0                PCB  stress                                                No  stress

     4                Bacterial  does--under  stress                             Bacterial  dose

    4-11              Survival  and  accumulation                                Survival  and  accumulation
                     --under stress

    12                Transfer  to  fresh  aquarium                              Transfer  to  fresh  aquarium  (4)
                     --post-stress (2)

    12-19             Survival  and  release                                     Survival  and  release
                     --post-stress

    NOTE:  The  numbers  in  parentheses  above  identify  the  aquaria  in  which  the  oysters  were  placed.

                TABLE 3A-2.  RELEASE*  OF  TOTAL  VIABLE BACTERIA (TVC) FROM
                               OYSTERS FOLLOWING PCB-STRESS AND E. COLI DOSING

                                       Stressed                                           No Stress
    Day                                              Percenttt                                                  Percenttt
                Water**         Tissuett            Released               Water**            Tissuet          Released

    12       2.5  x  10o2      2.8  x  105           0.007              3.5  x  102           2.6  x  105           0.01

    13       5.3  x  103        1.2  x         104   1.9                5.6  x  103           3.6  x  105            1.5

    14       4.8  x  103       2.2  x  105           2.0                2.3  x  105           1.2  x  105         190.0

    17       1.5  x  106       3.4  x  106           3.8                2.2  x  106             5  x  104         407.0

     * Release from, oyster to water, assuming no growth in water.

    **TVC  per ml

     tTVC per 100 g of tissue

    ttCumulative percent released, E  Water/ ,   Tissue x 100

                                                        3A-5

      7

      5    9

           /Addition of E               o�

        0   1  2  3  4  5  6  7  8  9 '1 1 12 13 14 15 16 17 IS
                              Days
      3A-6

    o 3\

                             3A-6

                 - 4           /

                O I
                             A

                  0
                 w E

                               o  r~3-0
                 -o_

                 C                                                                    '

                    0     12    13    14    15    16    17    le    19
                                      Days

                                                              75151A151

    Figure 3A-2. Accumulation and Excretion of E. co/i by Oysters Following PCB Stressed and Unstressed Conditions.
    ( E. coil Tissue Accumulation with PCB-Stress; A E. coli Tissue Accumulation with No Stress; � E. coil Excretion
                         with PCB-Stress; oE. coli Excretion with No Stress).

                                       3A-7

    added to the aquarium water (Figures 3A-1 and 3A-2). There was significantly greater survival of E. coli
    in the non-stressed oysters, from Day 12 through Day 19, compared with stressed oysters, which
    eliminated all accumulated E. coli by Day 19. The peak in E. coliaccumulation, occurring at Day 14 in the
    non-stressed oysters, was most likely due to experimental error or may have been growth of E. coli in the
    oyster tissue, a rather doubtful but not impossible situation.
               Elimination of E. coil, as can be seen in Figure 3A-2 was interesting, in that those E. coil lost
    from stressed oysters were not recovered in the aquarium water. The resulting conclusion is that these
    cells were no longer viable. However, in unstressed oysters, E. coli was recovered in the water at Day 14,
    corresponding to the marked loss of E. colifrom unstressed oyster tissue. Although E. co/i recovered from
    aquarium water was an insignifcant amount of the total accumulation of E. coilbythe oysters (<1 .0%), it
    was significantly more than was recovered from oysters dosed with PCB 1254.
               The depressive effect of PCB 1254 on the elimination (or depuration) by the oyster of total
    viable bacteria was clearly evident (Table 3A-2). Elimination of the viable heterotrophic bacteria by PCB-
    stressed oysters amounted to a maximum of 3.8 percent of the total bacteria accumulated, compared
    with 407 percent for the control oysters; although, initial accumulation of TVC was approximately the
    same.
               These data support two theories: (1) E. coli is sensitive to PCB 1254 and (2) the ability of the
    oyster to accumulate bacteria is not inhibited by PCB, but depuration is diminished.

      3A3.2 PCB Stress and the Accumulation of Salmonella Typhimurium
               Accumulation of S. typhimurium by stressed and unstressed oysters revealed patterns
    similar to those of E. coli, with some exceptions. It was immediately obvious that the quantitative rate of
    recovery of Salmonella, using bismuth sulfite agar was much less than that of E. coil. This was evident
    from the discrepancy observed between TVC and the numbers of recovered Salmonella following addi-
    tion of more than 106 cells per ml to the water of each aquarium (Figure 3A-3). However, results for
    groups of oysters receiving the same treatement would not be affected bythe problem of quantitation.
               As was noted for E coil (Figure 3A-1), the number of Salmonella in the aquarium water
    decreased rapidly, starting at the time of addition of the bacteria four days after PCB dosing. There was a
    slight difference between decline in Salmonella levels between eight and twelve days while the
    aquarium water without PCB showed what could be interpreted as growth of the Salmonella paralleled
    with a rise in total viable bacteria. Both increases ceased at the thirteenth day, with a precipitous drop in
    the number of S. typhimurium in the control aquaria. In general, the decline in the number of Salmonella
    was much less gradual than that noted for E. co/i although the length of time during which a detectable
    number of viable cells could be recovered was approximately the same, i.e., ten days. The total viable
    counts followed closely the trends observed for Salmonella, with higher TVC concentrations detected in
    the unstressed environment.
               It was not possible to follow depuration of S. typhimurium because of a defect in one of the
    aquaria preventing removal of the oysters to a fresh, sterile environmentfor purging experiments. It was
    possible, however, to assay accumulation of S. typhimurium in the presence of low levels of residual
    Salmonella in the initial dosing tanks.
               At Day 6, oysters in both environments accumulated approximately one-tenth the concentra-
    tion of cells present in the surrounding water (Figures 3A-3 and 3A-4).Minor loss of Salmonella from
    control oysters between Days 6 and 12 may have been responsible for the observed increase in concen-
    tration of Salmonella in the water (Figure 3A-3). As the concentration of Salmonella in the water declin-
    ed following Day 1 2 (Figure 3A-3), a dramatic reduction in the concentration of Salmonella in the tissues
    occurred (Figure 3A-4). The results indicated that depuration of Salmonella by the oyster occurred.
               Comparisons between accumulation of Salmonella by stressed and unstressed oysters are
    presented in Table 3A-3. There was little difference noted between the groups in absolute accumulation
    of Salmonella or in the relative percentage accumulation of Salmonella. One difference noted, however,
    was the high initial rate of accumulation of bacteria.by unstressed oysters at Day 6. It is of interest to note
    that the only deaths of oysters in all the experiments occurred between Days 6 and 14 among the control
    oysters dosed with Salmonella. Salmonella typhimurium was recovered from the gut of one of the dead
    animals. The evidence is suggestive, but not conclusive of death induced by Salmonella.

                                                     3A-8

     6-                                0

     C               I'

    4 -

       :_o I2  3  4  5  6  7  8  9  10 11 1e 13 14 15 16
                                Days
                            3A-9

       j               Addition of Salmonell/

                                3A-9

                          6

                           5.

                        4- 4

                        A-                       .                          \

                       4-

                       cm
                        rn*

                        .o

                             O  |  2  3  4  5  6  7  8  9  10 11 12 13 14 15 16 17
                                                         Days

                                                                                       75151A153

    Figure 3A-4. Accumulation of Total Viable Bacteria (TVC) and Salmonella Typhimurium by the Oyster, Crassostrea
    Virainica Following PCB Stress ( TVC with PCB Stress; o TVC with No Stress; A Salmonella with PCB Stress;
                                            nSalmonella with No Stress).

                                                        3A-10
                          0~
                           0o                                      0I   21   41   61
                                   t-~~~~Dy

                                        o~~~~~~~~~~~~~~~55A5

         Figure 3A-4~~..Acmlto   fTtlVal  atra(V)adSamnlaTpiuimb   h  ytr   rsote

              TABLE 3A-3. ACCUMULATION* OF SALMONELLA TYPHIMURIUM IN OYSTER
                                       TISSUE FOLLOWING PCB STRESS

                              Stressed                                                       No Stress
    Day
              Water**          Tissuet         Accumulatedtt             Water**          Tissuet         Accumulatedtt

     6      4.4 x 103         4.8 x 103               109.0             1.7 x 103         1.3 x 104            764.7

    12      4.7 x 103         1.9 x 104               261.5             7.5 x 103         5.5 x 103            201.1

    14       1.0 x 101        3.0 x 102               264.5             2.0 x 102         4.0 x 102            201.1

    15      1.0 x 100         2.8 x 101               265.0             3.0 x 101         5.0 x 101            201.0

     *Accumulation, assuming no growth of Salmonella in tissue

    **Salmonella per ml aquarium water

     t Salmonella per 100 g oyster tissue

    ttCumulative percent Accumulated, E Tissue/ f Water x 100

         TABLE 3A-4. ACCUMULATION OF TOTAL VIABLE BACTERIA (TVC) IN OYSTER TISSUE
                            FOLLOWING PCB STRESS AND SALMONELLA DOSING

                               Stressed                                                     No Stress
    Day
              Water**         Tissue**         Accumulated***            Water*           Tissue**        Accumulated***

     6      3.13.1 x   10.1 x 104                     10.0              4.6 x 105         1.2 x 105              26.0

     9      8.0 x 105         6.3 x 104                8.5              8.0 x 105         1.6 x 105               22.2

    12      4.8 x 104         1.4 x 104                9.3              1.6 x 106         5.6 x 104               11.7

    13      1.6 x 105         1.6 x 104                9.4              6.8 x 105         6.7 x 104               11.4

    14       1.2 x 105        1.3 x 104                9.3              5.6 x 105         2.0 x 105               14.7

      * TVC per ml

     ** TVC per 100 g tissue

    *** Cumulative percent accumulated, ~ Tissue/ Z Water x 100

                                                      3A-11

             Accumulation of total heterotrophic bacteria in oyster tissue was greater in unstressed oysters
    (Figure 3A-4). This observation was made for TVC in the E. coli accumulation experiments. In terms of
    relative percent accumulation of TVC, accumulation by the control oysters ranged from 26 to 1 1.4 per-
    cent of the total number of Salmonella, compared with 10.0 to 8.5 percent for PCB-stressed oysters
    (Table 3A-4).
             Janssen (1974) reported oyster retention of 2.8 x 104 S. typhimurium per oyster from water
    containing 2 x 105 cells per ml after 48 hours exposure. Although it is difficult to compare the results
    reported by Janssen on the basis of per oyster accumulation, it does appear that the results of this in-
    vestigation are comparable in the case of the unstressed oysters.
              Several preliminary conclusions can be drawn from the results of these investigations to date.
    As expected, the oyster, Crassostrea virginica, demonstrated an ability to concentrate enteric bacteria.
    The effect of PCB stress on oysters apparently is a more complex process than was initially considered in
    terms of bacterial accumulation and depuration. A stress appears to be imposed on the bacterial popula-
    tion, as well as on the oyster. The end result is that PCB stress artificially produces what superficially
    could be considered oysters of higher bacteriological quality than was, in fact, the case. Upon harvest, it
    is possible that the oyster, held under conditions conducive to bacteria growth, would demonstrate
    marked increases in total count and, correspondingly, coliform count. In fact, this may explain in partthe
    anomalous conditions observed in the Chesapeake Bay when harvested shellfish yield unexpectedly
    high coliform counts. Effects of temperature and other factors during storage and shipping also must be
    considered, of course. The latter was not part of the study reported here.
              This observation was totally unexpected, as can be judged from the foregoing hypothesis in
    which it was assumed that PCB stress would result in poorer bacteriological quality. On the other hand,
    indications are that PCB stress may result in a lessening of the ability of the animal to purge itself of
    bacteria. These observations require further study before they can be accepted as fact. In the interim, ex-
    perimental work continues with the soft shell clam, another estuarine invertebrate, as the test animal to
    determine whether the effects observed for the oyster are specific or are applicable to other estuarine
    animals.

                                                     3A-12

    3A4. REFERENCES

    APHA, 1970. Recommended Procedures for the Examination of Seawater and Shellfish. 4th ed.
           American Public Health Association, Inc., Washington, D. C.

    Duke, T. W., J. I. Lowe, and A. J. Wilson, Jr., 1970. A Polychlorinated Biphenyl (Aroclor 1254) in the
            Water, Sediment, and Biota of Escambia Bay, Florida. Bull. Environ. Contam. Toxicol. V. 5, pp.
            171-180.

    Fugate, K. J., D. 0. Cliver, and M. T. Hath, 1 975. Enteroviruses andPotentialBacteriallndicators in Gulf
           Coast Oysters. J. Milk Food Technol. V. 28, pp. 100-104.

    Hansen, D. J., P. R. Parrish, and J. Forester, 1974. Aroclor 1016: Toxicity to and Uptake by Estuarine
           Animals. Environ. Res. V. 7, pp. 363-373.

    Hansen, D. J., P. R. Parrish, J. I. Lowe, A. J. Wilson, Jr., and P. D. Wilson, 1971. Chronic Toxicity, Uptake,
           and Retention of Aroclor 1254 in Two Estuarine Fishes. Bull. Environ. Contam. Toxicol. V. 6, pp.
            113-119.

    Janssen, W. A., 1974. Oysters: Retention and Excretion of Three Types of Human Waterborne Disease
           Bacteria. Health Lab. Sci. V. 6, pp. 20-24.

    Risebrough, R. W., P. Rieche, S. G. Herman, D. B. Peakall, and M. N. Kirven, 1968. Polychlorinated
           Biphenyls in the Global Ecosystem. Nature V.220, pp. 1098-1102.

    Sayler, G. S., J. D. Nelson, Jr., A. Justice, and R. R. Colwell, 1975. The Incidence of Salmonella spp.,
           Clostridium botulinum and Vibrio parahaemolyticus in an Estuarine Environment. Submitted to
           Appl. Microbiol.

    Veith, G. D. and G. F. Lee, 1970. A Review of Chlorinated Biphenyl Contamination in Natural Waters.
           Water Res. V. 4, pp. 265-269.

                                                   3A-13

                  APPENDIX 3B

    ENUMERATION AND ISOLATION OF SALMONELLA
          IN THE ESTUARINE ENVIRONMENT
         USING NON SELECTIVE ENRICHMENT

    3B1. INTRODUCTION

             Results of recently published studies accomplished in our laboratory have shown that large
    populations of fecal indicator organisms can be found in the water and bottom sediment of Chesapeake
    Bay and its sub-estuaries (Carney et al., 1975, Sayler et al., 1975). However, demonstration of the
    presence of enteric pathogens, specifically Salmonella spp., was not successful (Carney et al., 1975;
    Sayler et al., 1975). It was postulated that a low frequency of occurrence of Salmonelleae, combined with
    an inefficient method for enumeration of these organisms in the estuarine environment, were responsi-
    ble for failure to detect authentic Salmonella spp. in areas where large populations of fecal coliforms
    were present (Sayler et al., 1975b).
             An investigation was undertaken to evaluate available methodsfor enumeration and isolation
    of Salmonella spp., particularly with application to the estuarine environment. Also, an objective of the
    study was to investigate the relationship between occurrence of enteropathogenic bacteria and their
    associated indicator organisms.

                                                    3B-1

    3B2. MATERIALS AND METHODS

       3B.2.1 Sampling
                Thirty-four Chesapeake Bay water and sediment samples were collected during the period
    March 31, 1975 to June 20, 1975. The samples were collected at eleven sampling stations located in an
    area from Baltimore, Maryland to Norfolk, Virginia (Figure 3B-1).
                Water samples were collected using two sampling techniques. Bottom water was sampled
    at one to two meters above the sediment-water interface with a two-liter sterile Niskin bag sampler
    (General Oceanics, Miami, Fla.). Surface water samples were pumped on board ship via a submersible
    pump into 10 percent formalin-rinsed holding tanks. The submersible pump and holding tanks were rins-
    ed with water from the given sampling site prior to the collection of the sample to be analyzed. Surface
    water was then concentrated from a volume of 100 gallons (about 400 liters) to five to ten liters using a
    hollow fiber dialysis ultrafiltration system (Amicon Model DC30; Amicon Corp., Lexington, Mass.).
                The upper ten centimeters of the sediment was sampled with a non-aseptic petite Ponar
    grab. The sediment samples were aseptically subsampled and appropriately diluted for microbiological
    examination.
                Methods employed for measurement of temperature, dissolved oxygen, salinity, and
    transparency have been reported elsewhere (Sayler et al., 1975a).

       3B.2.2 Bacterial Enumeration
                A diagram of the microbiological procedures followed in analyzing the samples collected in
     the study is given in Figure 3B-2. Methods and media employed for determining the total viable bacterial
     counts (TVC), most probable number of coliforms (MPN) and of fecal coliforms (F-MPN) have been
     described elsewhere (Sayler et al., 1975a). However, the total viable bacterial counts in samples of 20
     percent salinity were determined using Marine Agar 2216 (Difco Laboratories, Detroit, Mich.).
                Enumeration of Salmonella spp. was attempted using the classical selective enrichment
     procedure including incubation at elevated temperature (Spino, 1966). Non-selective enrichment also
     was used. Selective enrichment by Salmonella spp. was done using tetrathionate broth (Difco) and
     selenite cystine broth (Bioquest, Cockeysville, Md.). Triplicate tubes of each medium were inoculated
     with one milliliter of a one-tenth dilution of bottom sediment. Bottom water samples (100 ml) were
     filtered through a 0.45-/m membrane. Additional enrichment broths were inoculated with one milliliter

                                                    3B-2

                                            5S USOIEANN     4     AN
         CHESAPEAKE BAY
           O  5  10 SOOT CAL MILES

                               MALTIMO RE

        .39'
                      WASMINITON  %     9

                                                            J.0

                    37-~~~~~~~~~~~~3

                               ~~~~~~~~~7- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~S

                                                                              7515 1A154

    Figure 38- 1. Chesapeake Bay Stations Sampled in the

                    Study of March -June, 1975

                                   3B-3

                                               SAMPLE

    UBYE  agar              Lactose  Broth              Selenite Cystine Broth         Tetrathionate  Broth
    25C, 4 wk         25C, 4-8 hr + 20 hr 35C            42.5C + .5C, 24 hr            42.5C + .5C, 24 hr

                               I                   I
                           EC Broth    Selenite Cystine Broth
                         44.5 C, 24 hr       42.5 C, 24 hr

                                                                Selective Differential Isolation Media
                                                                            42.5C, 24hr

                                                                                  I
                                                                     Biochemical Characterization

                                                                     Serological Characterization

    Total Count   Total Coliforms   Fecal Coliforms                              Salmonella
                                                            I
                                                   DATA ANALYSIS

                                                                                              75151A155

                   Figure 3B-2. Procedure for Enumeration and Identification of Salmonella
                                    Employing Non-Selective Enrichment

                                                    3B-4

    of the dialysis concentrate of the surface water samples. Inoculated selective enrichment media were
    immediately placed in a constant temperature water bath and incubated at 42.5�Cfor 24 hours. Incuba-
    tion up to 48 hours in selenite cystine and tetrathionate broth was unsuccessful for recovery of con-
    firmed Salmonella spp. (Sayler et al., 1975b).
                Non-selective enrichment for Salmonella was achieved by inoculation of nine replicate lac-
    tose broth (Difco) tubes in triplicate, using 0.1 ml, 1.0 ml and 10.0 ml volumes of bottom water, surface
    water concentrate, or sediment dilution. The inoculated tubes were allowed to incubate at ambient
    temperature (about 250C) for approximately four hours, followed by incubation at 350C for a combined
    total incubation time of 24 to 48 hours. Immediately after non-selective enrichment, the lactose broth
    tube cultures were transferred to EC broth (Difco) and selenite cystine broth and incubated 24 hours at
    44.5 + .50C and 42.5 + .50C, respectively. Thereby, fecal coliform and Salmonella  enumeration,
    respectively, were calculated from tubes showing confirmed growth in the medium.
                Following non-selective and selective enrichment, the selenite cystine and tetrathionate
    broth cultures were streaked onto Bismuth Sulfite Agar (Difco) and the inoculated plates were incubated
    at 350C for 24 to 48 hours. Isolated colonies were purified and maintained on Nutrient Agar (Difco)
    (Sayler et al., 1975a) or on Trypticase Soy Agar (BioQuest).

      3B2.3   Characterization of Isolates
               All of the pure cultures were biochemically characterized using the API 20 system (Analytab
    Products Inc., Plainview, N. Y.), and they were identified to species using the API computerized profile
    register. Confirmation of each of the strains of Salmonella was done serologically at the Center for Dis-
    ease Control (CDC), Atlanta, Georgia.

                                                    3B-5

    3B3. RESULTS AND DISCUSSION

      3B.3.1  Recovery of Salmonella
                A total of 34 samples was collected at the 11 Chesapeake Bay sampling sites and four (11 .8
    percent) were found to contain Salmonella spp. As shown in Table 3B-1, all strains of Salmonella were
    recovered using the non-selective enrichment method. Also, all of the isolates were obtained at a single
    sampling station. Significantly the concurrent selective enrichment method, which employs
    tetrathionate or selenite broth, resulted in no presumptive or confirmed Salmonella spp. isolation.
                A total of 1 2 Salmonella strains were obtained, including 11 Salmonella enteritidis, serotype
    derby and one Salmonella enteritidis, serotype infantis. A presumptive Salmonella was concluded to
    have been misidentified and was biochemically and serologically confirmed as Klebsiella pneumoniae,
    Type 45. Of approximately 1300 known serotypes, the two Salmonella enteritidis serotypes are among
    the 12 most frequently encountered from human and non-human specimens (Martin and Ewing, 1969).
                The 12 Salmonella enteritidis strains were isolated from samples collected at Jones Falls
    (Station A in Figure 3B-1) in Baltimore harbor. Compared with the other stations sampled (Table 3B-2),
    Jones Falls is a shallow, low salinity site located in the northwest branch of Baltimore harbor. It is located
    at the confluence of Jones Falls, a stream carrying sewage treatment effluent, and Baltimore harbor. Ex-
    tending outward to the Chesapeake Bay proper, the water was progressively brackish and of a greater
    depth, although not necessarily containing fewer coliforms. There was no significant (a = 0.05) correla-
    tion of Salmonella recovery with either transparency, temperature, dissolved oxygen or TVC. A signifi-
    cant negative correlation (r = -0.45) at the 90 percent probability level was observed between salinity
    and Salmonella recovery using the non-selective enrichment technique.
                Salmonella spp. were recovered with greater frequency from sediment, although theywere
    recovered from both bottom water and the concentrated surface water samples (Tables 3B-2 and 3B-3).
    A significant correlation was observed for fecal coliform MPN and presence of Salmonella enteritidis (r =
    0.65, P = 0.95) in both water and sediment samples. Assuming the presence of Salmonella spp. to be
    related to incidence of fecal coliforms, a regression equation (Y = 0.002X + 0.006, r2 = 0.42) was com-
    puted from the data given in Tables 3B-2 and 3B-3. It was estimated that one Salmonella would be
    recovered for every 497 fecal  coliforms. This value is comparable to other estimates of fecal col iform den-
    sities related to Salmonella recovery (Lear and Jaworski, 1969; Spino, 1966; Van Donsel and Gelreich,
    1971). Quantitative estimates of the incidence of Salmonella spp. computed for the data from the non-
    selective primary enrichment MPN, indicated Salmonella levels ranging from zero to 9.1 per 100 ml in
    the water and from 3.6 to 36 per 100 g in the sediment (Table 3B-3). Van Donsel and Geldreich (1971)
    have previously reported elevated Salmonella counts in sediment to be higher, compared with water, but
    at a ratio of 14,000 fecal coliforms to one Salmonella, a ratio much different from the ratio of 10 to 30
    fecal coliforms to one Salmonella observed in this study (Table 3B-3).

                                                    3B-6

       TABLE 3B-1. RECOVERY OF SALMONELLA FROM CHESAPEAKE BAY SAMPLES EMPLOYING
                              NON-SELECTIVE AND SELECTIVE ENRICHMENT

                                                 Confirmed* Salmonella
    Source
                                                   Enrichment Method

                              Tetrathionate           Selenite                  Lactose-Selenite            Percent

    Samples        (34)                  0                     0                            4                     11.8

    Sampling
      Sites       (11)                  0                     0                            1                      9.1

    *Biochemical and serological confirmation

                                                      3B-7

               TABLE 3B-2. PHYSICAL, CHEMICAL, AND MICROBIOLOGICAL CHARACTERISTICS OF CHESAPEAKE BAY SAMPLES FROM WHICH
                                                      RECOVERY OF CONFIRMED SALMONELLA WAS OBTAINED

                                                                     Dissolved                                                                  Fecal
                                     Sample  Depth*    Salinity    Oxygen    Transparency Temperature                            Coliform       Coliform
                Station             Type    (m)          (0/oo)      (mg/1)           (m)           (�C)              TVC          MPN          MPN            Salmonella

           A    Jones Falls**           W      2.6          1.4        6.9              0.6         22.6           1.8 x 106    >  1,100         738                  3
                                        S                                                                          1.9 x 107    >  1,100         745                  9

           B    Fort McHenryt           W      6.5         3.9        10.3              0.7         21.1           5.9 x 106    >  1,100         132                  0
                                        S                                                                          1.1 x 107    >  1,100         571                 0

           C    Colgate Creekt          W      9.1         3.9         8.5              0.8         22.5           1.4 x 106    >  1,100          93                  0
                                        S                                                                          1.7 x 107    >  1,100          20                 0

           D    Fort Howardt            W      4.5         3.2         6.8              2.0         18.6           1.6 x 105           240          0                 0
                                        S                                                                          7.1  x 106    >  1,100          0            '    0

    co     E    Middle Rivert            W      5.7         0.6         9.1              1.0         19.5           8.3 x 104        --           --                  0
                                       S                                                                          8.0 x 105        --           --                   0

           F    Chester Rivertt         W     10.0         8.6         9.5              2.0         14.5           6.0 x 104            14          0                 0
                                        S                                                                          3.1 x 106          460          0                 0

           G    Tolley Bartt            W      6.5         7.0         6.2              1.8         15.1           2.0 x 105              3.6       0                 0
                                        S                                                                          3.2 x 106    >  1,100           3.6               0

           H    Solomonstt              W      9.7        10.9         8.5              1.7         23.0           1.8 x 104           460          3.6               0
                                        S                                                                          4.1 x 106          210          0                 0

           I    Tangier Islandtt        W      6.1        14.0         3.6              2.3         23.0           5.0 x 104            23          0                 0
                                        S                                                                          2.9 x 106             9.1       0                 0

           J    Cape Charlestt          W    28.0         25.8         7.4              3.3         --             2.2 x 105           240          0                 0
                                        S                                                                          2.3 x 106          240          0                 0

           K    Little Creektt          W      8.2        20.3         5.8              1.7         25.4           3.3 x 104             9.1       0                  0
                                        S                                                                          1.5 x 107         1,100         9.1               0

            * Samples collected 1.0 meter above the sediment-water interface.                  t Samples collected in March and May  1975; mean value given.
           ** Samples collected in March, May, and June 1975; mean value given.               tt One sample.

        TABLE 3B-3. RECOVERY OF SALMONELLA ENTERITIDIS FROM SAMPLES OF WATER AND
        SEDIMENT COLLECTED AT JONES FALLS STATION BY THE NON-SELECTIVE ENRICHMENT
                                                 PROCEDURE

    Sample                                Coliform             Fecal                   Number of            Salmonella
    Type                      Date           MPN               Coliform MPN            Salmonella               MPN

    Water*                    5/75        >1,100                  1,100                      1                  3.6

                            6/75       >1,100                      15                     0                  0

    Sediment**                5/75        >1,100               >  1,100                      8                 36.0

                            6/75       >1,100                     35                      1                  3.6

    Dialysis Concentrate***  5/75         >1,100                  1,100                      2                  9.1

                            6/75

      * Bottom water collected one meter above the sediment-water interface.

     ** Sediment grab sample collected from the upper 10 cm of the sediment.

    ** 40-fold concentration of a surface water sample.

                                                     3B-9

      3B.3.2! Evaluation of Enrichment Techniques
               The enumeration of Salmonella employing highly selective enrichment and plating media
    with elevated temperature (42.50C) is a recognized standard method (APHA, 1971 ). There is the tenden-
    cy to apply this procedure for enumeration of pathogens to all types and classes of water. The initial ob-
    jective in the use of selective temperature and medium was to enumerate Salmonella in samples heavily
    contaminated with both potential pathogens and related enterics (Spino, 1966; Harvey and Price, 1968).
    Harvey and Price (1968) stated that a lower temperature of incubation may be required for samples con-
    taining smaller populations of Salmonella or organisms in need of resuscitation. In addition, Thomson
    (1 955) noted that non-selective nutrient broth enrichment for Salmonella typhimurium was equally ef-
    ficient as selenite broth. Isenberg et al. (1969) found that a variety of selective plating media was equally
    suited for isolation of Salmonella from mixtures of fecal bacteria when employing an incubation
    temperature of 370C.
                When applying the selective or non-selective enrichment method for isolating Salmonella
    from estuarine samples, one must considerthe physical and chemical characteristics of the environment
    as well as the residence time of the organisms in the environment. Heat resistance of Salmonella in-
    cubated at temperatures less than 35�C is significantly less than that of Salmonella recovered from
    warmer environments (Ng et al., 1969; Parker-Baird et al., 1970). Furthermore, stationary cells appear to
    be more resistant to elevated temperature than younger cells (Ng et al., 1969). Parker-Baird et al., (1970)
    showed decreased heat tolerance with increased salinity. Ng et al., (1969) reported that carbon-limited
    cells may be more heat resistant than nitrogen-limited cells.
                All these factors may have direct influence on enumeration of Salmonella from extra-
    intestinal sources. Salmonella may be poor competitors in the aquatic environment (Hendricks, 1972)
    and enumeration of these organisms may be dependent upon factors that have little effect upon clinical
    or food isolates.
                From the data on recovery of Salmonella enteritidis (Tables 3B-1 and 38-4), it is concluded
     that a gradual, step-wise increase in temperature of incubation and the use of a non-selective primary
     enrichment should be employed for enumeration of environmentally stressed Salmonella.
                It is of interest to note that a greater number of enterics and related organisms was also
    recovered with the Salmonella (Table 3B-4). However, these were not a serious interference, con-
    sidering that neither of the other selective enrichment methods was able to detect the presence of
    Salmonella.
                Approximately seven percent of the cultures isolated using the non-selective enrichment
    methods were confirmed as Salmonella spp. Of the total of 246 cultures collected and examined, five
    percent (i.e., one of 20) were confirmed to be Salmonella spp. In an earlier study employing a viarety of
    selective media and enrichment temperatures, it was found that four of 1 79 cultures examined could be
    tentatively classified as Salmonella species. However, none of these was confirmed serologically (Sayler
    et al., 1975b).
                Of significance also was that several other potential pathogens were enumerated and
    isolated using the non-selective enrichment procedure. These included Klebsiella spp., Pseudomonas
    aerginosa, Yersinia enterocolitica, and Pasteurella multocida. Thus, it is apparentthatthe non-selective
    enrichment techniques may be extremely valuable in assessing the occurrence of a variety of pathogens
    in the estuarine environment.

       3B.3.3 Salmonella Characterization
                The API 20 Enterobacteriaceae identification system was found to be well-suited for applica-
    tion in this estuarine microbiology study. As seen from the data given in Table 3B-5, there was a signifi-
     cant variation in the biochemical characteristics of strains serologically identical. In accordance with
     accepted biochemical tests, Culture No. 42 would have been discarded because of the production of in-
     dole. Similarly, Cultures No. 23 and 57 would have been suspect because of acetoin production. All but
     two of the Salmonella enteritidis isolates were unable to decarboxylate lysine. These observations con-
     firm the position taken by Martin and Ewing (1969) that all suspected Salmonella should be thoroughly
     characterized, both biochemically and serologically. No single isolate matched exactly the reference set

                                                     3B-10

       TABLE 3B-4. COMPARATIVE RECOVERY OF SALMONELLA AND RELATED ENTERIC BACTERIA
                             USING THE NON-SELECTIVE ENRICHMENT PROCEDURES
                                                   ENRICHMENT METHOD
                                                                                                        Total
    Identified Isolates*         Tetrathionate**            Selenite,**         Lactose-Selenite ****  Recovered Percent
                                Number   Percent        Number   Percent         Number   Percent
                               Recovered of Total   Recovered of Total   Recovered of Total

    Klebsiella pneumoniae             5        20.0          26        44.1          50         30.7          81        32.1
       K. rhinoscleromatis            0         0.0           3          5.1           0         0.0           3          1.2
       K. ozaenae                     0         0.0           1          1.7           2         1.2           3          1.2

    En terobacter cloacae             1         4.0           3          5.1         26         16.0          30         12.2
       E. aerogenes                   1         4.0           0          0.0           6         3.6           7          2.8
       E. agglomerans                 0         0.0           0          0.0           3         1.8           3          1.2

    Pseudomonas aeruginosa            1         4.0           1          2.0         21         31.3          23          9.3
       P. fluorescens                 0         0.0           0          0.0           1         6.0           1          0.4
       P. putrefaciens                0         0.0           0          0.0           1         0.6           1          0.4

    Proteus mirabilis                12        48.0           3          5.1           0         0.0          15          6.1
       P. morganii                    0         0.0           0          0.0           1         0.6           1          0.4
       P. rettgeri                   0          0.0           0          0.0           1         0.6           1          0.4
       P. stuartii                   3         12.0           3          5.1           0         0.0           6          2.4

    Citrobacter freundii              1         4.0          14        23.7            9         5.5          24          9.7

    Salmonella enteritidis            0         0.0           0          0.0         12          7.2          12          4.8

    Escherichia coli                 0          0.0           0         0.0           5          3.1           5          2.0

    Yersinia enterocolitica          0          0.0           0         0.0           2          1.2           2         0.8

    Serratia marcescens              0          0.0           0         0.0            2         1.2           2          0.8
       S. liquefaciens               0          0.0           0         0.0            1         0.6           1         0.4

    Pasteurells multocida            0          0.0           0         0.0            1         0.6           1         0.4

    Misc. spp.
       Petobacterium                 0          0.0           1         1.7           0          0.0           1         0.4
       Erwinia                       0          0.0           0         0.0           1          0.6           1         0.4
      Alcaligenes                   0          0.0           0         0.0           2          1.2           2         0.8
       Flavobacterium                0          0.0           0         0.0           2          1.2           2         0.8

       Unidentified                  1         4.0           4          6.8          16         9.8          21          8.5

    Total                           25                      59                      163                     246

        *Preliminary identification employing API 20 and computer profile register. Salmonella enteritidis identifica-
         tion was confirmed serologically.
      **18 to 24-hour incubation at 42.50C in tetrathionate broth.
     **'18 to 24-hour incubation at 42.50C in selenite-cystine broth.
    ****4 to 8-hour incubation at ambient temperature in lactose broth, followed by an addition 14 to 20-hours
         at 350C and transfer to selenite cystine broth with incubation at 42.50C for 18 to 24-hours.

                                                           3B-11

          TABLE 3B3-5. COMPARISON OF BIOCHEMICAL CHARACTERISTICS OFSALMONELLA ENTERITIDIS ISOLATED FROM ESTUARINE SAMPLES WITH
                                                                   THOSE OF CLINICAL ISOLATES

                  Test                              Salmonella enteritidis Strain No.                     Observed Reaction           Reference Reaction *
                    or                                                                                                  Mean
                Substrate           23   36   42   50   51   52   53   55A  55B  57   61   128             Sign**      Percent        Sign            Percent

          ON PG                    -    -    -    -    -    -    -          -     -    -     -     -                     0              -0
          Arginine
             dehydrolase      -        -       -    -    -    -    -    -    -    -  -    -                 +           33*3         -.+)              92.8
          Lysine
             decarboxylase         -    -    -    -    -    -    -    -    -    -  -    -                   +           16.7           +               94.9
          Ornithine
             decarboxylase     .       .    .    .    .    .    .    .- .    .    .    .                    +           91.7           +               96.7
          Citrate                  +    +    +    +    +    -    +    -    -           -    -     -+                    50.0         +(+M*             90.8
          H-2S                     +    +    +    +    +    -    +    -    +    -           -     +         +           66.7           +               93.7
          Urease                   -    -    -    -    -    -    -    -    -    -    -    -                 -0                         -                0
    cw     Tryptophane
        IFdearninase               -    -    -    -    -    -    -    -    -    -    -    -                 -0                         -                 0
    Pi Indole                       -    +    -    -    -    -    -    -    -    -    -    -                 -8.3                       -                0
          Voges-Proskauer          +    -    -    -    -    -    -    -  -             -    -    -          +           16.7           -                0
          Gelatin                  -    +    -    -    -    -    -    -    -    -    -    -                 -8.3                       -                0
          Glucose                  +    +    +    +    +    +    +    +    +    +    +    +                 +         100.0            +              100.0
          Mannitol                 -    -    +    +    +    +    +    +    +    +    +    +                 +          83.3            +              100.0
           I nositol                -    -    +    +    +    +    +    +    +    +    +    -                 +          75.0         + (+) -            39.1
          Sorbitol                 -    -    +    +    +    +    +    +    +    +    +    +                 +          83.3            +               97.9
           Rhamnnose                -    -    +    +    +    +    +    +    +    +    +    +                 +          83.3            +               95.2
          Sucrose                  -    -    -      -     -     -    -     -     -     -    -     --0                                                   0
           Melibiose                -    -    +    +    +    +    +    +    +    +    +    +                 +           83.3           +91.6
          Arnygdaline              -    -    -      -     -     -    -     -     -     -    -     --0                                                   0
          Arabinose                -    -    +    +    +    +    +    +    +    +    +    +                 +           83.3           +               99.4
          Nitrate                  +    +    +    +    +    +    +    +    +    +    +    +                 +         100.0            +              100.0
          Oxidase                  -    -    -    -    -    -    -    -    -    -    -    -                 -0                         -0

            'Edwards and Ewing (3)
           **Greater than ten percent recorded as +
         '**Positive after three days
        ****API reference

    of biochemical reactions for Samonella enteritidis as given by Edward and Ewing (1972). However, the
    overall observed mean (occurrences greater than ten percent recordered as + observation) exactly
    matched the reference reaction, except for the (16.7%*) Voges-Proskauer reaction.
               The API profile register facilitated the correct identification of the unknown isolates. Iden-
    tification in this study was based on the probability of occurrence and was not dependent upon a specific
    reaction or reaction pattern.
               Smith et al., (1 972) reported 100 percent accuracy for the identification of Salmonella spp.
    and a 96.4 percent overall accuracy when the API 20 Enterobacteriaceae test system was employed.
    Washington et al., (1971) demonstrated greater than 90 percent accuracy for a number of
    Enterobacteriaceae. Twelve of 13 Salmonella isolates obtained in this investigation were serologically
    confirmed, following biochemical identification, which resulted in a net accuracy of 92.3 percent for
    Salmonella enteritidis. As indicated by other investigators, the manufacturer's instructions must be
    closely followed in order to achieve accurate results. It should be pointed out that all isolates obtained
    when using selective and non-selective enrichment procedures were tested in an identical manner.
    Therefore the recovery of Salmonella, employing the non-selective enrichment procedure, was not an
    artifact of the identification procedure.
                It is concluded from this study that a non-selective primary enrichment medium, when used
    in conjunction with a stepwise increase in temperature of incubation, is efficient in isolating Salmonella
    and other pathogens frequently missed when standard, recommended selective enrichment and
    elevated temperature enumeration methods are employed. It is necessary, however, to accept a certain
    degree of interference by other enteric bacteria because of the less stringent enrichment conditions.
    Therefore, a large number of organisms often must be screened and the identification will require the
    use of a probability matrix for frequency of occurrence of characteristics, rather than a monothetic
    classification based on selected biochemical reactions. Clearly, the presence of a potential public health
    hazard otherwise would not be detected.

