ARA Projects
 

Featured Project: The Conundrum of the PFOA Human Half-life

A coalition of interested parties is being formed to explore and possibly resolve the conundrum in human 1/2 life for perfluorooctanote (PFOA), which is reflected in differences in safe doses world-wide of 750-fold (Mikkonen et al., 2020). A recent paper has been submitted that addresses this conundrum in part (Dourson and Gadagbui, 2021). This collaboration started in April of 2021 with nominations to an advisory committee* who will then lead the coalition through a series of virtual and possibly face-to-face meetings, with conclusions expected later this year. Toxicology Excellence for Risk Assessment (www.tera.org) has been designated as the nonprofit organization to support this coalition by the ARA Steering Committee. Because TERA is a 501c3 nonprofit organization, all donations to this effort are tax deductible.

For interest in joining the coalition, please contact Michael Dourson.

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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.

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Featured Project: 1,4-Dioxane Analysis

EPA's IRIS 1,4-dioxane external peer review in 2012 suggested reviewing the histopathology slides from the NCI 1978 dioxane cancer bioassay in mice to ascertain whether non cancer pathology was evident, since, if evident, this would support the evaluation of a regenerative hyperplasia MOA by EPA staff. TERA scientists worked with Dr. Gene McConnell and staff of the NTP to reevaluate these mouse liver slides, and the results were sent to EPA staff in 2013 and published as Dourson et al., 2014. In brief, the reread of the slides showed extensive non cancer pathology, thus supporting the regenerative hyperplasia MOA. However, this evaluation also led to the desire to evaluate the mouse liver slides from a series of Japanese studies on 1,4-dioxane. In the summer of 2014, five US states and TERA scientists requested these full studies from our Japanese colleagues. These studies were received in the fall of 2014, and were then translated and analyzed during the winter of 2015. A report of this translation and a draft analysis was prepared and sent around to requesting states in July of 2015. As described in a second publication by Dourson et al. 2017, the additional information and translations are also supportive of a regenerative hyperplasia MOA.


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Recent Projects
 

  • Workshop: Lessons Learned, Challenges, and Opportunities with the US Endocrine Disruptor Screening Program.
    The Endocrine Disruptor Screening Program (EDSP) was implemented by the US Environmental Protection Agency (EPA) by issuing the first round of test orders in 2009 for information on 67 chemicals (59 pesticide active ingredients and 8 pesticide inert ingredients). The request includes information from a battery of screening assays, referred to as Tier 1, includes five in vitro assays, four mammalian assays, and two non-mammalian assays. Tier 1 screening of this initial list...
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  • KIDS + CHEMICAL SAFETY KIDS + CHEMICAL SAFETY,
    is a go-to source for balanced, scientifically accurate chemical health information. The website focuses on the latest chemical-related health concerns, news, and science developments related to children's chemical risks. The site is a collaboration of multiple organizations: Visit KIDS +CHEMICAL SAFETY.

  • 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:....Learn More

  • Peer Review of Section 4.2, Carcinogenic Potential, of the Development Support Document for Isoprene, Draft April 2013
    The Toxicology Division of the Texas Commission on Environmental Quality (TCEQ) has prepared a draft Development Support Document (DSD) that outlines the hazard assessment and dose-response processes used to derive health-protective Effects Screening Levels (ESLs) and Unit Risk Factors (URFs) for isoprene...Learn More

  • Peer Review of Section 4.2, Carcinogenic Potential, of the Development Support Document for Hexavalent Chromium, Draft March 2013
    The Toxicology Division of the Texas Commission on Environmental Quality (TCEQ) has prepared a draft Development Support Document (DSD) that outlines the hazard assessment and dose-response processes used to derive health-protective Effects Screening Levels (ESLs) and Unit Risk Factors (URFs) for hexavalent chromium......Learn More

  • 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 

    • 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

  • Workshop: Lessons Learned, Challenges, and Opportunities with the US Endocrine Disruptor Screening Program

  • 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. Michael Dourson.

  • 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 Perchlorate or contact Dr. Michael Dourson

  • 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