Impact of New USEPA Policies on Risk-Based Remedial Decisions

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Impact of New USEPA Policies on Risk-Based Remedial Decisions

Authors:
Brian Magee, Ph.D. and Norman Forsberg, Ph.D. (Arcadis US, Inc.)

 

Luncheon Speaker:

Brian Magee, Ph.D.

Arcadis US, Inc.

Speaker Bio:

Dr. Magee is Senior Vice President and Principal Toxicologist at Arcadis. He has over 35 years’ experience in the field of toxicology and risk assessment. Dr. Magee is a nationally recognized expert in the toxicology of PAHs and PAH-containing mixtures and in bioavailability as a critical parameter in realistically assessing risk at waste sites. Dr. Magee has performed risk assessments of former manufactured gas plants, petroleum refineries, coke ovens, tar plants, wood treatment plants, chemical plants, landfills, petroleum spill sites, mine sites, and others. In addition, Dr. Magee has also performed risk assessments of combustion facilities, including municipal solid waste combustors, hazardous waste combustors, petroleum-, bitumen-, petroleum coke-, and coal-fired power plants, cement kilns, and industrial boilers. Additionally, Dr. Magee has provided expert testimony regarding the risks posed by exposure to chlorinated solvents, chlordane, lead, complexed cyanides, formaldehyde, PAH-containing mixtures, including coal tar, coal tar pitch, creosote, diesel fuel, and fuel oils, and other chemicals.

Abstract:

USEPA released four new toxicity values for benzo(a)pyrene (BaP) in January 2017. The new values, which are based on both cancer and non-cancer effects, are now being used to calculate the June 2017 Regional Screening Levels (RSLs). These values will affect all risk-based criteria and standards for BaP and other Polycyclic Aromatic Hydrocabons (PAHs) that are included in the calculation of benzo(a)pyrene-toxic equivalents (BaP-TE). PAHs are major components of coal tar waste found at former Manufactured Gas Plant (MGP) sites, so the regulatory status of PAHs greatly affects MGP site cleanups. USEPA has concluded that BaP is 7.3-times less potent as an oral carcinogen than previously thought. This change will increase all risk-based criteria for soil and water by 7.3-fold.

USEPA had initially proposed an onerous dermal slope factor, but the final value has been delayed pending further work, as has USEPA’s final relative potency factor approach for PAH mixtures that proposed a longer list of PAHs of concern.

This talk will address the implications of the new toxicity values and the role site-specific bioavailability adjustments can play in increasing site cleanup targets. All MGP sites should be reviewed immediately to determine if planned actions are still necessary and to determine if cleanup goals can be modified. Assuming a typical target risk level of 1×10-5, industrial/commercial soils with BaP-TE exceeding about 3 mg/kg would have required remedial action. Now such soils with BaP-TE as high as 21 mg/kg may not require any action. In cases where site BaP-TE is slightly higher, site-specific bioavailability testing can increase the clean-up criterion by an additional 7-fold or higher.

With the uncertainties concerning USEPA’s program priorities, many remedial decisions of PAH sites will fall to the states. As examples, Massachusetts, Michigan, Florida, Texas, and Virginia are using the new toxicity factors but not the pending USEPA longer list of PAHs of concern. They are using the standard list of seven potentially carcinogenic PAHs to calculate BaP-TE concentrations. To more fully understand the states’ approaches, the results of a survey will be presented.

Risk updates will also be presented on other issues of importance to the MGP community, including a status update on USEPA’s reassessment of the carcinogenicity of naphthalene vapors, updates on benzene, toluene, ethylbenzene, and xylenes toxicity and risk assessment, and new approaches to vapor intrusion assessment.

 

To view the full Agenda for MGP 2017 view this link:

http://mgpsymposium.com/agenda/

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