                                                  3B-13

    3B4. ACKNOWLEDGEMENTS

             The technical assistance of J. Huntley and A. Murlin, Center for Disease Control, Atlanta, Ga.,
    is greatly appreciated. Dr. Don Brenner, C.D.C., provided helpful discussion in preparation of this
    manuscript. This investigation was supported by the National Oceanic and Atmospheric Administration
    Sea Grant, Project No. 04-5-15811 and National Science Foundation Grant No. BMS72-02227-A02.
    Shiptime aboard the R/V RIDGELY WARFIELD was made available by The Johns Hopkins University
    through National Science Foundation Grant No. GD31707. Acknowledgment is made to the captain and
    crew of the R/V RIDGELY WARFIELD for their excellent field assistance.

                                                 3B-14

    3B5. REFERENCES

    APHA, 1971. Standard Methods for the Examination of Water and Waste Water. 13th ed. American
           Public Health Association, Washington, D. C., pp. 697-702.

    Carney, J. F., C. E. Carty, and R. R. Colwell, 1975. Seasonal Occurrence and Distribution of Microbialln-
           dicators and Pathogens in the Rhode River of Chesapeake Bay. Appl. Microbiol. V. 30.

    Edwards, P. R. and W. H. Ewing, 1972. Enterobacteriaceae, 3rd ed., W. H. Ewing (ed.). Burgess
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    Harvey, R. W. S. and T.H. Price, 1968. Elevated Temperature Incubation of Enrichment Media for the
           Isolation of Salmonella from Heavily ContaminatedMaterials. J. Hygiene Camb. V. 66, pp. 377-
           381.

    Hendricks, C. W., 1972. Enteric Bacterial Growth Rates in River Water. Appl. Microbiol. V. 24, pp. 168-
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    Isenberg, H. D., S. Kominos, and M. Siegel, 1969. Isolation of Salmonella andShigellae from anArtificial
           Mixture of Fecal Bacteria. Appl. Microbiol. V. 18, pp. 656-659.

    Lear, D. W., Jr. and N. A. Jaworski, 1969. Sanitary Bacteriology of the Upper Potomac Estuary.
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           trol Administration, Dept. of Interior Technical Report V. 6.

    Martin, W. J. and W. H. Ewing, 1969. Prevalence of Serotypes of Salmonella. Appl. Microbiol. V. 17, pp.
           111-117.

    Ng, N., H. G. Bayne, and J. A. Garibaldi, 1969. Heat Resistance of Salmonella: The Uniqueness of
           Salmonella Senftenberg 775 W. Appl. Microbiol. V. 17, pp. 78-82.

    Parker-Baird, A. C., M. Both royd, and E. Jones, 1970. The Effect of WaterActivity on the Heat Resistance
           of Heat Sensitive and Heat Resistant Strains of Salmonellae. J. Appl. Bacteriol. V. 33, pp. 515-
           522.

                                                   3B-15

    Sayler, G. S., J. D. Nelson, Jr., A. Justice, and R. R. Colwell, 1975a. Distribution andSignificance of Fecal
           Indicator Organisms in the Upper Chesapeake Bay. Appl. Microbiol. V. 30, pp. 625-638

    Sayler, G. S., J. D. Nelson, Jr., A. J. Justice, and R. R. Colwell, 1 975b. The Incidence of Salmonella spp.,
           Clostridium botulinum, and Vibrio parahaemolyticus in an Estuarine Environment. Appl.
           Microbiol. In press.

    Smith, P. B., K. M. Tomfohrde, D. L. Rhoden, and A. Balows, 1972.APlSystem:A Multitube Micromethod
           or Identification of Enterobacteriaceae. Appl. Microbiol. V. 24, pp. 449-452.

    Spino, D. F., 1966. Elevated-Temperature Technique for the Isolation of Salmonella from Streams. Appl
           Microbiol. V. 14, pp. 591-596.

    Thomson, S., 1955. The Numbers of Pathogenic Bacilli in Feces in Intestinal Disease. J. Hygiene V. 53,
           pp. 217-224.

    VanDonsel, D. J. and E. E. Geldreich, 1971. Relationships of Salmonellae to Fecal Coliforms in Bottom
           Sediments. Wat. Res. V. 5, pp. 1079-1087.

    Washington, J. A. II, P. K. W. Yu, and W. J. Martin, 1971. Evaluation of Accuracy of Multitest
           Micromethod System for Identification of Enterobacteriaceae. Appl. Microbiol. V. 22, pp. 267-
           269.

                                                    3-1 6

                                             CHAPTER 4

                                             ESTUARINE
                                          SEDIMENTOLOGY

    4.1  Bottom Sediments                                                             H. D. Palmer
                                                                                 Oceanic Division
                                                                 Westinghouse Electric Corporation

    4.2  Suspended Sediments                                                          J. R. Schubel
                                                                 Marine Sciences Research Center
                                                                      State University of New York
                                                                            Stony Brook, New York
                                                                                             and
                                                                                     W. B. Cronin
                                                                         Chesapeake Bay Institute
                                                                     The Johns Hopkins University

    ABSTRACT

           Analyses of both suspended and bottom sediments recovered during the course of the Upper Bay
    Survey support the contention that the finer grain-sizes of natural origin carry the highest concen-
    trations of chlorinated hydrocarbons. The origins of these materials include internal (generally biogenic)
    sources, marginal contributions from shoreline erosion, and external sources contributed by fluviatile
    agents, especially those associated with high volume runoff accompanying the spring freshet. The fine-
    grained bottom deposits located in the central part of the Chesapeake Bay form a sink for chlorinated
    hydrocarbons. The suspended load is localized in the turbidity maximum occupying a region some 30km
    long upstream from Tolchester.
           During 1974, the estimated yield of sediment from the Susquehanna River, the major source of
    water and suspended sediment in the upper bay, was 0.8 x 106 metric tons, a value some 20 percent
    lower than the averages obtained over several years of record. Much of the suspended sediment par-
    ticles recovered may be considered agglomerates produced by biological activity. Electrostatic floccula-
    tion appears to play a minor role in the formation of agglomerates, and biogenic precipitation is con-
    sidered the primary depositional agent for the fine-grained materials in suspension.

                                        TBLE OF CONTENTS

    Paragraph                                                                                                            Page

    4.    ESTUARINE SEDIMENTOLOGY ................................................4-1
    4.1   Bottom Sediments ..........................................................4-1

    4.1.1.1  Physiographic and Geologic Setting............................................4-1
    4.1.1.2 Previous Work .............................................................4-2

    4.1.2.1  Field Techniques ...........................................................4-5
    4.1.2.2  Laboratory Techniques.......................................................4-5
    4.1.3  Sedimentology .............................................................4-5
    4.1.3.1  Bottom Sediments ..........................................................4-5
    44.1isuson..........................................................4.............41
    44.1u.ay........................................................4...............42
    4.1.6  Acknowledgements ........................................................4-31
    4.1.7  References ...............................................................4-31
    4.2          Suspended Sediment in the Waters of the Upper Chesapeake Bay .................4-34
    44.2Itoucin.............................................................4...........43
    4.2.2  Sources of Sediment .......................................................4-34
    4.2.3  Suspended Sediment Population .............................................4-41
    4.2.4    Distributions of Temperature, Salinity, and Total Suspended Solids.................4-41
    4.2.4.1  Temperature and Salinity ...................................................4-41
    4.2.4.2  Total Suspended Solids.....................................................4-41
    4.2.5   Size Distribution of Suspended Particles.......................................4-42
    44.2.Mtos5..........................................................4..............44
    44.2.Rsls5...........................................................4..............44
    44.23Dsusin.............................................................4...........49
    4.2.6  Acknowledgements ........................................................4-62
    4.2.7  References ...............................................................4-62

                                         LIST OF FIGURES

    Figure                                                                                                               Page

    4-1    Bathymetric Chart of the Upper Chesapeake Bay .................................4-3
    4-2          Generalized Geologic Map of the Upper Chesapeake Bay and Bottom
             Sample Station Locations ....................................................4-4
    4-3    Sample Record from Coulter Counter Analyses ..................................4-6
    4-4    Distribution of Sand in the Upper Chesapeake Bay ...............................4-7
    4-5    The Silt-Sand Ratios in the Upper Chesapeake Bay...............................4-8
    4-6   Percent Clay in Bottom Sediments.............................................4-9
    4-7    The Three Sources of Sediment to the Bay.....................................4-1 1
    4-8          Satellite (ERTS-1) Photograph of the Upper Chesapeake Bay,
             April 3, 1974 .............................................................4-12
    4-9    Scanning Electron Microscope Images of Quartz Silt.............................4-1 3

                                                iii

                                         LIST OF FIGURES (Continued)

    Figure                                                                                     Page

    4-10      Distribution of Quartz Silt in Bottom Sediments ............................................................... 4-14
    4-11      Scanning Electron Microscope Image of Mica (Muscovite) from Bay Sediments ...........4-15
    4-12      Distribution of Mica in Bay Sediments ................................................................. 4-16
    4-13      Scanning Electron Microscope Image of Glauconite Grain ..............................................4-18
    4-14      Distribution of Glauconite in Bay Sediments ..................................................................4-19
    4-15      Scanning Electron Microscope Images of Slag Fragments in
               Upper Bay Bottom Sediments ............................................................................................. 4-20
    4-16      Distribution of Slag and Coal in Bottom Sediments ....................................... 4-21
    4-17      Diatom Frustule Comprising Some of the Biogenic Debris in
               Bottom Sediments of the Upper Bay .................................................. 4-22
    4-18      Triangle Diagram for Displaying Sediment Size Characteristics ......................... .............4-23
    4-19      Pattern of Sample Distribution for Bedload Materials and Pattern
               of Sample Distribution for Deposits Resulting from Suspended Sediment .....................4-23
    4-20      Triangle Diagram for Bottom Samples Recovered During the Upper Bay Survey .......... 4-24
    4-21      Comparison of Mean Grain Size, in Phi Units ................................................................4-26
    4-22      Comparison of Mean Grain Size, in Phi Units ................................................................4-27
    4-23      Comparison of Mean Grain Size, in Phi Notation .............................................................4-28
    4-24      Chlordane Concentrations in Bottom Sediments from Baltimore Harbor
               and the Chester River .......................................................................................................... 4-29
    4-25      Polychlorinated Biphenyl Concentrations in Bottom Sediments from
               Baltimore Harbor and the Chester River ........................................  ................4-30
    4-26      DDT Residue Concentrations in Bottom Sediments from
               Baltimore Harbor and the Chester River ......................................................... 4-30
    4-27      Ensemble Average of the Susquehanna River at Conowingo, 1929-1966 .....................4-35
    4-28      Discharge of the Susquehanna River at Conowingo in 1973 .......................................... 4-37
    4-29      Discharge of the Susquehanna River at Conowingo in 1974 .......................................... 4-37
    4-30      Concentration (mg/I) of Suspended Sediment in the Susquehanna River
               During 1973 ...................................................4-38
    4-31      Concentration (mg/I) of Suspended Sediment in the Susquehanna River
               During 1974 ........................................4-38
    4-32      Suspended Sediment Discharge of the Susquehanna River
               at Conowingo During 1973 ................................................................................................. 4-39
    4-33      Suspended Sediment Discharge of the Susquehanna River
               at Conowingo During 1974 ................................................................. 4-39
    4-34      Photomicrograph of Sample of Suspended Sediment from Upper Chesapeake Bay ......4-44
    4-35      Photomicrograph of Sample of Suspended Sediment from Upper Chesapeake Bay ......4-45
    4-36      Photomicrograph of Sample of Suspended Sediment from Upper Chesapeake Bay ......4-46
    4-37      Photomicrographically Determined Number-Size Distributions
               of Suspended Sediment.... ........................................              4-48
    4-38      Photomicrographically Determined Number-Size Distributions of Suspended
                Sediment ................................................... 4-48
    4-39      Histograms of the Mean Sizes of All Samples ................................................... 4-56
    4-40      Histograms of the Modal Class of Equivalent Projected Diameters ...............................  4-57
    4-41      Histogram of the Modal Class of Equivalent Projected Diameters ..................................4-58

                                                         iv

                                            LIST OF TABLES

    Table                                                                                         Page

    4-1       Statistical Properties of the Number-Size Distributions of the
              Suspended Particle Population of the Upper Chesapeake Bay .....................4-49
    4-2       Statistical Properties of Volume-Settling Velocity Distributions of
              Samples of Suspended Sediment from Upper Chesapeake Bay ....................4-60

    4. ESTUARINE SEDIMENTOLOGY

      4.1 Bottom Sediments

           4.1.1 Background

                   4.1.1.1 Physiographic and Geologic Setting
                          The Chesapeake Bay is recognized as one of the largest estuaries in the world,
    and within the United States it is the longest (290 km) and second largest (11,390 km2) estuarine system.
    This report is focused upon the geological and sedimentological relationships present in what will be
    referred to as the upper Chesapeake Bay. This portion of the bay lies north of the confluence of the
    Severn River and the bay proper, and discussion will be limited to studies performed in that area.
                          The dendritic form of the upper Chesapeake Bay is inherited from the drowned
    tributary network which fed the ancestral Susquehanna River during the most recent (Holocene) period
    of depressed sea level (Hack, 1957). Earlier courses for this major east coast river are speculative
    (Hansen, 1966; Weaver and Hansen, 1966), and recent but controversial interpretations of
    aeromagnetic anomalies suggest that the upper Chesapeake Bay orientation may reflect early and per-
    sistent conformity to a deep fault-bounded basin (Higgins and others, 1974a, 1974b; Hansen, 1974).
                          Relief in the coastal plain bordering the upper bay is subdued, and the most
    prominent positive features are the low terrace scarps which face the bay. The origin of these erosional
    features is not clear, but several studies (Schlee, 1957) suggest that those terraces higher than 30
    meters may be ascribed to fluviatile agents, whereas those at lower elevations may be marine in origin.
    Discussion of these features is cited in Palmer (1972), and new evidence supplied by DeAlteras (1975)
    and Hicks (1972) provides additional argument for regional uplift and subsidence, respectively, in the
    central Atlantic coastal plain.
                          The units forming the physical margins of the upper bay are soft, unconsolidated
    to weakly cemented Cretaceous and Tertiary sandstones, siltstones, and similar detrital deposits which
    are subject to accelerated shoreline erosion as a result of nearshore processes (Schubel and others,
    1972) and local groundwater conditions (Palmer, 1973). Their contribution to upper Chesapeake Bay
    sedimentary processes will be discussed later. Much of the bay's margin consists of wetland areas
    whose dominant flora, Spartina, tends to bind and retain soft materials. However, exposed beach and
    bluff areas are prone to erosion produced by a combination of elements acting from both the bay and

                                                    4-1

    onshore. Conservative estimates of property loss in this area account for scores of acres per year which
    are lost to the bay, and similar figures are quoted for other regions within Chesapeake Bay.
                          Much of the upper Chesapeake Bay consists of shoal areas marginal to tributaries
    and/or shorelines faced by bluffsof soft sedimentary units. The general bathymetric configuration of the
    area is shown in Figure 4-1, and it will be noted that the mean depth is quite shallow - less than four
    meters. This is a common feature in the shallow estuaries of the Atlantic coastal plain since the present
    bathymetric character reflects the recent drowning of river and stream courses and a redistribution of
    shoreline erosional products and beach materials. Thus, extensive shoals bordering the major channel
    are a reflection of a recent, and at present incomplete, readjustment of a former fluviatile terrain to a
    drowning event. The tidal flow accompanying such drowning now is redistributing these materials,
    which in many places within the upper bay derived from shoreline erosion. The main channel (thalweg)
    of the upper bay is in part an inherited feature and also a result of dredging by the U.S. Army Corps of
    Engineers. Circulation of upper bay waters is affected by the displacement of the thalweg to the eastern
    margin of the upper bay, and the effect of this feature on sediment distribution will be examined in a later
    section.
                          The structure and stratigraphy in the two regions forming the eastern and
    western boundaries of the upper bay are profoundly different (Figure 4-2). The western shore consists of
    a relatively thin veneer of Mesozoic and Cenozic sedimentary units which wedge out against the
    crystalline Appalachian Province (or Piedmont Province) consisting primarily of Paleozoic metamorphic
    units which locally surround Precambrian and Paleozoic intrusive rocks. The Cretaceous and younger
    sedimentary units of the Coastal Plain Province thicken and dip to the southeast, and along the axis of the
    present Chesapeake Bay, these formations reach a thickness of nearly 800 meters. Along the Atlantic
    shoreline of the Delmarva Peninusla, the thickness of this clastic wedge reaches at least 2,280 meters
    (Vokes, 1957) and definite basement (metamorphic rocks similar to Baltimore gabbros) are cored at a
    depth of 2,180 meters near Berlin in Worcester County, Maryland. A concise description of the geologic
    framework of this entire region may be found in Maher and Applin (1971).
                           Sedimentary units of the coastal plain which border the upper bay consist of flat-
    lying beds of weakly cemented sandstones, siltstones, and clays. Gravel lenses are not uncommon, and
    in local areas gravels may be sufficiently abundant to form economic concentrations. An examination of
    Figure 4-2 will reveal most of the shoreline of the Upper Bay consists of Quaternary alluvium. On the
    basis of mineralogy, fossil content, and elevation, Cleaves and others (1968) have subdivided the
    Pleistocene of this region into the Upland and Lowland deposits, but for the purpose of this report this dis-
    tinction has not been made. The weak nature of these formations is a major factor in both shoreline ero-
    sion and in the introduction of detrital materials into the Upper Bay. The importance of marginal
    sedimentary processes will be discussed under a later section.

                   4.1.1.2 Previous Work
                           A summary of previous geological work in the area of the Upper Bay is provided by
    Palmer (1972), and it will not be repeated here. However, continuing studies in the sedimentology of the
    bay have resulted in a number of recent communications which bear upon the origin and distribution of
    Chesapeake Bay sediments. Gas contained within bay sediments has been found to create acoustically
    impenetrable zones (Schubel and Schiemer, 1973), a factor which has frustrated many efforts to record
    high resolution seismic reflection profiles in this area. The upper bay region displays numerous ex-
    amples of gas-charged sediments.
                           Sedimentological studies related to the transport of trace metals and chlorinated
    hydrocarbons on particulate matter have been reported by Palmer (1972), Helz (1974), and Palmer and
    Munson (1974). Investigations in regional sedimentation are discussed by Palmer and others (1973),
    Owens and others (1974), Palmer (1974), Nichols (1975), Siegrist (1975), and Merryman and Palmer
    (1975). The accelerated production of suspended sediment due to urban construction in the Pautuxent
    River watershed is discussed by Roberts and Pierce (1 974), and the role of groundwater in shoreline ero-
    sion in the upper Chesapeake Bay is described by Palmer (1973). Many of the agents and processes ac-
    ting in the upper bay are also present in large tributaries, and the comprehensive Chester River Study
    summarized by Clarke and others (1972) provides insight into mechanisms which determine transport
    and depositional processes.

                                                      4-2

                                                                             75151A156
    Figure 4-1. Bathymetric Chart of the Upper Chesapeake Bay
                     (Contour Interval 10 Feet)

                               4-3

                                                                                         75151A17
          Figure 4-2. Generalized Geologic Map of the Upper Chesapeake Bay
                      and Bottom Sample Station Locations.
            (Darkest grey shades are metamorphic and igneous rocks of
        the Piedmont province. Medium grey is Cretaceous sedimentray rocks,
    and lightest grey represents Quaternary deposits. Baltimore is shown as stippled
                    area in center left; Annapolis at lower left)

                                         4-4

           4.1.2 Techniques

                   4.1.2.1 Field Techniques
                          Field techniques employed to collect both bottom and suspended sediment
    samples followed standard techniques. Bottom samples were recovered with either a Ponar or Ekman
    grab sampler. Representative portions of the materials to be analyzed for sedimentological parameters
    were retained in cartons and returned tothe laboratory. All sampleswere analyzed as quickly as possible
    after recovery.

                   4.1.2.2 Laboratory Techniques
                          The initial set of 55 bottom sediment samples were wet-sieved through a 62-
    micron sieve, and where the coarse fraction (sieve diameter greater than 62 microns) was sufficiently
    large to warrant analyses by size fraction, the sand fraction was split into whole phi (d) classes. In many
    cases, standard settling tube routines were not employed because of the high percentage of abnormally
    light (low specific gravity) sand size particles, and routine sieving techniques were used instead. Much of
    the sand size material in the fine-grained samples consists of coal (sp. gr. of about 1.5) and slag which
    contains an abundance of bubbles which yield various specific gravities for individual particles. Fine
    materials (those passing the 62-micron sieve) removed from the initial set of samples were run by stan-
    dard pipette analyses (Royse, 1970).
                          Samples recovered during subsequent cruises were analyzed using the Coulter
    Electronics particle size analyzer (Model TA) employing apertures of 140, 100, and/or 30 microns. For a
    description of this technique, see Swift and others (1972). Representative plots from these analyses are
    presented in Figure 4-3.
                          Fine-grained sediments from estuaries, rivers, and other non-marine regions
    often are enriched in organic materials which, because of their propensity for inducing flocculation,
    make size analyses difficult. A number of analytical techniques have been proposed to deal with such
    materials. The approach used in this study included soaking the fine fraction (material passing the 62-
    micron sieve) in a 30 percent hydrogen peroxide solution heated to 50-540C for periods of several days,
    and subsequent transfer to a 50 percent acetone-water mixture for final deflocculation. The materials
    were then transferred to a one-liter graduate and sampled according to standard pipette methods at
    periods of zero, two, and eight minutes to provide weights for fractions down to 16 microns. The remain-
    ing suspensate in the graduate was re-stirred, re-sampled, and passed through a 15-micron mesh fabric
    sieve to remove slag, coal, and other particles of coarse to medium silt size. Materials passing the 15-
    micron mesh were then analyzed in the Coulter Counter employing a 30-micron aperture. (Thresholds
    for maximum particle size detection in the Coulter Counter are generally one-half the aperture
    diameter, hence the 15-micron mesh provides an upper cutoff for the 30-micron aperture). All size data
    were combined in a single program which accepts inputs from settling tube analyses, pipette fractions,
    and the Coulter Counter analyses. These data were then entered in the data base.

           4.1.3 Sedimentology

                   4.1.3.1 Bottom Sediments
                          The distribution of bottom sediment type in the upper Chesapeake Bay varies
    markedly over short distances, and at fixed points as well, since the influx of coarser materials to the
    sedimentary system is often seasonal and a function of the magnitude of the spring freshet from the Sus-
    quehanna and lesser tributaries. During this study, the preliminary set of samples provided the basis for
    preparation of general maps of sediment distribution based upon sand, silt, and clay content (Figure 4-4
    thru 4-6). These must be considered approximate representations, because it is economically impossible
    (and scientifically irrelevant) to sample on a fine grid which would cover all tributaries, small em-
    bayments, etc. where sediment texture can vary widely over distances of tens of meters.

                                                     4-5

                                                                                                                                                                                                        CCLULTER   C   LECTRON II 'C.
                   ~D:COULTER COUNTER" Model T&TA  ./~2  PARTICLSIZE IANALYSIS                                                                                                                    ........    ...
                        _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _-                                               A DE                                                                   A -~ ( d )   3:oN 2 N   L = ( L V .100 =

                                                                                                                              FOT MODEL T                                    FOR MODEL TA
       ...IP.....                                                                                                   AE....1SIE   SERIA I: I                                                  �E   I*I    A.        I.I  N     ,-      A
                                     I .................. Ilr                                                                                               I                    tu I                 II

            t  I                                                                                                                         I                                        I      I I  II                     I     II
                151   .11     650110        T   .              70 9 I03  4 2 1.20      0 A0   2.0   .17   4.0    5.04   0.0   8I0   100   12.7   16.0   20.2   25.4   22.0  40.2   0.    64.0   806  101.6  128   16I    2

    3rJ0

          .... I ..I ...l           '"i ......IIIlil ~ii ........I'"'1111" ... .       .         ... i .....1 [i,, ........M1 ...I" ....... ....1)11  11 '11  11 ....I i,/, , i,)   , T    ,    [    iiil ....I iilI I1 !1   1!111

                   2I              3       a                           0         15      20          3o       4     5         I  8  ~10             (15     29          30      40    50         o  80 ;13 ice      1 50       xx
                                                                                                          MICRON DIAMETER L.g Scale

                                                                                                                                                                                                                                   75151A158
                                                                 Figure 4-3. Sample Record from Coulter Counter Analyses.
                                                                        (Both histogram and cumulative frequency curves
                                                                             are presented. Sample is from Station ?A.)

                                                                                     75151A159
       Figure 4-4. Distribution of Sand in the Upper Chesapeake Bay.
        (Generally sand is confied to shoals along the Eastern Shore.
    Areas where sand is the dominant sedimentary component are shaded.)

                                     4-7

                                                                                      75151A160
      Figure 4-5. The Silt-Sand Ratios in the Upper Chesapeake Bay.
      (Ratios indicate the prevalence of finer materials in the central
    part of the upper bay. Contours show distribution of ratio values.)

                                    4-8

                                                                                     75151 A161
                        Figure 4-6. Percent Clay in Bottom Sediments.
             (Percentages are shown by contours. Highest concentrations are located
                  in the central bay area where turbulent energy is minimal.)

                                           4-9
     {   ! m{{{{ j
     Jl~    swm             l  ~.::,.II,:::lmwTtlll~
                             �   Jwm~~~~~~~~~~~~~~~~~~~m~~~~;~

                     g~~~~~~~~~~~~~~~~~~~~~~55A6
                                        F~~~~~~~~~~~~~~~igue -.PecnCaynBotmSdets
    ~~~~~Prenae a r        h    w        yconor.Highs ocnrtosaeoae

                                    in the  centra/ bay  rea   where turbulen energy is   minimaL

          II~~~~~~~~~~~~-

                          From the earliest work reported by Ryan (1953), it has been known that the bulk of
    Chesapeake Bay sediment is fine-grained materials which settled out in the sluggish flow associated
    with the low gradients provided by the nearly flat coastal plain. Because of the low gradients of the
    mouths of tributaries, themselves estuaries to the larger Chesapeake Bay estuary, much of the coarse
    load carried by the rivers and streams is deposited before it reaches the bay.
                          As pointed out by Schubel and Biggs (1969), there are three sources of sediment
    to the upper Chesapeake Bay: internal, marginal and external (Figure 4-7). Although their classification
    was applied to seston (suspended material), it is equally applicable to bottom sediments. Application of
    this concept is evident (but not specified) in sedimentological studies as early as that of Hunter (1914)
    and much later by Kofoed and Gorsline (1966). The effects of shoreline erosion (marginal sources) as a
    major source of coarse materials is discussed by Slaughter (1966, 1967), Schubel and others (1972), and
    Palmer (1972a, 1973, 1974).
                           Figure 4-4 reveals a general trend toward high concentrations of sand in the
    marginal areas of the upper bay, and although the limited number of samples renders this map far from a
    complete inventory of sandy locations, several trends appear to emerge. It will be noted that
    predominantly sandy areas are common to the eastern shoreline of the upper bay, while such extensive
    shoals are lacking or reduced along the western margin. Consideration of the annual regional wind field
    indicates an overwhelming westerly component to all but late spring winds. Considering the relatively
    broad fetch and exposed nature of the eastern shore, it seems logical to assume a much greater rate of
    sediment generation through destruction of marginal deposits along the eastern margin of the upper bay
    than along the western shoreline. The major exception to marginal sources is that of the Susquehanna
    Flats, the large delta formed at the head of the bay, where much of the flood deposits from spring freshets
    accumulate. (This was the site of major accumulations of coarse materials following the record dis-
    charges accompanying Tropical Storm Agnes in June 1973). Due to a fortuitous break in the often cloudy
    spring skies, the peak flow for the 1974 freshet was photographically recorded by an ERTS-1 (Earth
    Resources Technology Satellite) orbit on April 3, 1974 (Figure 4-8.) In the course of studies under a
    separate contract, data for suspended sediment concentrations were obtained during this event. Size
    analyses showed that as much as 50 percent of the suspended sediment in the water column at this site
    was of silt size (62 to 4 microns diameter) and that concentrations of seston reached 45 mg/liter. Both
    parameters are higher than average; these freshet events must be considered significant occurrences
    with regard to total sediment budgets in the upper bay (Schubel, 1972).
                           An examination of the silt content in sediments of the upper Chesapeake Bay
    provides a significant insight into the hydraulic processes which affect the distribution of detrital
    materials in regional bottom sediments. These are the particles derived from pre-existing materials
    (rocks, sedimentary deposits, etc.) as opposed to particles resulting from biologic activity, agglomeration
    of fine particles into a single larger composite particle, and man's activity (slag, coal from mining
    operations, etc.).
                           Clay-size materials (particles having diameters less than four microns) are fre-
    quently involved in biologic and chemical processes which form agglomerated masses having settling
    velocities much higher than those for their'individual constituent particles. Therefore, the evaluation of
    local hydraulic regimes based upon size analyses is biased to an unknown degree, depending upon the
    efficiency of agglomerative processes and the ensuing disruption of these agglomerates during process-
    ing of sediment samples for size analyses. In an effort to determine the local hydraulic processes affec-
    ting sediment distribution in the upper Chesapeake Bay, attention was directed to the finest particles
    which do not participate in agglomerative processes. These are the silts. The distribution of this size and
    composition was accomplished by scanning electron microscopy (SEM) and x-ray fluoresence.
    Representative SEM images, and distribution maps for selected mineral components, are shown in
    Figures 4-9 through 4-12.
                           Quartz is by far the most common mineral in the silt and the sand fractions of the
    upper bay's bottom sediments (Figure 4-10). Only one local area contains less than 80 percent quartz,
    and regional val'ues are generally greater than 90 percent (Figure 4-9). The quartz silt commonly appears
    in two shapes: (1) as a rounded, generally equidimensional grain with surface textures displaying
    evidence of fluviatile abrasion (Figure 4-9b and c; see Krinsley and Margolis, 1969 for discussion of sur-
    face textures), and (2) as irregular plate-like chips with surface textures attributable to glacial grindings
    (Figure 4-9a). Muscovite (Figure 4-1 1) is the dominant mica in the bay, and in local areas can account for

                                                     4-10

                                                                                      75151A162
          Figure 4-7. The Three Sources of Sediment to the Bay.
       (Sources are shown in schematic form. Internal sources are bio-
    genic and from resuspension. Marginal sources are those of shoreline
     erosion; external sources are the contributions from tributaries.)

                                   4-11

                                                                                               75151A163

    Figure 4-8. Satellite (ER TS- 1) Photograph of the Upper Chesapeake Bay, April 3, 1974.
              (Peak flows associated with the spring freshet have created turbid
                conditions at the mouth of the Susquehanna River. The
                    station  denoted by the figure 13 was occupied on
                                           this date.)

                                              4-12

    QUART                                      ' 'i i H                              i !;  "

                                                                                                    75151A164
              Figure 4-9. Scanning Electron Microscope Images of Quartz Silt
                             (Bar scale is 20 microns in length.)

                                               4-13

                                                                                  75151A165
    Figure 4- 10. Distribution of Quartz Silt in Bottom Sediments.
              (Contours are in percent quartz content)

                                4-14

                                                                                             75151A166

    Figure 4-1 1. Scanning Electron Microscope Image of Mica (Muscovite) from Bay Sediments.

                                             4-15

                                                                             75151 AI67
    Figure 4- 12. Distribution of Mica in Bay Sediments.
                (Con tours are in percent)

                           4-16

    more than five percent of the total sediment (Figure 4-12). Glauconite (Figure 4-13) is a common
    accessory mineral throughout the upper Chesapeake Bay (Figure 4-14), and silt size particles display an
    etched appearance common to chemical weathering processes affecting grain surfaces. Slag and coal
    (Figure 4-15) are found in localized areas. The coal generally is concentrated in the headward portion of
    the upper bay, while the slag is centralized about the mouth of the Patapsco River (Figure 4-1 6). Biogenic
    components (Figure 4-17) are ubiquitous, reflecting internal contributions to sediments throughout the
    entire bay.
                           Analyses for clay mineralogy were not performed during this study, but the
    preliminary work of Palmer (1972a) in the Chester River and more detailed studies in the upper
    Chesapeake Bay by Owens and others (1974) reveal the following relative abundances: illite, 39.9 per-
    cent; kaolinite, 261 percent; montmorillonite, 21.1 percent, and chlorite, 12.9 percent. The general dis-
    tribution of clays in the upper bay was shown in Figure 4-6.

           4.1.4 Discussion
                   The centralization of clays and silts in the broad area between the Patapsco and Chester
    Rivers is a reflection of the regional hydraulic regime. Here the circulation is more sluggish than in the
    channel area which occupies the eastern margin of the upper bay. Within this area, sand-silt ratios reach
    a maximum value of 47 (see Figure 4-5), and clay content also is higher than elsewhere in the upper bay
    (see Figure 4-6). Consideration of published circulation patterns in this section of the bay (ESSA, 1968)
    and discussions with workers participating in this study imply that, although a true gyre does not exist in
    this broad segment, tidal currents are indeed slower than the average velocities encountered in more
    restricted cross-sections of the upper Chesapeake Bay. For this reason, one may consider this region to
    be a sediment sink in that diminished current speeds promote the settlement of finer grained materials.
    Consideration of the sand-silt-clay ratios for samples with respect to particle size provides some insight
    into mechanism which lead to the deposition of the finer fractions of the bay's sediment load.
                   Sediment size data may be conveniently presented on a triangular diagram in which the
    apices represent the three major size components (Figure 4-1 8). If the sediment recovered from the floor
    of the bay moves as bedload, that is, in traction along the bottom in response to fluid drag, then there
    should be a regular diminution of size (usually quantified as a mean or median particle diameter for a
    given sample) in a downstream direction (Figure 4-19, Left).This is the concept of the graded river in
    which the materials deposited in the river bed are adjusted to the flow regime in the river at that point.
    The coarser particles are left upstream in the region of swift flow, while the finer materials are carried
    past the site to be deposited in an area of more tranquil flow. Under these conditions where bedload
    dominates, the distribution of a suite of samples would appear as shown in (Figure 4-19, Left). But as
    many workers have shown, the silt and clay fractions of sedimentary deposits have particle diameters
    such that the threshold velocity required to initiate movement (to pick upa particle) is much greater than
    that velocity required to maintain it in suspension (Smith and Hopkins, 1972). For this reason, one can
    expectthat silt and clay, once entrained in the fluid, cannot travel as bedload but only as a suspended load
    (part of the seston discussed in this section). Under such circumstances, one may expect a distribution of
    sample points similar to that shown in Figure 4-19, Right. In this figure, the distribution of points
    representing samples is scattered across the central part of the diagram, and the poor sorting implies a
    fluctuation in the transport energy which in turn determines the nature of the deposit. This figure dis-
    plays the normal distributional pattern of sample points from estuarine studies (Palmer, 1972; Faas,
    1972; Nichols, 1972; Merryman and Palmer, 1975), and it holds true for upper Chesapeake Bay samples
    taken for this study (Figure 4-20).
                   If one compares the relatively high threshold velocity required to entrain a silt particle
    with the relatively low settling velocity for the same particle, it is apparent that there will be poorer sor-
    ting with a decrease in mean particle size. This is because deposition will take place only when tur-
    bulence, and not necessarily velocity, diminishes to a value below that of settling for a given grain size.
    With decreasing particle diameter, the point is approached where sustained background turbulence ex-
    ceeds settling velocity, and the particles may be considered to be in permanent suspension. According to
    Schubel (1 971 ), upper Chesapeake Bay turbulence may be considered to be about 1 0-3 cm/sec, which
    corresponds to a settling velocity for particles having a diameter of four microns (at 200C).

