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User's Guide (June 2015)

Table of Contents

For assistance/questions please use the rsl table contact us page


This guidance sets forth a recommended, but not mandatory, approach based upon currently available information with respect to risk assessment for response actions at CERCLA sites. This document does not establish binding rules. Alternative approaches for risk assessment may be found to be more appropriate at specific sites (e.g., where site circumstances do not match the underlying assumptions, conditions and models of the guidance). The decision whether to use an alternative approach and a description of any such approach should be documented for such sites. Accordingly, when comments are received at individual CERCLA sites questioning the use of the approaches recommended in this guidance, the comments should be considered and an explanation provided for the selected approach.

It should also be noted that the screening levels (SLs) in these tables are based upon human health risk and do not address potential ecological risk. Some sites in sensitive ecological settings may also need to be evaluated for potential ecological risk. EPA's guidance "Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessment" http://www.epa.gov/oswer/riskassessment/ecorisk/ecorisk.htm contains an eight step process for using benchmarks for ecological effects in the remedy selection process.

1. Introduction

The purpose of this website is to provide default screening tables and a calculator to assist Remedial Project Managers (RPMs), On Scene Coordinators (OSC's), risk assessors and others involved in decision-making concerning CERCLA hazardous waste sites and to determine whether levels of contamination found at the site may warrant further investigation or site cleanup, or whether no further investigation or action may be required.

Users within and outside the CERCLA program should use the tables or calculator results at their own discretion and they should take care to understand the assumptions incorporated in these results and to apply the SLs appropriately.

The SLs presented in the Generic Tables are chemical-specific concentrations for individual contaminants in air, drinking water and soil that may warrant further investigation or site cleanup. The SLs generated from the calculator may be site-specifc concentrations for individual chemicals in soil, air, water and fish. It should be emphasized that SLs are not cleanup standards. We also do not recommend that the RSLs be used as cleanup levels for Superfund Sites until the recommendations in EPA's Supplemental Guidance to Risk Assessment Guidance for Superfund, Volume I, Part A ("Community Involvement in Superfund Risk Assessments" http://www.epa.gov/oswer/riskassessment/ragsa/pdf/ci_ra.pdf) have been addressed. SLs should not be used as cleanup levels for a CERCLA site until the other remedy selections identified in the relevant portions of the National Contingency Plan (NCP), 40 CFR Part 300, have been evaluated and considered. PRGs (Preliminary Remediation Goals) is a term used to describe a project team's early and evolving identification of possible remedial goals. PRGs may be initially identified early in the Remedial Investigation/ Feasibility Study (RI/FS) process (e.g., at RI scoping) to select appropriate detection limits for RI sampling. Typically, it is necessary for PRGs to be more generic early in the process and to become more refined and site-specific as data collection and assessment progress. The SLs identified on this website are likely to serve as PRGs early in the process--e.g., at RI scoping and at screening of chemicals of potential concern (COPCs) for the baseline risk assessment. However, once the baseline risk assessment has been performed, PRGs can be derived from the calculator using site-specific risks, and the SLs in the Generic Tables are less likely to apply. PRGs developed in the FS will usually be based on site-specific risks and Applicable or Relevant and Appropriate Requirements (ARARs) and not on generic SLs.

2. Understanding the Screening Tables

2.1 General Considerations

2.2 Exposure Assumptions

2.3 Toxicity Values

2.4 Chemical-specific Parameters

3. Using the SL Tables

3.1 Developing a Conceptual Site Model

3.2 Background

3.3 Potential Problems

4. Technical Support Documentation

4.1 Residential Soil

4.2 Composite Worker Soil

4.3 Indoor Worker Soil

4.4 Outdoor Worker Soil

4.5 Construction Worker Soil

4.6 Recreational Soil or Sediment

4.7 Recreational Surface Water

4.8 Tapwater

4.9 Resident air

4.10 Worker air

4.11 Ingestion of Fish

4.12 Soil to Groundwater

4.13 Supporting Equations and Parameter Discussion

5. Special Considerations

5.1 Cadmium

5.2 Lead

5.3 Manganese

5.4 Vanadium Compounds

5.5 Uranium

5.6 Chromium (VI)

5.7 Aminodinitrotoluenes

5.8 PCBs

5.9 Xylenes

5.10 Arsenic

5.11 Total Petroleum Hydrocarbons (TPHs)

5.12 Soil Saturation Limit (Csat)

5.13 SL Theoretical Ceiling Limit

5.14 Target Risk

5.15 Screening Sites with Multiple Contaminants

5.16 Deriving Soil Gas SLs

5.17 Mutagens

5.18 Trichloroethylene (TCE)

5.19 Mercuric Chloride (and other Mercury salts)

5.20 Cyanide (CN-)

6. Using the Calculator

Table 1. Standard Default Factors

7. References

For assistance/questions please use the rsl table contact us page

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