[Federal Register Volume 65, Number 152 (Monday, August 7, 2000)]
[Rules and Regulations]
[Pages 48172-48174]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-19786]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[FRL-6844-7]


National Oil and Hazardous Substances, Pollution Contingency 
Plan; National Priorities List

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final deletion of the Superfund Site from the National 
Priorities List (NPL).

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SUMMARY: EPA Region 5 announces the deletion of the Windom Municipal 
Landfill Site (Site) from the National Priorities List (NPL) and 
requests public comment on this action. The NPL constitutes Appendix B 
of 40 CFR Part 300 which is the National Oil and Hazardous Substance 
Pollution Continency Plan (NCP), which EPA promulgated pursuant to 
Section 105 of the Comprehensive Environmental Response, Compensation 
and Liability Act of 1980, as amended, (CERCLA). EPA and the Minnesota 
Pollution Control Agency (MPCA) have determined that the Site poses no 
significant threat to public health or the environment and, therefore, 
further remedial measures pursuant to CERCLA are not appropriate.

DATES: This ``direct final'' action will be effective October 6, 2000 
unless EPA receives dissenting comments by September 6, 2000. If 
written dissenting comments are received, EPA will publish a timely 
withdrawal of the rule in the Federal Register informing the public 
that the rule will not take effect.

ADDRESSES: Comments may be mailed to Gladys Beard, Associate Remedial 
Project Manager, U.S. Environmental Protection Agency, Superfund 
Division, U.S. EPA, Region 5, 77 W. Jackson Blvd., (SR-6J), Chicago, IL 
60604. Requests for comprehensive information on this Site is available 
through the public docket which is available for viewing at the Site 
Information Repositories at the following locations: U.S. EPA Region 5, 
Administrative Records, 77 W. Jackson Blvd., Chicago, IL 60604, 312-
886-0900; and The Minnesota Pollution Control Agency, 520 Lafayette 
Road North, Saint Paul, Minnesota 55155-4184.

FOR FURTHER INFORMATION CONTACT: Gladys Beard (SR-6J), U.S. 
Environmental Protection Agency, 77 W. Jackson, Chicago, II, (312) 886-
7253, FAX (312) 886-7253, e-mail [email protected]

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction
II. NPL Deletion Criteria
III. Deletion Procedures
IV. Basis of Intended Site Deletion
V. Action

I. Introduction

    The U.S. Environmental Protection Agency (EPA) Region 5 announces 
the deletion of the Windom Municipal Landfill Site, Windom, Cottonwood 
County, Minnesota, from the National Priorities List (NPL), Appendix B 
of the National Oil and Hazardous Substances Pollution Contingency Plan 
(NCP), 40 CFR part 300. EPA identifies sites that appear to present a 
significant risk to public health, welfare, or the environment and 
maintains the NPL as the list of these sites. EPA and the State of 
Minnesota have determined that the remedial action for the Site has 
been successfully executed. EPA will accept comments on this action 
thirty days after publication of this action in the Federal Register.
    Section II of this action explains the criteria for deleting sites 
from the NPL. Section III discusses the procedures that EPA is using 
for this action. Section IV discusses the history of the Windom Site 
and explains how the Site meets the deletion criteria. Section V states 
EPA's action to delete the Site from the NPL unless dissenting comments 
are received during the comment period.

II. NPL Deletion Criteria

    Section 300.425(e) of the NCP provides that Sites may be deleted 
from, or recategorized on the NPL where no further response is 
appropriate. In making a determination to delete a Site from the NPL, 
EPA shall consider, in consultation with the state, whether any of the 
following criteria has been met:
    (i) Responsible parties or other persons have implemented all 
appropriate response actions required;
    (ii) All appropriate Fund-financed response under CERCLA have been 
implemented, and no further response action by responsible parties is 
appropriate; or
    (iii) The remedial investigation has shown that the release poses 
no significant threat to public health or the environment and, 
therefore, taking of remedial measures is not appropriate.
    Even if the Site is deleted from the NPL, where hazardous 
substances, pollutants, or contaminants remain at the site above levels 
that allow for unlimited use and unrestricted exposure, EPA's policy is 
that a subsequent review of the Site will be conducted at least every 
five years after the initiation of the remedial action at the Site to 
ensure that the Site remains protective of public health and the 
environment. In the case of this Site, EPA conducted a Five-Year Review 
in February 1995 and a second one in December 1999. Based on these 
reviews, EPA determined that conditions at the Site remain protective 
of public health and the environment. As explained below, the Site 
meets the NCP's deletion criteria listed above. If new information 
become available which indicates a need for further action, EPA may 
initiate remedial actions. Whenever there is a significant release from 
a site deleted from the NPL, the site shall be restored to the NPL 
without the application of the Hazard Ranking System (HRS).

