The use of the TEQ approach in wild bird species
- Univ. of Utrecht (Netherlands). Research Inst. of Toxicology
- Univ. of Umea (Sweden)
- Canadian Wildlife Service, Hull, Quebec (Canada). National Wildlife Research Center
Several studies in recent years have focused on the sensitivity of different species of wild birds to dioxin-like compounds, including some PCBs. Methods included the use of egg injection and primary hepatocyte cultures. Parameters measured were induction of CYP1A1, porphyrin accumulation and embryo toxicity. Based on results from these studies, either relative toxic or biochemical equivalency factors (TEFs) or relative species sensitivities have been reported. The question rises whether these data are sufficient to include them in the risk assessment for wild bird species. The most common biomarker used in the TEQ approach for birds is clearly CYP1A1 induction in both in vivo and in vitro studies. Field studies showed correlations between e.g. PCDD and PCB levels with CYP1A1 induction and effects on reproduction. When comparing bird and rodent studies it can be discussed, if the relationship between CYP1A1 induction and toxic effects in birds has been studied sufficiently to justify use of CYP1A1 as marker for dioxin-like toxicity in birds. In contrast with some rodent species the correlation between in vivo and in vitro CYP1A1 induction and in vivo toxic effects has not been studied in detail in birds. Porphyrin accumulation as endpoint in bird studies comprises another problem in the CYP1A1 based TEQ calculation. In avian primary hepatocyte cultures there are structure-activity differences in CYP1A induction and porphyrin accumulation. It will be discussed whether porphyrogenic potency should be included in the determination of avian TEF values.
- OSTI ID:
- 203623
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9614%%135
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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