Remedial Action Guideline Revisions

1. Remedial Action Guideline Revisions David Wright, Director Division of Remediation, BRWM MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION Protecting Maine’s Air, Land and Water

2. Presentation Outline

3. Setting Clean-up Goals atHazardous Substance Sites

4. Remember … RAGs are guidelines, notrules, & not “standards”

9. RAGs use a “Risk Based” Approach

10. RAGs use a “Risk Based” Approach • RME: Reasonable Maximum Exposure - highest exposure that is reasonably anticipated to occur at a site. • Chronic exposure • subchronic for construction worker • Risk Level: • NC: > Health Index (HI) of 1 by target organ, and • Carc: > Incremental Lifetime Cancer Risk (ILCR) of10-5 • 1 in 100,000 • Soil: Ceiling set at 10,000 PPM (1%)

12. Programs / Clean-up Approval Process

13. Applicable Media Soil Groundwater IndoorAir

14. Applies to Sites Contaminated With: • Hazardous Substances (including Waste Oil) • Mixture of Hazardous Substances & Petroleum

15. Applicable Site Types • Sites where these Routes of Exposure predominate • Ingestion • Soil • Groundwater • Skin Contact • Soil • Groundwater • Breathing • Outdoor Soil vapor & Dust • Indoor - Vapor Intrusion Image from Oregon State University Fact Sheet Diltamehrin, downloaded 6/14/2013 http://npic.orst.edu/factsheets/DeltaGen.html

16. Applicable Site Types& Sites where these Exposure Scenarios predominate

18. Not Applicable to Ecological Risk • when to conduct an ecological risk assessment • evidence of chem exposure to ecological receptors • visible physical evidence (sheens or neat product, etc.) • analytical data • PBTs in the top two (2) feet of soil • Receptors: surface water, sediment, wetlands, or biota • Consider runoff or other exposure pathways • Current or future potentialexposure

19. Definitions A. Background Contaminants 6 B. Background Locations 6 C. Contaminant 7 D. Contaminant of Potential Concern(COPC) 7 E. Environmental covenant7 F. Exposure Pathway 7 G. Exposure Point 7 H. Exposure Point Concentration (EPC) 7 I. Hazard Index (HI) 7 J. Hazard Quotient (HQ) 8 K.Hazardous Substance 8 L.Hazardous Substance Site 8 M.Incremental Lifetime Cancer Risk (ILCR) 9 N.Neat material 9 P.Project Lead 9 Q.Public Water 9 R.Urban Fill 9

20. Responsibilities

21. RAGs are part of the basic remediation process

22. Conceptual Site Model • Dynamic - Based on • all available site information • COPCs • Background Contaminants • Areas of Concern • Migration Pathways • Receptors (human / Eco) • Format • Concise Narrative • Figures /Tables • Understandable by Investigators and future owners Image from: Cox-Colvin & Associates Environmental Services, “EPA’s Revised Vapor Intrusion Guidance” downloaded 6/14/2013 from: http://www.coxcolvin.com/EPA_VI_Guidance.php

23. Emergency Removals First Imminent Threats Containers Neat Material

24. Site Investigations • RAGs - do not include investigation guidelines • Except for a few common issues…

25. Sampling • Representative of site conditions • DQOs • RAG tables • Call DEP if matrix interference, etc., preclude detecting down to RAG

26. Sampling Mercury Chromium Sample for hexavalent Chromium (+6) and trivalent chromium (+3), not total chromium. • Sample for Speciated mercury, not Total • Soil RAG for: • “Mercuric chloride and other inorganic mercury compounds”; • Indoor Air RAG for: • Elemental Mercury Image from Wikipedia, downloaded 6-18-2013: https://en.wikipedia.org/ wiki/Chromium

