Biological effects of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in bald eagle (Haliaeetus leucocephalus) chicks
- Canadian Wildlife Service, Delta, British Columbia (Canada). Pacific Wildlife Research Centre
- Canadian Wildlife Service, Ottawa, Ontario (Canada). National Wildlife Research Centre
- Univ. of British Columbia, Vancouver, British Columbia (Canada)
- Univ. of Saskatchewan, Saskatoon, Saskatchewan (Canada). Western Coll. Veterinary Medicine
- Woods Hole Oceanographic Inst., MA (United States). Dept. of Biology
During the 1992 breeding season, eggs of bald eagles (Haliaeetus leucocephalus) were collected within a gradient of exposure to chlorinated hydrocarbon pollutants on the southern coast of British Columbia. Twenty-five eggs were placed in a laboratory incubator, of which 18 hatched; chicks were sacrificed within 24 h. Hatching success was not significantly different between eggs taken from pulp mill sites and reference sites. A hepatic cytochrome P4501A (CYP1A) cross-reactive protein was induced nearly sixfold in chicks from near a pulp mill at Powell River compared to those from a reference site. Hepatic ethoxyresorufin-O-deethylase (EROD) and benzyloxyresorufin O-dealkylase (BROD) activities were also significantly elevated in chicks from nests located near pulp mills compared to reference sites. A hepatic CYP2B cross-reactive protein was threefold higher in chicks from pulp mill versus reference sites, but the difference was not significant. Residual yolk sacs of eggs collected near pulp mill sites contained greater concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) compared to reference areas. No significant differences in concentrations of polychlorinated biphenyls (PCBs), non-ortho congeners, and organochlorine pesticides occurred among sites. Regressions showed that the hepatic CYP1A cross-reactive protein and EROD and BROD activities were positively correlated with 2,3,7,8-TCDD, 2,3,7,8-TCDF, and toxic equivalents (TEQs{sub WHO}--World Health Organization toxic equivalence factors) in yolk sacs. No significant concentration-related effects were found for morphological, physiological, or histological parameters, such as chick growth, edema, or density of thymic lymphocytes. Using hepatic CYP1A induction as a biomarker, a no-observed-effect-level of 100 ng/kg and a lowest-observed-effect-level of 210 ng/kg TEQs{sub WHO} on a whole egg (wet weight basis) are suggested for bald eagle chicks.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 264322
- Journal Information:
- Environmental Toxicology and Chemistry, Vol. 15, Issue 5; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Chlorinated hydrocarbon and mercury levels in bald eagles (Haliaeetus leucocephalus) found dead in British Columbia, 1988--1993
A critique of biomarkers in environmental toxicology: A case study in birds