                                                     4-17

                                                                                        75151A168
    Figure 4-13. Scanning Electron Microscope Image of Glauconite Grain.
           (The grain is front center of angular quartz silt particle.
                           Scale bar is 20 microns.)

                                     4-18

                                                                                   75151A169
        Figure 4-14. Distribution of Glauconite in Bay Sediments.
     (Contours are in percent Broad grey arrows are slag trajectories
    from the Patapsco River; narrow black arrows are coal trajectories
                     from the Susquehanna River.)

                                  4-19

                                                                                    75151A170
    Figure 4-15. Scanning Electron Microscope Images of Slag Fragments in
                       Upper Bay Bottom Sediments.
                          (Scale bar is 20 microns.)

                                   4-20

                                                                                   75151A171
    Figure 4-16. Distribution of Slag and Coal in Bottom Sediments.
                       (Contours are in percent)

                                 4-21

                                                                             75151A172
    Figure 4-17. Diatom Frustule Comprising Some of the Biogenic Debris in
                   Bottom Sediments of the Upper Bay.
                        (Scale bar is 20 microns.)

                                 4-22
               "~iF    'c*?~                     !~ ....~~~~~~~~~~~~~'

     1'5 ~ii~i

                                 4-22

                                           /SANDY  S I LTY
                                           CLAY  CLAY

                                   -  /CLAYEY/ SAND-  CLAYEY
                                     SAND SILT-CLAY SILT

                                           SILTY   SANDY
                         / SAND \   SAND                          SILT                  SILT

                                                                                                       75151A173
                              Figure 4-18. Triangle Diagram for Displaying Sediment
                                               Size Characteristics.

                          CLAY                                                            CLAY

                           / *                                                             .

    SAND                                                SILT       SAND                                                  SILT

                        BEDLOAD                                                      SUSPENSION
                                                                               w/SETTLING
                                                                                                       75151A174
                       Figure 4-19. (Left) Pattern of Sample Distribution for Bedload Materials.
                (Trend for graded deposits is shown by arrows; with diminishing currents the deposit
                         decreases in size from sand, through silt, and ultimately to clay.)

             (Right) Pattern of Sample Distribution for Deposits Resulting from Suspended Sediment.
                       (Once placed in suspension, silt size particles are carried as suspended
                            load and deposited with various mixtures of sand and clay.)
                                                       4-23

                           CLAY

                      /~~~~~
                                       0..

                                         S.

               SAN/D  SILT

           SAND~~~~~~~~~~ SIL

                                                           75151A175
    Figue 4-20. Triangle Diagram for Bottom Samples Recovered During the Upper Bay Survey.
                 (Note correspondence with Figure 4-19, Right.)

                              4-24

                   However, the bottom sediments contain finer material which have settled from suspen-
    sion during periods of quiescence, and the bulk of suspended sediment (the modal class) lies in a size
    range of 0.60 to 0.74 microns (Figure 4-20). Inasmuch as turbulence is highly variable and transitory,
    local variations in size distribution with both space and time are common. Yet, it is possible to determine
    trends such as those shown by Figures 4-5 and 4-6 which reveal hydraulic controls on bottom sediment
    distribution. Thus, Figure 4-5 provided a picture of longterm integration of the turbulence and velocity
    fields within the upper bay, and it may be considered an indicator of the sinks for materials carried by the
    five fractions of sedimentary deposits.

           4.1.5 Summary
                   The purpose of the bottom sampling program was to determine the geographic distribu-
    tion of sediment types and to seek correlations between size distribution and concentrations of various
    chlorinated hydrocarbon compounds in the upper Chesapeake Bay. Sediment distribution has been
    covered in previous sections, but in summary, we may present the concentration data compared to size.
                   Figures 4-21 through 4-23 display concentration values for most of the bottom sediment
    samples described previously. In all three cases, there is a general upward slope as size diminishes and
    concentration increases. In Figure 4-21, the concentration increases. In Figure 4-21, the concentration
    of PCB (Aroclor)1 254) averages about 0.09 ppm., with maximum values reaching well over 1 ppm. The
    same appear valid for the total PCB, but the average here is somewhat higher centered around 0.15 ppm
    (Figure 4-22). Total DDT values are lower (Figure 4-23), with an estimated average about 0.05 ppm,
    although this figure relies on fewer data points than the other two figures.
                   The implication drawn from these three plots is similartothat established for the Chester
    River Study (Clarke, et al., 1 972) that an increase in concentration of both chlorinated hydrocarbons and
    trace metals (not addressed here) will be found in the finer fractions of natural sediments. Mechanisms
    for such situations are discussed in that report and will not be repeated here. However, one may make
    comparisons between the two regions, since analytical and sampling techniques were identical for both
    the Upper Bay Survey and the Chester River Study. Comparison of the total PCB concentration between
    the two areas indicates that in the upper Chesapeake Bay, bottom sediments generally carry a greater
    burden of PCB's than do those of the Chester River, a major eastern shore tributary to the upper bay.
    Figures 2 through 13 in Clarke et al. (1972) show a general relationship of spring and early summer data
    points which fall between 0.1 5 and 0.25 ppm. This is the general range for many points from the upper
    bay (Figure 4-22), but about one-third of the latter lie above 0.3 ppm. Such values were not recorded dur-
    ing the Chester River Survey.
                   Common values of total DDT for the Chester River fall between 0.01 and 0.05 ppm.
    (Figures 2 through 1 5 of Clarke et al., 1972). However, more than one-half the bottom samples from the
    upper bay showed values in excess of 0.05 ppm., the upper limitfor Chester River materials. The conclu-
    sion which must be drawn from Figure 4-23, as well as from the PCB data shown in Figure 4-22 is that
    the upper Chesapeake Bay sediments in certain areas contain relatively high concentrations of these
    chlorinated hydrocarbon compounds. The higher values on these two figures are generally attributed to
    their proximity to, or recovery from, the Patapsco River. Other data presented elsewhere in this report
    display the concentrations and locations in graphic form (Chapter 6, Figures 6-2 and 6-3).
                   It seems clear that the concentration of fine-grained sediments in the central part of the
    upper bay, as shown in Figures 4-5 and 4-6, may form a sink for much of the chlorinated hydrocarbon
    compounds originating in the Patapsco River tributary. This appears to be the case with trace metal con-
    centrations described by Helz (1974), and it is suspected that the same is true for PCB, DDT, and the other
    compounds of local origin. If this is the case, much of the material introduced by various local tributaries
    and from various industrial activities will be trapped in the region immediately outside (and also within)
    this tributary. For this reason, plans for maintenance and/or new dredging activities the area where
    these materials may be accumulating should be carefully studied prior to the dislocation and transport of
    burdened spoil materials. As Figures 4-21 through 4-23 show, there can be an order of magnitude
    difference in concentration for a given size class, suggesting that local variations may be quite high in
    relation to the total variance in concentration. Again, such distributional variations suggest that specific
    studies of local areas, as opposed to reconnaissance surveys, should be implemented for specific dredg-
    ing projects involving the removal of materials carrying significant burdens of chlorinated hydrocarbons.

                                                     4-25

                    l~~~~~~~~~~~~

                                                        *3.7

    .01[
       -                                   *                                                         0

                    2 4                                           6                      8                      10

                                                                                                     75151A176
                            Figure 4-21. Comparison of Mean Grain Size, in Phi Units.
          ~~(.1The-                                             1254 is in partsper million.

                                    One point lies at 3.7?ppm, off graph at top.
                           In phi notation, larger values compare to smaller particle size.)

                                                      4-26
                                                     S~~~~~~~~

                                                 *~~~~~~ S

                                                  ** 6

                                        .~~~~~~~~ I

                             .

        .01         2                      4           :6                                 8                     10

                                                          0

                                                                                                     75151A 176
                            Figure 4-2 1. Comparison ofMllean Grain Size, in Phi Units.
                         (The concentration of Aroclor�) (PCB- 1254 is in parts per million.
                                    One point lies at 3.7 ppm, off graph at top.
                           In phi notation, larger values compare to smaller particle size. J

                                                      4-26

         10

                                                                  3.7
            0
    a-

    -J
        =                                                           3.                                    **

                          E~~~~~~~~~~~~~~~~~

                           D.01~~~
                f:3.~~~~~~~~~

                       .I~~~~~~-                                                                                     0~~ ~42

        .01             -,
                                                                                     0~~~ 0

                         2                       4                        6                        8                       10
                                                                 0

                                                                                                               75151A176
                                 Figure 4-22. Comparison of Mean Grain Size, in Phi Units.
                                (The concentration of total PCB, is in parts per million. One
         point lies at 3.7 ppm off the graph at top. In phi notation, larger values compare to smaller particle size.)

                                                            4-27

       a   -.1-                                *

    a.
    I--

               1--0 ~ ~ ~ ~

                                                                                      0

                                  0                                              .
                                                                                      *
                                                                                 .~~~~~

       .01               ,                      I                       ,                       ,            _
                        2                      4                       6                       8                      10

                                                                0

                                                                                                            75151A177
                              Figure 4-23. Comparison of Mean Grain Size, in Phi Notation.
                          (The concentration of total DDTis in parts per million. In phi notation,
                                     larger values correspond to smaller particle size.)

                                                           4-28

                   To confirm the premise that finer grain sizes are enriched in chlorinated hydrocarbons,
    an analysis was performed on different size fractions of two bulk samples one from the Baltimore harbor
    area and one from the mouth of the Chester River. The samples, consisting of about 18 kg (40 pounds) of
    sediment, were placed in a large container with distilled water, stirred, and left to settle. At appropriate
    intervals, a tray was placed in the suspension and left in place to collect fine-grained sediment as it
    settled through the water. Then, film of sedimentwas removed, classified for grain size, and analyzed for
    chlorinated hydrocarbon content. The results of this experiment are presented in Figures 4-24 through
    4-26.
                   The concentration of chlorinated hydrocarbons as a function of grain size is clearly evi-
    dent from these tests. With a decrease in grain size of only two phi units, a pronounced increase in con-
    centration was evident. In addition, with but one exception, the Chester River samples were significantly
    lower than similar sized materials from the Baltimore harbor. In view of the data presented elsewhere in
    this report, this was not surprising, and this simple test confirmsthefactthat the finer fractions of the up-
    per Chesapeake Bay sediments are carrying the major part of chlorinated hydrocarbon residue in the
    aquatic environment.

                                      ED BALTIMORE HARBOR
                                 2.15-      CHESTER  RIVER    -
                             CL

                             co

                                   7.0         758.0                8.5 9      .
                                   (SYx)                (4y)                   (2jA)
                                                      mean 0

                                     +  BELOW DETECTION LIMIT AT 7.08 0

                                                                                                  7515 A178
                           Figure 4-24. Chlordane Concentrations in Bottom Sediments from
                                       Baltimore Harbor and the Chester River
                                        (depicted as a function of grain size.)

                                                       4-29

                  3.0-
                        I  IBALTIMORE  HARBOR
                        M   CHESTER RIVER

                  2.5-

                  2D-

                a
                  1.5-

                   1.0-

                   .5-

                    O{                               ... I  I  .... I
                     70       .5        8.0       8.5      9.0
                    (8g)               (4/)               (2 p )
                                    mean 0
                                                                                 75151A179
    Figure 4-25. Polychlorinated Biphenyl Concentrations in Bottom Sediments
                 from Baltimore Harbor and the Chester River
                    (depicted as a function of grain size.)

                        = BALTIMORE HARBOR
                   .40- LM CHESTER RIVER

                   .35-

                 _.30-                            [

                   .10-

                   .05-

                   .01 I  I  I  I
                     Z0       Z5        8.0      8.5       9.0
                    (8B)               (4,)               (2.)
                                    mean 0
                       + = 0.0004 AT 7.03 0
                         =0.0052 AT 7.08 0                                            85151A180
       Figure 4-26. DD T Residue Concentrations in Bottom Sediments from
                    Baltimore Harbor and the Chester River
                     (depicted as a function of grain size.)

                                     4-30

           4.1.6 Acknowledgements
                  The Upper Bay Survey required extensive field operations and long hours aboard ship. It
    is a pleasure to acknowledge the able support provided by Grey Lyons, Manu Swain, Jeff Nolder and Rick
    Woll. The tedious and difficult laboratory analyseswere conducted byTehana Merryman. Scanning elec-
    tron microscope work was performed under the direction of Bob Wytkowski of the Westinghouse
    Research and Development Laboratory in Pittsburgh. The technical competence and dedication of all
    these assistants contributed to the successful completion of this aspect of the survey.
                  Editorial comments by M. Grant Gross and Jerry Schubel contributed to the final
    manuscript.

           4.1.7  References

    Biggs, R.B., 1970. Sources and Distribution of Suspended Sediment in Northern Chesapeake Bay.
           Marine Geol., V. 9, pp. 187-201.

    Clark, W.D., H.D. Palmer, and L.C. Murdock, (eds.), 1972. Chester River Study, Vol. 11, Westinghouse
           Electric Corp., Annapolis, 251 pp.

    Cleaves, E.T., J. Edwards, Jr., and J.D. Glaser, 1968. Geologic Map of Maryland. Maryland Geological
           Survey, Baltimore, Md.

    DeAlteras, J.T., 1975. Possible Evidence of Late Quaternary Uplift in the Area of Wachapreague,
           Virginia. in Abstracts with Programs, Geol. Soc. America, V. 7, p. 47.

    ESSA, 1968. Tidal Current Charts, Upper Chesapeake Bay. Environmental Science Service Admin. rpt,
           12 pp.

    Faas, R.W., 1972. Mass Physical and EngineeringProperities of Some York River Sediments. in Environ-
           ment Framework of Coastal Plain Estuaries, B.W. Nelson (ed.), Geological Society of America
           Memoir No. 133, pp. 169-212.

    Hack, J.T., 1957. Submerged River System of Chesapeake Bay, Geological Society of America Bull.,
           V. 68, pp. 817-830.

    Hansen, H., 1974. Interpretation of Chesapeake BayAeromagneticAnomalies: Comment, Geology, V.2,
           pp. 449-450.

    Helz, G.R., 1974. Trace Metal Inventory for the Upper Chesapeake Bay, Md. in Abstracts with program,
           Geological Society of America, V. 6 pp. 789-790 (abstract).

    Hicks, S.D., 1972. On the Classification of Trends of Long PeriodSea LevelSeries. Shore and Beach,
           V. 40, No. 1, pp. 20-23.

    Higgins, M.W., I. Zietz, and G.W. Fisher, 1974. Interpretation ofAeromagneticAnomalies Bearing on the
           Origin of Upper Chesapeake Bay and River Course Changes in the Central Atlantic Seaboard
           Region: Speculations. Geology, V. 2, pp. 73-76.

    Higgins, M.W., I. Zietz, and G.W. Fisher, 1974. Interpretation of Chesapeake Bay Aeromagnetic
           Anomalies, Bearing on the Origin of Upper Chesapeake Bay and River Course Changes in the
           Central Altantic Seaboard Region: Speculations. Geology, V. 2, p. 450.

                                                   4-31

    Holdahl, S.D., and N.L. Morrison, 1974. Regional Investigations of Vertical Crustal Movements in the
           U.S., Using Precise Relevelings and Mareograph Data. in R. Green (editor), Recent Crustal
           Movements and Associated Seismic and Volcanic Activity. Tectonophysics, V. 23, pp. 373-390.

    Hunter, J.F., 1914. Erosion and Sedimentation in the Chesapeake Bay Around the Mouth of the Chop-
           tank River. U.S. Geological Survey Prof. Paper 90-B, pp. 13-14.

    Kofoed, J.W. and D.S. Gorsline, 1966. Sediments of the Choptank River, Maryland. Southeastern
           Geology, V. 7, pp. 65-82.

    Krinsley, D.H. and S.V. Margolis, 1969. A Study of Quartz Sand Grain Surface Textures with the Scan-
           ning Electron Microscope. Trans., New York Acad. Sci., Ser II, V. 31, pp. 457-477.

    Maher, J.C. and E.R. Applin, 1971. Geologic Framework and Petroleum Potential of the Atlantic Coastal
           Plain and Continental Shelf. U.S. Geol. Survey Prof. Paper 659, 98 pp.

    Merryman, T., and H.D. Palmer, 1975. The Nature, Origin, andDistributionofDetritalSiltinSedimentsof
           The Upper Chesapeake Bay, Maryland in abstracts with program, Geol. Soc. America, V. 7,
           pp. 94- 95.

    Nichols, N.M., 1972. Sediments of the James River Estuary, Virginia. in Environmental Framework of
           Coastal Plain Estuaries, B.W. Nelson (ed), Geological Society of America Memoir No. 133, pp.
           169-212.

    Nichols, M.M., 1975. Escape or Entrapment? Case for Chesapeake Tributaries. in EOS-Trans.; Amer.
           Geophysical Union; V. 56, p. 88 (abstract).

    Owens, J.P., L.A. Sirkin, and K. Stefansson, 1974. Chemical, Mineralogic, andPalynologic Character of
           the Upper Wisconinan-Lower Holocene Fill in Parts of Hudson, Delaware, and Chesapeake Es-
           tuaries. Jour. Sed. Petrology, V. 44, pp. 390.

    Palmer, H.D., 1972a. GeologicalInvestigations in Chester River Study, V. II, W.D. Clarke, H.D. Palmer &
           L.C. Murdock, (eds), Westinghouse Electric Corp., pp. 75-137.

    Palmer, H.D., 1972b. Trace Metals Investigations in Chester River Study, V. II, W.D. Clarke, H.D. Palmer
           & L.C. Murdock, (eds), Westinghouse Electric Corp., pp. 47-59.

    Palmer, H.D., 1973. Shoreline Erosion in Upper Chesapeake Bay: The Role of Groundwater. Shore and
           Beach, V. 41, N. 2, pp. 18-22.

    Palmer, H.D., K.T.S. Tzou, R.W. Onstenk, and D.M. Dorwart, 1973. Estuarine Sedimentation Regime,
           Chester River, Maryland in Abstracts with Programs, Geol. Soc. America, V. 5, pp. 204-205
           (abstract).

    Palmer, H.D., 1974. Estuarine Sedimentation, Chesapeake Bay, Maryland, USA. in International Sym-
           posium on Interrelationships of Estuarine and Continental Shelf Sedimentation, Mem. Inst.
           Geol. Bassin Aquitaine, N. 7, pp. 215-224.

    Palmer, H.D., and T.O. Munson, 1974. Sediments as Vehicles for Trace Metals and Chlorinated
           Hydrocarbons: Upper Chesapeake Bay. in Abstracts with Programs, Geol. Soc. America, V. 6, p.
           62 (abstract).

    Roberts, W. P., and J.W. Pierce, 1974. Sediment Yieldin the Pautuxent River (Md.) Undergoing Urbaniza-
           tion, 1968-1969. Sedimentary Geol., V. 12, pp. 179-197.

                                                    4-32

    Royse, C.F. Jr., 1970. An Introduction to Sediment Analysis. 180 pp.

    Ryan, J.D., 1953. Sediments of Chesapeake Bay. Maryland Department of Geology, Mines and Water
           Res., Bull. 12, 120 pp.

    Schlee, J., 1957. Upland Gravels of Southern Maryland. Geol. Soc. America Bull., V. 68, pp. 1371-1409.

    Schubel, J.R., 1968. Suspended Sediment of the Northern Chesapeake Bay. Tech. Rpt. No. 35,
           Chesapeake Bay Instit., The Johns Hopkins University, 264 pp.

    Schubel, J.R., 1971. Estuaries and Estuarine Sedimentation; in the Estuarine Environment, various
           chapters, Amer. Geol. Instit., Short Course Lecture Notes, Washington, D.C.

    Schubel, J.R., 1972. Suspended Sediment Discharge of the Susquehanna River at Conowingo,
           Maryland, During 1969. Chesapeake Science, V. 13, pp. 53-58.

    Schubel, J.R. and R.B. Biggs, 1969. Distribution of Seston in Upper Chesapeake Bay. Chesapeake
           Science, V. 10, pp. 18-23.

    Schubel, J.R., H.H. Carter, E.W. Schiener, and R.C. Whaley, 1972. A Case Study ofLittoralDrift Based on
           Long-term Patterns of Erosion and Deposition. Chesapeake Science, V. 13, pp. 80-86.

    Schubel, J.R., and E.W. Schiemer, 1973. The Cause of the Acoustically Impenetrable, or Turbid,
           Character of Chesapeake Bay Sediments. Marine Geophys. Res., V. 2, pp. 61-71.

    Siegrist, H.G., 1975. Sediments of the Chesapeake Bay. The Chesapeake Chemist, Jan. 1975, pp. 6-7.

    Slaughter, T.H., 1966. Are We Conserving Maryland's TidalLands? Maryland Conservationist, V. 43, pp.
           9-13.

    Slaughter, T.H., 1967. Shore Erosion Control in Tidewater Maryland. Washington, Academy Sci., Jour.
           57.

    Slaughter, T. H., 1967. Vertical Protective Structures in the Maryland Chesapeake Bay. Shore and
           Beach, V. 35, pp. 7-17.

    Smith, J.D. and T.S. Hopkins, 1972. Sediment Transport on the ContinentalShelf off of Washington and
           Oregon in Light of Recent Current Measurements. in Shelf Sediment Transport: Process and
           Response, D.J.P. Swift, D.B. Duane and O.H. Pilkey, eds, Dowden, Hutchinson and Ross, Inc.,
           Stroudsburg, Pa., pp. 143-180.

    Swift, D.J.P., J.R. Schubel, and R.E. Sheldon, 1972. SizeAnalysis of FinegrainedSuspendedSediments:
           A Review. Jour. Sed. Petrol, V. 42, pp. 122-134.

    Vokes, H.E., 1957. Geography and Geology of Maryland. Maryland Geological Survey, Bulletin 19, 243
           pp., Revised by J. Edwards, Jr., 1968.

    Weaver, K.N. and H.J. Hansen, 1966. AnAncientBuriedRiverChannelisDiscovered. Maryland Conser-
           vationist, V. 43, pp. 9-12.

                                                   4-33

      4.2 Suspended Sediment in the Waters of the Upper Chesapeake Bay

           4.2.1  Introduction
                   For the purposes of this discussion, the upper Chesapeake Bay is defined as the segment
    of the bay proper north of 38057'N. It is generally shallow with a mean depth of nearly four meters. The
    hypsometry of the bay has recently been described by Cronin and Pritchard (1975). The bottom
    sediments are predominantly mud-silt and clay-except in the littoral zone where sand locally derived
    from erosion of the coast predominates (Ryan, 1953; Schubel, 1968a; Palmer, this volume).
                   The upper Chesapeake Bay is clearly the estuary of the Susquehanna River. The Sus-
    quehanna, entering at the head of the bay, is the only river that discharges directly into the main body of
    the Chesapeake Bay. All of the other rivers discharge into estuaries that are tributary to the bay proper.
    The Susquehanna, with a longterm average discharge of about 985 m3/sec, supplies approximately 90
    percent of the total freshwater input to the bay north of 39057'N. The characteristic seasonal variation in
    the riverflow, high discharge in late winter and early spring followed by lowto moderate flowthroughout
    the summer and most of thefall, is revealed by an ensemble average taken by month from the Conowingo
    Dam records of 1929-1966 as shown in Figure 4-27 (Boicourt, 1969).
                   The Susquehanna flow regime and the associated circulation patterns generated within
    the upper Chesapeake Bay in response to the varying role of the river produce two distinctive dis-
    tributions of suspended sediment and concomitant patterns of sediment transport. The first
    characterizes the spring freshet and other periods of very high riverflow. The second, characteristic of
    periods of low to moderate riverflow, typifies most of the remainder of the year. These are particularly
    evident in the upper 30 to 40 km of the bay. Farther seaward, the coupling of the distribution and
    transportation of suspended sediment to the discharge of the Susquehanna is less apparent.

           4.2.2 Sources of Sediment
                   The ultimate sources of sediments to the upper Chesapeake Bay are rivers, shore ero-
    sion, and biological activity within the bay. An additional source of sediment to the upper bay-a prox-
    imate source-is the transport of sediment from more seaward segments of the estuary by the net up-
    stream flow of the lower layer. Thus, the sources of sediment to the upper bay are external, internal, and
    marginal. The predominant source of fine-grained sediment isthe fluvial input, and it isthe only one con-
    sidered in this report.
                   The Susquehanna River is the only significant source of fluvial sediment to the upper
    Chesapeake Bay. The sediment being discharged is predominantly clay and silt; the coarser particles are
    entrapped in the reservoirs along the lower reaches of the river. All of the other rivers debouch into es-
    tuaries, and the bulk of their sediment loads are trapped in the upper reaches of those tributaries. These
    tributaries probably act as sediment sinks rather than sources to the main body of the bay. Not only do
    they entrap most of the sediment introduced by their rivers, but they also entrap fine sediment carried
    into them from the bay proper, sediment derived primarily from the Susquehanna. This mechanism has
    been described on a number of occasions over the years by D.W. Pritchard (personal communication) and
    by Schubel (1968a, 1972a), and was demonstrated by the Chester River Study (Clarke et al., 1972).
                   During most years, the bulk of the sediment is discharged during the normal spring
    freshet when both riverflow and the concentration of suspended sediment are high. Since the spring of
    1 966, the Chesapeake Bay Institute has been monitoring the input of suspended sediment by the Sus-
    quehanna River by sampling the discharge at the Conowingo Hydroelectric Plant (Schubel, 1968b;
    1971 a; 1974). In the twelve-month period from April 1, 1966 through March 31,1967, the Susquehanna
    discharged an estimated 0.6 x 106 metric tons of suspended sediment into the upper Chesapeake Bay
    (Schubel, 1968b). In 1969 the estimated input was approximately 0.3 x 106 tons (Schubel, 1971 b). In
    1972-the year of Tropical Storm Agnes-the Susquehanna discharged an estimated 33 x 106 tons of
    sediment into the upper bay, more than 95 percent of which was discharged in June following Agnes
    (Schubel, 1974).

                                                    4-34

      3000
                                                CONOWINGO NATURAL RIVER FLOW
                                                ENSEMBLE AVERAGE BY  MONTH
    (I)
    ' 2000 -                                            1929-- 1966

       1 000 -

           O
               JAN  FEB  MAR  APR  MAY   JUN  JUL  AUG  SEP  OCT  NOV  DEC

                                                                                         75151A181
               Figure 4-27. Ensemble Average of the Susquehanna River at Conowingo, 1929-1966.
          (An estimate of the monthly streamflow entering the Chesapeake Bay is depicted in Figure 5-12,
         and the discharge of the Susquehanna River in 1973 and 1974 is shown in Figures 4-28 and 4-29.)

                                                4-35

                  Estimates of the suspended sediment discharge of the Susquehanna River were made
    also for the period covered by this report. The same procedures were followed. Daily water discharge
    records for the Susquehanna River at Conowingo, Maryland, were furnished by the Conowingo
    Hydroelectric Plant. The data for 1973 and 1974 are plotted in Figures 4-28 and 4-29. During the same
    period, water samples were collected on nearly a daily basis from the tailrace of the hydroelectric plant
    for determining the concentrations of total suspended solids and of combustible organic matter. Water
    samples were collected with a specially-constructed, weighted, 1.2-liter water bottle that was lowered
    from the top of the dam through the discharge. The samples were filtered through preweighed 47 mm,
    0.6 #im APD Nuclepore filters.* The filters were desiccated over silica gel at ambient temperature for at
    least 72 hours and reweighed, then the concentrations (mg/I) of total suspended solids were calculated.
    All weighings were made to �0.01 mg. The concentrations of total suspended solids during 1973-74 are
    plotted in Figures 4-30 and 4-31.
                  The suspended sediment discharge was estimated in the following way: Each suspended
    sediment concentration was multiplied by the mean daily water discharge averaged over the period
    (defined by the mid-points between sampling dates) and by the length of this time interval to obtain the
    mass of sediment discharged during that period. Next, these data were summed to generate the total
    mass of suspended sediment discharged by the Susquehanna River into the upper Chesapeake Bay dur-
    ing 1973-74. The suspended sediment discharge data are plotted in Figures 4-32 and 4-33 as the
    cumulative mass percent and as the mass of suspended sediment discharged each month.
                   The procedure described above results in an estimated discharge of 1.2 x 1 06 metric tons
    for 1973 and of 0.8 x 1 06 metric tons for 1 974. A number of assumptions are involved in the determina-
    tion of the estimated suspended sediment discharge. It was assumed that each suspended sediment
    concentration was representative of the entire mass of water being discharged at the time of sampling.
    This assumption is probably reasonable, because the suspended sediment is very fine-grained and
    because the samples were collected directly from the well-mixed discharge water of the Conowingo
    Hydroelectric Plant. It was assumed also that each concentration was representative of the time interval,
    one to two days, defined by the midpoints between sampling dates. This assumption is reasonable ex-
    cept when water discharge may change markedly in a short time. The other assumptions are incor-
    porated in the averaging which is implicit in the calculation. To evaluatethese assumptions, the calcula-
    tion will be examined more closely. The following terms are defined:

                   Di   =  the mass of sediment discharged during a time interval A t,.

                   ti   =  the time interval defined by the midpoints between sample dates.

                   DE  =  the estimated mass of sediment discharged during the year.

                   Ci   =  the average concentration of suspended sediment over the time interval Ati.

                   Ci   =  the measured instantaneous suspended sediment concentration at the specific
                            time t within the time interval A ti.

                   C   =  the instantaneous suspended sediment concentration averaged overthe cross-
                            section of discharging water.

                   R   =  the instantaneous water discharge.

                        R = the mean water discharge averaged over the time interval A ti.

    * Nuclepore polycarbonate filters are produced by General Electric, and are distributed by Arthur H.
       Thomas and other scientific supply houses. (APD is average pore diameter.)

                                                    4-36

          JAN   FEB  MAR   APR  MAY   JUN   JUL   AUG   SEP  OCT   NOV  DEC
         .  .... I -   ... --II ... . I .  I .... . ....  II .... I   .  I ....  I ... I .... I  .... 210
      55 _                                                                      - 200
                                                                          - 190
      50-                                                                       - 180
                                                                          - 170
      45-                                                                        - 160
                                                                          - 150
      40-                                                                        - 40

                                                                          '.130
      35'- .-I 20
      35-
                                                                          -120
    o 30-                                                                         - I10 I
                      ~~~~~~~~x                                                  1~~~~~-I00
      25-                                                                        - 90 x
                                                                            80
      20 \    n       irI\1 n\I    70
                                                                            60
      15

         Figure10  4-28.-DischargeoftheSusquehannaRiveratConowingoin1973.40
                                                                            30
                        ~~~~~~~~~~~5-                                               hn  I Il  ,Il  20
                                                                            10
          JAN   FEB  MAR   APR  MAY   JUN   JUL  AUG   SEP   OCT   NOV   DEC
                                       1973
                                                                                75151A182
         Figure 4-28. Discharge of the Susquehanna River at Conowingo in 1973.

         JAN   FEB  MAR   APR  MAY   JUN  JUL   AUG   SEP  OCT   NOV   DEC
                                                                           210
                                                                         - 200
      55-                                                                        -190

      50-                                                                        -180
                                                                          -170
      45-                                                                        -160
                                                                          - 150
      40-                                                                        -140
                                                                          - I 30
                                                                          -1 20

                                                                          -I00
     2 25                                                                        -90
    ~"         I      II           I\                                         I~h- 80
                       ~~~~~~~~~~20 -1   nl~~~~ I  I 1- 70
                                                                           - 60
      15-
                                                                            50
                        lo:0-~~~~~~~~~ ~40
                                                                          30
                                                                          -  20

       0                                           ..... 0
         JAN   FEB  MAR   APR  MAY   JUN   JUL   AUG   SEP  OCT   NOV   DEC
                                        1974

                                                                                75151A183
          Figure 4-29. Discharge of the Susquehanna River at Conowingo in 1974.

                                       4-37

                    JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
                 21  1......................1.....                   ,,,..210

                200-                                                               200

                I 80                                                               180

                I 60 -                                                             160

                I 40     [                                                          40

                I I 0-                                                            - -110

                100-                                                              -100

               9o-                                                               - 90 E

                80-                                                                80 9

              o 70-                                                                 70

               60-                                                                 60,
              (,   .                                                                  0-
                 "50-                                                               50

                   i: 41-4

                 30                                                              30

                    JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
                                               1973

                                                                                                      75151A184

    Figure 4-30. Concentration (mg/I) of Suspended Sediment in the Susquehanna River
         (on the downstream side of the Conowingo Hydroelectric Plant) During 1973.

                    40JA   FEB  MAR   APR  MAY   JUN  JUL  AUG   SEP  OCT  NOV  DEC

                130-                                                                     -130

                120-                                                                     -120

                110--                                                                     110

                100-                                                                     - 100

               = 90-                                                                      -90

                 80 -                                                                       80

               0 70 -                                                                       70 �0

                60-                                                                         60

                50-                                                                       - 50 c
               =,

               .40                                                                          40

                 <40            SipW  ll    /?*20  A

                 10                                                                         10

                     JAN  FEB  MAR   APR  MAY   JUN  JUL  AUG   SEP  OCT  NOV  DEC
                                                  1974

                                                                                                      75151A185

    Figure 4-31. Concentration (mg/l) of Suspended Sediment in the Susquehanna River

       (on the downstream side of the Conowingo Hydroelectric Plant) During 1974.

                                                4-38

         1200JAN  FEB  MAR  APR  MAY   JUN  JUL  AUG  SEP  OCT  NOV  DEC 1200
          ..1200    ,..........  .....i....  .....,..... i.....  .....,.....  ....i,  , ,   -100
         1150-                                                                    1150
         l1O0 -  00  90
        n1050                                   -                                  105
        o1000 -                                                                   -1000)-
        0 950-                                                                    -9509- 80
          900 -                                                                     9005
          850-                                 -                                    850
        - 8Mo~  70
        1'800-                                                                     -800
        - 750-                                                                   - 750 x
          _ 700-                                                                  -700 6
        w 650-                                                                    -650'      U
         60 -                                                                     -600-- 50
        550-                                                                      - 550 �
        o' 500-                                                                   - 500
                          o                                                           - ~~~~~~~~~~~~~~~~~40  m
          450- - 450                                                                         B
        Z 400-                                                                    - 400o
          350-                                                                   -350E- 30
        s 300o-                                                                   -300
        o 250- -250-  20
        . 200-  - 2oo-00
        aW 150o-                                                                  -150a

           50                                                                    - 50
              JAN  " FEB  MAR  APR  MAY   JUN  JUL  AUG  SEP  OCT   NOV  DEC
                                           1973

                                                                                        75151A186

    Figure 4-32. Suspended Sediment Discharge of the Susquehanna River at Conowing During 1973
         (plotted as cumulative mass percent and as the mass discharged during each month).

        800JAN  FEB  MAR   APR  MAY   JUN  JUL   AUG   SEP   OCT  NOV   DEC                 100

       0                                       750          -
       I700-                                                                         700-90
        650                                                                         - 650 .  - 70
       b( -                                                                          6       00
       b 550-                                                                        550'02-70
       -~500-                                                                         500    6
         450                                   -  450
        I 400-                 /                                                   - 400  50
       5O5                                                                                 - 350 /
                                                                             -0o 40
       Z5o-                   /                                                     - 300 o. o
        250-              /                                                          250    30
       � 200 -                                                                      - 200 �
       0 150-                                               -1  50 $- 20

                         0B~~~~~~~~~~o- 0
       a 50- - - -                                                                  - 50 10
       m)    JAN   FEB  MAR  APR  MAY   JUN  JUL   AUG   SEP  OCT   NOV   DEC           0
                                           1974

                                                                                         75151A187

    Figure 4-33. Suspended Sediment Discharge of the Susquehanna River at Conowingo During 1974
         (plotted as cumulative mass percent and as the mass of sediment discharged each month).

