[Federal Register Volume 61, Number 106 (Friday, May 31, 1996)]
[Notices]
[Pages 27349-27351]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-13431]



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ENVIRONMENTAL PROTECTION AGENCY
[FRL-5510-3]


Soil Screening Guidance

AGENCY: Environmental Protection Agency.

ACTION: Notice of availability of Soil Screening Guidance.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) has developed 
the Soil Screening Guidance which is now available. This guidance 
presents a framework for developing soil screening levels (SSLs), 
focusing primarily on a simple methodology for developing site-specific 
screening levels, but including generic levels and the opportunity to 
do more detailed modeling. The guidance can serve as a tool to expedite 
the evaluation of contaminated soils at sites addressed under the 
Comprehensive Environmental Response, Compensation, and Liability Act 
(CERCLA), commonly known as Superfund. The guidance is intended to be 
used to screen out areas of sites, exposure pathways, or chemicals of 
concern from further consideration, assuming certain conditions are 
present, or to determine that further study is warranted at a site. It 
is not a rule, does not have the force of a regulation, nor should it 
be interpreted to represent cleanup standards for a site.
    The Soil Screening Guidance is presented in three documents: (1) a 
Quick Reference Fact Sheet, which provides an overview of the 
development and use of soil screening levels; (2) a User's Guide, which 
provides details for implementing a simple methodology for calculating 
site-specific SSLs; and (3) a Technical Background Document (TBD), 
which presents generic SSLs and the technical foundation for the 
methodology for establishing SSLs. These documents are available from 
the National Technical Information Service at the address listed below. 
Additional supporting information, including summaries of previous 
outreach activities, is available for inspection in the Superfund 
Docket at the address listed below.
    As part of the development of the Soil Screening Guidance, EPA 
conducted extensive outreach and peer review. A major component of that 
outreach was providing the document for public comment (59 FR 67706, 
December 30, 1994). As a result of comments received during the public 
comment period and the independent scientific peer review conducted 
concurrently, several changes were made to the guidance. The highlights 
of that process are presented below. In addition, EPA has developed a 
more detailed Response to Comments on the public review draft and the 
independent scientific peer review. This document is also available 
from the National Technical Information Service (see below).

DATES: The Soil Screening Guidance was signed by Assistant 
Administrator Laws on May 17, 1996 and is now being published by 
National Technical Information Service (NTIS).

ADDRESSES: Copies of the draft Soil Screening Guidance may be ordered

[[Page 27350]]

through the NTIS at (703)487-4650 as follows:

Soil Screening Guidance Quick Reference Fact Sheet, 9355.4-14FSA, PB96-
963501, EPA/540/F-95/041
Technical Background Document for Soil Screening Guidance, 9355.4-17A, 
PB96-963502, EPA/540/R-95/128
Soil Screening Guidance: User's Guide, 9355.4-23, PB96-963505, EPA/540/
R-96/018
Soil Screening Guidance: Response to Comments, 9355.4-22, PB96-963506, 
EPA/540/R-96/019

    Members of the public are invited to inspect the docket developed 
to support the Soil Screening Guidance at the Superfund Docket, U.S. 
Environmental Protection Agency, 1235 Jefferson Davis Highway, 
Arlington, Virginia. [Docket Number SSL]. The docket is available for 
inspection between 9:00 a.m. and 4:00 p.m., Monday through Friday, 
excluding Federal holidays. Appointments to review the docket can be 
made by calling (703) 603-9232. The public may copy a maximum of 266 
pages from the docket free of charge, however a charge of 15 cents will 
be incurred for each additional page, plus a $25.00 administrative fee.

FOR FURTHER INFORMATION CONTACT: The RCRA/Superfund Hotline at (800) 
424-9346 (in the Washington, D.C. metropolitan area, (703) 412-9810). 
The Telecommunications Device for the Deaf (TDD) Hotline number is 
(800) 553-7672 (in the Washington, DC metropolitan area, (703) 412-
3323). You may also contact David Cooper, Office of Emergency and 
Remedial Response (5204G), U.S. Environmental Protection Agency, 401 M 
Street, S.W., Washington, D.C. 20460, at (703) 603-8763.

SUPPLEMENTARY INFORMATION:

Introduction

    The U.S. Environmental Protection Agency (EPA) responds to releases 
and threatened releases of hazardous substances under the authority of 
the Comprehensive Environmental Response, Compensation, and Liability 
Act of 1980 (CERCLA). Regulations governing such responses are found in 
the National Oil and Hazardous Substances Pollution Contingency Plan or 
NCP. The process for remedy selection in the NCP generally requires 
that a remedial investigation be performed to identify the nature and 
extent of contamination at National Priorities List (NPL) sites. From 
sampling results, as well as site observations obtained in the field, 
specific contaminants and exposure pathways of concern are identified 
and used in a baseline risk assessment performed to determine whether 
remedial action is warranted. (See source documents 1 and 2 listed at 
the end of this document.)
    Today's Federal Register notice announces the availability of a new 
tool which may reduce significantly the time it takes to complete soil 
investigations and cleanup actions, as well as improve the consistency 
of these actions across the nation. The guidance was written to enhance 
the efficiency of remedial investigation/feasibility study (RI/FS) work 
at Superfund National Priorities List (NPL) sites. This guidance on 
developing soil screening levels is expected to assist site managers in 
quickly identifying contaminated soil of potential concern and in 
screening out from further consideration those soils that do not 
warrant additional study.
    The Soil Screening Guidance presents three recommended methods for 
developing risk-based, soil screening levels, but emphasizes a simple, 
site-specific approach. The formulae and exposure assumptions used to 
develop the screening levels have been taken from the Risk Assessment 
Guidance for Superfund 1,2 and have been widely accepted in the 
Superfund program for a number of years. These levels are then compared 
to on-site soil contaminant levels. Areas of a site which fall below 
the screening levels may be eliminated from further assessment. Areas 
above the screening levels generally warrant further evaluation of the 
potential risks that may be posed by site contaminants to determine the 
need for response action. While the guidance is recommended for use as 
a screening tool to determine if further study of specific portions of 
a site is warranted, the levels should not be interpreted to represent 
cleanup standards for a site.

