Review of the Environmental Protection Agency's Draft IRIS Assessment of Tetrachloroethylene http://www.nap.edu/catalog/12863.html
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Introduction
4. Is EPA’s conclusion that there is not a strong basis for preferring any one PBPK model for use in the risk assessment soundly and transparently characterized? COMMITTEE’S APPROACH The committee reviewed the material presented in EPA’s draft IRIS assessment for scientific soundness, balance, and transparency. By the nature of the charge, the focus was on parts of the document that were critical for determining neurotoxicity and cancer end points. The review included evaluation of some of the primary literature cited by EPA, its approaches to evaluating and modeling data, and options for performing qualitative and quantitative assessment of uncertainties. Public comments submitted to EPA and to the committee on the draft assessment were considered. The committee also held public meetings at which it had the opportunity to ask questions of EPA staff, to obtain input from invited speakers who were doing research on tetrachloroethylene or related scientific issues, and to hear from other interested parties. To identify new studies that should be considered in EPA’s IRIS assessment, the committee performed a literature search for papers published from July 2004 (the official cutoff for EPA’s comprehensive literature search) to March 2009. For the purposes of its review, the committee restricted its searches to MEDLINE and EMBASE. MEDLINE is produced by the U.S. National Library of Medicine and covers over 5,200 biomedical journals published in the United States and over 80 foreign countries. EMBASE is produced by Elsevier Science and indexes over 4,800 journals with a focus on the international literature. A simple search for “tetrachloroethylene,” its synonyms, and its Chemical Abstracts Service registry number was performed. Literature retrieval was limited to studies pertinent to the evaluation of adverse health effects, such as toxicology studies (including studies on toxicokinetics and mode of action) and epidemiology studies. Other sources of information that the committee considered included compilations of toxicology and human health information from national and international agencies and organizations, such as the Agency for Toxic Substances and Disease Registry, the International Agency for Research on Cancer, the California Environmental Protection Agency, and the European Union. Relevant publications from the National Research Council and the Institute of Medicine were also consulted. The committee and staff examined the reference lists included in EPA’s draft assessment, major epidemiologic studies, review articles, and major compilations for relevant citations. Smaller targeted literature searches were performed to identify pertinent older literature and papers on specific topics and to gather general background information.
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