                                            4-39

                  The mass of suspended sediment discharged over the time interval, T, of one year where
                                    n
                               T=.   At
                                   i=1
                  was estimated by
                                     n        n
                               DE= D  -           CR  At-                                         (1)
                                    i=1      i=1
                   Equation (1) also may be written as
                                      n             n
                               DE=   --  . CX  Ri At  i +  C  _C)At                               (2)
                                     i=1           i=1
                   The true value of the sediment discharged over thetime intervalT may be expressed by
                                      n
                               DT =  (CR)i t                                                      (3)
                                     i=1
    where
                               (CR) =- A      CRdt
                                      (C' ,iiAti

    The instantaneous values of C and R can be expressed as the sum of a mean value and mean deviation.
    Thus, for the time interval, At, one can write
                               C = Ci + C'i
                               R = Ri + R'i
    If one takes the product of these and averages, he obtains

                               (CR)i = Ci Ri    + C'i R i +    Ci R'i + C'i R';

    which reduces to
                               (CR)i = Ci Ri + C'i R'i                                            (4)

    The terms C, Ri and Ci R. both equal zero, since Re= i =O. And it is obviousthatCi R= C Ri if one averaged
    over the same time interval used to define Ei and Ri. The term C Rdoes not equal zero however, except
    under very special circumstances or unless the variables are uncorrelated (which is not the case here).
                   Using Equation (4), Equation (3) can be rewritten as
                                      n             n
                                DT = C 'i 'ii+          C', R'. Ati.                               (5)
                                     i=1           i=1
    The difference between the true suspended sediment discharge (5) and the estimated discharge (2) is
    then DT - DE or
                                           n          n
                                DT-DE=  .   CDi RAti-.  (Ci -C) Ri ti.                            (6)
                                          i=1        i=1

                   The error in the estimate (2) of the mass of suspended sediment discharged during the
    time interval, T, then is given by the difference of two terms. The first term on the right side of Equation (6)
    depends on the correlation between the fluctuations of the suspended sediment concentration and the
    water discharge during the time interval Ati. The suspended sediment concentration was generally
    measured by daily intervals; thus, one assumption implicit in the calculations used here is that the cor-
    relation of the fluctuations of river discharge and suspended sediment concentration at frequencies
    higher than one per day may be ignored. In general, the concentration of suspended sediment increased

                                                     4-40

    with river discharge and therefore, the correlation between them is positive. The first term on the right of
    Equation (6), then, is positive, and our estimate of the suspended sediment discharge, DE, tends to be less
    than the true value, DT.
                   The second term on the right side of Equation (6) depends on the difference between a
    single determination of the suspended concentration taken at a specific time t during the time interval Ati
    and the mean value of the suspended sediment concentration overthetime interval Ati. This term may be
    either positive or negative; hence, it may either add or subtract from the bias introduced into the estimate
    by the first term. Since there were 316 suspended sediment determinations in 1973 and 346 deter-
    minations in 1974, and since there is equal probabilitythat (Ci -Ci)for any single setwill be either positive
    or negative, the effect of this term on the estimate is probably quite small. It follows that the calculations
    of 1.2 x 106 metric tons for 1973 and 0.8 x 106 metric tons for 1974 are probably underestimates, but it
    cannot be said by how much. The estimates could not have been improved easily. Sampling at frequen-
    cies more often than once per day does not seem warranted, because only daily mean water discharge
    records are available.

           4.2.3 Suspended Sediment Population
                   At any point in time and space, Chesapeake Bay's suspended sediment is a subpopula-
    tion of the bay's total sediment population. It is made up of newly introduced inorganic sediment from
    rivers and shore erosion which has not been deposited; of living plankton; of organic detritus which has
    not settled out; and of previously deposited organic and inorganic sediments which have been
    resuspended from the bay's floor. At any given time, all of these components are present, but their
    relative abundances vary both temporally and spatially.
                   The inputs of new sediment have already been described. Schubel (1 968a) demonstrated
    the importance of a proximate source of sediment-the resuspension of bottom sediments by tidal scour
    - to the suspended sediment population of the upper 20 to 30 km of the bay. Subsequent observations
    have confirmed the importance of this process in determining the concentrations of total suspended
    solids, particularly in the upper 20 to 30 km of the estuary, where depths are shallow and tidal mixing is
    intense. Farther seaward, the effects of resuspension are observable only near the bottom.

           4.2.4 Distributions of Temperature, Salinity, and Total Suspended Solids

                   4.2.4.1 Temperature and Salinity
                          Conductivities and temperatures were determined with a Chesapeake Bay In-
    stitute Induction-Conductivity-Temperature-indicator (ICTI). These measurements have a precision and
    accuracy of �0.020C in temperature and �0.02 milliohms per centimeter in conductivity. Salinities,
    calculated from the temperature and conductivity data, have an accuracy and precision of +0.030/oo.
                          The distributions of temperature and salinity in the upper Chesapeake Bay at ap-
    proximately monthly intervals from December 1973 to November 1974 are plotted in Figures 1 thru 27 in
    Volume III, Appendix B. The station locations are the same as those described in other sections of this
    report. The primary purpose of collecting these data was for input to the numerical model (Hunter,
    Volume IV).

                   4.2.4.2 Total Suspended Solids
                          Measured volumes of water, collected with a submersible pump, were filtered
    through preweighed 47 mm, 0.6/t pore diameter nuclepore filters. Volumes were determined to the
    nearest three milliliters, and usually, approximately 500 ml of water were filtered. The filters were rinsed
    a number of times to remove any sea salt, placed in individual desiccators, and desiccated over silica gel
    at ambient temperature for at least 72 hours. After drying, the filters and their sediment loads were re-
    weighed, and the concentrations of total suspended solids were calculated. All weighings were made to
    �0.01 mg. Selected samples were combusted at 5000C for 30 minutes and re-weighed to determine the

                                                    4-41

    loss of mass after combustion. These data provide the concentrations of combustible organic matter, and
    they are most commonly reported as the percent of the total concentrations accounted for by combustible
    organic matter.
                          The distributions of total suspended solids (suspended sediment) in the upper
    Chesapeake Bay at approximately monthly intervals from October 1 973 to November 1 974 are shown in
    Figures 28 through 45 in Volume ill, Appendix B. The station locations are the same as those described in
    earlier sections of this report.
                          The primary objective of collecting these data was to provide input to the
    numerical model described elsewhere in this report (Hunter, Volume IV). However, a general description
    of the processes that control the distributions of suspended sediment in the upper bay is included for
    completeness. This discussion is based not only on observations made during this study, but on the vast
    body of data gathered over the past ten years in studies supported by the State of Maryland.
                          The Susquehanna River discharges nearly 90 percent of the total freshwater in-
    put to the upper Chesapeake Bay, as defined in this report. As pointed out previously, the upper bay is
    clearly the estuary of the Susquehanna River, which is the only significant supplier of freshwater and
    also of fluvial sediment. During the spring freshet and other short periods of very high riverflow, the
    suspended particle population is closely linked to the ultimate source of most of the new sediment, the
    Susquehanna. During these periods there is a downstream gradient of the concentration of total
    suspended solids (suspended sediment).
                           At other times of the year, however, the concentrations of suspended sediment
    typically are higher in the upper 30 km of the estuary (Tolchester to Turkey Point) than farther upstream
    in the source river, or farther seaward in the estuary. During these periods, the internal sediment
    sources-primary productivity, shore erosion, and the resuspension of bottom sediments by tidal
    scour-play a more important role. The significance of tidal resuspension is particularly evident in the
    bay from Tolchester to Turkey Point where, coupled with the net non-tidal estuarine circulation, it
    produces the turbiditymaximum (Schubel, 1968c). Sediment discharge by the Susquehanna is relatively
    less important but still significant.
                           In more seaward segments of the upper bay, the effects of tidal resuspension are
    apparently only near the bottom. The distribution of suspended sediment away from the bottom is con-
    trolled largely by primary productivity, the introduction of newfluvial sediment bythe Susquehanna, and
    the escape of fine resuspended sediments from the zone of the turbidity maximum.
                           Schubel (1968a, b; 1969; 1972a, b) has discussed in some detail the processes
    that control the distribution and transportation of suspended sediment in the upper 30 km of the
    Chesapeake Bay (Turkey Point to Tolchester). Biggs (1970) has described the sources and distribution of
    suspended sediment in the upper bay from its head at Turkey Point to seaward of the Bay Bridge at An-
    napolis. For a thorough discussion the reader is referred to these publications.

            4.2.5 Size Distribution of Suspended Particles

                   4.2.5.1 Methods
                           The particle size distributions of the suspended particles were determined with a
    photomicrographic Zeiss Particle Size Analyzer TGZ-3. The technique consists of measuring the particle
    images on photomicrographs with the semi-automatic Zeiss analyzer. The entire procedure involves four
    steps: (1) sample collection (2) slide preparation, (3) photography of the sample, and (4) measurement of
    the particle images with the Zeiss Particle Size Analyzer.
                           Sample Collection - Water samples collected with a submersible pump were im-
    mediately filtered through 0.22,u APD Millipore filters. After filtration, the filters and sediment were
    washed several times with distilled water to remove any sea salt and stored in a desiccated box. Several
    volumes were filtered at each sample depth to help ensure the proper density of particles on the filter sur-
    face. For microscopic size analyses the ideal sample is a single-particle layer with no particle touching
    another.

                                                     4-42

                          Slide Preparation - The filters were cleared (rendered transparent) by im-
    pregnating them with a liquid having the same index of refraction (n=1.510). An appropriate mix, deter-
    mined empirically, of Zeiss mounting media was used.
                           Photography of Sample - The cleared filters and their sediment loads were
    photographed with a phase microscope. Phase microscopy was used to enhance the visibility of the par-
    ticles, many of which have little color and have a refractive index near 1.51; hence they are nearly invisi-
    ble under ordinary light. The photography was done on a Zeiss Standard Universal Microscope equipped
    with a bright-field, phase-contrast, dark-field condenser having a numerical aperture of 1.4. The light
    source, a 6V-1 5W lamp built into the microscope, was adjusted for Kiihler illumination. The light was
    filtered with a green interference filter having maximum transmission at 546 mu to increase resolving
    power. A Neoflour Ph 40/0.75 objective was the working objective. The objective was used in conjunc-
    tion with an 8X eyepiece, and with the Optovar set at 1.50. Thus, t he approximate observed magnifica-
    tion was 40 x 8 x 1.5 = 480. The camera factor was 0.5X, hence the image magnification was about 240.
    The negatives were enlarged to produce a total magnification of 2000X. This final magnification was
    carefully adjusted to this value by projecting an image of a stage micrometer photographed on each roll of
    film and adjusting the enlarger until the desired magnification was obtained. The fine-grain film, Kodak
    Pan X, was developed in Microdol developer. The 40X objective has a theoretical useful magnification of
    about 1500; therefore, a 2000X enlargement contains some empty magnification. Previous analyses
    with a 1 OOX objective having a theoretical useful magnification of 2500X (Schubel, 1968a) indicate that
    the empty magnification resulting from the procedures used in this study does not falsify the determina-
    tion of the particle size distributions. The upper limit of useful magnification is a theoretical limit, not a
    practical one.
                           The smallest particle image that can be measured with the Zeiss Particle Size
    Analyzer in the mode employed was 1.2 mm. With a magnification of 2000X this corresponds to a parti-
    cle diameter of 0.6/.
                           Fields that were photographed were selected at random. Generally 10 to 20
    photographs were taken of each sample. Examples of typical photomicrographs are shown in Figures 4-
    34 through 4-36.
                           Particle Size Measurement - The particle images on the photomicrographs were
    sized with a Zeiss Particle Size AnalyzerTGZ-3, a semi-automatic device in which the eye and judgement
    of the operator participate in the measuring process. The principal components of the instrument are a
    light source, a lens system, and an adjustable iris diaphragm. This diaphragm is correlated via a com-
    mutator with 48 telephone counters, each counter corresponding to a certain operative interval of the iris
    diaphragm. The instrument is equipped also with a cumulative counter which registers the total number
    of particles measured. The iris diaphragm is illuminated from below and is imaged as a sharply defined
    circular light spot in the plane of the plexiglass plate that supports a photomicrograph. The
    photomicrograph is moved by hand until the center-of-area of the particle's image lies approximately at
    the center of the measuring mark. The particle image is then measured by adjusting the diaphragm until
    the light spot has an area equal to that of the particle image. For irregular particles one attempts to adjust
    the diameter of the spot sothat the total area of those parts of the particle.protruding beyond the measur-
    ing mark is equal to the re-entrant areas. Once the diaphragm is appropriately adjusted, the foot switch is
    depressed. This activates the proper counter; a hole is automatically punched into the particle image, and
    the total registered on the cumulative counter is increased by one. The photomicrograph is shifted then
    to another particle image, and the process is repeated. For each sample depth, 1,500 to 2,000 particles
    were measured. An experienced operator can measure approximately 1,000 particles in 30 to 45
    minutes. A sample of 1,000 particles was found to be adequate to secure agreement between pairs of the
    mean and standard deviation calculated on successive cycles of sample size doubling to within 15 per-
    cent of the average of each pair of values.
                           The particle size measured by this procedure is obviously an equivalent diameter-
    the diameter of a circle having an area equivalent to that of the projected area of the particle in question.
    This diamter is defined as Di. The measure of size required for the numerical model is the average settl-
    ing velocity of the particles; a value much more difficult to determine than Dm. The settling velocity (size)
    distribution of a population of fine particles is most commonly determined by a sedimentation analysis.

                                                     4-43

                                                                                              75151A188

    Figure 4-34. Photomicrograph of Sample of Suspended Sediment from Upper Chesapeake Bay.
               (The sample was collected on a Millipore filter, cleared with cedar oil,
              and photographed using phase microscopy. Total magnification 2000X.)

                                              4-44

       as

                                                                               75151A189
    Figure 4-35. Photomicrograph of Sample of Suspended Sediment from Upper Chesapeake Bay.
             (The sample was collected on a Millipore filter, cleared with cedar oil,
            and photographed using phase microscopy. Total magnification 2000X.)
                                        4-45

                                                                                                75151A 190
    Figure 4-36. Photomicrograph of Sample of Suspended Sediment from Upper Chesapeake Bay.
              (The sample was collected on a Millipore filter, cleared with cedar oil, and
                photographed using phase microscopy. Total magnification 2000X.)

                                               4-46

    The results of the analysis generally are expressed in terms of an equivalent diameter (D,)-the diameter
    of a sphere with a density equal to that of the particle and having a settling velocity equivalent to that of
    the particle. For any given particle, Ds and Dm need not be equal, and they seldom are. D. is frequently
    referred to as a Stokes' diameter, but in fact, it is a velocity. Two particles having the same Ds will settle
    with the same speed in a fluid. Their shapes, surface areas, cross-sectional areas, projected diameters,
    and volumes may differ markedly, as may any of their orthodox statistical measures of size.
                           We have attemped to estimate characteristic settling velocities for the suspended
    particle population of the upper Chesapeake Bay in a variety of ways: (1) by calculations from Stokes' law,
    using measured values of Dm and particle density, (2) by direct measurement of the settling velocity size
    distribution with a Mine Safety Appliance Particle Size Analyzer (Schubel, 1968a), and (3) bycalculation
    on theoretical grounds.

                   4.2.5.2 Results
                           Number-Size Distributions - The number-size distributions were determined for
    samples of suspended sediment from three depths-surface, mid-depth, and one meter above the bot-
    tom-at 10 to 13 stations during each of four seasons-December 1973, March 1974, June 1974, and
    September 1 974. The data for each of the individual distributions are included in the Upper Bay Survey
    Data Base (Volume III) and are not repeated in this chapter. The Data Base also contains the volume-
    transformations of the number-size data. Several representative number-size distributions are plotted in
    Figures 4-37 and 4-38. Each of the these figures depicts the percent (by number) of particles with
    equivalent projected diameters (Dm) greater than any particular size indicated on the abscissa.
                           The statistical properties of all the number-size distributions are summarized in
    Table 4-1. In calculating these statistics, the 48 size classes of the analyzer and the classes added with a
    template to cover the larger particles were grouped by threes to form 25 classes. The statistics calculated
    are standard moment measures. The mean is the first moment about zero, and the standard deviation is
    the square root of the second moment about the mean. The skewness and kurtosis are defined in terms of
    the second (,u2), third (,p3), and fourth (/a4) moments by

                                   Skewnes = 12 3
                                               ,2 /2

                                    Kurtosis=  4
                                             P2

                           The 25-class midpoint, Xv, used in the calculations is defined by

                                   Xv      X t3v -2 f3v-2 +%3v-1 f3v-1 f3v-1 +63v f3v
                                   X    v  XV=
                                                          f3v-2      + f3v

    which reduces to                     3v

                                         E Ci fi
                                        i = 3v-2
                                   Xv =
                                          3v

                                         i= 3v-2
    where ~i are the mid-points of the 75 sub-classes, fi the frequency of observations in each sub-class, and
    v= 1,...20.

                                                      4-47

                999

                99.5-                                          STATION IA 13DEC., 1973  -
                990 -
                                                                 - Surface
                                                                 ----- Mid-Depth(5m)
                95.0 -                                           --- Im off Bottom

             f 90.0-

                700-

             E 50.0--

               o300-

             . 10.o--

                 5.0-                                -

                  1.0-
                 0.5_
                                                O.,5 _               nj .a, -is        -
                               I             ,                     I  ,    'l l        -
                   0.1                0.5     1.0                 5.0    10.0    20.0 30.0
                                                        Dm (p)                                          75151A191

    Figure 4-37. Photomicrographically Determined Number-Size Distributions of Suspended Sediment
                        (from three depths at Station IA on December 13, 1973).

                 99.9 I I   I I                  ,I    I    I      I I II1I        I  -

                 99.5-:                   |       STATION lOB  13DEC., 1973
                99.5-
                99.0 -
                                                   -- Surface

                     95.0-         l-               --A--- Mid- Depth (5m)

             z 90.0-

              0      -

                 70.0-

              E  500-

              30.0 -

             o" 10.0-

                 5.0 -

                  1.0 -
                  0.5-                                                                  -

                             _   I    I Il I            I   I  Ii  Iii II-
                    0.1                0.5     1.0                5.0      10.0    20.0 30.0
                                                        Dm (Ip)                                         75151A192

     Figure 4-38. Photomicrographically Determined Number-Size Distributions of Suspended Sediment
                        (from two depths at Station 10B on December 13, 1973).

                                                     4-48

              TABLE 4-1. STATISTICAL PROPERTIES OF THE NUMBER-SIZE DISTRIBUTIONS OF THE
                      SUSPENDED PARTICLE POPULATION OF THE UPPER CHESAPEAKE BAY

                                                   Mean        Standard
          Date                 Depth                (/u)        Deviation         Skewness          Kurtosis
                                                                 (#)

    Station lA:
          Dec 13, 73          Surface                1.3           0.8               1.2               7.2
                              Mid-Depth             1.3           0.9               2.3              37.4
                              Bottom                1.4           1.1               3.5              86.8

          Mar 21, 74           Surface               1.5           2.0               5.2             156.8
                              Mid-Depth             1.4           1.3               3.1              74.5
                              Bottom                1.4           1.2               2.2              29.7

         Jun 13, 74           Surface               1.6           2.5               4.7             117.9
                              Mid-Depth             1.4           1.1               1.5              12.9
                              Bottom                1.9           1.5               1.6              15.0

         Sep 20, 74           Surface               1.4           1.7               3.3              54.3
                              Mid-Depth             1.5           1.4               2.8              61.3
                              Bottom

    Station 2B:
         Dec 14, 73           Surface               1.4           0.8               1.2               9.2
                              Mid-Depth             1.4           0.8               1.4              12.0
                              Bottom                1.5           0.9               1.6              15.8

         Mar 20, 74          Surface                1.2           0.9               3.7             126.8
                              Mid-Depth             1.3           1.0               1.1               5.7
                              Bottom                1.3           1.1               1.9              19.5

         Jun 13, 74           Surface               1.9           1.7               1.7              14.2
                              Mid-Depth             1.6           1.2               1.4               9.9
                              Bottom                1.6           1.4               1.7              16.1

         Sep 20, 74           Surface               1.8           2.0               2.4              34.7
                              Mid-Depth             1.6           1.7               1.9              18.7
                              Bottom                1.8           2.1               2.4              32.4

                                                          4-49

            TABLE 4-1. STATISTICAL PROPERITIES OF THE NUMBER-SIZE DISTRIBUTIONS OF THE
              SUSPENDED PARTICLE POPULATION OF THE UPPER CHESAPEAKE BAY (Continued)

                                                   Mean       Standard
          Date                 Depth                (#)         Deviation         Skewness          Kurtosis

    Station 3B:
          Dec 14, 73          Surface                1.3           1.1               5.0            200.7
                              Mid-Depth             1.3           0.9               1.8              18.8
                              Bottom                1.3           0.9               1.3              10.2

          Mar 20, 74           Surface               1.6           1.4               1.6              14.2
                              Mid-Depth             1.5           1.5               2.2              34.1
                              Bottom                1.3           1.2               1.9              20.5

          Jun 13, 74           Surface
                              Mid-Depth             1.5           1.1               1.4              12.3
                              Bottom                1.6           1.3               1.5              13.4

         Sep 20, 74           Surface               1.4           1.3               2.0              23.5
                              Mid-Depth             1.6           1.4               1.9              20.8
                              Bottom                1.8           1.5               1.3               8.6

    Station 4B:
          Dec 14, 73           Surface               1.6           1.2               2.1              33.3
                              Mid-Depth             1.4           1.1-              2.1              30.3
                              Bottom                1.4           0.7               1.1               6.4

          Mar 20, 74           Surface               1.4           1.2               2.2              34.8
                              Mid-Depth             1.2           0.9               1.6              14.0
                              Bottom                1.4           1.4               3.3              71.3

          Jun 13, 74           Surface               1.4           1.3               1.7              16.8
                              Mid-Depth             1.6           1.3               1.4              10.8
                              Bottom                1.6           1.3               1.5              12.4

          Sep 20, 74           Surface               1.7           1.4               1.8              22.7
                              Mid-Depth             1.5           1.3               1.9              20.0
                              Bottom                1.8           1.8               3.5              99.7

                                                           4-50

            TABLE 4-1. STATISTICAL PROPERTIES OF THE NUMBER-SIZE DISTRIBUTIONS OF THE
               SUSPENDED PARTICLE POPULATION OF THE UPPER CHESAPEAKE BAY (Continued)

                                                   Mean       Standard
          Date                 Depth                (ju)        Deviation         Skewness           Kurtosis
                                                                  (#)

    Station 5A:
          Mar 21, 74           Surface               1.3           1.0               1.7              17.1
                              Mid-Depth             1.3           1.0               2.4              45.4
                              Bottom                1.3           1.1               2.2              30.3

         Jun 13, 74           Surface               1.4           1.0               1.3               8.4
                              Mid-Depth             2.0           2.0               2.0              23.0
                              Bottom                1.7           1.6               1.4              10.3

    Station 5B:
          Dec 14, 73           Surface               1.7           1.2               1.7              21.9
                              Mid-Depth             1.4           0.8               1.0               4.6
                              Bottom                1.5           1.0               1.0               5.1

          Mar 21,74            Surface               1.1           1.7              10.3             523.4
                              Mid-Depth             1.3           1.1               1.9              19.2
                              Bottom                1.5           1.7               2.4              37.7

          Jun 13, 74           Surface               1.4           1.4               3.4              65.6
                              Mid-Depth             1.6           1.8               3.8              88.2
                              Bottom                1.7           1.6               1.8              17.1

          Sep 20, 74           Surface               1.4           1.0               1.6              15.5
                              Mid-Depth             1.6           1.3               1.4              10.4
                              Bottom                2.0           2.0               2.1              31.0

    Station 6C:
          Dec 14, 73           Surface               1.5           1.1               1.3               9.2
                              Mid-Depth             1.3           0.9               1.5              14.1
                              Bottom                1.5           1.0               2.0              41.3

          Mar 20, 74           Surface               1.4           1.0               1.5              11.9
                              Mid-Depth             1.6           1.2               1.6              19.2
                              Bottom                1.3           1.2               2.2              29.4

          Jun 13, 74           Surface               1.6           1.5               3.7              81.0
                              Mid-Depth             2.2           1.9               3.6             101.2
                              Bottom                2.5           1.8               1.5              12.3

          Sep 20, 74           Surface               1.5           1.6               3.0              55.8
                              Mid-Depth             1.7           1.5               1.6              12.8
                              Bottom                2.6           2.9               1.7              18.0

                                                           4-51

            TABLE 4-1. STATISTICAL PROPERTIES OF THE NUMBER-SIZE DISTRIBUTIONS OF THE
             SUSPENDED PARTICLE POPULATION OF THE UPPER CHESAPEAKE BAY (Continued)

                                                 Mean       Standard
          Date                Depth               (W)         Deviation         Skewness          Kurtosis
                                                                (#)

    Station 7A:
         Dec 13, 73          Surface               1.2          0.7               1.2              7.7
                             Mid-Depth             1.2          0.8              1.5              12.7
                             Bottom                1.3          0.8               1.2             11.0

         Mar 21, 74          Surface               1.4          1.0               1.5             14.9
                             Mid-Depth            1.3           0.9              2.2              36.0
                              Bottom               1.4           1.2              3.4              99.8

         Sep 18, 74          Surface               1.4           1.0              1.4               9.9
                             Mid-Depth             1.6          1.3              3.6             104.4
                              Bottom               2.0           1.7              1.6              16.0

    Station 8B:
          Dec 14, 73          Surface               1.3          0.9               1.6             20.8
                              Mid-Depth            1.5           1.1              1.2               7.1
                              Bottom               1.7           1.5              1.2               7.3

    Station 8C:
          Dec 12, 73          Surface               1.8          1.2               2.9             78.0
                              Mid-Depth             1.6          1.1               1.3             10.8
                              Bottom               2.1           1.8               1.5             18.3

          Mar 20, 74          Surface               1.3          0.9               1.4             13.6
                              Mid-Depth             1.5          1.1              1.6              17.2
                              Bottom               1.5           1.4              2.0              28.7

          Jun 13, 74          Surface               2.1           1.8              2.4             50.1
                              Mid-Depth             1.4          1.0               1.8             23.7
                              Bottom               1.8           1.3              1.7              18.3

         Sep 18, 74          Surface               1.3           1.2              2.0             25.1
                              Mid-Depth            2.0           1.9               1.5             13.9
                              Bottom               1.7           1.6              1.7              16.7

                                                          4-52

            TABLE 4-1. STATISTICAL PROPERTIES OF THE NUMBER-SIZE DISTRIBUTIONS OF THE
              SUSPENDED PARTICLE POPULATION OF THE UPPER CHESAPEAKE BAY (Continued)

                                                   Mean        Standard
          Date                 Depth                (/z)        Deviation         Skewness          Kurtosis
                                                                 (M)

    Station 9A:
          Dec 14, 73          Surface                1.6           1.2               1.4              12.7
                              Mid-Depth             1.9           1.3               1.2              12.4
                              Bottom                2.0           1.5               1.2               8.1

          Mar 21, 74           Surface               1.4           1.1               1.5              12.6
                              Mid-Depth             1.7           1.0               1.7              24.1
                              Bottom                1.8           1.5               3.1              73.3

         Jun 13, 74           Surface               1.5           1.9               4.7             ;34.1
                              Mid-Depth             1.7           3.0               4.8             112.8
                              Bottom                1.2           1.2               4.4             141.9

         Sep 18, 74           Surface               1.4           1.3               4.0             107.6
                              Mid-Depth             1.3           1.1               2.4              34.9
                              Bottom                1.6           1.3               2.3              38.3

    Station 10B:
          Dec 13, 73          Surface                1.8           1.7               2.2              35.2
                              Mid-Depth             1.8           1.5               1.2               7.7
                              Bottom                2.0           1.6               1.0               4.8

          Mar 20, 74          Surface                1.3           1.0               1.5              14.2
                              Mid-Depth             1.4           1.1               1.4              10.7
                              Bottom                1.7           1.5               1.8              21.2

          Jun 13, 74           Surface               1.2           0.9               3.3              86.7
                              Mid-Depth             1.5           1.2               1.4              10.2
                              Bottom                1.2           0.9               2.1              28.1

          Sep 13, 74           Surface               1.4           1.2               2.7              56.0
                              Mid-Depth             1.5           1.2               1.7              16.6
                              Bottom                1.6           1.7               2.1              23.2

                                                           4-53

            TABLE 4-1. STATISTICAL PROPERTIES OF THE NUMBER-SIZE DISTRIBUTIONS OF THE
              SUSPENDED PARTICLE POPULATION OF THE UPPER CHESAPEAKE BAY (Continued)

                                                  Mean       Standard
         Date                Depth                (#)         Deviation         Skewness          Kurtosis
                                                                (M)

    Station 11A:
         Mar 20, 74          Surface                1.4          1.0               1.1               7.0
                             Mid-Depth             1.3          1.0               1.6              14.8
                             Bottom                1.4          1.2               1.9              21.9

         Jun  13, 74         Surface                1.4          1.1               1.7              17.1
                             Mid-Depth             1.3          1.1               2.1              27.5
                             Bottom                1.2          0.9               2.1              34.6

    Station 11 B:
         Dec 12, 73          Surface                1.8          1.3               1.1               7.8
                             Mid-Depth             1.5          1.3               1.5              13.0
                             Bottom                2.0          1.9               1.6              14.6

         Mar 20, 74          Surface                1.2          1.0               1.8              19.3
                             Mid-Depth             1.3          0.9               1.5              11.3
                              Bottom                1.5          1.3               1.8              21.9

         Sep 18, 74          Surface                1.4          1.5               5.1            160.5
                              Mid-Depth             1.3          1.0               1.6              15.4
                              Bottom                1.5          1.0               1.8              24.5

                                                          4-54

                          A histogram of the mean sizes, D,, of the 140 samples analyzed for this study is
    plotted in Figure 39. This figure also includes a histogram for similar data from an earlier study by
    Schubel (1 968a). In the earlier study, the 161 analyses reported by Schubel were all from the upper 40
    km of the bay-upstream from Station 6. There is an apparent shift of the mean diameter toward smaller
    sizes in the present study relative to the data reported earlier by Schubel (1 968a). One might attribute the
    increase in the frequency of smaller mean diameters in the present study to the influence of more
    seaward samples-samples which were not obtained in the earlier study. While this explanation is
    geologically appealing, it is not supported bythe observations. No clearly defined longitudinal gradient of
    mean particle size was indicated by either study.
                          The mean size, DB, is relatively constant both temporally and spatially, ranging
    from 1.2 to 2.6 u, and with 65 percent of the samples having a Dm between 1.2 to 1.6 p. There is generally
    an increase in mean size near the bottom, which results from the resuspension of coarser bottom
    sediments. The uniformity of the number-size distribution of the suspended particles is due to the large
    numbers of very small particles that are ubiquitous throughout the upper bay.
                          There is a tendency for the number-weighted mean equivalent projected
    diameter, D,, to shift toward smaller values in late winter and earlyspring when the input of fluvial sedi-
    ment is high. This shift was also reported in an earlier study by Schubel (1 968a). The volume-weighted
    mean Stokes' diameter, however, tends to shift toward larger sizes during this period.
                          The skewness and kurtosis are of unknown significance in samples of very fine-
    grained suspended sediment. Because they are defined in terms of higher moments, they are, of course,
    much less stable than the mean and standard deviation. The standard deviation is a measure of the
    sorting of the sample and is expressed in microns. All samples were well-sorted, but the near-bottom
    samples tended to be somewhat less well-sorted because of the period resuspension and deposition of
    bottom sediments.
                          Histograms of the modal size class of each sample for each of the four sampling
    periods are plotted in Figure 4-40. A cumulative histogram for all samples is plotted in Figure 4-41. The
    most significant features of the suspended particle population revealed by these figures are: (1 ) the un-
    iformity of the suspended particle population (particularly away from the bottom) in both time and space
    and (2) the preponderance of very fine particles. The upper limits of the various size classes are:

           Class                                        Upper Limit (bt)

              1                                             0.74
              2                                             0.90
              3                                             1.09
             4                                             1.32
              5                                             1.61
              6                                             1.96

                          The number-size distribution is, of course, dominated by the more frequently oc-
    curring very small particles. Moreover, it is relatively insensitive to the much rarer large particles which,
    although infrequent, dominate the volume-size distribution of the suspended particle distribution.
                          Volume-Size Distributions - The volume-size distributions of the suspended
    particles were calculated from the experimentally-determined number-size distributions by making the
    conventional assumption that each particle population was made up of a polydisperse system of spheres.
    The assumption is not true, of course, but no shape factors have been determined for fine-grained
    natural sediments in Chesapeake Bay or elsewhere in the natural environment. Let's briefly examine
    some of the implications of this assumption.
                          When one transforms equivalent projected diameters, Di, into equivalent volume
    diameters, D., the equivalent volume diameter is defined as the diameter of a sphere with the same
    volume as the particle in question. If the volume diameters obtained bythis transformation are to provide
    a useful measure of the true volume diameters, eitherthe particles should be approximately spherical, or
    shape factors should be employed.

                                                     4-55

                            ALL SAMPLES

                                                        n40-  O    THIS STUDY
        40--

                                                        .E~i:  EARLIER STUDY

                             L   ..:s.    ....
         30-

    I-

         10-                 :f': 5

          0 I I I                        !                                     l      I
             1.0           1.4            1.8            2.2           2.6           3.0

                                           Dm (/z)

                                                                                            75151A193
                Figure 4-39. Histograms of the Mean Sizes of All Samples.
          (The samples include all from the Upper Bay Survey and those of an
    earlier study (Schubel, 1968a) which dealt only with the upper 30 km of the bay.)

                                           4-56

    12 -                                       12-

          -  (a) DECEMBER 1973                     *.......  (b) MARCH 1974

    8-                                         8

                       I                   ~~~~~~~~Z)
           z~~~~~~~~

    4      4

                                                    0~~~ ~               -t
       01'2'3 4'5  6    ~                           1  2 3'4 1516
              MODAL CLASS                                 MODAL CLASS

                                             12 -

          W c JUNE 1974                                  (d) SEPTEMBER 1974

    8    ------

                                          LU

           z~~~~~~~~
    4                                         4

        0  ~                                   0
         1 *2 3'4  5'6                             1  2  3  4'5 6'

              MODAL CLASS                               MODAL CLASS

                                 -SURFACE
                                    MID-DEPTH
                                  BOTTOM                                       75151A194
          Figure 4-40. Histograms of the Modal Class of Equivalent Projected Diameters
           (for samples from the surface, mid-depth, and one meter above the bottom).

                                       4-57

    40 -

                    ALL SAMPLES CUMULATIVELY

    30 -

      O  X    I                  >,4-,
        1  2 1 314516

                    SURFACE
         ::::..::::::..... MID-WATER..

                                                                      75151A 195
         ,0  :. ......

    -1  Histogram of the Modal Class of EquivalentProjected Diameters

                          4-58
                    SURFACE

                                                                      75151A195

                          The bay's suspended particles have a broad spectrum of shapes ranging from
    spheres, through rods, to flakes. It would require an inordinate amount of work to determine shape fac-
    tors for these particles, and these factors would probably change with time and space. Since no shape
    factors have been determined to characterize the bay's suspended particles, the volume-size dis-
    tributions should be interpreted with prudence. During filtration the particles settle with their largest
    surfaces in the plane of the filter, and some composite particles may flatten when they contact the filter.
    Both of these factors result in an overestimate of the true volume diameters when the equivalent pro-
    jected diameters, D., are cubed to obtain the volume-size distributions. In summary, the volume
    transformations result in an overestimate of the true volume diameters and of the statistics associated
    with the volume-size distributions.
                          An additional factor to consider is the distorting effect that a few large particles
    can have. Particles with equivalent projected diameters greater than 1 0u are relatively rare. However, a
    single particle with a Dm of 20u has a volume equivalent to that of 8,000 particles with equivalent pro-
    jected diameters of 1 /u - assuming, as we have, that both have the same shape. For this reason, and
    those described previously, the volume-size statistics are much less stable than the number-size
    statistics.
                          All volume-size transformations are included in the Upper Bay Survey Data Base
    (Volume III) and are not included in this chapter. The volume-weighted mean diameter, Dr, ranged from
    about 3 to 40yp. In more than 70 percent of the samples, Dv, fell between 4 and 1 2/. In more than 57 per-
    cent of the samples, Dr, fell between 4 and 8/u.
                          Volume-Settling Velocity Distributions - Over the past ten years a relatively
    large number of determinations have been made of the volume-settling velocity(size)distributions of the
    particles suspended in the waters of the upper reaches of Chesapeake Bay. The measurements were
    made with a Mine Safety Appliance Particle Size Analyzer, and have been described in some detail by
    Schubel (1968a, 1969, 1971 b). On the basis of: (1) the results for the number-size distributions and (2)
    preliminary tests made with a Cahn Electrobalance Sedimentation Chamber, it was determined that
    further tests would not increase the precision and accuracy of our estimates of the mean particle settling
    velocities required for the numerical model.
                           Results of selected analyses run previously on samples from the upper
    Chesapeake Bay are summarized in Table 4-2.
                          At nearly all stations for which samples have been analyzed, there was a dis-
    placement of the volume-settling velocity distribution curve toward larger sizes with increasing depth.
    This characteristic increase of the mean Stokes' diameter, Ds, was almost always accompanied by an in-
    crease in the standard deviation. Schubel (1969) demonstrated that samples of suspended sediment
    collected from the surface waters of the upper 30 km of the bay had a range of D, from 2.3 to 6.0m,, and in
    more than 75 percent of the samples it was between 2.3 and 4.0u. At mid-depth Ds ranged from 3.4 to
    6.8p, and in over 75 percent of the samples it fell between 3.4 and 6.0y,. In the samples from one meter
    above the bottom, D, ranged from 4.2 to 12.2p, and was between 4.2 and 8.0,u in more than 75 percent of
    the samples Schubel (1 969) reported. The mean, the standard deviation, and the range of the mean all in-
    creased with depth. Schubel (1969) attributed these increases to the periodic resuspension of coarser
    bottom sediment by tidal scour. Later observations (Schubel, 1971) supported this conclusion.