Background

    In 1993 EPA's Office of Emergency and Remedial Response (OERR) 
developed a draft fact sheet entitled: ``Interim Soil Screening Level 
Guidance.'' This guidance discussed the development and use of risk-
based Soil Screening Levels (SSLs) for 30 common Superfund soil 
contaminants. The document was issued on September 30, 1993, to provide 
the basis for discussion of the SSL project with stakeholders and is 
available for review as background information in the Superfund Docket. 
The effort to develop such a guidance was requested under both the EPA 
Administrator's June 19, 1991, ``30-Day Study,'' and the more recent 
Superfund Administrative Improvements Initiatives announced by the 
Deputy Administrator on June 23, 1993. This guidance was subsequently 
revised and expanded to become the ``Soil Screening Guidance,'' dated 
December 1994. This guidance was provided to the public for comment (59 
FR 67706) and submitted to independent scientific peer review. As a 
result of comments received in this process, we made several changes to 
the document. Some of the most significant comments are highlighted 
here. The Response to Comments provides a more in-depth discussion of 
these changes and many other, less significant technical changes.
    (1) Guidance needs to be more user friendly. EPA has modified the 
presentation of the guidance because many people commented that it was 
not clear how to implement the guidance. The Soil Screening Guidance 
has been reorganized into a ``user's guide'' to provide more useful 
information on how to develop simple site-specific screening levels and 
compare those to contaminant concentrations found at sites.
    (2) Generic SSLs will be misused. The generic SSLs are still part 
of the framework, but they have been moved to the Technical Background 
Document in an effort to prevent their misuse. They now appear in a 
section which discusses the technical assumptions that go into the 
development of those numbers.
    (3) Generic SSLs are too conservative. Another impetus for moving 
the generic levels to the TBD is concern that the generic levels were 
too conservative. One of the modeling inputs leading to this 
conservatism is the assumption of an infinite source of contamination. 
To address this concern, the new guidance provides an opportunity use 
site-specific information to develop a conservative estimate of the 
volume of contamination at the site.
    (4) Sampling strategy was based on an assumption that is not 
appropriate for all sites. One of the peer reviewers commented that the 
approach for sampling the site to determine the contaminant 
concentrations was dependent on the assumption of a log-normal 
distribution of contamination that may not actually occur at the site. 
That approach has been replaced by a strategy that includes adequate 
sampling of surface soil in the exposure area, compositing of some 
samples to reduce laboratory costs, and comparison of the screening 
level with the maximum of the composite samples from each exposure 
area. The strategy balances the desire for a statistically based 
sampling strategy with the need to control the number of samples and 
the laboratory costs.

[[Page 27351]]

    (5) Non-residential land uses need to be considered. EPA received 
from many stakeholders that SSLs should be developed for other land 
uses such as industrial or recreational. EPA agrees in principle that 
other land uses need to be considered. However, as a first step in the 
development of screening levels EPA chose to focus on residential use 
because there is more agreement in the risk assessment community about 
the types of relevant pathways and assumptions appropriate for modeling 
residential exposures. Several of the Superfund reforms announced in 
October 1995 address non-residential land uses and should provide 
information which could be used to expand the soil screening guidance 
to other land uses.

Goals

    EPA's goal in developing this guidance is to provide a tool which 
can be used to expedite the evaluation of contaminated soils at sites 
addressed under CERCLA. The guidance is intended to be used to screen 
out areas of sites, exposure pathways, or chemicals of concern from 
further consideration or to determine that further study is warranted 
at a site. It may be used where assumptions made in developing the tool 
(e.g., residential land use, no ecological concerns) are consistent 
with conditions found at specific sites.
    This guidance is not intended to be, and should not be construed as 
a rule. Use of the guidance is not legally binding either on EPA staff 
or on other parties; rather it is intended to be a tool available for 
use under appropriate site-specific conditions. NPL sites do not all 
meet the conditions necessary for its use, consequently, EPA does not 
expect this tool to be useful at all NPL sites. EPA staff applying the 
guidance have discretion to follow it or diverge from it as site-
specific conditions may warrant, and each site-specific action will be 
explained on its own record.
    Please contact individuals and offices listed in the sections of 
this notice entitled ``Addresses'' and ``For Further Information 
Contact'' to learn more about the Soil Screening Guidance.

Source Documents

    1. U.S. EPA. 1989. Risk Assessment Guidance for Superfund: 
Volume 1: Human Health Evaluation Manual, Part A, Interim Final. 
EPA/540/1-89/002. Office of Emergency and Remedial Response, 
Washington D.C. NTIS PB90-155581/CCE.
    2. U.S. EPA. 1991. Risk Assessment Guidance for Superfund, 
Volume 1: Human Health Evaluation Manual (Part B, Development of 
Risk-Based Preliminary Remediation Goals). Publication 9285.7-01B. 
Office of Emergency and Remedial Response, Washington, D.C. NTIS 
PB92-963333.

    Dated: May 17, 1996.
Elliott P. Laws,
Assistant Administrator.
[FR Doc. 96-13431 Filed 5-30-96; 8:45 am]
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