III. Deletion Procedures

    The following procedures were used for the intended deletion of the 
Site:
    (1) All appropriate response under CERCLA have been implemented and 
no further action by EPA is appropriate; (2) The Minnesota Pollution 
Control Agency concurred with the proposed deletion decision; (3) A 
notice has been published in the local newspaper and has been 
distributed to appropriate federal, state, and local officials and 
other interested parties announcing the commencement of a 30-day 
dissenting public comment period on EPA's Direct Final Action to 
Delete; and, (4) All relevant documents have been made available for 
public review in the local

[[Page 48173]]

Site information repositories. EPA is requesting only dissenting 
comments on the Direct Final Action to Delete.
    For deletion of the Site, EPA's Regional Office will accept and 
evaluate public comments on EPA's Final Notice before making a final 
decision to delete. If necessary, the Agency will prepare a 
Responsiveness Summary, responding to each significant comment 
submitted during the public comment period. Deletion of the Site from 
the NPL does not itself create, alter, or revoke any individual's 
rights or obligations. The NPL is designed primarily for informational 
purposes and to assist Agency management. As mentioned in Section II of 
this document, Sec. 300.425(e) (3) of the NCP states that the deletion 
of a Site from the NPL does not preclude eligibility for future 
response actions.

IV. Basis for Intended Site Deletion

    The following site summary provides the Agency's rationale for the 
proposal to delete this Site from the NPL.