                   4.2.5.3 Discussion
                           The size distributions of suspended sediment in the upper Chesapeake Bay are
    determined by a combination of physical and biological processes. There is no convincing evidence that
    chemical flocculation is an important process in this environment. In the upper 30 km of the bay
    (upstream from Tolchester) in the region characterized by a turbidity maximum, the size distributions are
    determined primarily by physical procees. They are the periodic resuspension of bottom sediments by
    tidal scour and the net non-tidal estuarine circulation (Schubel, 1972a). Biological agglomeration of fine
    particles by filter-feeding zooplankton also appears to be important in producing many of the larger
    suspended particles, and in the initial deposition of fine sediment in this part of the bay (Schubel and
    Kana, 1972). The formation of the turbidity maximum, discussed elsewhere in this report and previously
    by Schubel (1 968a, 1968b), will be dealt with here only to the extent necessaryfor a meaningful discus-
    sion of the particle size distributions.

                                                     4-59

           TABLE 4-2. STATISTICAL PROPERTIES OF VOLUME-SETTLING VELOCITY DISTRIBUTIONS
          OF SAMPLES OF SUSPENDED SEDIMENT FROM UPPER CHESAPEAKE BAY (SCHUBEL, 1969).

                                                 D          Standard
                                                   s
         Date                Depth                            Deviation         Skewness          Kurtosis
                                                    (/~)~~(p

    Station Susquehanna (Same as Station 1A of Upper Bay Survey):
         Jun 1, 66           Surface                3.9          6.3               2.9             44.3
                             Mid-Depth             3.9          5.7               2.9             48.8
                             Bottom               4.3           6.5               2.8             42.1

    Station IIIC (Near Station 4B of Upper Bay Survey):
         May 31, 66          Surface               4.9           6.2               1.9             22.3
                             Mid-Depth             6.3          7.7               1.4              10.9
                             Bottom                6.6          8.2               1.4              11.5

    Station VF (Near Station 6C of Upper Bay Survey):
         May 31, 66          Surface               3.0           6.6               3.5             55.8
                             Bottom               4.5           7.1               2.2              27.0

    Station Susquehanna (Same as Station 1A of Upper Bay Survey):
         Aug 9, 66           Surface                3.6          3.5               1.5              18.3
                             Mid-Depth            4.4           6.7               2.4              30.4
                             Bottom                6.6          6.8               1.5              16.3

    Station IIIC (Near Station 4B of Upper Bay Survey):
         Aug 22, 66          Surface                2.3          3.6               2.3              28.2
                             Mid-Depth             3.5          5.2               3.2              59.2
                             Bottom               8.6          13.2               2.0              22.8

         *
          Ds is the Stokes' Diameter defined previously.

                                                         4-60

                          Throughout the zone of the turbidity maximum there is a natural background of
    suspended sediment which increases with depth. The intensity of the natural background at any depth is
    relatively constant over weeks or months. This natural background consisting of very fine-grained par-
    ticles having long settling times compared to their mixing time, is attributable in part directly to runoff
    and in part to resuspension, primary productivity, and shore erosion. The background particle population
    has a relatively narrow size distribution, and the temporal and spatial variabilityof the mean size is small
    (both in terms of the volume-weighted mean Stokes' diameter, Ds, and the number-weighted mean
    equivalent projected diameter, D.). The volume-weighted mean settling velocity of the background par-
    ticles of about 10-3 cm/sec is of the same order as the mean vertical mixing velocity (Schubel, 1968a,
    1 968b), thus explaining their sustained suspension.
                           Mixing here is taken to include both advection andturbulent diffusion. Continuity
    requires that the water flowing up the Chesapeake Bay in the lower layers of water be returned seaward
    in the upper layers, and hence there must be a vertical advection of water from the deeper layers intothe
    surface layers. The speed, Va, of this net vertical flow is zero at the surface and at the bottom, but it
    reaches a maximum speed of the order of 10-3 cm/sec near mid-depth. In addition, there is a vertical dif-
    fusion velocity, Vz, due to turbulence. Vz can be defined as the ration of Kz to H, where Kz is the vertical
    eddy diffusivity, and H is the water depth. Vz is also of the order of 10-3 cm/sec.
                           In the lower layer at stations deeper than about four meters and throughout the
    water column at shallower stations superimposed upon this natural background, there are semitidal
    fluctuations of the suspended sediment concentration which increase in magnitude near the bottom.
    These semitidal fluctuations are produced bytidal scour and fill. Large particles are resuspended with in-
    creasing current speed and settle out when the current begins to wane.
                           Serial observations of current velocity and the concentration of suspended sedi-
    ment show that maximum sediment concentrations recorded near times of maximum ebb and flood
    velocities exceed minimum concentrations recorded shortly after slack water by as much as a factor of 20
    at one meter above the bottom. These large fluctuations of the concentration of suspended sediment
    produce marked changes in the volume (and weight) size distributions of the suspended particle popula-
    tion. At one meter off the bottom, we have recorded variations in the volume-weighted mean Stokes'
    diameter of from less than 4,p near slack water to more than 1 2p on the preceding and succeeding max-
    imum ebb and flood velocities of about two knots. The variation of the number size distribution is very
    much less because of the large numbers of background particles which are present at all times.
                           The increases of: (1) the mean Stokes' diameter, D,, (2) the standard deviation
    with depth at each station, and (3) the increase in the range of D, with depth for samples collected from
    various stations at different times of the year all reflect the increasing effect of resuspension on the
    volume-size distribution of the suspended particle population as the bottom is approached.
                           Thus, the suspended particle population of the Chesapeake Bay's turbidity max-
    imum is composed of two sub-populations(1 )those particles which are in more or less continual suspen-
    sion throughout the water column and (2) those particles which are alternately suspended and
    deposited. Throughout the year, the background subpopulation is characterized by a unform and narrow
    size distribution, exept for the period of the spring freshet when the hydrographic conditions are marked-
    ly changed.
                           During the spring freshet when most of the year's supply of newfluvial sediment
    is introduced (Schubel, 1 968c), the increased competency of the rivers produces both a displacement of
    the volume-size distribution toward larger sizes and an increase in the dispersion of the volume-
    distribution compared to periods of moderate and low flow. The disperison of the number-size distribu-
    tion of the background particles also is increased during the spring freshet, but the mean is shifted
    toward smaller values because of the marked increase in the relativefrequencyof theveryfine suspend-
    ed and colloidal particles.
                           These changes of the particle size distributions do not persist for more than a few
    weeks. Most of the large particles discharged during the period of high river flow are deposited within the
    zone of the turbidity maximum, and the very fine particles are gradually purged from the upper bay by the
    net non-tidal seaward flow of the upper layer.

                                                     4-61

                          Where tidal resuspension and deposition produces a marked change in the con-
    centration of total suspended solids, there is a concomitant variation in the volume-settling velocity (size)
    distribution of the suspended particles. At two meters above the bottom in the upper reaches of the
    Chesapeake Bay, the concentration of suspended sediment may vary by as much as a factor of five. Serial
    observations of the volume-size distribution show that the distribution is successively displaced toward
    larger sizes with increasing ebb and flood current speeds, and then is displaced back to its background
    position as currents wane. The volume-weighted mean Stokes' diameter, the standard deviation, and the
    concentration of suspended sediment attain their maximum values near times of maximum ebb and
    flood current speeds, and their minimum values are attained near slack water. The mean Stokes'
    diameter, D,, may range from less than 3p to more than 10zu.
                          Nearer the bottom-the sediment source-the same pattern is observed, but the
    variations in both the concentration and the particle size distribution are greater. At 0.5 m above the bot-
    tom, the concentration may vary by as much as a factor of ten, and the mean Stokes' diameter may vary
    from about 3p near the time of slack water to greater than 20,u near the time of maximum ebb and flood
    current speeds (Schubel, 1971). With increasing distance above the bottom, the fluctuations are reduc-
    ed.
                          Seaward of the turbidity maximum, which ends at about Tolchester, the concen-
    trations of suspended sediment decrease. The number-size distributions do not show any consistent
    differences between samples collected from the zone of the turbidity maximum and those collected
    farther seaward in the estuary. This should be expected, however, because of the large numbers of ubi-
    quitous small particles. Tidal fluctuations in the concentration of suspended sediment and the volume-
    size distribution are restricted to a smaller part of the total water column, because the mean depth in-
    creases, and because the fine-grained bottom sediments are less readily resuspended than those farther
    upstream. This apparently is a result of the less rapid sedimentation rates, and the greater rates of
    reworking by benthos in the more seaward segments of the bay.
                          For the purposes of the numerical model described elsewhere in Volume IV, the
    appropriate choice of a settling velocity for the background population of suspended particles appears to
    fall in the range from 1 x 10-3 to 3 x 10-3 cm/sec.

           4.2.6 Acknowledgements
                   We thank Jeffrey Boggs and Christopher Zabawa for their assistance both in the field and
    in the laboratory during all phases of this project. Their contributions were manifold. We are also in-
    debted to C. Morrow for her fine laboratory work in the initial phase of the study. We thank Captains W. J.
    Gilbert and C. Wessels for their unfailing cooperation. Both of these men have the capacity to make sea
    work enjoyable even under the most trying conditions.
                   Contribution 223 of the Chesapeake Bay Institute of The Johns Hopkins University, and
    Contribution 135 of the Marine Sciences Research Center of the State University of New York.

           4.2.7 References

    Biggs, R.B., 1970. Sources and Distribution of Suspended Sediment in Northern Chesapeake Bay.
            Marine Geology, V. 9, pp. 187-201.

    Boicourt, W., 1969. A Numerical Model of the Salinity Distribution in Upper Chesapeake Bay. Technical
            Report 54 of the Chesapeake Bay Institute, The Johns Hopkins University, 69 p.

    Cronin, William B., and D. W. Pritchard, 1975. AdditionalStatistics on the Dimensions of the Chesapeake
           Bay and Its Tributaries: Cross-Section Widths and Segment Volumes per MeterDepth. Special
            Report 42 of the Chesapeake Bay Institute, The Johns Hopkins University, 478 p.

    Ryan, J.D., 1953. The Sediments of Chesapeake Bay. Maryland Department of Geology, Mines, and
           Water Resources Bull. 12, 120 p.

                                                     4-62

    Schubel, J.R., 1968a. Suspended Sediment of the Northern Chesapeake Bay. Technical Report 35 of the
           Chesapeake Bay Institute, The'Johns Hopkins University, 264 p.

    Schubel, J.R., 1968b. Suspended Sediment Discharge of the Susquehanna River at Havre de Grace,
           Maryland, During thePeriod I April 1966through31 March 1967. Chesapeake Science, V. 9, pp.
           31-135.

    Schubel, J.R., 1968c. TurbidityMaximum of Northern Chesapeake Bay. Science, V. 161, pp. 101 3-1015.

    Sch ubel, J.R., 1969. Size Distributions of the SuspendedParticles of the Chesapeake Bay Turbidity Max-
           imum. Netherlands Journal of Sea Research, V. 4 (3), pp. 283-309.

    Schubel, J.R., ed., 1971 a. The Estuarine Environment: Estuaries and Estuarine Sedimentation. Amer.
           Geol. Inst., Washington, Short Course Lecture Notes, 324 p.

    Schubel, J.R., 1971 b. Tidal Variations of the Size Distribution of Suspended Sediment at a Station in the
           Chesapeake Bay Turbidity Maximum. Netherlands Journal of Sea Research, V. 5 (2), pp. 252-
           266.

    Schubel, J.R., 1972a. Distribution and Transportation of Suspended Sediment in Upper Chesapeake
           Bay, pp. 151-167, in Environmental Framework of Coastal Plain Estuaries, Nelson, B.W. (ed.),
           Memoir 133 of the Geological Society of America, 619 p.

    Schubel, J.R., 1972b. Suspended Sediment Discharge of the Susquehanna River at Conowingo,
           Maryland, During 1969. Chesapeake Science, V. 13 (1), pp. 53-58.

    Schubel, J.R., and Kana, T.W., 1972. Agglomeration of Fine-Grained Suspended Sediment in Northern
           Chesapeake Bay. Powder Technology, V. 6, pp. 9-16.

    Schubel, J.R., 1974. Effects of Tropical Storm Agnes on the Suspended Solids of the Northern
           Chesapeake Bay, pp. 113-132, in Suspended Solids in Water, Gibbs, Ronald J. (ed.), Vol. 4,
           Marine Science, Plenum Press, N.Y., 320 p.

                                                  4-63

             CHAPTER 5

    HYDROLOGY AND METEOROLOGY

              K.T.S. Tzou
            Oceanic Division
    Westinghouse Electric Corporation

    ABSTRACT

           Chlorinated hydrocarbon pesticides and polychlorinated biphenyls were found in all major
    phases ofthe hydrologic cycle-intheatmosphere, precipitation,stormwaterrunoff,groundwaterflow,
    and receiving water bodies. Such significant findings were revealed in this study as the presence of 9
    ng/m3 of PCB in the air, 580 parts per trillion (ppt) of PCB in storm water, 283 ppt of toxaphene, and 180
    ppt of chlordane in rain water. Hydrological and meteorological parameters of concern also are
    presented and discussed for interpretation and correlation purposes.
           It is concluded that air and water movements are the major transport media for the chlorinated
    hydrocarbons. Rates of transport of these compounds in the atmosphere in precipitation and aerial
    fallout, and in stream flow are estimated based on some reasonable assumptions. Relatively high levels
    of chlorinated hydrocarbons in the storm water runoff indicate the need for a comprehensive study of the
    storm water inflow to the Chesapeake Bay and its water quality.

                                      TABLE OF CONTENTS

    Subject                                                                                          Page

    5.  HYDROLOGY AND METEOROLOGY..............................................5-1
    5.1nrouton.........................................................................1-
    5.2  Data Acquisition Techniques....................................................5-4
    5.2.1 Meteorological Data ...........................................................5-4
    5.2.2 Physical Parameter Cruises.....................................................5-4
    5.2.3 Multidisciplinary Cruises....................................................... 5-4
    5.2.4 Tidal Data Collections..........................................................5-4
    55.2Sra.Fos................................................................5........8-
    5.2.6  Chlorinated Hydrocarbons in Air-Dust, Rain Water, Storm Water
           and Ground Water ............................................................5-8
    5.3  Results and Discussion.......................................................5-12
    5.3.1 Chlorinated Hydrocarbons in Air-Dust ...........................................5-12
    5.3.2 Chlorinated Hydrocarbons in Rain Water.........................................5-13
    5.3.3 Chlorinated Hydrocarbons in Storm Water........................................5-13
    5.3.4 Chlorinated Hydrocarbons in Ground Water ......................................5-13
    5.3.5 Climatological Variations ......................................................5-18
    5.3.6  Variations of Water Temperature, Salinity, and Suspended Sediment .................5-18
    5.3.7 Fresh Water Inputs and Tidal Variations .........................................5-18
    5.4  Correlation Analyses and Discussion ............................................5-30
    5.4.1   Rate of Transport of Chlorinated Hydrocarbons in the Atmosphere....................5-30
    5.4.2 Chlorinated Hydrocarbons Return to Earth........................................5-30
    5.4.3  Chlorinated Hydrocarbons in Storm Water Runoff and Precipitation...................5-32
    5.4.4  Spring Freshet: Inputs of Sediments and Chlorinated Hydrocarbons...................5-32
    5.5oclsos ........................................................................53
    5.6  Acknowledgements...........................................................5-37
    55.eerne7..........................................................5..............53

                                               iii

                                                  LIST OF FIGURES

    Figure                                                                                     Page

    5-1  Flow Chart Showing the Kinetics of Pesticides ........................................................................5-2
    5-2  The General Hydrologic Cycle and its Long-Time Averages ...................................................5-3
    5-3  Station Location Map for the Upper Chesapeake Bay .............................................................5-6
    5-4 Station Location Map for the Chester River .............................................................................5-7
    5-5  Locations of Morrell Park, Sollers Point, and Fort Smallwood ................................................5-9
    5-6 Air-Dust Sampling Device ........................................................................................................5-10
    5-7  Installation of Air Sampling System at Sollers Point .............................................................5-10
    5-8  Installation of Rain Collector at Fort Smallwood Park ...........................................................5-11
    5-9  Storm Water Manhole on the DeSoto Road, Morrell Park ....................................................5-11
    5-10   Variations of Water Temperature, Salinity, Sigma-t and Suspended
             Sediment at Stations 01A and 04B .........................................................................................5-23
    5-11  Variations of Water Temperature, Salinity, Sigma-t and Suspended
             Sediment at Stations 07A and 11B .........................................................................................5-24
    5-12   Estimated Monthly Streamflow Entering Chesapeake Bay and Annual Mean Flow ..........5-25
    5-13 Cumulative Inflow to Chesapeake Bay, 1974 .........................................................................5-26
    5-14   Daily Mean Discharges for the Susquehanna River at Conowingo, Maryland ....................5-27
    5-15   Actual Water Level Variations at Havre de Grace and Matapeake, April, 1974 .................5-28
    5-16   Actual Water Level Variations at Havre de Grace and Matapeake, October, 1974 ............5-28
    5-17   Wind Rose for July 1974 at Baltimore Washington International Airport ...........................5-29
    5-18   Monthly Resultant Wind Speed and Direction at BWI Airport for 1974 ..............................5-31
    5-19   Precipitation and Concentrations of Chlorinated Hydrocarbons in Storm Water ................5-33
    5-20 Hourly Precipitations at Baltimore- March, 1974 ...................................................................5-34
    5-21   Estimated Monthly Inputs of Suspended Sediment from Susquehanna River ....................5-35

                                                    LIST OF TABLES

    Table                                                                                      Page

    5-1    Summary of Hydrological and Meteorological Data, Upper Bay Survey ................................5-5
    5-2    Chlorinated Hydrocarbons on Gelman Filter and Polyurethane Foam Plugs .......................5-14
    5-3  Chlorinated Hydrocarbons in Air-Dust Samples .....................................................................5-14
    5-4    Chlorinated Hydrocarbons and Suspended Particulate
             Matter in Air-Dust Samples .....................................................................................................5-15
    5-5 Chlorinated Hydrocarbons in Rain Water ...............................................................................5-16
    5-6  Chlorinated Hydrocarbons in Storm Water Samples .............................................................5-17
    5-7  Chlorinated Hydrocarbons in Ground Water Samples ...........................................................5-17
    5-8    Monthly Averages and Departures From Normal for Air Temperature, etc .........................5-19
    5-9    Water Temperature, Salinity, and Concentration of
             Suspended Sediment at Station A .......5-20
                         Suspended Sediment at Station 1A ~~... .......................... .....................................................52
    5-10   Water Temperature, Salinity, and Concentration of
             Suspended Sediment at Station 4B ........................................................................................5-21
    5-11  Water Temperature, Salinity, and Concentration of
             Suspended Sediment at Station 11B ......................................................................................5-22

                                                            iv

    5. HYDROLOGY AND METROLOGY

      5.1 Introduction
           Hydrological and meteorological aspects of the study were focused on the assessment of the
    sources and transport mechanisms of the chlorinated hydrocarbon pesticides and polychlorinated
    biphenyls (PCB's) in the upper Chesapeake Bay. Figure 5-1 is a flow diagram showing the kinetics of
    pesticides from the point of application through various media and finally entering human beings (Tzou,
    1972). Routes and modes of transport for PCB's are essentially similar to those for pesticides (Figure 5-1 )
    after they enter the ecological system.
           In general, fluid movements-air and water-are responsible for the transport of chlorinated
    hydrocarbon residues. The occurrence of residues in air and water at points far from sites of application
    can be illustrated from previous studies. In the latter half of 1964, DDT in dust over Pittsburgh averaged
    0.24 ppt. Cohen and Pinkerton (1966) collected dust-rain which was brought to Ohio by a dust storm
    originating in the Texas-Oklahoma-New Mexico area. Scientists from Michigan State University have
    found that the DDT concentration was highest in rivers having runoff originating primarily from city dis-
    charges rather than from agricultural areas. Another study in California indicated that about two tons of
    DDT enters San Francisco Bay every year from the Sacramento and San Joaquin Rivers. The
    Westinghouse Chester River Study showed that 28 grams of PCB, three grams of total DDT, and one
    gram of technical chlordane moved into Chester River each day from the Chesapeake Bay during the ear-
    ly spring freshet period, and only a small fraction of these compounds returned to the bay in late spring.
    (Tzou, 1972).
           In any ecological system study, the hydrologic cycle (Figure 5-2) always plays an important role as
    a transport media for pollutants. Evaporation-transpiration and precipitation-runoff are the main phases
    of the cycle (Butler, 1 957). Most of the chlorinated hydrocarbons originate from agricultural, municipal,
    and industrial areas. The major mechanisms for carrying these compounds from the land areas into the
    estuarine environments are wind drift, precipitation, surface runoff, storm sewer flow, and ground water
    flow. Vaporized chlorinated hydrocarbons in the air will be partially adsorbed on particulates and
    transported in the form of vapors and suspended particulates. Chlorinated hydrocarbon residues in

                                                     5-1

                   .... .. .?..
                    |  RUNOFF           T |GOD E

                1.:. ,-,-S'.'l1,,;,.i...
                    RIVER

      SUSPENDED    O   at        BOTTOM
      SEDIMENT      A           SEDIMENT

    PHYT  tA K O                                ZOPLANKTON

                           I.

                                         .      . oo

                                                                                         75151A196
     Figure 5-1. Flow Chart Showing the Kinetics of Pesticides (Tzou, 1972)

                                        5-2

       ;i~~~i:~~IIIII:~~~                       ATMOSPHERE

            III                         ~ ~~~~~~~EVAPORATION

     /1           -1+2                           SPRNGLTRIATIO

                                                      ~~~~~~~~~~~~(AND

    -~~~~~~~~~~~~~~~~~~~EERTO OCEA

                                         oo~~~~~~~~~~~~~~~~71 A3

              Figue 52   Te Gnerl Hdroogi  Cyle  abov) ad is Lng-imeAveage fo th

                                                 ~~~~~~~~~5-3

    water bodies tend to adsorb to the suspended sediment particles. Because of their abundance and large
    surface area, the smallest particles seem to carry the greatest residue burden. Hence, the rates of
    transport of chlorinated hydrocarbons can be evaluated from analyzing the transport of suspended sedi-
    ment in the water system.
           Descriptions of the data-gathering techniques, sample analyses, discussions of the results, and
    conclusions are presented in the subsequent sections of this chapter. Supportive graphs and tabulations
    of data from hydrological and meteorological studies can be found in Volume Ill, Appendix A.

      5.2 Data Acquisition Techniques
           Collection of hydrological and meteorological data is critical to the understanding of the transport
    mechanism of chlorinated hydrocarbons in the environment. In this study, data have been collected by a
    variety of methods from various sources. Table 5-1 summarizes the hydrological and meteorological
    data, and Figure 5-3 shows the locations of the sampling stations.

           5.2.1  Meteorological Data
                   The National Weather Service of NOAA at Baltimore Washington International Airport
    provided the meteorological data for the period from December 1973 through December 1974.
    Parameters included hourly variations of air temperature, barometric pressure, precipitation, wind
    speed, and wind direction.

           5.2.2 Physical Parameter Cruises
                   In support of the development of a mathematical model, Westinghouse participated in
    two field sampling programs during The Chesapeake Bay Institute's two 10-day cruises. The first cruise
    was conducted in the period from April 17 through April 20, 1974. Measured parameters included water
    temperature, conductivity, and suspended sediments. Westinghouse'sR/VNORTHSTARoccupied Sta-
    tion T3 on April 17 and 1 8 then moved to Station S3 on April 19 and 20 (Figure 5-3).
                   The second physical parameter cruise was accomplished in the period from October 8
    through 11, 1974. The Westinghouse vessel occupied Station SS4 on October 8, from 6:00 AM to 6:00
    PM, measuring parameters including water temperature, salinity, and suspended sediment (Figure 5-4).
    On October 9, it conducted the same operations except that no suspended sediment samples were taken.
    On October 10 and 11, it conducted two slack runs each day from Station C1 through Station C10,
    measuring temperature and salinity in the water column.

            5.2.3 Multidisciplinary Cruises
                   In order to provide synoptic measurements in the collection of field data for different dis-
    ciplines, six multidisciplinary cruises were conducted by a joint team of personnel from Chesapeake Bay
    Institute, University of Maryland, and Westinghouse Oceanic Division. Hydrological parameters includ-
    ed in the missions were water temperature, salinity, and suspended sediments in the water column. The
    six cruises were performed December 12 through 14, 1973, January 23 through 25, March 19 through
    21, May 3 through 5, July 31 through August 2, and September 18 through 20, 1974.

            5.2.4 Tidal Data Collections
                   The Oceanographic Division of NOAA furnished the latest available tidal data at three
    gauging stations-Havre de Grace, Baltimore, and Matapeake for the period from December 1973
    through December 1974.

                                                     5-4

          TABLE 5-1. SUMMARY OF HYDROLOGICAL AND METEOROLOGICAL DATA, UPPER BAY SURVEY, DEC. 1973 - DEC. 1974

                                      1973                                                   1974
                                     DEC    JAN    FEB    MAR           APR    MAY          JUN    JUL    AUG    SEP    OCT    NOV    DEC
    I.   Meteorological
          Data                        *        *       *       *          *       *          *        *

    II.  Physical Parameter
          Cruises                                                         *

    III.  Multidisciplinary
          Cruises                      *       *               *                   *

    IV.  Tide Data:

         i.   Havre de Grace           *       *       *       *           *       *          *       *       *        *
         ii.   Baltimore                               *       *           *       *          *       *
         iii.  Matapeake                               *                  *        *          *       * .   .   .

    V.   Stream Flows

         i.   Susquehanna River        *       *       *       *          *        *          *       *       *   .        ,        ,     ,
         ii.   Patapsco River          *       *       *       *          *        *          *       *       *   ,        .        ,     ,

    VI.  Chlorinated Hydrocarbons

         i.   Air-Dust                                                                                *   .
         ii.   Rain Water                                                                             *   ,        ,
         iii.  Storm Water                                     *          ,                          ,
         iv.   Ground Water                                                        *                  *        ,

     UPPER CHESAPEAKE BAY                          CONOWINGO
                                         SUSQUEHANNAR      DAM
                                                         I~~~~~
                                                  HAVRE l
                                                  DE GRACE   t~

           NAUTICAL MILES                                2

                           GUNP0O                          �ROEP

                                                   b     D      SASSAFRAS R

    BALTIMORE                POOLES IS,95a

                                  04(D    0   b4A

                                               TI~~

             ANNAPOLIS~s 811aKETS

                                            b~~~~~~~~~~~~~~~~~71 A0

           41~~ ~igr 5-.SainLcainMpfrteUerCepakBy

                      GO~~~~~~~~~~~~-

    NINEFOOT                         S
      NIKNNEOLOLOT                    SWAN PTI2              \I
      KNOLL

                                      LITTLE NECK I  OC  HALL

                                             WINDMILL PT

                                                 HUNTINGFIELD

                              S52X       , L OVEC2       P               __

                                 /// 5    ,,C6 C

                                        ISLA t            BAUWILSON PT%

                                T    C9               C110O
    SS2             SS3     GLOVE PT           SS4

                                                               /     EASTERN
                         /                                      (,'NECK

                       /  ISLAND                         BAYBUSH PTL

                                                                       75151A110
                  Figure 5-4. Station Location Map for the Chester River

                                       5-7

           5.2.5 Stream Flows
                  The major fresh water inflow to the upper Chesapeake Bay is from the Susquehanna
    River. The Water Resources Division, U. S. Geological Survey provided the streamflow data for the Sus-
    quehanna river at Conowingo Dam and for the Patapsco River at Hollofield, Maryland for the period from
    December 1973 through December 1974.

           5.2.6 Chlorinated Hydrocarbons in Air-Dust, Rain Water, Storm Water and Ground Water
                   Figure 5-5 shows the locations of Morrell Park, Sollers Point, and Fort Smallwood at
    which we collected storm water, air-dust, rain water, and ground water samples.
                   Air-dust Samples-The chlorinated hydrocarbon air sampling system used in this study
    is essentially similar to the high-volume air collector of the University of Rhode Island (Bidleman and
    Olney, 1973). The initial collector is a Gelman paper filter (pore size 0.3 mim). This is backed by an
    aluminum cylinder ten inches long and three inches in diameter containing two 3 in. x 3 1/2 in.
    polyurethane foam plugs. The foam plugs are one-half inch larger than the inside diameter of the
    aluminum cylinder to ensure a tight fit. The outlet of the air vacuum pump (Cadillac Air Pump) is con-
    nected to a flow meter (Fisher and Porter Product) to measure the flow rate passing through the system
    (Figure 5-6).
                   Figure 5-7 shows the installation of the air sampling system at Sollers Point, a State of
    Maryland air quality sampling station. Six air sampleswere collected during the study. A 24-hour sampl-
    ing period was chosen in coordination with the State's sampling program. Flow rates were recorded at
    the beginning and at the end of the period, assuming a linear variation during the sampling period. The
    total volume of air passing through the system ranged from 600 to 750 m3/day.
                   Rain Samples-Two types of rain collectors were used in this study. A one-meter square
    box made of sheet metal was installed at Fort Smallwood Park (Figure 5-8). The maximum capacity of this
    collector was five gallons.
                   Another type of rain collector was a glass container of 5 in. x 6 in. x 11 in. (height) with a
    small amount of mineral oil on the bottom to prevent the evaporation of collected water. It was installed
    at Sollers Point station at the same site as the State's air-dust fallout collector. Samples collected from
    these devices represented total precipitation and fallout from the atmosphere.
                   Storm Sewer Samples-The storm sewer outlet near DeSoto Road in Morrell Park,
    designed to carry storm water only, collects the runoff from a local residential area. Six five-gallon
    samples were collected here and analyzed for this study (Figure 5-9).
                   Ground Water Samples-One of the U. S. Geological Survey observation stations, a
    brick-lined well at Fort Smallwood Park, was selected for sampling ground water. It has a diameter of four
    feet and a water level about 14 feet from the ground. Five five-gallon samples were collected here and
    analyzed for this study.

                                                     5-8

                                                SOLLERS POIN

                                                               FORT SMALLWOOD

    1- -X_
                                                  /~~~~~~~~~~~~~~~~~~~~~~~~ /

                                                                                   I~~~~~~~~~~~~~~~~
                                                  ~~"-�j~~:� :��i:.  i   *   : ~~~~~~��;�~~~$i~~ iii~    ! ii

                                                                                                                         75151A111

         Figure 5-5  Locations of Morrell Park, Sollers Point, and Fort Smallwood

                                                                               75151A197
               Figure 5-6. Air-Dust Sampling Device

                                                                                75151A198

    Figure 5-7. Installation of Air Sampling System at Sollers Point

                                5-10

                                                                                  75151A199
    Figure 5-8. Installation of Rain Collector at Fort Smallwood Park

                                                                                 75151A200

    Figure 5-9. Storm Water Manhole on the DeSoto Road, Morrell Park

                                  5-11

      5.3 Results and Discussion

           5.3.1  Chlorinated Hydrocarbons in Air-Dust
                   The atmosphere has been suggested by many researchers as a major transport route of
    chlorinated pesticides (including PCB's) to the ocean (Risebrough et al., 1968; Cohen et al., 1966; Nisbet
    et al., 1972; Bidleman et al., 1974). In this study, six air-dust samples were collected from Sollers Point
    station; they were extracted and analyzed at the University of Rhode Island. A flow diagram describing
    the analytical procedure is presented below (Bidleman, 1974):

                                               Air Sample Extracts

                                                         silicic acid, 3g9, 3.3% water

      50 ml petroleum ether                                        10 ml dichloromethane
      "PCB fraction" PCB,                                          "pesticide fraction"
      DDE, some components                                         DDT, chlordane, DDD,
      of tech. chlordane,                                          dieldrin
      some sulfur compounds                                                     ,

                                                                                 EC-GC

      shake with Hg and conc. H2SO4                                shake with conc. H2SO4
                                                                      to remove dieldrin

              EC-GC                                                            EC-GC'

                   In the beginning of the field data collection, one four-inch Gelman filter followed bytwo 3
    in. x 3 1/2 in. diameter polyurethane foam plugs were used to trap chlorinated hydrocarbons from the
    air. The analytical results for the sample collected on July 22, 1974 are presented in Table 5-2.
                   Three principal findings resulted. First, only 9 percent of PCB and 18 percent of chlordane
    were found on the Gelman filter, although the filter was very dirty (estimated residue at about 55 mg of
    suspended particulate matter on the filter). Secondly, the Gelman filter contained almost no dieldrin nor
    DDT, which appeared on the first foam plug instead. Thirdly, the second foam plug contained no
    chlorinated hydrocarbons. Based on the experimental results of this sample, it was decided to eliminate
    the second foam plug in the subsequent data collection.

                                                   5-12

                     TABLE 5-2. CHLORINATED HYDROCARBONS ON GELMAN FILTER
                                   AND POLYURETHANE FOAM PLUGS

                         Sollers Point, July 22, 1974, Air Volume = 586 m3 (24 hours)

                                     PCB               Chlordane
                               (Aroclor (0 1254)   (alpha plus gamma)    Dieldrin        DDT
                                     (ng)*                (ng)              (ng)         (ng)

             Gelman Filter           342                  221

             First Plug            3,432                  982             123            62

             Second Plug

             Total                 3,774                 1,203            123            62

             **The abbreviation ng is nanograms.

                  Table 5-3 presents the total weight of chlorinated hydrocarbons in the filter and foam
    plug in nanograms per sample. Concentrations of chlorinated hydrocarbons and suspended particulate
    matter in air-dust samples are shown in Table 5-4. Amongyarious chlorinated hydrocarbons found in the
    air samples, PCB (Aroclorl1 254) had the highest concentration, ranging from three to nine nanograms
    (ng) per cubic meter. The highest chlordane (alpha plus gamma) concentration was three nanograms per
    cubic meter. The DDT and dieldrin concentrations were relatively small.
                  In a field study conducted by EPA in 1967 and 1968 (Stanley, 1971), the maximum levels
    of pesticides found in air samples from Baltimore were:

                                    p,p' - DDT   - 20 ng/m3
                                    o,p' - DDT   - 3  ng/m3
                                    p,p' - DDE   - 2  ng/m3
                                    Lindane     - 3  ng/m3
                                    Alpha - BHC-  5  ng/m3
                                    Gamma - BHC-2   ng/m3

                  Because of the different localities and methods of collection, it is difficult to compare the
    results of the U. S. Environmental Protection Agency's study and those of the present study. However,
    from previous work it can be concluded that the level of DDT (p,p' -) in the atmosphere has decreased in
    recent years.

           5.3.2 Chlorinated Hydrocarbons in Rain Water
                  The airborne chlorinated hydrocarbons return to earth mainly through rain and, to a
    lesser extent, by falling dust (Matsumura, 1972). In this study, a total of eight rain samples were collected
    and analyzed. Concentrations of chlorinated hydrocarbons in each of the rain samples are presented in
    Table 5-5.
                  At the Fort Smallwood station, toxaphene as high as 283 ppt was detected in the sample
    collected from August 28 through September 4. Maximum concentrations of chlordane and benzene
    hexachloride (BHC) appeared in the October sample with 4 ppt for chlordane (alpha plus gamma) and 51
    ppt for BHC (alpha plus gamma). The PCB's and DDT were considerably lower than other concentrations
    at the 0-4 ppt level.

                                                  5-1'

                  TABLE 5-3. CHLORINATED HYDROCARBONS IN Al R-DUST SAMPLES,
                                   SOLLERS POINT, MARYLAND, 1974

                                          PCB           DDT          Chlordane
                       Air Volume     (AroclorO 1254)  (pp'-)      Alpha      Gamma        Dieldrin
       Date              (m3)             (ng*)          (ng)       (ng)       (ng)         (ng)

       July 16
       (24 hours)         673             2,701         110         510        491         215

       July 22
       (24 hours)         586             3,774          62         648        555         123

       July 30-31
       (48 hours)        1,448            9,425         --         1,988      1,742

       August 21
       (24 hours)          745            6,778         --          715        640           55

       October 8
       (24 hours)         620             1,455           9         370        365           74

       October 26
       (24 hours)          628            1,566            9         191       205           52

       *The abbreviation ng is nanograms.

                   Samples collected at the Sollers Point station (Table 5-5) were quite different from those
    collected at the Fort Smallwood station. Higherconcentrations of PCB's(1 30 ppt)and chlordane (1 80 ppt
    for alpha plus gamma chlordane)were detected. The difference in resultsforthe two sampling stations is
    probably attributable to the locality. Fort Smallwood is a recreation park, and Sollers Point is a residential
    area with an industrial neighborhood, hence, closer to a variety of sources of these materials.

           5.3.3 Chlorinated Hydrocarbons in Storm Water
                   Materials commonly on street surfaces have been found to contribute substantiallyto ur-
    ban pollution when washed into receiving waters by storm runoff (Sartor and Boyd, 1 972). A pilot study
    was conducted for the Upper Bay Survey in order to determine the concentrations of chlorinated
    hydrocarbons in a storm water system of Baltimore. Table 5-6 presents the analytical results of the six
    samples taken. Concentrations as high as 580 ppt for PCB and 63 ppt for chlordane were found in the
    sample collected on March 29, 1974.

           5.3.4 Chlorinated Hydrocarbons in Ground Water
                   After entering the surface runoff, water-borne pollutants may infiltrate into the ground
    water system. Five ground water samples were collected and analyzed to compare the concentrations of
    chlorinated hydrocarbons in various hydrologic systems. Total PCB ranged from 1 to 26 ppt; total DDT
    varied from 1 to 6 ppt; highest chlordane was 2 ppt, and highest dieldrin was 3 ppt (Table 5-7).

