VI Draft Guidance: Overview of Comments to November, 2002 OSWER VI Guidance

1. VI Draft Guidance: Overview of Comments to November, 2002 OSWER VI Guidance Michael Sowinski DPRA, Inc.

2. Presentation Overview • Overview the Major Points By Commenters • Comments Organized By: • Generally Applicable Comments • Tier I Comments • Tier II Comments • Tier III Comments • Appendices • Summarize Primary Issues Raised

3. Overview of Comments Provided • 30 Commenters • 18 Government (Federal & State) • 4 Industry Trade Associations • 7 Consultants • 1 Public Interest Group • 6 EPA Supporting Documents • Widely Ranging Comments • Available on E-Docket

4. Generally Applicable Comments • Many Praises for the Effort • Guidance is Overly Conservative • Guidance is Overly Complex • Guidance is Over/Under Prescriptive • VI Guidance will Cause Cleanup Delays • VI Guidance will Delay EI Attainment

5. Generally Applicable Comments:Risk Assessment/Risk Management Issues • Use of Phrase “Pathway Incomplete” vs. “Complete w/Acceptable Risk” is Confusing • Use of OSHA PELs for Occupational Setting! • Appropriateness of the MCL Floor • Incremental vs. Cumulative Risk • Hazard Quotient of 0.2 vs. 1.0.

6. Generally Applicable Comments:Risk Assessment/Risk Management Issues (cont.) • Indoor Sources & Background Contamination! • Procedures to Discriminate Needed • Generic AFs Do Not Account for Background • Guidance Should Provide Citations for Available Background Data (Background Floor) • Tables 2 and 3 • Acceptable Risk? (10-4 – 10-6) • Ever-Changing Toxicology Demands Living Tables. • Extrapolated vs. Non-Extrapolated Values • Short Term vs. Long Term Exposure • Detection Levels vs. Risk Targets for Air and Groundwater

7. Generally Applicable Comments:Scope of Guidance • Applicability to Petroleum Hydrocarbons • Citing Biodegradation, Deal with Petroleum Hydrocarbons Separately • UST Sites vs. Petroleum Hydrocarbon Sites • Do Not Endorse RBCA Guidance • Table 1 COC List • Inclusion of Additional COCs • COC List vs. CAA Hazardous Air Pollutants • COC List vs J & E Spreadsheets • Retroactive Application at CERCLA/VCP Sites • Relation to CERCLA Risk Assessment

8. Generally Applicable Comments:Purpose of Guidance • Need for Guidance on Additional Items • More Advice on Air Sampling • Prepare a Background Source Study • Advice on Delineating Risk, Cumulative Risk, and Triggers for Cleanup Actions • How to Measure for Model Inputs • Guidance Should be Less Prescriptive • Risk Management vs. Risk Assessment

9. Tier 1 Comments • Precluding Factors • Ask Once • More Justification Needed/Suggestions Provided • CSM Should Include Breakdown Products • Should Consider Presence of Vapor Barriers During Tier 1 • The Use of Existing vs. New Data – Need Clarity • What Qualifies as Reasonable Estimate of GW

10. Tier 1 Comments • 100 Foot Lateral and Vertical Limits • Future Development Issues • Design and Enforcement of Institutional Controls • Guidance Lacks Direction on This • Immediate Action • Focus on Background Contamination • Use of Engineering Controls – Needs Clarity

11. Tier 2 Comments:General • Use of Bulk Soil Samples • Joint Use of Soil Gas & Groundwater Samples – Need Clarity. • Generic vs. Chemical Specific AFs

12. Tier 2 Comments:Empirical AFs • Generic AFs are Over Conservative • Utilize Max. vs. Mean IA Data • Site Selection Bias Exists • Does Not Adequately Account for Background • Henry’s Law Based Equilibrium Assumption • Suggestions Provided for Alternative AFs • More Field Data Required (Data Quality Guidelines Should Be Imposed On Submitting Agency) • Same Database to Create & Validate Data

13. Tier 2 Comments:JEM Inputs for Figure 3 • More Details Needed to Support Figure 3 Development • Figure 3 Should Assume 10C not 25C • Figure 3’s 5L/min Assumption Conflicts w/Diffusive Transport Assumption • Figure 3 Should Consider More Soil Types • Construction Characteristics Not Properly Accounted For – Commercial Building AFs Vary Greatly from Residential AFs

14. Tier 3 CommentsJEM Model • Requires Sophisticated Expertise • Need Better Rationale for Input Parameters • Critical Parameters for JEM • JEM Use Considerations • Effects of Soil Sorption • Transport Across Capillary Fringe • Aqueous Phase Diffusion • Presence of NAPL

15. Appendix A: Data Quality Assurance Considerations • Appropriateness of the Use of the Visual Sampling Plan • Practical Experience Shows That PDLs are Higher Than Appendix A Lists • Explain That Entire Analyte List for Listed Methods Need Not Be Tested • For TO-15, List Costs for SCAN and SIM Mode.

16. Appendix B: Development of A CSM • Provide Hypothetical Site to Illustrate CSM Development • Need Clarity on How To Identify and Deal With Sensitive Populations

17. Appendix D: Development of Tables 1, 2, and 3. • Calculations for Acceptable Indoor Air Levels Do Not Match With Those Used by Region III and Region VI. • Table D-1 Should List Solubility, Henry’s Law, and Maximum Calculated Vapor Concentration • Table D-1 Should Exclude Contaminants That Do Not Meet the Two-Pronged Toxicity and Volatility Test • Table 2 Should Include Screening Values for Non-Residential Scenarios

18. Appendix E: Relevant Methods and Techniques • Appropriateness of Sub-Slab Sampling • Sampling Recommendations Are Not Technically Defensible (indoor air!, soil gas, gw, sub-slab, soil) • Include “Post Sampling” Survey Form

19. Appendix G: Relevant Methods and Techniques (cont.) • More Advice Needed on Sampling for Model Inputs (i.e., soil moisture, bldng. characteristics) • Need More Careful Accounting of Background Contamination • Water Table vs. Water Column Sampling

20. Summary of CommentsSteps to Success