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Notice of Availability of the Draft Supplemental Guidance for Dermal Risk Assessment, Risk Assessment Guidance for Superfund, Volume I, Part E

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Information about this document as published in the Federal Register.

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AGENCY:

Environmental Protection Agency.

ACTION:

Notice of availability, request for comment, request for data.

SUMMARY:

The U.S. Environmental Protection Agency (EPA) has developed and is requesting public comment on a draft Risk Assessment Guidance for Superfund: Volume I Human Health Evaluation Manual (Part E, Supplemental Guidance for Dermal Risk Assessment) (RAGS Part E). EPA is also requesting data pertinent to reducing the uncertainty and variability in assessing the risks from dermal exposure. RAGS Part E is available electronically on the Internet at http://www.epa.gov/​superfund/​programs/​risk/​ragse/​index.htm. This guidance is intended to assist risk assessors and others in addressing concerns resulting from the evaluation of dermal exposure risk assessment pathways. It proposes a consistent methodology for assessing the exposures from the dermal pathway for Superfund human health risk assessments. It incorporates and updates principles of the EPA (1992) interim report, “Dermal Exposure Assessment: Principles and Applications”.

DATES:

You may submit comments and data until February 8, 2002. Comments received after that date may be considered to the extent feasible.

ADDRESSES:

You are invited to submit written comments and data to: EPA, Superfund Docket RAGS Part E, Mail Code 5202G, 1200 Pennsylvania Ave, NW., Washington, DC 20460. For cost savings the draft RAGS Part E document is available electronically on the Internet at http://www.epa.gov/​superfund/​programs/​risk/​ragse/​index.htm. EPA plans to print the document only after it is finalized. The Superfund Docket, containing the RAGS Part E document and public comments, is physically located at 1235 Jefferson Davis Highway, Arlington, Virginia. Appointments to review the docket can be made by calling (703) 603-9232.

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FOR FURTHER INFORMATION CONTACT:

Contact the RCRA/Superfund Call Center at (800) 424-9346; from the Washington, DC, metropolitan area call (703) 412-9810. The Telecommunications Device for the Deaf (TDD) number is (800) 553-7672; from the Washington, DC, metropolitan area the number is (703) 412-3323. For technical inquiries, you may contact Lee Hofmann, Office of Solid Waste and Emergency Response, Mail Code 5101, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460: telephone number 202-260-2230, email hofmann.lee@epa.gov.

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SUPPLEMENTARY INFORMATION:

Background

In January 1992, the Office of Health and Environmental Assessment (OHEA), in the Office of Research and Development (ORD) of the U.S. Environmental Protection Agency (EPA) issued an interim report, Dermal Exposure Assessment: Principles and Applications (DEA). The DEA provided guidance for conducting dermal exposure assessments and was peer-reviewed by EPA's Science Advisory Board. A Workgroup was subsequently formed to develop guidance for Superfund based on the DEA. In August 1992, a draft Superfund Interim Dermal Risk Assessment Guidance was circulated for comment but was never issued. This current guidance supersedes the 1992 Superfund document.

This 2001 Superfund RAGS Part E, Supplemental Guidance for Dermal Risk Assessment (RAGS Part E) is the result of Superfund RAGS Part E Workgroup Start Printed Page 63707meetings from FY 95 through FY 01 on issues associated with the characterization of risk resulting from the dermal exposure pathway. RAGS Part E updates recommendations presented in the DEA, and incorporates additional information from the Exposure Factors Handbook (U.S. EPA, 1997a) and scientific literature, as cited. Users of this guidance are strongly encouraged to review and understand the material presented in the DEA. This guidance is considered interim, pending release of any update to the DEA from ORD. As more data become available, RAGS Part E may be updated.

This Supplemental Guidance for Dermal Risk Assessment (RAGS Part E) has undergone external peer review in January 1998 and in February 2000. Also, EPA's Risk Assessment Forum conducted a Peer Consultation Workshop on this document in December 1998.