                                                    5-14

                         TABLE 5-4. CONCENTRATIONS OF CHLORINATED HYDROCARBONS AND SUSPENDED PARTICULATE MATTER
                                                    IN AIR-DUST SAMPLES, SOLLERS POINT, MARYLAND, 1974

                                          PCB                       DDT                      Chlordane              Dieldrin      Suspended
                       Date                (Aroclor 1254)             ( pp'-)          Alpha          Gamma                         Particulate Matter
                                           (ng/m3)*                  (ng/m;)           (ng/m3)       ng/m3)         (ng/m3)        (ug/mr)

                       July 16             4                          <1               < 1            <1             <1             91
                       (24 hours)

                       July 22             6                          <1                  1              1           <1             94
                       (24 hours)

                       July 30-31          7                          --                  2              1
                       (48 hours)

                       August 21           9                          --                  1           <1             <1
                       (24 hours)

                       October 8           3                          --               <1             <1             <1             61
    71    "             (24 hours)

                       October 26          3                          --               <1             <1             < 1
                       (24 hours)

        *The abbreviation ng is nanograms, and ug is micrograms.

            TABLE 5-5. CONCENTRATIONS OF CHLORINATED HYDROCARBONS IN RAIN WATER

                                                           Chlordane                       Benzene Hexachloride
                             Total PCB     Total DDT    Alpha   Gamma    Toxaphene    Alpha                 Gamma
    Date (Time)                 (ppt)          (ppt)       (ppt)     (ppt)       (ppt)        (ppt)           (ppt)

                                     Samples at Fort Smallwood, Maryland, 1974

    Jul 30(12:00
    noon) - Aug. 7
    (8:00 AM)                      2             2

    Aug. 28 (12:00
    noon) - Sep. 4
    (8:15 AM)                                                2       <1          283           15               2

    Sep. 4 (8:15 AM)
    - Sep. 28 (12:00
    noon)                                                                        167            4               3

    Sep. 28 (12:00
    noon) - Oct. 1
    (8:30 AM)                                              <1       <1            44           11               4

    Oct. 1 (8:30 AM)
    - Oct. 16 (10:00
    AM)                                          4           2         2          86           37              14

                                        Samples at Sollers Point, Maryland, 1974

    Jul. 29 (10:00 AM)
    Aug. 30 (10:00 AM)           130            11          23        13                       18

    Aug. 30 (10:00 AM)
    Oct. 3 (7:30 AM)                                        19       15          220

    Oct. 3 (7:30 AM)
    Nov. 1 (8:30 AM)            120             22         94        90

                                                         5-16

            TABLE 5-6. CONCENTRATIONS OF CHLORINATED HYDROCARBONS IN STORM WATER
                                SAMPLES, MORRELL PARK, MARYLAND, 1974

                                                          Chlordane                       Benzene Hexachloride
                            Total PCB     Total DDT    Alpha   Gamma    Toxaphene    Alpha                Gamma
    Date (Time)                 (ppt)         (ppt)       (ppt)    (ppt)        (ppt)       (ppt)           (ppt)

    Mar. 29
    (8:30 AM)                    27             12           9        2

    Mar. 29
    (6:00 PM)                   580              5         42        21

    May 3
    (7:30 AM)                    46            31

    Sep. 4
    (7:30 AM)                   190            12           4         2

    Oct. 16
    (9:00 AM)                   --            --          <1       <1             13           2              <1

    Nov. 5
    (11:00 AM)                    7              7           8        5         --          --                 3

                       TABLE 5-7. CONCENTRATIONS OF CHLORINATED HYDROCARBONS
                     IN GROUND WATER SAMPLES, FORT SMALLWOOD, MARYLAND, 1974

                                                                       Chlordane
                                    Total PCB        Total DDT        Alpha      Gamma         Dieldrin
            Date (Time)                 (ppt)            (ppt)          (ppt)       (ppt)          (ppt)

            May 3 (8:45 AM)              26                6                                         3

            Jul. 17 (10:30 AM)             1                2             1           1              1

            Sept. 4 (8:30 AM)             8                 1             1           1

            Oct. 16 (10:30 AM)            2                2              1           1

            Nov. 5 (12:00 noon)           9                               1           1

                                                       5-17

           5.3.5 Climatological Variations
                  A detailed study of the climatological variations in the upper Chesapeake Bay area is
    beyond the scope of this investigation. However, the climatological data at Baltimore Washington Inter-
    national Airport are presented for interpretation and correlation purposes.
                  The variations of air temperature, barometric pressure, precipitation, and wind speed and
    direction for December 1973 through December 1974 are presented in Volume Ill. Table 5-8 shows the
    monthly averages and departures from normal of the above mentioned parameters except barometric
    pressure for 1 974. Note that 1 974 had a relatively warm winter (50F. above normal for December) and a
    relatively cool summer (about 40F. below normal). Unusually dry weather occurred in July (3.22 inches
    below normal precipitation), and relatively wet weather occurred in December (2.44 inches above nor-
    mal). Monthly average wind speeds were all below normal for the entire year, with an extreme of 3.1
    miles per hour below normal for January.

           5.3.6 Variations of Water Temperature, Salinity, and Suspended Sediment
                   Detailed seasonal variations of water temperature, salinity, sigma-t*, and suspended
    sediment in the upper Chesapeake Bay are presented in Volume il. Examples are shown in Figures 5-10
    and 5-11. Tables 5-9, 5-10 and 5-11 show summaries of results at three depths for three key
    stations-the mouth of the Susquehanna River (1A), Worton Point East (4B) and Kent Island Middle
    (11B).
                  Water temperatures at Station 1 A were quite uniform throughout the water column. The
    maximum difference was only about 0.70C on July 31. Seasonal changes in surface temperature ranged
    from 2.70C on January 24 to 26.90C on July 31. At Station 11 B, the maximum difference was 3.80C in
    temperature between surface and bottom. Its surface temperature changed from 3.0�C on January23 to
    25.20C on July 31.
                   Salinity was very low and uniform at Station 1 A-only 0.05 �/oo on December 14, 1973.
    At station 11 B, surface salinity varied from 5.4 �/oo on January 23 to 12.0 �/oo on September 18. Its
    maximum salinity on the bottom was 15.9 �/oo on September 18.
                   Concentrations of suspended sediment at Station 1 A reached 42.7 mg/I near the bottom
    on December 14, 1973. The concentrations reached as high as 80.8 mg/I near the bottom on March 20
    and 92.1 mg/I on the surface on May 2 in the region of turbidity maximum near Station 4B (Schubel,
    1971). At Station 11 B, concentrations of suspended sediment varied from 3.0 mg/I to 5.2 mg/I on the
    surface and varied from 11.9 mg/I to 27.9 mg/I near the bottom.

           5.3.7 Fresh Water Inputs and Tidal Variations
                   Figures 5-12 and 5-13 showthe estimated monthly streamflow entering the Chesapeake
    Bay in 1974 and the annual mean flow from 1950 to 1974. The annual mean flow for 1974 was 76,900
    cfs in which about 52 percent (39,900 cfs) came from the Susquehanna River. As shown in Figure 5-14,
    the spring freshet for 1974 occurred on April 5, when the daily mean discharge reached its maximum of
    198,000 cfs (5,609 cms).
                   Volume IIIl contains data for fresh water inflows from the Susquehanna River at Con-
    owingo and from the Patapsco River at Hollofield, Maryland.
                   Available tide data at three key locations-Havre de Grace, Baltimore, and Matapeake are
    presented in Volume IIIl. Figures 5-15 and 5-16 show the actual water level variations during the spring
    freshet in April and the low water period in October.
                   Current data at ten stations in the upper bay, which the Chesapeake Bay Institute
    collected for Corps of Engineers in 1971, were analyzed; results of this analysis provided additional infor-
    mation for the Chesapeake Bay Institute to verify their mathematical model of the Upper Chesapeake
    Bay. The data are recorded in Section 4 of Volume III.

    *Sigma-t is a, = (Pt -1) 1,000, where P, is the density of water at temperature t�C.

                                                    5-18

    TABLE 5-8. MONTHLY AVERAGES AND DEPARTURES FROM NORMAL FOR AIR TEMPERATURE, PRECIPITATION,
                              WIND SPEED AND DIRECTION, BALTIMORE, MARYLAND, 1974

                 Air Temperature                   Total Precipitation                        Wind Speed and Direction
             Averages       Departures        Precipitation      Departures         Resultant      Ave.         Dept.       Normal
             (�F)           from Normal       (Inches)           from Normal       Vel. Dir.       Speed        From        Prevail.
                                (�F)                             (Inches)          (mph)           (mph)       Normal       Direct.

    Jan      37.9           +4.5               2.92              +0.01              2.6 WNW          7.3        -3.1        WNW

     Feb      33.8           -1.0               0.94              -1.87              4.2 WNW          9.5        -1.4        NW

    Mar      45.2           +2.4               4.12              +0.43              3.2 WNW         10.4        -1.2        WNW

    Apr      55.3           +1.5               2.59              -0.48              5.4 W           10.2        -1.3        WNW

    May      61.9           -1.8               3.58              -0.03              1.9 SW           8.9        -1.1        W

    Jun      68.5           -3.9               2.84              -093               0.7 W            8.4        -0.8        WNW

    Jul      76.5           -0.1               0.85              -3.22              2.7 W            8.2        -0.5        W

    Aug      75.0           +0.1               5.85              +1.64              1.7 SSW          6.5        -2.4        W

    Sep      67.5           -1.0               5.45              +2.33              1.7 W            6.8        -2.3         S

    Oct      55.3           -2.1               1.53              -1.28              2.8 WNW          6.8        -2.8        NW

    Nov      48.2           +2.1               1.39              -1.74              5.1 W          9.4          -0.5        WNW

    Dec      40.3           +5.0               5.70              +2.44              2.8 WNW          8.6        -1.0        WNW

    TABLE 5-9. VARIATIONS OF WATER TEMPERATURE, SALINITY, AND CONCENTRATION OF SUSPENDED
                            SEDIMENT AT STATION 1A (BOTTOM DEPTH: 13.0 m)

    Month                     Dec. 73       Jan. 74       Mar. 74        May 74        Jul. 74        Sep. 74

    Day                       14            24            20             03            31             20

                                                   Water Temperature (�C)

    Surface                   5.09          2.73          5.28           16.08         26.93          22.68

    Mid-Water                5.06           2.69          5.27           15.98         26.47          22.55

    1 m Off Bottom           5.04           2.68          5.31           15.94         26.24         22.44

                                                       Salinity (0/oo)

    Surface                  0.05           0.13          0.11           0.12          0.13           0.13

    Mid-Water                0.05           0.14          0.10           0.12          0.13           0.13

    1 m Off Bottom           0.05           0.11          0.11          0.12           0.13          0.13

                                             Concentration of Suspended Sediment (mg/l)

    Surface                  41.33          32.49          11.30          9.58         23.89           4.68

    Mid-Water                41.57          31.27         13.32          15.03          6.90           5.09

    1 m Off Bottom           42.74          33.86         14.86          16.73         29.72         12.29

                                                       5-20

    TABLE 5-10. VARIATIONS OF WATER TEMPERATURE, SALINITY, AND CONCENTRATION OF SUSPENDED
                             SEDIMENT AT STATION 4B (BOTTOM DEPTH: 12 m)

    Month                     Dec. 73       Jan. 74       Mar. 74        May 74        Jul. 74        Sept. 74

    Day                       14            23            20             2             31             19

                                                      Water Temperature (�C)

    Surface                   4.61          1.98           5.47          17.09          26.94         23.54

    Mid-Water                4.89           1.65          5.26           16.90         25.59          23.14

    1 m Off Bottom           5.03           1.80          5.16           16.86         25.51          23.13

                                                        Salinity (�/oo)

    Surface                   0.18          0.29          0.08           0.12          2.20           2.73

    Mid-Water                0.35           1.63          0.08           0.07          3.99           3.41

    1 m Off Bottom           0.47           2.52          0.09          0.08           4.54          3.48

                                               Concentration of Suspended Sediment (mg/l)

    Surface                                               41.74          92.11          12.27         13.62

    Mid-Water                                             49.31          48.95         22.94          28.37

    1 m Off Bottom                                        80.80          40.15         62.94          30.75

                                                       5-21

    TABLE 5-11. VARIATIONS OF WATER TEMPERATURE, SALINITY, AND CONCENTRATION OF SUSPENDED
                              SEDIMENT AT STATION 11 B (BOTTOM DEPTH: 14.5 m)

     Month                     Dec. 73       Jan. 74        Mar. 74        May 74        Jul. 74        Sep. 74

     Day                       12            23             20             01            31             18

                                                    Water Temperature (�C)

     Surface                   7.65           2.96          6.05           15.14         25.23          23.10

     Mid-Water                 8.13          4.42           6.05           14.34         24.41          23.76

     1 m Off Bottom            9.91          5.23           6.08           11.37         23.44          24.04

                                                          Salinity (�/oo)

     Surface                   10.14           5.37          6.77           5.79          10.92         11.95

     Mid-Water                  9.89          12.44         10.05           7.38         12.58          13.71

     1 m Off Bottom            15.49          15.23         13.59          10.50          15.77         15.94

                                                 Concentration of Suspended Sediment (mg/I)

     Surface                    5.18           3.02          8.08           3.38           4.32          3.50

     Mid-Water                  4.20           9.28          6.91           3.72           6.18          3.61

     1 m Off Bottom            27.94         14.48          14.80          11.89         18.72          19.06

                                                         5-22

                                          LIPPER  E3AY  SURVEY  STFRTI0N  0318
                                                             TZHc C 114-IMSO 3    0/17

                 TIEI4PCRITUIIM  C C 3          GRLXNZIV r PFT 2             SIGMR-T C5115/3000 CII CM3       C1131. OF SEMZMENT CH6./L3
            j     190  "is3   Rol.E   %snl.11    FAN    (PAD   19.3   20.3014 . LOA US    (930   (.00   V5.111.10    119.211  k030    0Jon  -10.29

        C,                                  I

    cm ~~~~~~UPPER  E2AY  SURVEY  STRTI0N  OLI.2
            K3                                              TZIME C 1:5%13-3.3sa 2    03/20/74~~~35

                         TENFERRTU~~~~r C C 2 ~ERMLNXTY C PPT I              s5Z tMR-r crims/3.ooo Lu Cm2    CON. OF SEXIMENT CHIG/1-
              "I PAID1.3     10.0 0.0   I30 q.vD.1j) "a  19.10   1F40   9.00      q*0 (.00       (9.50 T.0    1.00.10 J                   0.501

        M-                                                                                                                                .

                                                                                                                                          7515IA201

             Figure 5- 10. Variations of Water Temperature, Salinity, Sigma-t and Suspended Sediment at Stations 01A and 04B

                                       UPPER E1FY SURVEY STFRTION C17R
                                                       TZMC C XZ-33a2101  3    03/21/TI-

               TM1PEIMRTURE c C 3                SRLMNITY C ~PF  3           SITfr1R-T CBM5/.013D CU C112        CON. OF' SEM114ENT CMG/L3
         Mo    19.0 -og  o I~J  BADJ  A~lU   !3J3 MAN            IJJ3    9.31    az  inn  %po   IPUif   15..n    12.8 .in    jPxII   p.111  10.3    quja

       &a      +

    W ~~~~UPPER    R Y  SURVEY  STFRTI0N  IIE3
                                                      TZMtC C 011"-13aS4 3    133D/70/

               TEMPERFITURE C C 3               SRLINITY C PFT 3             SITr'l;-T CGMS/3.133 CLU CH3       CO3N. OF SEZMIMNT rM/:
         -I .u   "n    413.00   40.00   NIADJ  B~ .UD   TPAo    ,u   ODJo .no       so    1P.0a   1~.Do    Mn~o is    -1P.nm   20.05   30.00   40.13

      W&.-
      it

      W

                                                                                                                               751 51 A202

            Figure 5-1 1. Variations of Water Temperature, SalinitY, Sigma-t and Suspended Sediment at Stations 07A and 118B

        400

                  u-~ ~ ~~~~~~~~~~~~~~~dFI

    LU
        LU    ~~    Monthly mean streamf low
                    into Chesapeake Bay (1974)
                  C Cu rre nt y ea r-   A ve rag9e -- -
            10     ~Unshaded area indicates range
                   Kbetween highest and lowest                                                         _
                �zKvalues of  the 23-'year record

      <    ~ JAN    FEB    MAR   APR    MAY   JUNE   JULY   AUG    SEPT   OCT    NOV    DEC

    0

            -    Annual  mean  streamflow into Chesapeake  Bay by calendar years
         30    1 1   fI  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  I  II I
           1950            55            '60            '65            '70            '75            1980

                                                                                               75161A203
        Figure 5-12. Estimated Monthly Stream flow Entering Chesapeake Bay and Annual Mean Flow
                                            (USGS, Jan. 1975)

                                                    5-25

       ESTIMATED CUMULATI'VE STREAMFLOW ENTERING CHESAPEAKE BAY
                ABOVE INDICATED SECTIONS BY MONTHS, DURING 1974

      240 0             i             i

      220-

                     ~~~~~~~~~~~~~~4 E

                  1~~~~~~~~~~~~~~~~~4,

    ojs

    IL-

    LA-   ...

       ,rA:

                ~~~~100~~~~~~~~A               IDCATED CAROSLECTOS

                    ~~~~~~~~~~~~~~~~~~~~~~~40

                '-~~~~~~~~~~~~~~~~..           ...... 4.....

                                          ::::: ::...      Mouth of Chesapehakenay
              40                                           B   Above mouth of~~~~~~..... ........... ..

            0  ......~                .....   . . . . ...f  heaeae  o

           J F MA MJ J A SON D

                                                                              75151 A204
             Figulre 5-13. Cumulative In flow to Chesapeake Bay, 1974 (USGS, Jan. 1,975)

                                           5-26

        SUSQUEHRNNR RIVER RT C0N1NINE[0 MRRYLRNI

                          JRILY MEAN IIIECHRRSE

                                   RPRIL 1974
                              C MONTHLY RVERRSE 1S 2574 CM5 3

                                                            1 CMS    3S.3 U-9

      5000-

      iO~O -
    U1

    U

    q ooo-
    U
      3000-

                               II 12                       2 1 3   2's                 3,
                                          ZRYS

                                                                         75151 A205

           Figure 5-14. Daily Mean Discharges for dhe Susrquehanna River at Conowingo, Maryland

                                         5-27

            RCTURL TIIE
            HRVRE  IE GRRCE  C RPRIL 197+ 3                   TIME IN MRYS

           .0   2  *           *   10  12  2*  16  lB  20  22  2*  26  28  30

            MRTRPERKE I RPRIL  197+

            O        *    &   8    10   12  1*   16   18  20   22   2*  26   25   3O

          .I
          , IAA \"VA hA vMAAAAAvj NO

                                                                                     75151 A206
      Figure 5-15. Actual Water Level Variations at Havre de Grace and Matapeake, April, 1974

            ACTURL TI2E
            HRVRE  DE GRRCE C BECTEBER 197- 3                    TIME  IN DRYS

          5D o            L        I IA  la 12  1'-  1   1.   0

            6,=4V      'IAVV

            MRTRPERKE  C BCETBER 197L 3

           .D    2 Z      6         10  12   *   12  1168  20  22   2   26  28   0

                                  .3 ..    .6  1.                      26 A

                                                                                     75151A207
    Figure 5-16. Actual Water Level Variations at Havre de Grace and Matapeake, October, 1974

                                          5-28

      5.4 Correlation Analyses and Discussions

           5.4.1 Rate of Transport of Chlorinated Hydrocarbons in the Atmosphere
                   Figure 5-17 shows the wind rose for July 1974 at Baltimore. The average wind velocity
    was 2.7 mph (1.2 meter/sec) from the west (2700).
                  Assume that the average concentrations of chlorinated hydrocarbons from three air
    samples taken in July 1974 (See Table 5-4.) represent the mean values in the atmosphere for the entire
    month at Sollers Point station. Then, the rates of transport for PCB and chlordane in an area of one
    square meter on the vertical air section for the month of July can be obtained as below:

                 PCB            17 mg/m2/month
                Chlordane       7 mg/m2/month

                  The modes of transport of chlorinated hydrocarbons in the atmosphere are similar to the
    modes of other airborne pollutants. Vaporized chlorinated hydrocarbons will be partially adsorbed on
    particulates, transported with the prevailing winds, and deposited on land or water by particle sedimen-
    tation or rain-out. Figure 5-18 shows the summary of the resultant wind speed and direction at the
    Baltimore Washington International Airport for 1974. Obviously, the overall wind was from west or
    north-west direction. Therefore, part of the chlorinated hydrocarbons in the Chesapeake Bay could
    originate on the western shore areas.

           5.4.2 Chlorinated Hydrocarbons Return to Earth
                  As an approximration, one example is worked to estimate the total return of chlorinated
    hydrocarbons from the atmosphere to earth through precipitation and sedimentation of particles. Basic
    data used for computation are as follows:

                Station                   Sollers Point, Maryland (Table 5-5)
                Sampling Period           October 3, 7:30 AM to November 1, 8:30 AM
                                           (697 hours)
                Effective Collecting Area  5 in. x 6 in. = 30 in.2
                Total PCB                 58 ng
                Total DDT                  1 lng
                Chlordane                 92 ng

                  For the month of October 1974 (744 hours) on a one-acre area in the neighborhood of
    Sollers Point, the rates of transport can be estimated as follows:

                Total PCB      13 mg/acre/month
                Total DDT       3 mg/acre/month
                Chlordane      21 mg/acre/month

                                                  5-29

        23RLTIMORE E LJULY 1974- D

                  RCCUMULRTEM WIND SPEED C M/S 3

                          N
                   NNW                 NNE
                        woo

            NW         3    1 0

                        300
        WNW /                                           ENE

       w   IE

                   WESE

                SW~~~~

                                                  75 151A208

    Figure 5-17. Wind Rose for July 1974 at Baltimore Washington International Airport

                          5-30

                                    00JUL
    w  ---'   --'                                        0  L                              I                         I--"E

                                                                                                                            75151A112

         Figure 5-18.  Monthly Resultant Wind Speed and Direction at Baltimore Washington International Airport for 1974

           5.4.3 Chlorinated Hydrocarbons in Storm Water Runoff and Precipitation
                   The Morrell Park storm water outlet was designed to carry surface runoff from the street
    only. During the dry weather periods, there was a small amount of ground water in the system. Figure 5-
    19 shows the intensity-duration curve for the storm event of March 29 and 30, 1974. The previous rain
    event occurred on March 21 (Figure 5-20) and was followed by a seven-day dry period. As shown in
    Figure 5-19, two samples were collected, one at 8:30AM (the rain started at 12:00 noon) and one at 6:30
    PM on March 29. Significant changes in chlorinated hydrocarbon concentrations were revealed in
    Figure 5-19. Total PCB increased from 12 ppt to 580 ppt; total DDT decreased from 12 ppt to 5 ppt, and
    chlordane increased from 11 ppt to 63 ppt. Results obviously suggest that the street runoff contained
    high concentrations of PCB's and chlordane washed from the area.

           5.4.4 Spring Freshet: Inputs of Sediments and Chlorinated Hydrocarbons
                  The Susquehanna River, the upper Chesapeake Bay's only major source of fresh water,
    discharges more than 97 percent of the total fresh water and fluvial sediment into the upper portion of
    the Bay (Schubel, 1969). During the first week of April 1974, the average discharge was 139,200 cfs (3,-
    943 cms), See Figure 5-14. If it is assumed that the average concentrations of suspended sediment and
    chlorinated hydrocarbons at Station 2B (see Figure 5-3)for April 3 and 4were the same as the values for
    April 1 through 7 at Conowingo gauging station, then the inputs of sediment and chlorinated hydrocar-
    bons can be estimated as:
                Suspended Sediment    35.9 mg/l
                Total PCB                10.1 ppt
                Total DDT                 1.0 ppt
                Chlordane                 0.3 ppt

                   Forthe firstweekof April 1974, the total volume of discharge was 2.39 x 109 m3. Thus, the
    approximate rates of input are:

                Suspended Sediment    85,703 metric
                                            tons/week
                Total PCB                24 kg/week
                Total DDT                 3 kg/week
                Chlordane               0.8 kg/week

                   Based on the available data-averaged concentrations of chlorinated hydrocarbons in the
    suspended sediments at Station 1A were:

                Total PCB                0.633 ppm
                Total DDT               0.035 ppm
                Chlordane               0.030 ppm

                   Figure 5-21 shows the monthly inputs of suspended sediments from the Susquehanna
    River into the Chesapeake Bay. If it is assumed that these sediments carried the same concentrations of
    chlorinated hydrocarbons as the sediments at Station 1 A, the total inputs of chlorinated hydrocarbons to
    the bay can be estimated as:

                Total Suspended          800,000 metric
                Sediment                  tons for 1974
                Total PCB                506 kg/year
                Total DDT                 28 kg/year
                Chlordane                 24 kg/year

                                                   5-32

                                                                      Chlordane
          .50 -          Date (Time)         Total PCB    Total DDT    Tech.       a-    A-
                                          (PPT)        (PPT)       (PPT)   (PPT)    (PPT)

                        Mar. 29                 27            12        10       9        2
                        (8:30 AM)

         .40-             Mar. 29                580             5        97      42       21
                        (6:30 PM)

    0
    - .30-

    r /

        .20 -

                             8:30 AM                    6:30 PM

        .10-

        .00
          0.0              6.0             12.0             18.0              0.0               6.0

                                                           MARCH 29  |  MARCH 30
                                                                                                                                      75151 A209

                     Figure 5-19. Precipitation and Concentrations of Chlorirfated Hydrocarbons in Storm Water

                                              E3RLTIM0FRE

               2JRILY PREEIITRTFITIN FR0   MIRREH 197H-

                   SW,~        MON         TU C          E          THU     FRI             S~R
            .so-       .01.                        no                               .002_

          .'30

      J30

    I
    Z    .20-

         .10                                                                              .

                  SUN         M13N        TUC                     THU          FRI         SFIT
            S13    la.003 *        .o   .0       0, .12 7313'E"D1    Z 0.    i   3 1    31+,9

    w    .313
    I
    U
    Z    2
    H    .1

         .10 -nm i

                  SUN     a IaMNW         TUC 0  _1 W.E2          THU         FRI          SRT
            2.0        .0  1 .1    00 192    .0]2.              21'      0  913     .00 Do 2      no

    I
    U
    Z    2
      H .2.0-

                  SUN         MON         TUC         WEIJ        THU         FRI          SRT
               2.     .00 lE        0 19.2     .0D2,       13.002     ~      2      .02          0

      .3 .40-

    Z    2

      Ho

                               .~~~~~~~~~~~~~~~~~~~~~~~~~55 21

             Figur 5       -0 oryPrcptto a atmr, ac,17

                                         I                    I~~-3

           JAN   FEB  MAR   APR   MAY   JUN   JUL   AUG   SEP   OCT   NOV   DEC
    ;;800oo,, ,JA , , , ., ..  ~~  ,  , I.  ,                             . ,  .... ,  . ,  . ,  ..  100I,, .,, .,...,,,,    ,80 ,oo
    0 750-                                                                           750 �
    _700-                                    90
    - 650                                     -                                               80
    E 600-                                                                          - 600,
    x 550-                        -                                                   550�-- 70
     500-                                                                          - 500
                         '"u -                                                               60 n
      450-                                                                         - 450O
    , 400 -                                                                        - 400      = 50
    0 350-                                                                          - 350 C
    FD                                                                                    a - 40
    - 300-                                                                          - 300 -
    w 250-                                     - 250 UJ - 30
    z                                                                                    z

    ,,, 200 -                                                                      - 200 C
    "150-                                                                            150    20

      2~loo=                                    -35
     50-u                                                                              50 -

    un    JAN   FEB  MAR   APR  MAY   JUN   JUL   AUG   SEP  OCT   NOV   DEC
                                            1974

                                                                                       75151A211
            Figure 5-21. Estimated Monthly Inputs of Suspended Sediment from Susquehanna River
                                 into Chesapeake Bay, (Schubel, 1975)

                                                5-35

      5.5 Conclusions

           The hydrological and meteorological investigations of this study were focused primarily on the
    understanding of distributions and transport mechanisms of chlorinated hydrocarbons in the upper
    Chesapeake Bay environment. It is no surprise to note that the major phases of the hydrologic
    cycle-evaporation, precipitation, surface runoff, ground water flow, and the receiving water body are all
    contaminated more or less with chlorinated hydrocarbon residues. Important conclusions from this
    study can be summarized as follows:

           *    Chlorinated hydrocarbons in the atmosphere are mainly in the vapor state. Only 9 percent of
                the PCB and 1 8 percent of the chlordane were found in the suspended particulate matter
                trapped by the Gelman filter. The highest levels of chlorinated hydrocarbons in the at-
                mosphere were 9 ng/m3 PCB, 3 ng,/m3 chlordane, and less than 1 ng/m3 DDT. For the
                month of July 1974, estimated rates of transport of PCB and chlordane over the Sollers
                Point neighborhood were:

                PCB             17 mg/m3/month
                Chlordane        7 mg/m2/month

           *   Airborne chlorinated hydrocarbons return to earth through precipitation and aerial fallout.
                Toxaphene as high as 283 ppt was detected in Fort Smallwood rain samples. At Sollers
                Point, 130 ppt PCB and 180 ppt chlordane were found in the rain samples. Forthe month of
                October 1974, estimated transports of chlorinated hydrocarbons from air to earth in the
                Sollers Point area were:

                 PCB             13 mg/acre/month
                 DDT              3 mg/acre/month
                 Chlordane       21 mg/acre/month

           *    Significant changes in chlorinated hydrocarbon concentrations were found in a storm
                water system before and after a rain storm. At Morrell Park station, it was found that PCB in-
                creased from 12 ppt to 580 ppt, DDT decreased from 12 ppt to 5 ppt, and chlordane in-
                creased from 11 ppt to 63 ppt for the rain storm of March 29, 1974.
           *    Concentrations of chlorinated hydrocarbons in ground water samples were less than those
                in rain water and storm water samples. Maximum levels at Fort Smallwood were 26 ppt
                PCB, 6 ppt DDT, and 2 ppt chlordane.
           *    In 1974, the spring freshet from the Susquehanna River occurred in the first week of April.
                Its daily mean discharge reached 5,609 cubic meters per second at Conowingo on April 5.
                Estimated inputs of sediment and chlorinated hydrocarbons at the month of the Sus-
                quehanna River for this period were:

                 Suspended sediments       85,703 metric tons/week
                 PCB                       24 kg/week
                 DDT                        3 kg/week
                 Chlordane                 0.8 kg/week

                                                   5-36

            Total inputs of suspended sediment and chlorinated hydrocarbons for the entire year were es-
    timated as:

                 Suspended sediments       800,000 metric tons/year
                 PCB                       506 kg/year
                 DDT                        28 kg/year
                 Chlordane                  24 kg/year

       5.6 Acknowledgements
           The writer wishes to express his deepest appreciation to the Westinghouse Ocean Research
    Laboratory staff and the following individuals for their assistance and cooperation in carrying out the
    hydrological and meteorological investigations of the Upper Bay Survey.

            Dr. T. F. Bidleman of the University of Rhode Island.
           Dr. D. W. Pritchard of The Johns Hopkins University.
           Mr. W. B. Solley, Mr. W. E. Webb, and Ms. C. Richardson of the U. S.
             Geological Survey.
           Mr. W. S. Hasfurther, Mr. E. L. Hartman, and Mr. T. C. Chase, Jr. of
             the City of Baltimore.
           Mr. D. Stewart of the U. S. F. Constellation.
           Mr. R. H. Beman and Mr. E. Spencer III of the Maryland Bureau of
             Air Quality Control.
           Mr. S. C. Berkman of the Tide Branch,
             U. S. National Ocean Survey (NOAA).
           Mr. F. Davis of the U. S. National Weather Service (NOAA).

      5.7 References

    Biddleman, T. F., 1974. Personal Communication.

    Biddleman, T. F. and C. E. Olney, 1973. ChlorinatedHydrocarbons in the Sargasso Sea Atmosphere and
           Surface Water, Science, V. 183, pp. 516-518.

    Butler, S. S., 1957. Engineering Hydrology, Prentice-Hall, Inc., Englewood Cliffs, N. J.

    Cohen, J. and C. Pinkerton, 1966. Widespread Translocation of Pesticides byAir Transport andRain-out.
           In Organic Pesticides in the Environment, Amer. Chem. Soc., Advan. Chem. Ser. 60:1630176.

    Risebrough, R.W., R.J., Huggett, J.J., Griffin, and E.D., Goldberg, ed., 1968. Pesticides. Transatlantic
           Movements in the Northeast Trades. Science V. 159, pp. 1233-1236.

    Sartor, J. D., and G. B. Boyd, 1972. Water Pollution Aspects of Street Surface Contaminants, EPA-R2-
           081, Environmental Protection Agency, Washington, D. C.

    Schubel, J. R., 1969. Distribution and Transportation of SuspendedSedimentin Upper Chesapeake Bay.
           Chesapeake Bay Institute, Technical Report 60, November.

                                                   5-37

    Schubel, J. R., 1971. Tidal Variation of the Size Distribution of Suspended Sediment at a Station in the
           Chesapeake Bay Turbidity Maximum, Netherlands Journal of Sea Research, V. 4, pp. 283-309.

    Shubel, J. R., 1975. Upper Bay Survey Report, Vol. II, Section 4.2

    Stanley, C. W. et al., 1971. Measurement of Atmospheric Levels of Pesticides, Environmental Science
           and Technology, V. 5 (5) pp. 430-434.

    U. S. G. S., 1975. Estimated Streamflow Entering Chesapeake Bay, USGS Publication.

                                                    5-38

              CHAPTER 6

            BIOCHEMISTRY

             T. 0. Munson
            Oceanic Division
    Westinghouse Electric Corporation

    ABSTRACT

           The Upper Bay Survey was a multidisciplinary program to studythe rates, routes, sources, sinks,
    and reservoirs of chlorinated hydrocarbons (CHC's) in the upper Chesapeake Bay. Samples of
    zooplankton, suspended sediments, bottom sediments, benthic organisms, water, rain, air, ground
    water, and storm sewer effluent were analyzed for chlorinated hydrocarbons, including chlorinated
    pesticides and polychlorinated biphenyls (PCB's). Chlordane (a pesticide banned in 1975), PCB's (a group
    of industrial chemicals) and DDTR (the total residues of the pesticide DDT, which was banned in 1972)
    were found in all types of samples analyzed. Traces of toxaphene (a chlorinated pesticide) were found in
    some samples taken in the area of Baltimore harbor.
           The sediments in Baltimore harbor were found to contain the highest levels of CHC's in upper bay
    sediments, although, the concentrations of C-IC's in the bottom sediments in the bay were two to three
    times higher, on the average, than those found previously in the Chester River. The suspended
    sediments in Baltimore harbor contained the highest levels of PCB, chlordane, and DDTR (3.8, 0.34, and
    0.30 ppm, respectively). The highest PCB and DDTR values in zooplankton were found at the head of the
    bay near the mouth of the Susquehanna River (PCB, 7.5 ppm; DDTR, 4.2 ppm). The chlordane values in
    zooplankton usually were highest in Baltimore harbor, the highest value being 0.14 ppm.
           Positive correlations were found between the concentration of suspended sediments in the
    water and the concentration of CHC's in the water column on suspended sediments and between the
    zooplankton biomass in the water and the CHC concentration in the water column associated with
    zooplankton. Apparently, the CHC's are transported while associated with suspended sediments. When
    zooplankton blooms occur, CHC's pass from the suspended sediment to the zooplankton with the
    zooplankton bio-concentrating the CHC's five to eight times over the levels found in the suspended
    sediments.
           The Susquehanna River appears to be the major source of CHC's to the upper Chesapeake Bay.
    Although, Baltimore harbor appears to have localized sources of CHC's which cause high levels of PCB,
    chlordane, and DDTR in this harbor, it is not clear whetherthe harbor contributes important quantities of
    PCB and DDTR to the bay. The data do suggest that the net transport of substantial quantities of chlor-
    dane from the harbor to the bay does occur.

