ARA Projects

Featured Project: Trichloroethylene (TCE) Risk Assessment Guidance for Contaminated Sites

A coalition of interested parties is forming a workgroup to develop practical application guidance for the use of USEPA Reference Concentration (TCE RfC) and Inhalation Unit Risk (IUR) values for trichloroethylene for the purpose of site cleanup and closure. The goals of the coalition include:

1. Develop additional risk assessment guidance on how to interpret the non-cancer endpoint when it is used for deciding clean-up standards or acceptable exposure levels when closing sites.

2. Clarify the issues surrounding the potential developmental cardiac malformations for use in understanding clean-up standards and...

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Featured Project: Beyond Science and Decisions: From Problem Formulation to Dose-Response Assessment

This multi-party collaboration to continue the discussion was set forth by the National Academy of Science's Science and Decisions: Advancement of Risk Assessment (2009). Over 50 organizations have come together under the aegis of the Alliance for Risk Assessment (ARA), to conduct a series of meetings, with the ultimate goal of consensus among the participants on a methods compendium highlighting key considerations for applying dose-response techniques for common risk assessment applications. The Dose Response Framework is now available from the National Library of Medicine and is intended to serve as an evergreen database for assisting risk assessment decision-making.

Save the Date - Workshop V - November 2nd

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Workshop IV Meeting Report Now Available

Featured Project: PFOA-PFOS Interim Risk Assessment for Contaminated Sites

The perfluorochemicals (PFCs), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are contaminants of emerging environmental concern that do not have federal promulgated standards. These PFCs are under increased scrutiny by the regulatory community as they are environmentally persistent, bioaccumulative in living organisms, and are demonstratively toxic in various experimental animals at modest doses. Several Federal and State agencies and other regulatory bodies worldwide have developed advisory levels for PFOA and/or PFOS. However, these advisory levels are disparate, and NCSAB recently declined to finalize an assessment for PFOA due in part to a conflicting database...;

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Recent Projects
  • State Hazard Evaluation Lending Program (StateHELP)

    • StateHELP: The Oregon Health Authority has asked the ARA to help review an in vitro anylsis of arsenic bioavailability. Contact: Bryn Thoms.
    • StateHELP: Cincinnati- The City of Cincinnati Office of Environmental Quality asked the ARA to help evaluate the exposure scenario and health effects of Outdoor Wood-fired Boiler (OWB) emissions.  View Report  Materials submitted at Public Hearing

    • StateHELP: Tennessee - Tennessee Department of Health's Environmental Epidemiology Program asked the ARA for assistance evaluating the statistical methods used to model a Trichloroethylene plume in groundwater. Contact: David Borowski

    • StateHELP: TCE - The ARA has been asked by numerous states to develop and publish a paper cataloging the risk management values used by different state agencies to regulate Trichloroethylene. View manuscript.

  • Peer Review of Texas Commission on Environmental Quality (TCEQ) Guidelines to Develop Inhalation and Oral Cancer and Non-Cancer Toxicity Factors Final Report
  • Peer Review of the Texas Commission on Environmental Quality (TCEQ) Arsenic Chronic Cancer Assessment: Letter peer review to evaluate the chronic cancer portions of the ESL Development Support Document (DSD) for arsenic compounds

    As a follow-up to last year's review of the non-cancer and acute toxicity assessments for arsenic, a letter peer review was conducted to evaluate the chronic cancer portions of the ESL Development Support Document (DSD) for arsenic compounds developed by the TCEQ. The Toxicology Division of the Chief Engineer's Office has prepared a DSD that outlines the hazard assessment and dose-response processes used to derive chronic cancer Effects Screening Levels (ESLs) for arsenic compounds following inhalation exposure. The toxicity values were developed using RG-442 Guidelines to Develop Effects Screening Levels, Reference Values, and Unit Risk Factors (TCEQ 2006). The panel of experts was asked to review the assessment and the underlying toxicity data on arsenic compounds to reach conclusions regarding the chronic cancer ESL Derivation.  Final report is now available.