Elements of the RAGS Part E Approach

Risk Assessment Guidance for Superfund: Volume I-Human Health Evaluation Manual (Part E, Supplemental Guidance for Dermal Risk Assessment) (RAGS Part E) is structured to be consistent with the four steps of the Superfund risk assessment process: hazard identification, exposure assessment, toxicity assessment, and risk characterization. RAGS Part E is organized into six chapters and four appendices. To provide an indication of the scope of the document, we have included the Table of Contents below:

1.0 Introduction and Flowchart

1.1 Introduction

1.2 Organization of Document

1.3 Flowcharts

2.0 Hazard Identification

2.1 Choosing Contaminants of Concern for the Dermal-water Pathway

2.2 Choosing Contaminants of Concern for the Dermal-soil Pathway

3.0 Exposure Assessment

3.1 Estimation of Dermal Exposures to Chemicals in Water

3.1.1 Standard Equation for Dermal Contact with Chemicals in Water

3.1.2 Exposure Parameters

—Permeability coefficient for compounds in water (Kp in cm/hr)

—Chemical concentration in water

—Skin surface area

—Event time, frequency and duration of exposure

3.2 Estimation of Dermal Exposure to Chemicals in Soil

3.2.1 Standard Equation for Dermal Contact with Chemicals in Soil

3.2.2 Exposure Parameters

—Skin Surface Area

—Soil-to-Skin Adherence Factors

—Recommended Soil Adherence Factors

—Dermal Absorption Fraction from Soil

—Age-adjusted Dermal Factor

—Event Time, Exposure Frequency and Duration

3.3 Estimation of Dermal Exposure to Chemicals in Sediment

4.0 Toxicity Assessment

4.1 Principles of Route-to-route Extrapolation

4.2 Adjustment of Toxicity Factors

4.3 Calculation of Absorbed Toxicity Values

4.4 Direct Toxicity

5.0 Risk Characterization

5.1 Quantitative Risk Evaluation

5.1.1 Risk Calculations

5.1.2 Risks for All Routes of Exposure

5.2 Uncertainty Assessment

5.2.1 Hazard Identification

5.2.2 Exposure Assessment

—Dermal Exposure to Water—Uncertainties Associated with the Model for DAevent

—Dermal Exposure to Soil

5.2.3 Toxicity Assessment

5.2.4 Risk Characterization

6.0 Conclusions/Recommendations

6.1 Summary

6.2 Exposures Not Included in Current Dermal Guidance

6.3 Recommendations

7.0 References

Appendix A: Water Pathway

A.1 Dermal Absorption Model

A.1.1 Calculation of Parameters in Daevent

A.1.2 Model Validation

A.2 Estimation of Kp for Organic Compounds

A.3 Estimation of Kp for Inorganic and Ionized Organic Compounds

A.4 Uncertainty Analysis

A.5 Screening Procedure for Chemicals in Water

A.6 Procedures for Calculating Dermal Dose

A.6.1 Stepwise Procedure for Calculating Dermal Dose Using Given Equations

A.6.2 Stepwise Procedure for Calculating Dermal Dose Using Spreadsheets

Appendix B: Screening Tables and Reference Values for The Water Pathway

Table B.1: Flynn Data Set

Table B.2: Predicted Kp for 200's Organic Contaminants In Water

Table B.3: Calculation of Dermal Absorbed Dose for Organic Chemicals in Water

Table B.4: Calculation of Dermal Absorbed Dose for Inorganic Chemicals in Water

Appendix C: Soil Pathway

Appendix D: Sample Calculations

RAGS Part E focuses on dermal contact with soil and water, and it does not provide guidance on quantifying dermal absorption of chemicals resulting from exposure to vapors. The Superfund RAGS Part E Workgroup agreed with the finding in the DEA report that many chemicals, with low vapor pressure and low environmental concentrations, cannot achieve adequate vapor concentration to pose a dermal exposure hazard. For chemicals with the potential to achieve adequate vapor concentrations, this guidance assumes that they are primarily absorbed through the respiratory tract.

Goals

EPA welcomes feedback on this draft RAGS Part E document. EPA is seeking public comment at this time in order to ensure hearing the widest range of views and obtaining all information relevant to the development of policy. In addition, EPA is soliciting data pertinent to reducing uncertainty and variability in assessing risks from dermal exposure. EPA will review public comments received on the draft RAGS Part E document and will make appropriate changes in the document. EPA expects to respond in a summarized manner to the principal comments received on the draft RAGS Part E document as a matter of public information.

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Dated: November 30, 2001.

Michael H. Shapiro,

Principal Deputy Assistant Administrator, Office of Solid Waste and Emergency Response.

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[FR Doc. 01-30457 Filed 12-7-01; 8:45 am]

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