Site Background and History

    The City operated a municipal landfill from the 1930's to 1974. The 
Site covers approximately 11.4 acres and accepted municipal refuse, and 
manufacturing waste including paint sludges, from the Toro Company. 
Concern about the proximity of the Site to the City's municipal well 
field prompted the MPCA to evaluate the potential of the landfill to 
impact the wells. Analysis of the groundwater consistently revealed 
volatile organic compounds downgradient of the landfill. The Site was 
listed on the National Priorities List in April 1986. On June 24, 1986, 
the MPCA issued a Request for Response Action (RFRA) to the City and 
the Toro Company, which required them to conduct a Remedial 
Investigation (RI), and Feasibility Study (FS), and to prepare a 
Response Action Plan (RAP).
    The City conducted the RI to determine the extent and magnitude of 
contamination in 1987, and followed that with a Feasibility Study in 
1988. The City submitted the RAP in January 1989, which was revised in 
March 1989, and subsequently, approved by the MPCA. The RAP included 
the following response action objectives:
     Protect the municipal water supply;
     Minimize leachate generation; and
     Control contaminant migration.
    The EPA Region V Administrator concurred with the MPCA Record of 
Decision (ROD) and the selected remedy for the Site on September 29, 
1989. The major components of the selected remedial action included: 
(i) protection of the municipal water supply through modifications to 
the existing water plant; (ii) minimization of leachate generated by 
grading and capping of the Site; and (iii) monitoring of groundwater 
quality with a contingency plan to be implemented if significant 
groundwater impacts are detected at the Site perimeter.
    The groundwater at the Site is located in glacial outwash deposited 
from the Des Moines lobe during the Wisconsin glaciation. The glacial 
outwash is underlain by a thick, low permeability clay layer, which 
serves as a natural barrier to water flow and protects deeper aquifers 
from contamination. Depth to the water table is about 50 feet the 
ground surface. The saturated thickness of the sand and gravel deposit 
ranges from 50 to 150 feet. The direction of groundwater flow is 
generally to the southwest toward the Des Moines River, but can be 
locally affected by extended pumping from the municipal system.
    Water quality monitoring in the early 1980s revealed that 
chlorinated volatile compounds (VOCs) were detected near the fill area, 
most notably 1,1,2,2-tetrachloroethene (PCE), 1,1,2-trichloroethene 
(TCE), cis-1,2-dichloroethene(DCE), and vinyl chloride (VC). As a 
result of active groundwater pumping and treatment and natural 
attenuation, contaminant concentrations have declined to the point that 
DCE and VC have become the only compounds detected consistently at the 
landfill since 1996. There have been no quantified detections of VC 
since April 1998. In fact there have been no quantified detections of 
any VOC compound analyzed at the Site since July 1998.
    Various inorganics historically have been detected slightly above 
background levels. A notable exception is nitrate, which was detected 
at a level of 15 milligrams per liter (mg/l) at MW1. Inorgancis were 
dropped from the monitoring program in 1997. Two consecutive years of 
inorganic data indicated levels below the action levels, including MW1 
where the nitrate concentration dropped to 0.1 mg/l.
    The City well field is located northwest of the Site. City Well 7 
is the closest well to the Site, and is approximately 500 feet 
northwest of the Site. City Well 7 was impacted with VOC 
concentrations, most notably VC as high as 26 micrograms per liter (ug/
l) in April 1990. As a result, City Well 7 was removed from the 
municipal supply system. City Well 7 was used as a groundwater recovery 
well and connected to the spray treatment system at the landfill. City 
Well 7 operated as a recovery well until August of 1994. City Well 7 
remains disconnected from the public water supply and monitoring shows 
there have been no detections of vinyl chloride since July 1993.
    To protect the water supply, the filter units at the municipal 
water treatment plant were modified in September 1988. The purpose of 
the modifications was to enhance aeration of raw water and hence, 
remove low levels of VOCs. Modifications of the filter unit involved 
installation of: (1) a series of pressure spray nozzles on the header 
distribution pipe to the filter; and (2) power roof ventilators with 
mist eliminators in the filter venting system. These modifications 
break the raw water into fine droplets when sprayed onto the gravity 
filter and increase airflow through the existing vents.
    The City constructed a new water treatment plant in 1997. The first 
step in the new water treatment plant process is aeration. The primary 
purpose of the aerator is to enhance oxidation of iron and manganese 
but this aerator also has the dual purpose of volatizing any VOCs. The 
aerator is comprised of numerous slotted trays through which a forced 
draft fan blows to aerate the water much like a stripping tower. After 
the aerator, the water flows to an open detention tank and filter 
basins that provide additional opportunities for volatilization.
    Construction of the landfill cap began on June 1, 1989. The 
landfill surface was graded to obtain a minimum slope of 2 percent and 
a maximum slope of 25 percent. After grading, the landfill was covered 
with two layers of low-permeability material compacted in six-inch 
lifts. A six inch granular buffer was placed on the low-permeability 
material layer which, in turn, was covered by a layer of topsoil. 
Vegetation was established on the final cover. A gas venting system was 
also installed upon completion of the cap. The cap has been regularly 
inspected and maintenance performed as required. Maintenance has 
included mowing the vegetation, repairing minor erosion as necessary, 
and pocket gopher control.
    The ROD called for initial periodic monitoring of groundwater with 
subsequent implementation of a contingency plan for contaminant 
migration control if established water quality limits were exceeded. 
The contingency action specified in the FS, and adopted in the ROD was 
a groundwater pump-out treatment system to control and treat the VOCs 
in the groundwater. When monitoring of City Well 7 and monitoring well 
MW-9C detected concentrations of vinyl chloride above the action level, 
initiation of groundwater remedial activities were triggered in 
accordance with the RAP.

[[Page 48174]]