  • Peer Workshop on Toxicological Assessment and Development of RfDs for Acetanilide Degradates Under the auspices of the Alliance for Risk Assessment (ARA), TERA convened a 2-day independent expert peer workshop to develop Reference Doses (RfDs) for the degradates: alachlor t-ESA, alachlor t-OXA, acetochlor t-ESA, and acetochlor  t-OXA.  The meeting, supported by Monsanto and Dow AgroSciences, was held on Monday and Tuesday, May 11 and 12, 2009 at the Northern Kentucky University METS Center located near the Greater Cincinnati International Airport.  The public was invited to attend and to provide written and/or oral comments.  The meeting also was also available in real time to registered off-site observers via a web cast. To access the final TERA Meeting Report, please click here.

  • Peer Review of the Texas Commission on Environmental Quality (TCEQ) Development Support Document for Nickel: acute inhalation and chronic noncarcinogenic and carcinogenic inhalation toxicity; odor and vegetative effects

  • Peer Review of the Texas Commission on Environmental Quality (TCEQ) Development Support Document for Arsenic: acute inhalation and chronic noncarcinogenic inhalation toxicity; odor and vegetative effects

  • Mercury Exposure from Broken Compact Fluorescent Light Bulbs (New Zealand Ministry of Health)

  • Dose Response Boot Camp

Past Projects
  • Development of a Relative Source Contribution for RDX (U.S. Army)

  • State Hazard Evaluation Lending Program (StateHELP)

    • StateHELP: Minnesota - The Minnesota Pollution Control Agency asked the ARA to help develop a white paper describing various methods that could be used to estimate probabilities of adverse effects, i.e., risks, from pollutant concentrations that approach or exceed their RfDs or RfCs, or when hazard indexes approach or exceed a hazard index of one for multiple pollutants with the same target organ and exposure route. The paper assumes that there has been some refinement of exposure and toxicity information; for concentrations in air - the estimated emission rates are correct, refined dispersion modeling has been done, and the result incorporates fairly up-to-date toxicity information. The paper includes a description of how human benchmark dose information can be used, using examples such as methyl-mercury or other methods to demonstrate the risk estimation methodology. To view the developed tiered implementation system, please click here.

    • Arsenic in Soil (Hawaii Department of Health and Texas Commission on Environmental Quality)

    • Scientific Advisory Panel for the California Green Chemistry Initiative (California Department of Toxic Substance Control)

    • Ohio Wellhead Protection

    • North Carolina: Sandhills Area Land Trust (SALT)  

  • Peer Review of 1-3 Butadiene Development Support Document (Texas Commission on Environmental Quality)  

  • Noncancer risk assessment workshop for the Mid-South Society of Environmental Toxicology and Chemistry (SETAC) annual meeting, Nashville, Tennessee, May 2007.  

  • Dosimetric Adjustment in Risk Assessment, and Benchmark Dose Modeling in Risk Assessment workshop.  Presented at the EPA Region 4 Air Toxics Summit, Atlanta, Georgia, March 2007

  • Benchmark Dose Modeling in Risk Assessment Workshop. Presented to Northland Society of Toxicology, Minneapolis, Minnesota, October 2006

  • Cincinnati, Ohio Site Risk Assessment Review provided independent review of comments submitted by a local environmental group regarding potential health risks due to emissions from an industrial facility.  For more details contact Dr. Andrew Maier

  • State of Indiana TCE Risk Values provided support for the analysis of potential cancer risk values for trichloroethylene based on data from cancer bioassays in mice.  The analysis included improved dosimetry using the most recent harmonized PBPK model, and developments of altenative approaches for combining data across bioassay data sets. 

  • Perchlorate Risk Assessment TERA developed an independent risk assessment value for perchlorate using information from human exposure studies. For more information see or contact Ms. Joan Strawson

  • Memphis, Tennessee Site Risk Assessment Review provided an independent review of a site risk assessment conducted by an industry group.  The review was conducted at the request of the City of Memphis.  For more details contact Dr. Bernard Gadagbui

  • State of Minnesota provided input to state on alternative risk assessment  methods for deriving risk values for pesticide degradates that are lacking adequate toxicity data. For more details contact Dr. Bernard Gadagbui