27. Vapor Intrusion • VI section modified to incorporate lessons from • EPA Study • DEP Triage Study • For persistent compounds • vapors travel along preferential pathways • risk unless overlain >10’ low perm soil; • gas investigations: step out from the source to building; • If completed pathway, sample subslab/ perimeter gas • If these samples >10X RAGs, sample Indoor air

28. Vapor Intrusion NEW! • For rapidly degrading compounds (petroleum): • Vapors need a continuing source & follow groundwater flow • Sample indoors only if gross contamination adjacent to building • Indoor Air Samples • analyze only for COCs • Compare results to RAGs table 2 • More: See VI guidance

29. Exposure Point Concentrations • EPC = chem conc in medium at EP • E.g. Soil Conc. in in a residential yard. • Grab samples: • 95th upper confidence limit of the mean • or max w/ small datasets • Multi-Incremental Sampling • compositing samples within a grid-based Decision Unit • if DU = EP, then compared results to RAG. • If multiple DUs, then compare RAG to the 95th UCL of the mean of DUs NEW!

30. Exposure Point Concentrations From: EPA, Supplemental Guidance to RAGS: Calculating the Concentration Term (OSWER, PB92-963373), May 1992

31. Using the RAGs

32. Target Risk Levels • Chronic exposure to RME • Risk Level: • NC: > Health Index (HI) of 1 by target organ, and • Carc: > Incremental Lifetime Cancer Risk (ILCR) of10-5 (=1 in 100,000)

33. Background • “Background Contaminants”- not from site releases. • Naturally occurring (e.g. lead) or man-made (e.g. DDT). • Site activity may release naturally occurring elements that are not considered background (e.g. buried waste liberates arsenic). • Background Concentrations Policy: • not required to clean up background, (but owner should warn users) • If background is higher than a RAG, clean-up to background level • If background is less than RAG, clean-up to RAG level • Options to determine background • Site Specific Samples • Revised Typical Background Values for soil: Metals and PAHs in table 1 • Literature Values • Other scientifically based methods NEW!

34. Background Study

35. Soil BackgroundEvolving Background Locations

36. Soil BackgroundEvolving Background Locations • 2010 • RAGs • 2011 Draft • RAGs • 2013 • RAGs • Rural Undeveloped • Metals • Rural Developed • PAHs • Rural • Metals • Rural • Metals, PAH • Urban Developed • PAHs • Urban • PAHs • Urban Fill • PAHs

37. Soil Background

38. Soil Background • Urban Vs Rural: DOT maps on Google Earth http://www.maine.gov/dep/gis/datamaps/statewide_layers/state_urban_compact_areas.kmz

39. Soil Background • Urban Fill Image from Structure Magazine, “How Ground Improvement Can Eliminate the Need for Costly Deep Foundation System, downloaded 6-18-2013 from: http://www.structuremag.org/ article.aspx?articleID=1577

40. Using the RAGs

41. Exposure Pathways & Scenarios • RAGs include pathways and scenarios with the greatest potential to cause health impacts at Maine Sites. • Soil Exposure Pathway (Table 1) w/ (5) exposure scenarios • Indoor Air Exposure Pathway (Table 2); w/ (2) exposure scenarios • GroundwaterExposure Pathway (Table 3); w/ (2) exposure scenarios. • Which ones are applicable at your site?

42. Exposure Pathways • Leaching to Groundwater • Residential • Park User • Commercial Worker • Excavation or Construction Worker

43. Exclusion of Pathways • Unrestricted site use preferred • Include future use • ICs must meet UECA standards • Variances => Risk Manual • Significant site exposure pathway or scenario missing from RAGs • Seeking Variances to exposure assumptions

44. Using the RAGs

45. Using The RAG tables – (mg/Kg)

46. Undertake Clean-up

47. Using the RAGs

48. Using the Risk Calculators UPDATED! • Excel Workbooks to calculate HI and ILCR from multiple contaminants • Soil • Water (2) • Air • Input EPC – the workbook does the rest http://www.maine.gov/dep/spills/publications/guidance/index.html#new_rag