    A groundwater recovery well (RWA) was installed along the western 
property boundary in September 1989. An aquifer test, coupled with a 
pilot treatment test, was conducted in October 1989. The tests showed 
that spray treatment of groundwater at the Site was effective in 
removing VOCs from recovered groundwater and the spray treatment 
process did not pose a significant health threat.
    Following approval of the final design, Recovery Wells B and C (RW-
B and RW-C) were completed on October 24, 1990. On October 31, 1990, 
the final recovery system began operation. This system consisted of 
Wells RW-A and RW-C, and City Well 7 discharging through two spray guns 
to the main spray treatment area, and RW-B pumping to spray area B. 
This system operated continuously in this configuration, except for 
brief period of downtime for operation and maintenance, until August 1, 
1994, when City Well 7 was removed from the treatment system. City Well 
7 was removed from the recovery system because it had not had a 
detection of vinyl chloride since April 1993.
    The system operated with the RW-B and RW-C configuration from 
August 1994 until April 9, 1998. RW-C was removed from the groundwater 
extraction system for the following reasons: it was always a clean well 
(except for a few one time unconfirmed VOC detections); landfill 
capture was able to be maintained without it; and it would change the 
groundwater flow stagnation points between recovery wells, thus 
enchancing cleanup. The system has operated with RW-A and RW-B since 
April 9, 1998.
    Each of the remedial objectives specified in the ROD has been 
accomplished. The City water supply has been protected through 
modifications to the former water treatment plant along with the 
construction of the new water treatment plant. The landfill capping has 
effectively reduced infiltration thereby reducing the risk of further 
groundwater impacts. The groundwater recovery and treatment system has 
effectively contained the VOC-impacted groundwater on-site and the 
treatment has now reduced all concentrations to below the laboratory 
detection limits.
    This site meets all the site completion requirements as specified 
in OSWER Directive 9320.2-3C, Procedures for Completion and Deletion of 
National Priorities List Sites and Update. In addition, the Safe 
Drinking Water Act (SDWA) (40 CFR Parts 141-146) establishes federal 
Maximum Contaminant Levels (MCLs) for public drinking water supplies. 
The MCL for vinyl chloride is 2.0 ug/1. Since there are non-detectable 
levels of vinyl chloride in each city well and the distribution system, 
the municipal water supply is in compliance with the SDWA and the 
established MCL for vinyl chloride.
    Monitoring of the landfill monitoring wells and city wells will 
continue on a semi-annual basis to maintain protection of the city 
water supply. MPCA will maintain project oversight reviewing data 
submitted and approving the monitoring plans.
    The City employees perform a monthly inspection of the Site as part 
of their routine monitoring. The inspections include an evaluation of 
soil erosion, settlement, vegetative cover maintenance, groundwater 
monitoring wells, and site security. Two times a year, typically April 
and October, a similar but more comprehensive inspection is performed 
by the PRPs.
    The City of Windom, submitted a Five-Year Review and 1998-1999 
Annual Evaluation Report to the MPCA in June 1999. This Five Year 
Review concluded that all remedial action objectives had been met and 
recommended that the groundwater extraction system be shut down and the 
site delisted from the NPL and the Minnesota Permanent List of 
Priorities (PLP). The MPCA concurred and the system was shut down on 
September 21, 1999. The Site was delisted from the PLP on February 2, 
2000. A contingency plan is in place to reactivate the system if MCLs 
are exceeded in any monitoring well or municipal well. Semi-annual 
groundwater monitoring will continue until the next Five-Year Review, 
which is scheduled for June 2004. At that time, the MPCA will determine 
if groundwater monitoring will continue.

V. Action

    The remedy selected for this Site has been implemented in 
accordance with the Records of Decision. The remedy has resulted in the 
significant reduction of the long-term potential for release of 
contaminants, therefore, threats to human health and the environment 
have been minimized. EPA and the State of Minnesota find that the 
remedy implemented continues to provide adequate protection of human 
health the environment.
    The MPCA concurs with the EPA that the criteria for deletion of the 
Site have been met. Therefore, EPA is deleting the Site from the NPL.
    This action will be effective October 6, 2000. However, if EPA 
receives dissenting comments by September 6, 2000, EPA will publish a 
document that withdraws this action.

List of Subjects in 40 CFR Part 300

    Environmental protection, Air pollution control, Chemicals, 
Hazardous substances, Hazardous Waste, Intergovernmental relations, 
Penalties, Reporting and recordkeeping requirements, Superfund, Water 
pollution control, Water supply.

    Dated: July 21, 2000.
William E. Muno,
Acting Regional Administrator, EPA, Region 5.
    Part 300, title 40 of chapter 1 of the Code of Federal Regulations 
is amended as follows:

PART 300--[AMENDED]

    1. The authority citation for Part 300 continues to read as 
follows:

    Authority: 33 U.S.C. 1321 (c)(2); 42 U.S.C. 9601-9657; E.O. 
12777, 56 FR 54757, 3 CFR, 1991 Comp.; p.351; E.O. 12580, 52 FR 
2923, 3 CFR, 1987 Comp.; p.193.

Appendix B--[Amended]

    2. Table 1 of Appendix B to Part 300 is amended by removing the 
site for ``Windom Dump, Windom, Minnesota.''
[FR Doc. 00-19786 Filed 8-4-00; 8:45 am]
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