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TOXIC EQUIVALENCY FACTORS (TEFS) FOR PCBS, PCDDS, PCDFS FOR HUMANS AND WILDLIFE
Citation:
Van den Berg, M., L S. Birnbaum, A. Bosveld, B. Brunstrom, P. M. Cook, M. Feeley, J Giesy, A. Hanberg, R. Hasegawa, S. W. Kennedy, T. Kubiak, J. C. Larsen, F. X. Rolaf van Leeuwen, AND A. Lien. TOXIC EQUIVALENCY FACTORS (TEFS) FOR PCBS, PCDDS, PCDFS FOR HUMANS AND WILDLIFE. ENVIRONMENTAL HEALTH PERSPECTIVES 106:775-792, (1998).
Description:
An expert meeting was organized by the World Health Organization (WHO) and held ih Stockholm on 15-18 June 1997. The objective of this meeting was to derive cohsensus toxic equivalency factors (TEFs) for polychlorinated didbenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxinlike poluchlorinated biphenyls (PCBs) for both humans, fish, and wildlife risk assessment. Based on existing literature data, TEFs were (re)evaluated and either revised (mammals) or established (fish and birds). A few mammalian WHO-TEFs were revised, including 1,2,3,7,8-pentachlorinated DD, octachlorinated DD, octachlorinated DF, and PCB 77. These amammalian TEFs are also considered applicable for humans and wild mammalian species. Furthermore, it was concluded that there was insufficient in vivo evidence to continue the use of TEFs for some di-ortho PCBs, as suggested earlier by Ahlborg et al. [Chemosphere 28:1049-1067 (1994)]. In addition, TEFs for fish and birds were determined. The WHO working group attempted to harmonize ETFs across different taxa for some compounds. In this respect, the absent or very low response of fish to mono-ortho PCBs is most noticeable compared to mammels and birds. Uncertainties that could compromise the TEF concept were also reviewed, including nonadditive interactions, differences in shape of the dose-response curve, and species responsiveness. In spite of these uncertainties, it was concluded that the TEF concept is still the most plausible and feasible approach for risk assessmehnt of halogenated aromatichydrocarbons with dioxinlike properties