                                      TABLE OF CONTENTS

    Section                                                                                   Page

    6.0  BIOCHEMISTRY...............................................................6-1

    6.2  Analytical Methods............................................................6-1
    6.2.1 Sample Collection.............................................................6-1
    6.2.2 Gas Chromatographic Methods..................................................6-4

    6.3.1 Bottom Sediments .........................................................I...6-5
    6.3.2 Suspended Sediments .........................................................6-9

    6.3.4 Benthic Organisms...........................................................6-16
    6.3.5 Laboratory and/In Situ PCB Exposure Experiments.................................6-16
    6.3.6 Other Samples ..............................................................6-16

                                       LIST OF FIGURES

    Figure                                                                                    Page

    6-1  Bottom Sediment Sampling Locations ............................................6-6
    6-2  PCB in Bottom Sediments..............................I........................6-7
    6-3  DDTR in Bottom Sediments.....................................................6-8
    6-4  Average PCB Concentrations by Stations.........................................6-10
    6-5  Average Chlordane Concentrations by Station.....................................6-1 1
    6-6  Average DDTR Concentrations by Station ........................................6-12
    6-7  Average PCB Concentrations by Date............................................6-13
    6-8  Average Chlordane Concentrations by Date.......................................6-14
    6-9  Average DDTR Concentrations by Date ..........................................6-15
    6-10   Concentration of Chlorinated Hydrocarbons in Water on Suspended Sediments.........6-22
    6-1 1 Chlorinated Hydrocarbons in Water on zooplankton ................................6-24
    6-12   Zooplankton Biomass vs Chlorophyll-a Concentration...............................6-25

                                           LIST OF TABLES

    Table                                                                                         Page

    6-1  Chlorinated Hydrocarbons in Benthic Organisms ..................................6-17
    6-2    Chlorinated Hydrocarbons in Suspended Sediments................................6-1 9
    6-3    Average Chlorinated Hydrocarbons Found in the Upper Chesapeake Bay ..............6-1 9
    6-4    Types and Levels of Chlorinated Hydrocarbons Found in the Chester River.............6-20

                                                 iv

    6. BIOCHEMISTRY

       6.1 Introduction
           The Chester River Study set the stage for the Upper Bay Survey. During the Chester River Study,
    it was learned that certain chlorinated hydrocarbons (CHC's) were present in the lower Chester River,
    and that these CHC's probably entered the Chester River from the upper Chesapeake Bay via the
    suspended sediments. The Upper Bay Survey then was implemented with the overall objective of study-
    ing the rates, routes, sources, sinks and reservoirs of chlorinated hydrocarbons in the upper Chesapeake
    Bay. A basic assumption used in the design of this program was that in the relatively turbid waters of the
    bay, the water insoluble CHC's would be adsorbed to suspended sediments in the water column rather
    than being present in solution. In addition, it was felt that CHC's probably could pass from the non-
    biological medium (adsorbed on suspended particulates) to the biological medium in the water column
    (the phytoplankton-zooplankton food chain).
           Although various types of samples were collected and analyzed for CHC's, the bulk of the field
    samples fell into four categories which will be presented and discussed in this section-bottom
    sediments, suspended particulates, zooplankton, and benthic organisms. Data from the remaining
    samples will be presented and discussed in the appropriate sections.

      6.2 Analytical Methods

           6.2.1  Sample Collection

                  6.2.1.1 Sediment Samples
                          Each bottom grab sample was spread out in a hexane-rinsed nine-inch dis-
    posable aluminum pie plate and allowed to air-dry completely (usually in one to two weeks). The dried
    sediments then were ground (using either a mortar and pestle or a Lamair Instruments Model 150 jaw
    crusher) and placed in a hexane-rinsed Mason jar fitted with an aluminum foil-lined cap.

                                                   6-1

                          Each ground sample was sieved through a one-millimeter screen (No. 18 sieve),
    and 50 grams were placed in a cleaned and checked* fritted glass thimble in a 500-milliliter Soxhlet ex-
    tractor. A wad of pre-extracted and baked glass wool had been placed in the thimble to prevent the sedi-
    ment from clogging the frit. The sample was then extracted for 12 hours with a 2:1 hexane-acetone solu-
    tion, and the extractwas concentratedto aboutten milliliters in a checked 500-milliliter Kuderna-Danish
    concentrator. The sample was then ready for clean-up.
                          Chromatographic grade (80-325 mesh) alumina which had been heated to 300�C
    overnight, cooled, and de-activated with five percent (weight to weight) distilled water was prepared
    fresh every two to three days. Thirty grams was placed on a pre-extracted glass wool plug in a Chromaflex
    chromatography column and topped with about five grams of anydrous sodium sulfate. The column then
    was washed with about 250 milliliters of hexane. After running the sample extract into the column, the
    chlorinated hydrocarbons were washed through with 225 milliliters of six percent (volume to volume)
    diethyl ether in hexane into the previously used Kuderna-Danish Concentrator (a clean bottom tube was
    attached) at a flow rate of five milliliters per minute. This eluate was then concentrated to about five
    milliliters and placed in a clean disposable culture tube with a teflon-lined screw cap.
                          About two milliliters of 1:1, 20-percent fuming sulfuric acid-concentrated sul-
    furic acid mixture was added to the alumina cleaned extract. The tube then was shaken for about a
    minute and allowed to settle for approximately three hours.
                          The supernatant was drawn off with a Pasteur pipet and placed in a 12-milliliter
    Kontes micro-concentrator sample tube. The acid layer was re-extracted with two four-milliliter portions
    of hexane. All of the extracts were combined in the micro-concentrator tube and then concentrated (us-
    ing a Kontes tube heater, Part K-720000) to about five milliliters and placed in a culture tube.
                          The bottom sediment samples were contaminated with sulfur which causes in-
    terference with the chromatographic analysis. Therefore, samples were treated two or three times with
    elemental mercury to remove the sulfur (Goerlitz and Law, 1971). Finally, the samples were put in tared
    culture tubes and weighed, and the volumes were calculated using 1.5 as the density of hexane.
                           The suspended sediment filters wers air dried for three to five days. Then they
    were torn into small pieces and extracted for eight hours in a Soxhlet extractorwith 300 milliliters of 2:1
    hexane acetone, a wad of pre-extracted glass wool having been placed in the extractor. The extract then
    was concentrated in a 500-milliliter Kuderna-Danish concentratorto aboutfive milliliters and placed in a
    culture tube. This extract then underwent the tube acid treatment described above. The final volume was
    taken to one milliliter or less, and again the volume was calculated byweight using the density of hexane.

                   6.2.1.2 Biological Samples
                           Oysters and Soft Shell Clams-The shellfish were shucked, drained, and
    homogenized to a puree in a Vortis homogenizer. Approximately ten grams was placed in a hexane-
    rinsed aluminum weighing pan and weighed to three significantfigures. The sample then was ground to
    a dry powder with anhydrous sodium sulfate with a mortar and pestle. The samples were Soxhlet ex-
    tracted as described in the bottom sediment procedure. If, after being concentrated to less than ten
    milliliters, the extract appeared to contain little lipid and/or insoluble material, the extract underwentthe
    small-tube acid clean-up described above. Otherwise, the extract received a fuming sulfuric acid treat-
    ment as described in the next paragraph (Munson, 1972).
                           A mixture of nine milliliters of 20 to 30 percent fuming sulfuric acid and nine
    milliliters of concentrated sulfuric acid was added slowly while stirring to 30 grams of Celite (Johns-
    Manville 545AW). About 200 milliliters of petroleum ether was immediately stirred intothe acid-wetted
    Celite, and the resulting slurrywas added to a 90 millimeter sintered-glassfilter funnel and packed down
    by pressing the upper surface with a small glass beaker. After draining off the excess petroleum ether
    above the surface of the packed column with vacuum, the column was washed with a second 200
    milliliters of petroleum ether which was discarded after removal from the column. Care was taken not to
    run the column dry.
                           The concentrated lipid extract then was added to the top of sulfuric acid-Celite
    column and slowly drawn down through it with a gentle vacuum. The acid-resistant chlorinated
    hydrocarbons were subsequently washed off the column with 400 milliliters of petroleum ether and the
     *See Section 6.2.1.5 for cleaning and checking procedures.

                                                      6-2

    filtrate concentrated to about five milliliters in a Kuderna-Danish evaporative concentrator. The resulting
    sample volume was measured, and the sample was stored in a 1 O0-milliliter culture tube sealed with a
    teflon-lined screw cap.
                           Considerable charring and discoloration usually occurred on the upper surface of
    the sulfuric acid-Celite column, but the concentrated filtrate was nearly always completely clear and
    colorless. However, if the lipid extract had not been concentrated enough to boil off all the acetone prior
    to addition to the acid column, the char and discoloration would pass through the column and con-
    taminate the filtrate sufficiently to require that the acid clean-up procedure be repeated.
                          Crabs-The legs and carapace were removed and discarded from each frozen
    crab. The total internal contents were scraped into a blender and reduced to a homogeneous puree. In the
    case of small crabs, several were mixed together. About ten grams of the puree were weighed, extracted,
    cleaned up, and analyzed exactly as described for shellfish.
                           Plankton-The frozen samples were defrosted as needed. Those samples which
    weighed ten grams or less (Wet and dry weights were determined as part of the biology program.) were
    placed directly into a mortar and ground to a powder with sodium sulfate. A ten-gram fraction was taken
    from larger samples and ground. The powder was then extracted for eight hours in a Soxhlet extractor
    with 300 milliliters of 2:1 hexane acetone solution. A wad of pre-extracted glass wool was placed in the
    Soxhlet to prevent the sample itself from siphoning over. The extracts were concentrated and acid-
    treated as described for the bottom grab sediments.
                           Extremely small plankton samples (0.1 grams or less) were shaken with five
    milliliters of hexane in a culture tube and tube acid treated directly.

                   6.2.1.3 Water Samples
                          Water samples such as rain and ground water were collected in five-gallon glass
    bottles. If the water level was well below the neck of the bottle, hexane-extracted distilled water was add-
    ed to raise the level. The bottles were placed on magnetic stirrers, and hexane was added to completely
    fill the bottle (about 50 milliliters). The water was extracted by drawing hexane down through it for about
    one hour. The hexane then was pipetted off; the procedure was repeated four more times, and the ex-
    tracts were collected. The extracts were passed through sodium sulfate before concentration in a 500-
    milliliter Kuderna-Danish concentrator to about five milliliters. These extracts then were submitted to
    the small tube acid treatment.
                          Samples which contained a lot of sediment were filtered through a pre-extracted
    Gelman 142-millimeter glass-fiber filter before extraction.

                   6.2.1.4 In Situ Experiment Samples
                           The preparation and analysis for the in situ experiment was much simpler than
    that for the majority of the program. Three types of samples-suspended sediments, clams and oysters,
    and water-were analyzed only for PCB 1254.
                           The wet suspended sediment filters were placed in 250-milliliter Erlenmeyer
    flasks and extracted by boiling with three 150-milliliter portions of 2:1 hexane acetone solution. The ex-
    tracts were concentrated, placed in culture tubes, and small tube acid treated as described above.
                           The clams and oysters were prepared for extraction exactly as described above,
    except each entire animal was ground to a dry powderwith anhydrous sodium sulfate rather than an ali-
    quot of the homogenate. The dry powder sample was placed in a 19 x 300-millimeter integral reservoir
    chromatography column with a pad of glass wool at the bottom. The sample was extracted by passing
     225 milliliters of hexane-acetone (2:1 solution) through the column at a rate of about five milliliters per
    minute (Hesselberg and Johnson, 1972). The extract was collected in a 250-milliliter flask and concen-
    trated to 40 milliliters as described above. The concentrated extract was cleaned-up, using the acid-
    Celite column as described above.
                           The water samples also were prepared as described, except that only three hex-
     ane extractions were made.
                           The Hewlett-Packard 5700A chromatograph with the computing integrator was
     used for all analyses, and a 4% SE-30/6%-SP2401 column packing was employed. There were relatively
    few conflicting peaks as the PCB 1254 concentration was so high. This fact, coupled with the use of the
     integrator, made quantitation simple and rapid.

                                                      6-3

                  6.2.1.5 Glassware
                          Glassware contamination posed some problems. Solvent blanks run in
    glassware which was simply washed with Alconox and water gave a great many interfering peaks when
    checked by gas chromatography. Therefore, a more extensive cleaning procedure was employed routine-
    ly. Glassware such as Kuderna-Danish concentrators, round bottom flasks used with the Soxhlet extrac-
    tors, and new culture tubes were soaked in chromic acid for several hours and then rinsed with tap
    water. The other glassware was washed with soap and water. All pieces were rinsed consecutively with
    hexane, petroleum ether, and acetone before baking overnight at 2500C.
                          Blanks were run on concentrators and Soxhlet extractors (with glass thimbles)
    before use. Soxhlets often had to be run empty for several nights before they became clean, especially
    after samples of bottom sediments had been extracted.
                          It was found that previously clean glassware, if allowed to remain idle in the
    laboratory for several weeks, became contaminated, requiring that the cleaning process be repeated.
    Cleaned culture tubes were stored in aluminum foil-covered beakers. Flasks, graduated cylinders, and
    other glassware were well rinsed with solvents before use.

           6.2.2 Gas Chromatographic Methods
                   In light of the relatively low levels of CHC's in most of the samples, qualitation and quan-
    titation was difficult even though great care was taken to minimize contamination of samples during the
    preparation and clean-up. A multitude of materials can cause electron-capture detector deflections and
    artifact peaks due to unknown compounds. Compounds other than known chlorinated hydrocarbon en-
    vironmental contaminents, indeed, were present on many of the chromatograms. In many samples,
    therefore, the key task in qualitation and quantitation of the chlorinated hydrocarbons of interest was to
    distinguish the artifact peaks and avoid confusing them with the compounds to be quantitated.

                   6.2.2.1 Instrumental Parameters
                          All analyses were done using either a Nuclear Chicago 5000series dual-column,
    gas-liquid chromatograph equipped with two nickel-63 electron-capture detectors or a Hewlet Packard
    5700A series gas-liquid chromatograph with a pulsed, nickel-63 electron-capture detector. The Hewlett
    Packard chromatograph also was equipped for the last half of the program with a Spectra-Physics Com-
    puting Integrator for Chromatography, System 1.
                          The fact that the two four-millimeter (inside diameter) columns in the Nuclear
    Chicago 5000 were not in dual ovens posed some difficulties in the column packing selection. Primarily,
    three packings were used in this instrument, all at 2000C. They were 4% SE-30/6%-SP-2401 on 100/
    120 Supelcon AW-DMCS (Supelco No. 01-1948) or 1.5%-SP2250/1-95%-SP2401  on 100/120
    Supelcon AW-DMCS used in 183-centimeter long, glass, U-shaped columns, and 5% DC 200/2.5%QF1
    on 80/100 mesh Chromosorb W-HP (Chemical Research Services PA-3) used in a 122-centimeter U-
    shaped column. Although, nitrogen gas flow was adjusted to give each column a suitable retention time
    for aldrin, the flow was maintained between 50 and 100 ml/min to ensure proper detection perfor-
    mance. The injection ports were at 2250C, and the detectors were at 2800C. Detector voltages were ad-
    justed so that 0.16 nanograms of aldrin gave a response of 60 percent of full scale at an attenuation of 4 x
    1 0-10 amps. Where necessary, samples were diluted to give responses thatfell within the linear response
    ranges of the detectors as determined by running standardization curves with varying concentrations of
    standards.
                          The Hewlett Packard chromatograph was equipped with only one detector. Either
    a 4% SE 30/6%-SPS401 on a 80/100 mesh Supelcon support run at 2050C or a 5%-DC-200/2.5% QF1
    on 80/100 mesh Chromosorb W-HP at 215�Cwas used. The columns were 183 centimeter coiled glass;
    the injection port heat was 2500C, and the detector heat was 3000C. The 95% argon/5% methane gas
    flow was set so that aldrin gave a retention time of about five minutes. This instrument did not
    necessitate diluting the samples, because the detector response was shown to be linear over nearly the
    entire range of the instrument.

                                                    6-4

                   6.2.2.2 Qualitation and Quantitation
                          The peaks on the chromatographic traces were identified by compa ring the reten-
    tion times relative to aldrin. The peaks were matched to the major peaks of the standard materials. Each
    polychlorinated biphenyl (PCB) had a least one major peak which made it distinctive from two others
    among the PCB's (1242, 1248, 1254, and 1262) analyzed. If all the major peaks were present for two or
    more PCB formulations, the peak heights (if analyzed on the Nuclear Chicago 5000) or the peak areas (if
    analyzed on the Hewlett Packard 5700 with the computing integrator) could be estimated using the dis-
    tinctive peak heights or areas as a guide. Either alpha or gamma chlordane was distictive from the PCB
    peaks depending on the column used. Separate standards were run for these, and the nondistinctive
    peak height/area was found by subtracting the estimated PCB peak height/area from it. DDE, DDD, and
    DDT heights and areas were found in a similar manner.
                          At the time the Chester River Study was begun, pure standards of alpha and gam-
    ma chlordane were not available, and the standard method utilized technical chlordane (a mixture of the
    alpha and gamma chlordane isomers and other compounds) as a reference standard (FDA, 1972). As
    reported at length in the Chester River Study (Clarke, et al., 1972), the method was chosen among a
    number of unsatisfactory alternatives. Now that pure standards of alpha and gamma chlordane are
    available, the method of choice seems to be to use them.
                          In this report, unless specified otherwise, all chlordane and total chlordane
    values represent the sum of the alpha and gamma isomers. One should bear in mind that these values
    are not directly comparable to values calculated using technical chlordane as the standard. An adjust-
    ment to make the values exact/ycomparable can be made onlywhen the samples have been analyzed us-
    ing the gas chromatographic column packings under identical conditions. An approximate comparison
    can be made between values calculated as total chlordane (alpha plus gamma) and values calculated as
    technical chlordane by multiplying the total chlordane values by 2.0.
                          Frequently an artifact would appear which masked major peaks on one or more
    columns. In this case, different columns would be used until one was found on which the artifact did not
    appear.
                          The quantitation itself used the peak height/area ratio of the major peaks, the
    total volume of the processed extract, the weight of sample extracted, and the volume of processed ex-
    tract injected relative to the amount of standard injected. In addition, standard aldrin was injected just
    prior to each sample to calibrate the response of the gas chromatograph to allow correction for the
    response of the machine which frequently changed slightly from sample to sample.

       6.3 Results

            6.3.1 Bottom Sediments
                   Bottom sediment samples were collected at the beginning of the program on a grid of 52
    stations spaced throughout the study area. Figure 6-1 depicts the sample stations, which match the
    numbers of samples recorded in Volume III, Section 4, Data Summary Reports (BOTM SED PPM). The ex-
    act station locations expressed in longitude and latitude are listed under files C414 and C41 5, Upper Bay
    Sediment Data Report. Figures 6-2 and 6-3 display the total PCB and DDTR, respectively, found in the
    bottom sediments at the various stations. The size of circles represents the concentration of the CHC
    found to make high and low concentrations easily recognized at a glance. (The exact values can be ob-
    tained by looking up the particular station of interest in Volume III, Section 4 in File C502 where C506
    equals BOTM SED PPM and C503 spans the period October 10 through 16, 1973).
                   From the data presented in Figure 6-2, one can see that the sediments of Baltimore har-
    bor are quite high in PCB compared with the rest of the bay, except the station at the mouth of the Gun-
    powder River. Although the range of values found for DDTR in the sediments is much less broad, and
    Figure 6-3 is much less dramatic than Figure 6-2, the highest values were found in Baltimore harbor and
    the mouth of the Gunpowder River. Chlordane was not identified in enough samples to make such a
    figure meaningful.
                   The results of analyzing 17 additional seasonal bottom sediment samples from Stations
    1 A, 5A, 7A, 7B, 10 B, 11 A, and 11 C are listed underthe appropriate files (where C506 equals BOTM SED
    PPM) in Volume Ill, Section 4. Although significant trends are not evident, some of the individual values
    will be discussed later.
                                                     6-5

    UPPER CH ESAPEAKE BAYI
                                            SUSQUEHANNA R.

                                                     HAVRE          0'-4
                                                      DE GRACE   4

                                                             4,L2

          NAUTICAL MILES

                                                   28        H~~~OWELL PTGOE

                                                          2         ~~~SASSAFRASR

                                          22

                                    1~~~~         25

                                                                                      751 51 Al13
                              Figure 6- 1. Bottom Sediment Sampling Locations
                                                6-6

      UPPER CH ESAPEAKE BAY
                   o  a - .oi ppm         SUSQUEHANNA

             0   1 O-.i0ppm                       HAV~RE
                                                    DE GRACE         ~ ~
                 .10 - 1.0 ppm

            U~~~. I.- 0.0 ppm

                              I                                  ~~~~~~~~~~~SASSAFRAS R

    BA    ORE                       ES

                                 Figure 6-2. PCB in Bottom Sediments           75151A114

                                              6-7

     UPPER CHESAPEAKE-BAY
                     0 0-.0! ppm        SUSQUEHANIN  R.b

                              01- I~~ppm        HAVRE
                                               DE GRAC
                        10- I.Oppmn

         01234567                              Q
          NAUTICAL MILES

                     ____                        *               ~~~~~~~~~~SASSAFRAS R

    BALT IMORE04

                            /VID~~~~~~~~~~~~~~

                                                                           75151 Al 15

                               Figure 6-3. DD TR in Bottom Sediments

                                          6-8

            6.3.2 Suspended Sediments
                   Figures 6,4, 6-5, and 6-6 present the average total PCB, average total chlordane, and
    average DDTR in the suspended sediment and zooplankton samples taken at each station (Figures 2-1
    and 5-3). The data have been presented: (1) as micrograms (10-6 grams) of CHC found divided by the
    grams dry weight (suspended sediment samples, Figures 6-4a, 6-5a, and 6-6a) or wet weight
    (zooplankton samples, Figures 6-4c, 6-5c, and 6-6c)extracted (bydefinitiion, parts per million, ppm), and
    (2) as nanograms (1 0-9 grams) CHC found in the sample divided by the liters of bay water filtered to get the
    sample (by definition, parts per trillion, ppt). The raw data can be found in Volume Ill, Section 4 by station
    where file C506 equals S SED DRY PPM, S SED H20 PPT, and PLANK WET PPM and PLANK H20 PPT.
    Although suspended sediment samples were taken from more than one depth at each station during
    each sampling period, the averages were computed from the values for all depths at each station com-
    bined. More complex bar charts representing the various depths separately did not indicate an obvious
    depth-related trend and were rather confusing.
                   Figures 6-4a, 6-5a, and 6-6a show that the average total PCB, total chlordane, and DDTR
    (sum of the DDE, DDD, DDT residues) were highest in the suspended sediments (on a dry weight basis)
    taken from Baltimore harbor (Station 7A). When the data are expressed as parts per trillion of CHC in the
    water on suspended sediment (Figures 6-4b, 6-5b, and 6-6b), a somewhat different pattern appears.
    The average PCB, chlordane, and DDTR values generally show a decreasing trend down the bay with the
    harbor station not as high (in the case of PCB) or about the same as the upper stations (in the case of
    chlordane and DDTR). This decreasing trend is not nearly as pronounced in the chlordane and DDTR
    figures as it is in the PCB figure.
                   Figures 6-7, 6-8, and 6-9 present the CHC data for suspended sediments and
    zooplankton averaged by data collected. As in the previous set of figures, the data are presented both as
    parts per million based upon the weight of sample extracted, and as parts per trillion based upon the
    volume of water filtered to yield the sample extracted.
                   Figures 6-7a and b seem to indicate that the total PCB concentration on the suspended
    sediments and in the water on suspended sediment decreased somewhat from Decemberthrough July.
    However, this apparent decrease probably is not real for several reasons. When the individual data points
    are plotted by collection date at each station and the resultant 18 bar charts examined, no such baywide
    seasonal trend is evident. In addition, the June and July data sets were quite limited in the number of
    samples analyzed, and the averages were not composed of values from all of the stations. (In particular,
    the harbor and upper stations were missing.) Figures 6-8a and b suggest a general increase in the chlor-
    dane from December through July, and a closer examination of the data from which the averages were
    derived supports the existence of a seasonal trend.
                   Figures 6-9a and b indicate a general increase in the DDTR concentration on the
    suspended sediment and in the water on suspended sediment from December through July. The detailed
    bar charts support the generally increasing trend evident in the average values.

           6.3.3 Zooplankton
                   The average PCB, chlordane, and DDT residues found in the zooplankton at each of the
    stations sampled are shown in Figure 6-4c, 6-5c, and 6-6c respectively. The values are expressed as
    micrograms of CHC found divided by the grams wet weight of zooplankton extracted (ppm). The spatial
    distribution of the average PCB in zooplankton (by station) shows a dramatically pronounced
    trend-decreasing down the bay from very high values at the upper stations. The average PCB values at
    Stations 1 A and 3B are about ten times the values at the lower stations. An examination of the data from
    which the average values were derived support this trend (although, as seen in Figure 6-7c, the values
    vary over a broad range from one collection period to the next). The DDTR values follow a similar trend,
    except in this case, Station 1A stands alone much higher, the rest of the stations showing generally
    decreasing values down the bay. This pattern is the result of two unusual samples from Station 1 A being
    included in the average values. The Station 1A zooplankton samples had DDTR values of 4.2 ppm in June
    and 3.9 ppm in September. These unusually high DDTR values resulted almost entirely from the
    presence of DDD in the samples. (More will be said about these anomalous samples later.)

                                                    6-9

         2.0-                                                         2.0-
     Z
     0                                                            z
         1 1.6-                                                   �  1.6-

     a  1.2-                                                         1.2-

     f- 0.8-                                                      cn 0.8-

                <                                                                       <i c    m                          Um U  <  m o   m  0mm o < m   m
                                 I  Is   ao                                               m              <o  o  _m
                     LO r                                                         M  LO -       r-  -  3  M 0 Io 0--

                 (a)          STATIONS                                          (c)                     STATIONS

        24.0- -                                                                                    0.35

        20.0-                                                       0.20-
     z                                                           z
     o                                                           o
        16.0-  0.16-
     .j

     h- 12.0-                                                    ' 0.12-
     a                              a
     aIL1 0n-                    n     nn- nn                    an
     IL 8.0-                          09                            0.08-
     I-(b)                   STATIONS

                                                               idr in Water on Plankton
     <4.0-                                                       <I

                ~-   LO             0 0    0       .-                       -               n 0  r- L               :0300 0 M-- 0    M-

                (b)          STATIONS                                          (d)                    STATIONS

                                                                                                                                      75151 Al 16
    Figure 6-4. Average PCB Concentrations by Stations (a) on Suspended Sediment, Dry, (b) in Water on Suspended Sediment, (c) on Plankton, Wet,
                                                               (d) in Water on Plankton

             0.12-

             0.10-                                                       0.10-
          z
          o                                                           z
             0.08-                                                     0
                        -1~~~~~~~~~~~~~~ 0.08 -
                        r                                           ~~~~~~~~~~~~~~~~~~~~-J
          w  0.06-                                                       0.06-
                                                                 LU
                        r~~~~~~~~~~
          c 0.04-                                                        0.04-              f
                        a_   cc~~~~~
             0.02f                          -  H                         0.02-         H  H          HH                     n    -   n

                   <  <  <  en  M ) <m    <o                                          M    m <       C   <o  <                            <
                                   co Cn -n  OD  c      -
                (a)                STATIONS                                  (C)                             STATIONS

    0)

             1.0-                                                      0.020-
          z z
          o                                                          0
          -  0.80-        -                                             0.016-
          -J

            0.60-                                                       0.012-
          w                                                          w
          UI       II                                               U
         H  0.40-                                                    ) 0.005-

            0.20- l                                                    0.004-  -           i              H

                      <    <    <   co    <CO          <(                       <     m     <          ~     <O            ~                  0
                                  -~ ~~~ ~~ ~~~~~~~~~~~~~~ Lo                                     r, P"--    co,   nt  N C CO 00   )00)   0C --
                (b)                                                         (d)
                               STATIONS                                                                    STATIONS
                                                                                                                                75151A1 17
        Figure 6-5. Average Chiordane Concentrations by Station (a) on Suspended Sediment, Dry (b) in Water on Suspended Sediment (c) on Plankton, Wet, (d) in
                                                                Water on Plankton

      0.125-                                                  0.125-
    z                                                       z
      0.100-                                               o0.100-

     0.75
    ir 0.075-                                                  0.075-
                a. LU~~~~~
      w                                         - a. nn  _n, no
     0.050-                                                    0.050-

                                                        0.05i0. 025-

                         STATIONS                                  (                         STATIONS

                                                             0.057

       1.25-                                                 0.024-
    z                                                      z
    0                                                      0
                                                       0.020-

                a                                        a~~~~~~~~~~ 0.016-
       0.75-
    wL W  0.012-
    CL                                                     a_
    (n  0.50-                                              C/'
    cc E
       0.25-'  0.004-

              (b)i    a inHHU                                        c <            m < HLMU    Co    M <

            (b)            STATIONS                                 (d)                        STATIONS
                                                                                                                75151A118
    Figure 6-6. Average DDTR Concentrations by Station (a) on Suspended Sediment, Dry (bJ in Water on Suspended Sediment (c) on Plankton, Wet (d) in Water
                                                        on Plankton

        1.2-    -                                                  2.0-
    z                                                           z
    o   1.0-                                                    0            -
                  -J?~~~~~~~~ -  1.6-
    E  0.8 -
                                                           r   1.2-
    a   0.6-

    Q)  0.                                                          0.8-
     _ 0.4-
        0.2-                                  1                    0.4-

               DEC JAN MAR MAY JUN JUL                                     DEC   JAN    MAR  MAY  JUN  JUL  SEPT
                                                                             17-24
            (a)             DATES
                                                                  (c)                      DATES

                                                                         0.30

       20.0-                                                      0.20-       '
    z                                                          o
    0
       16.0-                                                      0.16-

    '- 12.0-                                                   r  0.12-
    w
        8.0-                                 r                    0.08-

        4.0-                                                      0.04-

              DEC JAN MAR MAY JUN JUL                                     DEC    JAN    MAR  MAY  JUN  JUL  SEPT
                                                                             17 24
           (b)                                                           (d)                   DATES

                                                                                                                     75151A1 19
                      Figure 6-7. Average PCB Concentrations by Date (a) on Suspended Sediment, Dry (b) in Water on
                                  Suspended Sediment (c) on Plankton, Wet, (d) in Water on Plankton

              0.20 -                                                       0.05-
          z                                                             z
          O  0.16-                                                      O  0.04-

          - 0.12-  0.03-
          O-                                                            Xa
           2  0.08-                                                        0.02       '

              0.04-                                                         0.01                                                        n

                      DEC  JAN  MAR  MAY  JUN  JUL                                 DEC       JAN       MAR    MAY   JUN    JUL    SEP
                                                                                       17 24
                   (a)            DATES                                        (c).                        DATES

                                                                     0.012-

               92.0_                                                   z 0.010-
           z                                                            o
           O                                                            -I
              1.6-                                      -                  0.008-

              1.2-                                                      W 0.006-

           o 0.80-                                                         0.004-

              0.40-  0.002-

                      DEC  JAN  MAR  MAY JUN  JUL                                   DEC      JAN       MAR    MAY   JUN    JUL    SEP
                                                                                       17 24
                                  DATES                                                                 DATES
                 (b)                                                          (d)

                                                                                                                              75151A120

    Figure 6-8. Average Chlordane Concentrations by Date (a) on Suspended Sediments Dry (b) in Water on Suspended Sediment (c) on Plankton, Wet(d) in
                                                               Water on Plankton

                                                                                                                0.45        Q0.45
              0.10-                                                   0.10- -
           z                                                        z
           0                                                        0
           0.08-                                                       0.08-

           rr 0.06-                                                 n 0.06-
           - a.-
             0.04-                                                  (  0.04-

              0.02-   n                                                0.02-   n

                      DEC  JAN MAR MAY JUN  JUL                                DEC      JAN      MAR   MAY   JUN    JUL    SEPT
                                  DATES                                                17 24
                    (a)                                                      (c)                       DATES

               2.0-                                                    0.04-
           z                                                        z
           o                                                        o

               r 1.5-                                               i 0.03-
           a:                                                      aI-
           a   1.0-                                                 .- 0.02-

               0.5-                                                    0.01-

                      DEC  JAN MAR MAY JUN  JUL                                DEC       JAN      MAR   MAY   JUN   JUL   SEPT
                                  DATES                                               17 24
                   (b)) DATES                                                                       DATES
                                                                                                                          75151A121
    Figure 6-9. Average DDTR Concentrations by Date (a) on Suspended Sediment, Dry (b) in Water on Suspended Sediment (c) onPlankton, Wet (d) in Water
                                                              on Plankton

                   Figure 6-5c shows apparent highs in the chlordane values at Baltimore harbor Station 7B
    and Chester River Station 9C. The individual data do indicate that the Station 7B samples were high;
    however, the value for Station 9C is derived from a single analysis and may not be a representative value.
                   Figures 6-4d, 6-5d, and 6-6d present the respective average values as parts per trillion by
    station for PCB, chlordane, and DDTR based upon the volume of water filtered to obtain the sample ex-
    tracted. The PCB values now present quite a different picture compared tothose calculated using thewet
    weight of the sample. In this case. harbor Station 7A has byfar the highest average PCB level, due entire-
    ly to a value of 1 .3 ppt at this station in December. In fact, the values do not display a pronounced spatial
    trend when examined as individual bar charts segregated by collection date.
           When the chlordane values are expressed as parts per trillion in the water in or on zooplankton,
    the harbor still appears high (in this case, Station 7A). An examination of the individual plots supportthe
    average picture presented in Figure 6-5d; although, being single values, the numbers at Stations 9B and
    9C may not be representative of average conditions.
                   Figure 6-6d shows that the average DDTR pattern changes slightly when calculated as
    ppt DDTR in the water in zooplankton. The overwhelming high at the uppermost Station 1A remains,
    while the general trend of decreasing values proceeding down the bay appears to have become
    somewhat reversed. A detailed examination of the individual bar charts, while generally supporting the
    increasing trend down the bay, reveals that the overwhelmingly high average value at the head of the bay
    (Station 1A) results from two of seven samples (June and September) being very high in DDD.
                   Figures 6-7c and d presenting the average PCB values arranged by collection period
    show that the average PCB values were high during December and March when expressed both as parts
    per million based upon the wet weight of zooplankton extracted and as parts per trillion based upon the
    volume of water filtered to get the sample. An examination of 16 individual bar charts representing the
    data plotted by station and by date indicates that these two charts of the average values fairly present the
    trends evident in the data.
                   Figure 6-8c and d both appear to give a good representation of the trends apparent in the
    individual plots. The chlordane concentration in the zooplanicton (ppm, wet weight) appears fairly cons-
    tant during the sampling period except for a slight low in September. The concentration of chlordane in
    the water column in zooplankton(ppt), however, shows highs in three months-December, January, and
    March.
                   The average DDTR bar charts (Figures 6-9c and d) do not represent the trends in the
    actual data very well because of two previously mentioned samples with exceptionally high levels of
    DDD. Were it not for these two anomalously high samples at Station 1A (June and September), the
    overall monthly averages would show a pattern very similar to that seen for chlordane-a slight high in
    March in the concentration of DDTR in zooplankton (ppm) and high in December, January, and March in
    the water column concentration of DDTR (ppt in the water on zooplankton).

           6.3.4 Benthic Organisms
                   Samples of benthic organisms were collected and analyzed to provide an estimation of
    the movement of chlorinated hydrocarbons into this biological community. Table 6-1 presents the results
    of the analyses of benthic samples.

           6.3.5 Laboratory and In Situ PCB Exposure Experiments
                   Results from the analyses performed in support of dosing experiments using the PCB for-
    mulation ArocloA 1254 in the laboratory and in situ are presented and discussed in Chapter 2, Marine
    Biology.

                                                    6-16

    TABLE 6-1. CHLORINATED HYDROCARBONS IN BENTHIC ORGANISMS IN THE UPPER CHESAPEAKE BAY
                                                        (ppm)

                                                                                              TotalI
    Organism                          Station          Collection Date          Total P08      Chlordane DDTR

    SHELLFISH:

    Rangia cuneata                    4A               9/20/74                  0.081         0.0092      0.026
    Rangia cuneata                    50               5/03/74                  0.0090        0.0040      0.018
    Rangia cuneata                    5C               8/02/74                  0.12           0.010      0.055

    Rangia cuneata                    6A               3/22/74                  0.031         0.016       0.027
    Rangia cuneata                    6A               5/03/74                  0.087         0.054       0.23
    Rangia cuneata                    6A               8/02/74                  0.089         0.064       0.019

    Rang/a cuneata                    6A               9/20/74                  0.058         0.0066      0.027
    Rangia cuneata                    6B               3/22/74                  0.051         0.025       0.032
    Rang/a cuneata                    60               3/22/74                  0.031          0.016      0.0040

    Rang/a cuneata                    60               5/03/74                  0.0020        0.0002      0.00020
    Rang/a, cuneata                   60               8/02/74                  0.045         0.0059      0.024
    Rang/a cuneata                    60               9/20/74                  0.093         0.0042      0.029

    Rang/a cuneata                    8A               3/22/74                  0.094         0.017       0.047
    Rang/a cuneata                    8A               8/02/74                  0.074         0.0017      0.037
    Rang/a cuneata                   8A                8/26/74                  0.15.         0.033       0.056

    Rangia cuneata                    8A               9/20/74                  0.0084        0.012       0.023
    Rang/a cuneata                    8B               3/20/74                  0.043         0.011       0.019
    Rang/a cuneata                    10QA             5/03/74                  0.064         0. 0094     0.054

    Rang/a cuneata                    IOA              9/20/74                  0.029         0.051       0.028
    Crassostrea virgin/ca            88                1/25/74                  0.02 1        0           0.014
    Crassostreav/rgin/ca             IOA              1/25/74                  0.031         0.0098      0.014

    Crassostrea virgin/c              iOA              3/22/74                  0.054         0           0.034
    Crassostrea v/rg/nica             1 OA             8/02/74                  0.015         0.0099      0.017
    Crassostrea virgin/ca      1       1A              3/20/74                  0             0.017       0.025

    Brachiodontisrecurvus             8A               3/22/74                  0.046         0.016       0.015
    Macomna sp                        IOA              81021/74                 0.029         0.0099      0.031
    Shellfish Averages                                                          0.052         0.016       0.035

    CRABS:
    Call/nectes sap/dus               10A              3/02/74                  1.2           0.15        0.72

                                                         6-17

           6.3.6 Other Samples

                   6.3.6.1 Rain Water-Ground Water-Storm Water
                          The chlorinated hydrocarbon data for the rain water, storm water, and ground
    water samples are presented in Tables 5-5, 5-6, and 5-7, respectively and will be discussed later in this
    chapter. Substantial quantities of PCB and chlordane were found in the rain water samples from the
    collection station at Sollers Point as well as in the storm water samples. These compounds were also pre-
    sent in the air samples. An important point about the rain water samples is that two pesticides (tox-
    aphene and benzene hexachloride) which have not been found in abundance elsewhere in the study
    were found in substantial quantities in some of the rain water samples.

