RISK-BASED APPROACH TO CLEANUP

1. RISK-BASED APPROACH TO CLEANUP Presented by: Jere “Trey” Hess, P.E. MS Brownfields Program Coordinator

2. What is a Brownfield? • Any property with real or perceived contamination; • Remediation is necessary; • Has redevelopment potential; • Limited Use; and • Liability concerns and financial risk exist.

3. Background • Mississippi Brownfields Voluntary Cleanup and Redevelopment Act (1998) • Offers LIABILITY PROTECTION; • Allowed MDEQ to develop and implement a RISK-BASED remediation program; • Currently, does not include financial incentives like some other States.

4. LIABILITY PROTECTION • Once a property has been remediated to the satisfaction of MDEQ, MDEQ will not require further remediation in the future. • Needed assurance for: • Prospective purchasers • Lenders • Developers • It is similar to having an INSPECTION of a home before buying it and then having it repaired.

5. Site Characterization • Similar to the Home Inspection • The planning, sampling, analysis, and reporting that results in a three dimensional delineation of contamination at the Site. • A COMPLETE Site Characterization should result in the development of soil and groundwater plume maps.

6. Site Characterization

7. Site Characterization

8. Site Characterization

9. Site Characterization

10. What is a“Risk-Based”Site Evaluation? • The Traditional Site Evaluation of contaminant exposure has been driven by the actual or POTENTIAL on-site residential receptor (i.e., future day-care facility) • A Risk-Based Site Evaluation takes into account land use and engineering controls which may be used to reduce or eliminate exposure to contaminants or risk.

11. Introduction to the Brownfields Tiered Approach • The cornerstone of the Brownfields Program is a three-tiered risk-based process for evaluating human health and environmental risks. • Land use restrictions and engineering controls play integral roles in the three-tiered approach by reducing or eliminating the potential for exposure to contaminants and risk.

12. TIER 1 - Look-up Table • The highest concentration of each contaminant in each media (soil and groundwater) is compared to the values in the Tier 1 TRG Table. • The values in the Tier 1 TRG Table can either be used as DEFAULT remediation goals or as a screening tool that will trigger a Tier 2 Evaluation.

13. TIER 1 - Look-up Table

14. TIER 1 - Look-up Table

15. TIER 1 - Look-up Table

16. TIER 2 OPTIONS • Statistical Methods • Site Background • Regionally Prevalent Chemicals • Site-Specific Data • Eliminate/Minimize Exposure Routes • TPH Fractioning • Other Approved Methods

17. TIER 2 OPTIONS • Statistical Methods • The Upper Confidence Level (UCL) of the Mean concentration is compared to the Tier 1 TRG instead of the highest concentration. UCL of the Mean Mean Concentration Highest Concentration

18. TIER 2 OPTIONS • The background concentration can be used instead of the Tier 1 TRG level. • Must be statistically valid (typically, lognormal) • Must be collected from “clean” locations; • Locations must approved by MDEQ; and • Must be collected in a manner consistent with EPA Guidance. • Site Background • Naturally occurring chemical concentrations

19. TIER 2 OPTIONS • Regionally Prevalent Chemicals • Example: Arsenic in the Delta Region as a result of aerial application (crop dusting). • The regionally prevalent chemical concentration can be used instead of the Tier 1 TRG level in most cases. • Must follow the same criteria as described for background concentrations.

20. TIER 2 OPTIONS • Site-Specific Variables • Site-specific variables can be used to calculate “Site-specific” Remediation Goals • Examples: • exposure duration, • moisture content, • Porosity • Use the “Site-specific” Remediation Goals instead of the Tier 1 TRG levels.

21. TIER 2 OPTIONS • Eliminate/Minimize Exposure Routes • Institutional Controls and Engineering Controls can be used provided: • All complete exposure pathways eliminated; or • Contamination exposure is minimized to levels that will be protective to human health and the environment. • Example: • Engineering Control –Parking lot that CAPS contamination • Institutional Controls – Deed Notice and Brownfield Agreement • Contamination must remain confined within site boundaries and monitoring may be necessary.

22. TIER 2 OPTIONS • TPH Fractioning • Primarily utilized in cases where indicator constituent concentrations cannot be determined due to dilution and/or interference. • Massachusetts Method • Compare TRGs for six (6) Hydrocarbon Ranges • http://www.state.ma.us/dep/bwsc/vph_eph.htm • Other Approved Methods

23. TIER 2 OPTIONS • Other Approved Methods • Risk-Based Corrective Action (RBCA) • “EPA Mega-Rule” Risk Evaluation for PCBs • Illinois TACO Program • EPA Soil Screening Guidance Document Procedures

24. TIER 3 Risk Assessment • SITE-SPECIFIC RISK ASSESSMENT • Human Health Risk Assessment • Ecological Risk Assessment • Should be based on current EPA risk assessment guidance • Risk Assessment Guidance for Superfund (RAGS)

25. More Information • Internet Address: • http://www.brownfields.ms • MDEQ Contacts: • Trey Hess - Brownfields Program Coordinator • (601) 961-5654 • email: Trey_Hess@deq.state.ms.us • Jerry Banks - Hazardous Waste Division Chief • (601) 961-5221 • email: Jerry_Banks@deq.state.ms.us