Updates to HSRA RiskReduction Standards

Chris Saranko, Ph.D, DABT

Atlanta, GA

Georgia AWMA Regulatory Update Conference

May 11, 2017

Presentation Outline

• 2017 Hazardous Site Response Rulemaking

– Phased approach – Initial phase focused on updates to391-3-19-.07 (Risk Reduction Standards)

– Overview of EPD recommendations

– Implications

– Proposed timeline

• Chemical-specific issues

– Benzo(a)pyrene / PAHs

– Lead

Process Chart for the development of RRS (Rule 391-3-19-.07)

Initial EPD Proposed Update Concepts (#1)

• 391-3-19-.07 (4) – Essential Features of Corrective Action– Modify vapor intrusion language

– Add clarification on when ecological risk assessment may be required at a site

– Note that features apply for all Acts that refer to risk reduction standards (RRS)

• 391-3-19-.07 (6)-(10) – Criteria for Type 1 through 5 Standards– Add language regarding the toxicity and chemical-specific parameter hierarchy (i.e., OSWER

Directive 9285.7-53 and EPA’s RSL Chemical-specific Parameters Summary table)

– Update the volatilization factor (Equation 8) and particulate emission factor equations

– Update RAGS Equations 1,2, 7 and 8 consistent with EPA RSL risk equations (dermal exposurepathway, relative bioavailability, exposure time intervals)

– Remove language pertaining to Class C carcinogens assessed at 1×10-4 target cancer risk.

– Allow use of chemical surrogates approved by EPD

– Allow site-specific soil bioavailability to be used in site-specific RRS calculations for arsenic

– If MCL established residential standard defaults to that value

– For site-specific soil RRS, allow site-wide averaging

– Redefine surface soil depth interval as 0-1 foot

– Clarify that Type 4 soil criteria should include consideration of subsurface workers

– For non-residential add flexibility for unique site-specific conditions such as rails-to-trails

– Omit Appendix III, Table 2 (metals) as part of the default RRS determinations

– For Type 1 leaching, replace the App. III, Table 1 × 100 value with a default SSL.Add SPLP option.

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Initial EPD Proposed Update Concepts (#2)

• Appendix III Table 1 - Update Groundwater Criteria Values, but retain as basis for Type 1and 3

– Incorporate mutagenic age adjustment factors (for mutagenic carcinogens)

– Update the inhalation exposure pathway consistent with EPA’s RAGS Part F

– Update exposure factors used in criteria calculations consistent with OSWER Directive 9200.1-120 (EPA 2014)

– Remove all a-flags and the associated footnote (detection limits)

– Indicate instances where criterion is based on a chemical surrogate

– Add additional common constituents of concern

• Appendix III Table 3 - Update Parameters, Definitions and Standard Assumptions– Update all exposure factors consistent with OSWER Directive 9200.1-120 (EPA 2014)

– Add mutagenic age-dependent adjustment factors (for mutagenic carcinogens)

– Add dermal-related exposure factors for soil and groundwater

– Remove 10-4 target risk for Class C carcinogens

– Update PEF and VF equations listed consistent with EPA RSL calculations

– Include equation and default parameters for construction workers exposed to volatiles emanating fromgroundwater into a trench (VDEQ model)

• Miscellaneous– Update Appendix IV to cite EPA’s Adult Lead Model (instead of GA Lead Model)

– Correct Property Notice language [391-3-19-.08(1)(a)]

– Add potential for Director to designate an EPA Removal Action as meeting Type 5 [391-3-19-.06(7)]

– Minor corrections

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Updates to RAGS Equations (#1)

• Current equations for direct contact exposure come fromEPA’s RAGS Part B (1991)

– Dermal pathway not considered

– Inhalation pathway calculations follow guidance that has beenupdated

– Example Equations:

Groundwater – carcinogens (Eq. 1)

Soil – non-carcinogens (Eq. 8)

Updates to RAGS Equations (#2)

• Updated equations will mirror those used by EPA tocalculate the Regional Screening Levels (RSLs)

– Dermal pathway included

– Inhalation pathway follows RAGS Part F (EPA, 2009)

– Will EPD continue to calculate separate child and adult Type 2RRS values for carcinogens, or use a time-weighted “aggregate”scenario according to EPA?

Updates to RAGS Equations (#3)

• RSL Residential GW Equation (carcinogens)

Inhalation

Ingestion Dermal

Mutagenic Adjustment Factors

• EPA uses age-dependent adjustment factors (ADAFs) toadjust the intake/exposure for carcinogens identified asacting via a mutagenic mode of action

• Current EPA mutagen list includes 16 chemicals,including: trichloroethylene, vinyl chloride, andbenzo(a)pyrene

• ADAFs applied as multipliers to intake/exposure– Children 0 < 2 years 10x

– Children 2 to < 16 years 3x

– Adults 16 and older 1x

• Result is an approximate 2.5-fold decrease in thecalculated RRS values

Mutagenic Adjustment Factors (#2)

• RSL Residential GW Equation (mutagenic carcinogens)

Inhalation

Ingestion

Mutagenic Adjustment Factors (#3)

• RSL Residential GW Equation (mutagenic carcinogens)

Dermal

Exposure Factor Updates

• Appendix III, Table 1

• EPD recommends updating default exposurefactors to mirror current EPA recommendations(OSWER 9200.1-120, 2014)

– Adult body weight increases from 70 to 80 kg (↑ RRS)

– Residential exposure duration decreases from 30 to 26 years(↑ RRS)

– Changes to soil and water ingestion rates will depend onhow EPD incorporates age-averaging (generally ↓ RRS)

Potential Effects of Changes (#1)

• Table below shows comparison of current HSRA Type 2 residentialdirect contact values compared to EPA default residential RSLs.

Chemical Type 2 EPA RSL

Chloroform 3.9 3.2

Methylene Chloride 209 350

Naphthalene 55 38

Tetrachloroethylene 30 81

Arsenic* 6.1 6.8

Cadmium 78 10

Chemical Type 2 EPA RSL MCL

Chloroform 2.6 2.2 --

Methylene Chloride 74 110 5

Naphthalene 1.8 1.7 --

Tetrachloroethylene 19 41 5

Arsenic 0.6 0.5 10

Cadmium 16 9.2 5

Water (μg/L)

Soil (mg/kg)

Potential Effects of Changes (#2)

• Table below shows comparison of current HSRA Type 4 industrialdirect contact values compared to EPA default industrial RSLs.

Soil (mg/kg)

Chemical Type 4 EPA RSL

Chloroform 4.9 14

Methylene Chloride 1600 3200

Naphthalene 77 170

Tetrachloroethylene 150 390

Arsenic* 38 30

Cadmium 2000 980

Rulemaking Timeline

• June 2017 – Public Workshop

• August 5, 2017 – Draft to Board of Natural Resources

• December 2017 – Rule adoption

Chemical-Specific Issues (#1)

• Benzo(a)pyrene

– EPA’s IRIS Program released final updated toxicity values in Jan 2017

– Impacts to RSLs

Chemical-Specific Issues (#2)

• Lead

– EPA currently evaluating updates to IEUBK Model

– Driven by CDC’s elimination of the childhood blood lead “level of concern” of 10μg/dL in 2012 in favor of a “reference level” – currently 10 μg/dL

Questions / Discussion

Chris Saranko, PhD, DABT

Geosyntec Consultants

(678) 202-9258

csaranko@geosyntec.com