                   6.3.6.2 Conowingo Dam Samples
                          It became apparent as the analysis of the initial samples of suspended sediments
    and plankton got underway, that Station 1A was an area of high PCB concentrations. At the recommen-
    dation of the Board of Scientific direction, an attempt was made to gather data to resolve the question as
    to the origin of the material. (Was it being added to the system near Station 1 A, or was it actually coming
    down the Susquehanna River?) Table 6-2 presents the data which were obtained to address this ques-
    tion.
                          Suspended sediments were collected nearly simultaneously at Havre de Grace
    (Station 1A) and at the tailrace of the Conowingo Dam (Station 1 B) on two occasions. Attempts were
    made to gather samples on several other occasions, but fate seemed to be against this particular ef-
    fort-either one sample or the other was lost or was not taken due to oversight or misadventure.

       6.4 Discussion
           Table 6-3 summarizes the chlorinated hydrocarbon levels found in the various types of samples
    collected in the upper Chesapeake Bay. Although, the standard deviations indicate that the ranges of
    values are quite broad, the values are striking when compared to similar data from the Chester River
    Study-Table 6-4. The concentrations in bottom sediments are two to three times higher in the upper
    Chesapeake Bay than in the Chester River.* From Table 6-1, one can see that the PCB, chlordane, and
    DDTR in shellfish are about the same. CHC's in the single crab analyzed were more than 20 times higher
    than the average values for crabs from the Chester River. Although, the values from a single organism
    would usually be considered to have little statistical significance, the fact that the PCB, chlordane, and
    DDTR values were more than ten times higher than the highest values observed in the Chester River
    crabs suggest a significant difference. These comparisons will be discussed subsequently in this section.
            By comparing the bottom sediment (dry) data with the suspended sediment (dry) data, one can
    see that the PCB and chlordane concentration are four to ten times higher in the suspended sediments.
    The higher values in the suspended sediment probably occur for one, or most likely, both of the following
    reasons. The average grain-size of the suspended sediments is much smaller than that of the bottom
    sediments, resulting in a greater surface area for adsorption per unit weight as discussed in detail in
    Chapter 4, Estuarine Sedimentology. Although, the suspended sediments are primarily inorganic
    materials, the phytoplankton, which were included in these samples, probably bio-concentrated
    chlorinated hydrocarbons.
            If one accepts the above discussion, he is left with the dilemma that the DDTR does not appear
    higher in the suspended sediments as do the PCB and chlordane. But all uses of DDTwere banned in the
    United States at the end of 1972 (CEQ, 1972). If this ban had the effect of decreasing the DDT levels flow-
    ing into the Chesapeake Bay, the concentrations of DDT residues in the suspended sediments would be
    less relative to those in the bottom sediments. This is because the bottom sediment samples consist of
    materials deposited during the sampling year and during previous years as well, while the suspended
    sediment samples consist primarily of materials that entered the bay during the sampling year. While

    *As pointed out in discussing analytical methods in Section 6.2.2.2, to compare the total chlordane
    values presented in this report to the technical chlordane numbers recorded in the Chester River Study,
    the total chlordane values must be multiplied by 2.0.

                                                     6-18

      TABLE 6-2. CHLORINATED HYDROCARBONS IN SUSPENDED SEDIMENTS FROM HAVRE DE GRACE
                                (STATION 1A) AND CONOWINGO DAM (STATION 1B)

    STATION           DATE              TOTAL PCB*    CHLORDANE*                     DDE*  DDE*  DDT*

    1A (surface)     6/13/74            0.77                 0.30                    0.029   0.20    --

    1A (bottom)       6/13/74           0.83                 0.19                    0.10    0.73    0.53

    1 B              6/13/74            3.6                  0.29                    0.052   0.72    --

    1A              '9/20/74            9.3                  0.21                    --       0.23    --

    1B                9/20/74          10.                   0.077                   --       0.052   0.10

    *All of the values are expressed as nanograms of material extracted from suspended sediment divided by the volume
    of water (in liters) filtered to obtain the suspended sediment.

       TABLE 6-3. AVERAGE CHLORINATED HYDROCARBONS FOUND IN THE UPPER CHESAPEAKE BAY
                                        (Standard Deviations are in Parentheses)

    Sample Type             Number         Total PCB            Total Chlordane            Total DDT
                          of
                          Samples

    Shellfish
    (Wet, ppm)*             26          0.052 (0.037)        0.016 (0.017)           0.035 (0.041)

    Plankton
    (Wet, ppm)              70          0.50 (1.4)           0.041 (0.032)           0.16 (0.68)

    Suspended Sediment
    (Dry, ppm)**            66          0.92 (0.87)          0.061 (0.086)           0.057 (0.066)

    Bottom Sediment
    (Dry, ppm)              54          0.28 (0.57)          0.0052 (0.014)          0.051 (0.067)

    Plankton
    (H20, ppt)***           69          0.042 (0.164)        0.0038 (0.0083)         0.010 (0.035)

    Suspended Sediment
    (H20, ppt)              68          12 (14)              0.53 (0.88)             0.78 (1.5)

     *The values are expressed as micrograms CHC found per gram wet weight of material extracted.
    **The values are expressed as micrograms CHC found per gram dry weight of material extracted.
    ***The values are expressed as nanograms of CHC found per liter of water filtered to collect the material extracted.

                                                       6-19

      TABLE 6-4. TYPES AND LEVELS OF CHLORINATED HYDROCARBONS FOUND IN THE CHESTER
                                           RIVER (CLARKE, et al., 1972)

    Sample                    PCB'S                    Chiordane                 DDT (Total)

    OYSTERS:

      Average (ppm)          0.055                     0.036                     0.043
      Range (ppm)           0.016 to 0.250            0.009 to 0.160            0.0 to 0.150

    SOFT-SHELLED CLAMS:

      Average (ppm)          0.058                     0.014                    0.021
      Range (ppm)           0.013 to 0.180            0.0 to 0.038              0.0041 to 0.130

    FISH:

      Average (ppm)          0.185                     0.074                     0.134
      Range (ppm)           0.002 to 0.570            0.034 to 0.100            0.050 to 0.260

    CRABS:

      Average (ppm)          0.020                     0.014                    0.033
      Range (ppm)           0.0004 to 0.051           0.003 to 0.024            0.018 to 0.063

    SEDIMENTS:

      Average (ppm)          0.087                     0.0052                   0.016
       Range (ppm)           0.0 to 0.310              0.0002 to 0.014           0.0 to 0.063

                                                      6-20

    this explanation is plausible, it seems somewhat suspicious that samples were taken fortuitously at just
    the right time to yield exactly the same DDT residue levels in both the suspended sediments and the bot-
    tom sediments.
            The data in Table 6-3 also show that the CHC's are bio-concentrated in passing from the
    suspended sediment into the zooplankton. To evaluate the magnification, one must first convert the
    plankton (wet) values to plankton (dry) to allow comparison with the suspended sediment (dry) values.
    From Table 2-5 in Chapter 2, one finds that the December to September ratios of plankton dry weight to
    plankton wet weight range from 0.11 to 0.17. If one conservatively uses 0.10, he multiplies all of the
    plankton (wet) values by ten to convert to plankton (dry) and then calculates the following bio-
    concentrations as the CHC's pass from the suspended sediments to the zooplankton: PCB, 5.4; chlor-
    dane, 6.7; and DDTR, 28. The DDTR value seems unreasonably high, and it probably is. If the two
    anomalously high DDTR values mentioned earlier are excluded and the average is computed from the
    other 68 values, the average DDTR in plankton (wet) becomes 0.045, leading to a magnification of 7.9-a
    value more compatible with the others.
            One also could calculate approximate bio-magnification values from the shellfish data. The con-
    centrating ability of shellfish usually is expressed as the level accumulated in the shellfish tissue (wet
    weight)divided by the exposure concentration in the water. Using the values for CHC in the water column
    on suspended sediment, the shellfish concentration factors are approximately: PCB, 4,000; chlordane,
    30,000; and DDTR, 45,000. These values should be considered rough estimates, because the average
    values used for CHC's in the water column probably do not represent accurately the values at the water-
    bottom sediment interface inhabited by these shellfish.
                   The standard deviation values given in Table 6-3 emphasize the fact that the range of
    CHC values observed within any particular sample type was very broad. Upon examining the bar charts
    summarizing the data for CHC's on suspended sediment and zooplankton, one can see that the values
    vary greatly from one station tothe next during the same collection period or at the same station from one
    collection period to the next. Apparently these values fluctuate rapidly enough (temporally and spatially)
    that only the unusually large events in terms of time and/or space will be observed at enough points to
    describe a trend when the sampling is limited to a fairly small number of samples, as in this program. The
    multidisciplinary approach of this program, however, circumvents this problem somewhat by providing
    many different types of data which are comparable in space and time. As will be seen below, these data
    then can be examined for interrelationships relevant to the understanding of the dynamics of chlorinated
    hydrocarbon movements in the upper Chesapeake Bay.
           The CHC data for suspended sediments and zooplankton are expressed in two ways, as men-
    tioned earlier, but further amplification should be made. Environmental residues of chlorinated
    hydrocarbons (chlorinated pesticides and polychlorinated biphenyls) usually are reported as parts per
    million (ppm) dry weight (or wet weight) based upon the dry weight (or wet weight) of sample which was
    extracted for the analysis. If the levels are very low, parts per billion (ppb) or parts per trillion (ppt) also are
    used. The data then represent the concentration of CHC's present in that sample. In the consideration of
    transport of CHC's (rates, routes, etc.) the amount of CHC being transported by a water movement fre-
    quently is of more interest than the concentration of the CHC's on the suspended sediments in the water.
    Therefore, in addition to the data being presented in the usual fashion, the zooplankton and suspended
    sediment CHC data are presented as nanograms (1 0-9 grams) of CHC on zooplankton or suspended sedi-
    ment per liter of water (bydefinition, ppt). These values representthe amount of CHC associated with the
    suspended sediments or the zooplankton contained in a one liter sample of bay water. In a sense, the
    numbers can be compared directly because they have been normalized to a unit volume of water. For in-
    stance, in referring to Table 6-4, one finds the average PCB values in the bay water on suspended sedi-
    ment and zooplankton to be 12 ppt and 0.042 ppt, respectively. On the average, a given volume of bay
    water will have about 300 times as much PCB in the suspended sediment fraction as in the zooplankton
    fraction.
           Figure 6-10 is a log-log plot of total CHC* concentration in the water column on suspended sedi-
    ment (ppt) versus the concentration of suspended sediment in the water (milligrams per liter). Although
    the data points are widely scattered, the data could best be enclosed in a oblong field with an upward tilt

    *The sum of PCB, chlordane, and DDTR.

                                                    6-21

    z
    k    100
    o:
    z                                                      o

    n2                                                                                (

                                                        0
    r,.u                                          0                     O          (DE)

    -z    10

                                                   0

                                                    �.O.

           0.10                            1.0                           10.0                            100
                                        1.0                          J                                100

                           TOTAL CHC IN WATER ON SUSPENDED SEDIMENT
                                   (PARTS PER TRILLION)

                                                                                          75151A122
      Figure 6-10. Concentration of Chlorinated Hydrocarbons in the Water Column on Suspended Sediments
                              versus the Concentration of Suspended Sediments

                                                  6-22

    to its long axis. This indicates a positive relationship between the parameters plotted (if the parameters
    were unrelated-that is, varied independently, the long axis of the oblong would be either vertical or
    horizontal). The correlation obviously is not followed closely by all of the data, but in general, it indicates
    that the bay water samples which had high suspended sediment concentrations also had high levels of
    CHC's in the water on suspended sediments. If all suspended sediments in the water contained the same
    amounts of CHC's (ppm, dry weight), a perfect correlation would have been observed in Figure 6-10. The
    variations in the concentrations of CHC's on suspended sediments are responsible for the scattering of
    the data.
           Figure 6-11 is a log-log plot of total CHC's in the water on zooplankton (ppt) versus the
    zooplankton biomass in the water (milligrams per cubic meter). Although the data are somewhat
    scattered, there is an obvious positive relationship-as the zooplankton population in the water in-
    creases (increasing biomass), the amount of CHC's in the water on zooplankton increases. The existence
    of this relationship establishes that there is movement of CHC's into the aquatic food chains which in-
    clude the zooplankton community. The fact that the zooplankton population contains only a small fraction
    of the CHC's present in the water column, considered with the relationship observed in Figure 6-11,
    suggests that the movement of CHC's into the biological system (via zooplankton) from the non-biological
    system (suspended sediments) is not influenced bychanges in the concentration of suspended sediment
    but is regulated by whatever regulates the zooplankton population. One could visualize the suspended
    sediments in the water column as being a reservoir of CHC's which flow into the biological system when
    zooplankton blooms occur.
           Obviously, this concept is an over simplification of a very complex system. More likely, the
    phytoplankton are important in the transport of CHC's from the non-biological reservoir into the
    zooplankton food-chain. Unfortunately, the sampling procedure for gathering suspended sediments in-
    volved pumping the water through a filter, so the phytoplankton were included in the fraction called
    suspended sediments. To overcome this limitation, it had been hoped to estimate the influence of
    changes in the phytoplankton population through the use of measurements of the chlorophyll level in the
    water column. Figure 6-1 2 presents a log-log plot of the zooplankton biomass versus the chlorophyll-a
    concentration in the water column. These parameters appear to be independent variables. A similar plot
    (not shown) of the chlorophyll-a concentration versus the concentration of CHC's in the water column on
    zooplankton yielded a very similar result. If the phytoplankton have a direct role in the pathway of CHC's
    into the zooplankton community, the chlorophyll-a data here do not indicate it.
           Whatever the details of the pathway for CHC's from the suspended sediment reservoir into the
    zooplankton, it seems that only a very small percentage of the CHC's in the water column are associated
    with the zooplankton (average of 1 2 ppt PCB in the water column on suspended sediment versus 0.042
    on zooplankton). However, to quantify the rate of movement of the CHC's via this pathway one would
    need information about turnover rates in the plankton community. Regarding resource management,
    one should consider that a change in bay conditions which would increase the zooplankton population
    would probably have the effect of increasing the flow of CHC's from the suspended sediment reservoir
    into the biological system. This could create adverse consequences as all aquatic species of commerical
    interest at some time in their life cycle make up a part of the zooplankton community.
           The filtering of bay water by shellfish represents another direct route for th movement of CHC's
    from the suspended sediment reservoir into the biological system. Although one cannot directly assess
    the magnitude of this pathway in terms of mass-flow of CHC's, the data in Table 6-1 indicate that sub-
    stantial amounts of the CHC's present in the reservoir are accumulating in the tissues of shellfish in the
    upper Chesapeake Bay. These few data points probably do not accurately describe the CHC levels in
    shellfish in the upper bay, but they do indicate that Rangia cuneata accumulates chlorinated hydrocar-
    bons, and they give some idea at least of the minimum range of values.
           None of the CHC levels in shellfish approached the levels which the U. S. Food and Drug Ad-
    ministration has suggested as making edible tissues unfit for human consumption (5.0 ppm for PCB and
    DDTR; 0.30 ppm for chlordane). Nevertheless, all pathways into organisms which are routinely gathered
    for human consumption warrant further study because of the concern about potential detrimental
    effects of these chlorinated hydrocarbons. In July 1975, the U. S. Environmental Protection Agency

                                                    6-23

              1000                                                                                    C-c

                                                                                                                7A 11A

                100                                       A                      (Y-

        -o                                                                                                             A

        -<I

                                  10~~~~~~~~~~~~~~~~~~~~~~1C

                            Sc                      ~~          ~~~0.0   0.101                                                                  .

                              0                             ~~~~~~~TOTAL CHC IN WATER ON PLANKTON
                  0.60001                                        (PARTS PER TRI LLION)                                                     75151A123

    Figure 6-1 1. Chlorinated Hydrocarbons in the Water on Zooplankton (ppt) versus Zooplankton Biomass in the Water (mg/rnm3

      rr 100

                                    0                                                    0(

         1.0
          0.10                         1.0                          10.0                         100                         1000
                                                          ZOOPLANKTON BIOMASS
                                                       (MILLIGRAMS PER CUBIC METER)
                                                                                                                    75151A124
                            Figure 6-12. Zooplankton Biomass (mg/m3) vs Chlorophyll-a Concentration (pg/l) in the Water Column
    <,,,,~
    :�.-.                                                                �o
    -,- :~~
     "'<                                                            �  � �
    Orr                                                                   �n
                 '"'~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~~~1
            s, H �

                            Figure 6-172. Zooplankton Biomass (mg/m3) vs Ch/orophy/I-a Concentrat/on (tzg//) in the Water Column

    cancelled the registration of chlordane as a pesticide due to its carcinogenicity and persistence in the en-
    vironment. Also, the National Institute for Occupational Safety and Health has included PCB's and the
    DDT residues in a list of suspected carcinogens for which further information should be gathered
    (NIOSH, 1975).
           By far, the largest route for the transport of CHC's from the suspended sediment reservoir
    probably is a result of sediment deposition. The areas of deposition of fine-grain sediments can be
    visualized as sinks where the CHC's attached to suspended sediments collect. As in the Chester River
    Study (Clarke, et al., 1972), the chlorinated hydrocarbons in the bottom sediments were found highest
    where the median grain-size diameters were the lowest (Chapter 4, Marine Sedimentology). Baltimore
    harbor is a trapforfine-grain sediments in the upper Chesapeake Bay, and as such, functions as a sinkfor
    CHC's from the suspended sediment reservoir. Figure 6-2 shows that the PCB, for instance, was much
    higher in the sediments of Baltimore harbor than elsewhere in the bay. As will be discussed later in this
    section, the harbor sediments are probably high in CHC's for more reasonsthan justtheirfine grain size.
    It is necessary to analyze core slicesto establish thethree-dimentional concentration gradient in orderto
    estimate the mass of CHC's contained in the bottom sediment sinks. (A core from the Chester River was
    found to contain layers of widely varying levels of CHC's to a depth of 50 centimeters-Clarke et al.,
    1972.)
           A number of mechanisms exist for movement of CHC's out of the bottom sediment sinks. When
    one considers the fine-grain fractions in the upper Chesapeake Bay as a whole, resuspension of this
    material by tidal scour probably is the major re-entry route from the sinks to the suspended sediment
    reservoir (Schubel, 1972). In the Baltimore harbor area, however, maintenance dredging of navigational
    channels is a major mechanism for removal of sediments containing chlorinated hydrocarbons from the
    bottom sediment sink. Although the subsequent fate of this dredged material is a subject clouded by
    great controversy, during the dredging and subsequent overboard discharge of this material, undoubted-
    ly, a substantial quantity returns to the suspended sediment reservoir.
           A possible route for CHC movement from the sediment sinks into the biological system could be
    through deposit-feeding infaunal organisms inhabiting the fine-grain sediments. In particular, certain
    polychaetes are the most abundant macrofauna in silt-clay habitats including grossly polluted areas in
    Baltimore harbor (Hamilton, 1972). These organisms form a major part of the diet of crabs and certain
    species of fish in some areas. The magnitude of this pathway would depend upon the availability of the
    sediment adsorbed CHC's to the deposit-feeding organisms. (In other words, how much of the adsorbed
    CHC is stripped off the sediment upon passage through the gut of the organism?) Further, the turnover
    rates and population densities for the various organisms involved also are important to the magnitude of
    the pathway. This route is of particular interest because of the direct access to human beings via the
    crabs and bottom-feeding fish landed for market.
           In the investigation of possible sources of chlorinated hydrocarbons, high concentrations were
    found most often in the samples from two principal areas: (1) Baltimore harbor and (2) Station 1 Awhere
    the Susquehanna River joins the Chesapeake Bay.
           Nearly all of the suspended sediment in the upper bay originates from the Susquehanna River. In
    a typical year, a major portion of the yearly suspended sediment burden enters the bay during the spring
    freshet, a period of overpoweringly high flow usually occurring in March or April (Schubel, 1972). The
    period November 1 973 to November 1 974 was somewhat atypical in that the spring freshet was not as
    singular an event as usual. Using the data depicted in Figures 4-32 and 4-33 in Chapter 4, one finds that,
    during this 12-month period, about 55 percent of thetotal suspended sediment influxwas evenlydivided
    between the two months December and April, with the January, February, March and May influxes total-
    ing another 33 percent (10, 5, 12, and 6 percent respectively). Samples were taken during this program in
    each of these months except February and April.
           Suspended sediments collected at Station 2B April 3 and 4 were analyzed for CHC's under a
    program for the U. S. Office of Water Resources and Technology. The results were average PCB, 0.31
    ppm; average technical chlordane, 0.018 ppm; and average DDTR, 0.027 ppm. (The average ppt values
    are presented in Chapter 5, Section 5.4.4. A comparison of the concentrations of suspended sediment in
    the water at the times of sampling (December: 43 mg/I; January: 35 mg/I; March: 11 mg/I; April: 35
    mg/I) with the data in Figures 4-30 and 4-31 of Chapter 4 indicate that most of the samples fell near the
    peak influx periods. The CHC values measured at Station 1A and 2B at high river flow should represent a
    measure of the degree of contamination of most of the yearly influx of suspended sediments to the
    suspended sediment CHC reservoir.
                                                    6-26

            An examination of Figures 6-4a, 6-5a, and 6-6a shows that, except for Station 7A in Baltimore
    harbor, the suspended sediments passing Station 1 A during the high-flow conditions appeared to carry
    sufficient burden of PCB's and DDTR to account for the levels observed at the lower stations without
    postulating additional sources. The chlordane average appears somewhat low, however, suggesting ma-
    jor inputs other than from the Susquehanna River at high flow periods. Unfortunately, no CHC data were
    obtained upstream of Station 1A during high-flow conditions, but it seems most probably that CHC con-
    tamination on the suspended sediments derives from the watershed of the Susquehanna River rather
    than from sources at the head of the Chesapeake Bay. The data in Table 6-2, obtained during June and
    September, suggest that CHC's in the water column on suspended sediments are sufficiently high at
    Conowingo Dam to account for the levels measured at Station 1 A where the Susquehanna River water
    enters the bay. This point demands further study, however, as one could imagine localized inputs of
    CHC's from the urban-industrial complex in the region of Station 1A which were keyed to periods of high
    river-flow.
            In light of the mid-portion of the bay typically being characterized by a turbidity maximum* except
    for episodes during the infrequentperiods of high flow in the Susquehanna River, one would not expect
    the average CHC concentrations in the water on suspended sediment at Station 1 A to be higher than at
    Stations 5A and 8B, as was found. This atypical situation arises for two reasons:-first, the study period
    was atypical (as discussed above) in terms of river-flow, and second, nearly all of the suspended sedi-
    ment data presented in Figures 6-4, 6-5, and 6-6 came from samples collected during December,
    January, March, and May-periods of relatively high river-flow, hence, high suspended sediment load at
    Station 1A.
           Although Baltimore harbor appears to be an estuaryof the Patapsco River, the average daily flow
    of fresh water into the harbor is trivial-about one three-hundredth of the harbor volume (Pritchard,
    1968). The harbor has a three-layered circulation pattern. Bay water flows into the harbor in the top and
    bottom layers, and harbor water flows out in the middle layer, all being driven by the difference between
    the vertical salinity profile of Baltimore harbor and the Chesapeake Bay(Pritchard, 1968). The rate of this
    inflow and discharge from the harbor as a result of the circulation pattern was shown to be a fairly cons-
    tant 17,000 cubic feet per second-about ten percent of the harbor volume per day. (By way of com-
    parison, the 1974 average Susquehanna River stream-flow was 39,900 cubic feet per second.) One
    could view the harbor as a constant-volume reservoir which is diluted each day by ten percent of its
    volume with fresh input from the bay, and being constant volume, overflows ten percent of its volume
    back to the bay.
           It has been shown above that the sediments entering the bay from the Susquehanna River carry a
    chlorinated hydrocarbon burden similar to that found at the other stations except Baltimore harbor.
    These sediments make up the major part of the suspended sediments in the CHC-suspended sediment
    reservoir discussed earlier. The water moving into the harbor carries these contaminated sediments;
    therefore, the waters of the Chesapeake Bay represent a source of the chlorinated hydrocarbons to
    Baltimore harbor, as was demonstrated for the Chester River (Clarke, et al., 1972). However, several
    items of evidence suggest that this route may not be the most important source of CHC's to Baltimore
    harbor.
           The fine-grain bottom sediments in Baltimore harbor and the Chester River differ greatly in CHC
    content-the highest values observed in the Chester River falling well below those found in Baltimore
    harbor. On this basis alone, one might suppose the existence of local sources in the harbor. However, a
    sediment core from the Chester River showed two fine-grain layers which had CHC concentrations as
    high as some of the high values in the harbor sediments. Perhaps the deposition and resuspension
    processes in the harbor tend to cause an accumulation of fine-grain materials high in CHC's. Even if such
    a selection process did tend to cause the bottom sediments to approach the high values present in the
    CHC reservoir (suspended sediment, dry weight, Table 6-3), one still would have difficulty explaining
    some of the very high Baltimore harbor sediment CHCvalues without supposing the existence of localiz-
    ed sources, particularly of PCB and chlordane.

    *The turbidity maximum is defined as relatively high suspended sediment concentrations (see Chapter 4,
    Section 4.2.3.)

                                                    6-27

           An examination of the CHC content of the CHC-suspended sediment-reservoir in Baltimore har-
    bor (Station 7A in Figures 6-4b, 6-5b, and 6-6b) indicate that the amounts of PCB and DDTR present in
    the water column on suspended sediment are nearly the same as at the other stations outside the harbor.
    The net flux of these CHC's past the harbor entrance would seem to be zero; hence, at least as much PCB
    and DDTR would move from the harbor to the bay as is transported from the bay into the harbor. The
    amount of chlordane adsorbed on suspended sediment in the harbor water column appears to be suf-
    ficient to represent a significant source compared to the Susquehanna River, especially when one con-
    siders that the flow out of the harbor is almost half as great as the main stream-flow of the river. One can-
    not be certain from the datawhether much of the chlordane actually is transported to the bay with the
    water returning from the harbor, however. The bottom sediment data certainly indicates that a large por-
    tion must be entering the sediment sink in the harbor.
           Whether or not Baltimore harbor serves as an important source of chlorinated hydrocarbons to
    the bay cannot be determined unequ ivocally from the data gathered during this program. The presence of
    relatively high levels of petroleum hydrocarbons in the harbor water may solubilize enough of the CHC's
    to invalidate the assumption that the bulk of the CHC's move adsorbed tothe suspended particulates. To
    resolve this uncertainty one must measure the CHC's in the waters of the harbor as well as in the
    suspended particulates in the water.
           Far from clarifying the pathways of CHC movement in Baltimore harbor, the data presented here
    and in the other sections serve to indicate the complexity of the situation. In addition to the input from the
    bay, other inputs of unknown magnitude have been identified (e.g., aerial fallout, rainfall, dust, storm
    sewer flow). No doubt, additional inputs also would be identified if a pipe-by-pipe point source survey
    were made. Taken altogether, the data suggest that much of the CHC may be trapped out of the system by
    the high deposition rate in the harbor. Helz (1974) pointed out that, although the input of trace metalsto
    Baltimore harbor is quite high, these materials appear to be transported only a short distance before be-
    ing trapped in the bottom sediments.
           The few instances when residues of the chlorinated pesticide, toxaphene, were observed during
    this survey provide interesting support to the supposition that a major portion of the localized inputs of
    CHC's remained trapped in the harbor. In Chapter 5 (Hydrology and Meteorology), evidence was
    presented showing that rain water and storm water entering Baltimore harbor are sources of PCB, chlor-
    dane, and DDTR. In addition, toxaphene appears to be entering the harbor by these routes. At times, the
    toxaphene input is sufficient to enter the foodchain-the zooplankton sampled July 8 showed 1.7 ppm
    toxaphene based upon sample wet weight (0.013 ppt toxaphene in the water column on zooplankton).
    Apparently this material remains trapped in the harbor, because none of the suspended sediment or
    zooplankton samples elsewhere in the Chesapeake Bay showed any traces of toxaphene.
           As pointed out in Chapter 2, (Marine Biology), Baltimore harbor has a distinctive zooplankton
    community not found elsewhere in the bay, characterized by a very high population density four to five
    times greater than the other stations and dominated by a single organism, Eurytemora affinis. These
    organisms could be promoting the deposition of the CHC's from the suspended sediment-CHC reservoir
    by ingesting and pelletizing the fine-grain materials to form feces and/or psuedo-feces. In addition, if
    predation upon these organisms were not heavy, the die-off of mature individuals might result in con-
    siderable transport of CHC's into the bottom sediments. Studies should be pursued to assess whether
    significant transport of CHC's occurs into the biological food chain from the bottom sediment sink orthe
    zooplankton standing crop.
           The overall CHC movement and distribution in the upper Chesapeake Bay having been discussed,
    a closer examination of the individual CHC levels found is appropriate. The highest levels of total PCB in
    zooplankton occurred at the head of the Chesapeake Bay with values of 7.5 and 5.6 ppm at Station 1 A in
    December and March, respectively. The Station 3B zooplankton sample was 7.2 ppm in March. Residues
    of such magnitude at this trophic level make one wonder what might be found in organisms higher in the
    food chain.
            Two additional zooplankton samples collected at Station 1 A were also rather remarkable. The
    DDTR levels found in zooplankton were 4.2 ppm in June and 3.9 ppm in September. These astoundingly
    high levels (compared to elsewhere in the bay) were 97 percent DDD (most p,p'-DDD with some o,p'-
    DDD). This mixture could not result from the breakdown of DDT, but insead it most likely represents the
    use of DDD itself. (For instance, a mixture of the p,p' and o,p' isomers of DDD has been marketed as a
    pesticide under the trade name RothaneS)These occurrences do not appear to indicate a major source of

                                                     6-28

    DDD to the bay; while DDD is the most abundant DDT residue found in the upper Chesapeake Bay, this
    occurrence is not unusual for an estuarine environment. The absence of particularly high DDD levels in
    the Conowingo Dam samples taken in June and September might assure one that the material did not
    come from upstream of the Dam, except that high DDD was not present in the suspended sediment
    samples at Station 1A at these times either. A single event of this nature might be dismissed as in-
    teresting but probably not significant. However, the magnitude of the values and their repeated oc-
    currence seem to indicate a situation requiring further study.
           Aside from the very high CHC levels found in the bottom sediments in Baltimore harbor, the bot-
    tom sediments in the mouth of the Gunpowder River also were very high in PCB (1.3 ppm) and DDTR
    (0.27 ppm) compared to elsewhere in the upper bay. Access to this river is limited because it is part of the
    U. S. Army's Edgewood Arsenal/Aberdeen Proving Grounds complex. Therefore, only the sediments at
    the river mouth were sampled and analyzed. Although, further sampling would be necessary to deter-
    mine whether this area provides major amounts of CHC's to the bay, the values at the mouth of the Gun-
    powder River are too high to be a result of the suspended sediment deposition from the bay. Rather, they
    indicate localized sources of PCB and DDTR.

      6.5 Conclusions
           1.  Relatively high levels of the chlorinated hydrocarbons, PCB, chlordane, and DDTR were
                found in the samples from the upper Chesapeake Bay. CHC's in bottom sediments from the
                bay were two to three times higher than those found in the Chester River.
           2.   The bottom sediments from Baltimore harbor were found to contain the greatest amount of
                the CHC contaminants with values as high as 3.7 ppm for PCB, 0.082 ppm for chlordane,
                and 0.19 for DDTR.
           3.   The average concentrations of PCB, chlordane, and DDTR were highest in suspended
                sediments filtered from the water in Baltimore harbor, with high individual values of 3.8
                ppm for PCB, 0.34 ppm for chlordane, and 0.30 ppm for DDTR being found. When these data
                are presented as the amount of CHC present in the water column on suspended sediment,
               the average CHC values show a decreasing trend going down the Chesapeake Bay with the
                Baltimore harbor station not as high in the case of PCB, or about the same as the upper
                stations in the case of DDTR and chlordane. The chlordane is higher in the harbor than
                elsewhere in the bay.
          4.   The CHC residue concentrations found in zooplankton samples varied tremendously in time
               and space-so much, that the sampling frequency probably was not sufficiently high, tem-
               porally or spatially, for the average values to be entirely representative. The concentrations
               of PCB and DDTR in the zooplankton were highest at Station 1A at the head of the
                Chesapeake Bay (high values of 7.5 ppm PCB and 4.2 ppm DDTR). The most consistently
                high chlordane values in zooplankton were found in Baltimore harbor, the highest being
                0.14 ppm.
          5.   A positive correlation was found between the concentration of suspended sediments in the
               water and the concentration of CHC's in the water column on suspended sediments.
          6.   A positive correlation was also found between the zooplankton biomass in the water and
               the CHC concentration in the water column on zooplankton.
          7.  Apparently, the CHC's enter the Chesapeake Bay attached to suspended sediments via the
               Susquehanna River during periods of high river-flow. These suspended sediments appear
               to function as a reservoir for CHC's in the upper bay.
          8.   The principal movement from this reservoir probably is into bottom sediments which could
               be considered sinks or traps for sediment-adsorbed chlorinated hydrocarbons.
          9.   Resuspension probably represents the greatest pathway for movement of sediment ad-
               sorbed CHC's from the sinks, although re-working of sediments by deposit-feeding
               organisms is a possible route which needs further study.

                                                   6-29

            10. The amount of chlorinated hydrocarbons passing into the zooplankton community appears
                 limited only by the zooplankton population density rather than by fluctuations in the reser-
                 voir, because the amount of CHC present in the zooplankton standing crop never represents
                 more than a small fraction of that present in the suspended sediment reservoir.
            11. Another major pathway from the reservoir into the biological system is into the shellfish
                 populations of the upper Chesapeake Bay.
            12.  Baltimore harbor receives CHC's from the surrounding urban-industrial complex and from
                exchanging water and suspended sediments with the bay. Although the harbor appears to
                 be a significant source of chlordane, it is not clear whether a net transport of PCB and DDTR
                from the harbor into the bay occurs via the continuous exchange of harbor and baywater.
            13. The toxaphene observed in the rainfall and storm sewer samples appears to enter the food
                chain only in Baltimore harbor, and there only sporadically.
            14. The data showed bio-concentration of the CHC's by the plankton and shellfish in the bay.
                The zooplankton concentrated the CHC's five to eight times over that found in the suspend-
                ed particulate fraction. The shellfish concentrated the CHC's many thousands of times
                 higher than the levels in the water column (PCB, 4,000; chlordane, 30,000; DDTR, 45,000).

      6.6 References
    CEQ, 1972. Environmental Quality: Third Annual Report of the Council on Environmental Quality.
           G.P.O., Washington, D. C. 155 p.

    Clarke, W. D., H. D. Palmer, and L. C. Murdock, eds, 1972. Chester River Study, Vol. II, Westinghouse
           Electric Corp., Annapolis, Md., 251 p.

    FDA, 1972. Pesticide AnalyticalManual, Vol. I, Sec. 302.44c, Rev. 1972, Food and Drug Administration,
           U.S. Department of Health, Education, and Welfare, Washington, D.C.

    Goerlitz, D. F., and L. M. Law, 1971. Note on Removal of SulfurlnterferencesfromSedimentExtractsfor
           Pesticide Analysis. Bull. Envir. Contam. Toxicol., V. 6, pp. 9-10.

    Hamilton, D. H., Jr. 1972. Polychaetesofthe Chesapeake Bay. Ches. Sci., V. 13 (suppl.), pp. S 115-S 117.

    Helz, G. R., 1974. Trace Metal Inventory for the Upper Chesapeake Bay, Md., in The Geol. Soc. Amer.,
           Abstracts with Programs, V. 6 (7) October 1974.

    Hesselberg, R.J. and J.L. Johnson, 1972. Column Extraction of Pesticides from Fish, Fish Food and Mud,
           Bull. Environ. Contam. Toxicology, V. 7, p. 115.

    Munson, T. O., 1972. ChlorinatedHydrocarbon Residuesin MarineAnimals of Southern California. Bull.
           Envir. Contam. Toxicol., V. 7, pp. 223-238.

    NIOSH, 1975. Request for Information on Certain ChemicalAgents, National Institute for Occupational
           Safety and Health, U. S. Department of Health, Education, and Welfare, Center for Disease Con-
           trol. Federal Register 40 (No. 21): 26390-26496, G. P. O., Washington, D. C.

    Pritchard, D. W., 1968. Chemical and Physical Oceanography of the Chesapeake Bay in "Proceedings of
           the Governor's Conference on Chesapeake Bay" and "The Estuarine Environment, Estuaries and
           Estuarine Sedimentation" J.R. Schubel, convener, AGI Short Course Lecture Notes 30-31
           October 1971, Wye Institute, Md.

    Schubel, J. R., 1972. Distribution and Transportation of SuspendedSediment in Upper Chesapeake Bay.
           Geol. Soc. Amer. Memoir 133, pp. 151-167.

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