BIOLOGICAL EFFECTS OF POLYCHLORINATED DIBENZO-p-DIOXINS, DIBENZOFURANS, AND BIPHENYLS IN BALD EAGLE (HALIAEETUS LEUCOCEPHALUS) CHICKS

Abstract

During the 1992 breeding season, eggs of bald eagles (Haliaeetus leucocephalus) were collected within a gradient of exposure to chlorinated hydrocarbon pollutants, particularly from pulp mill point sources, on the southern coast of British Columbia, Canada. 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 (p Ͻ 0.05). 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 (p Ͻ 0.0005 and p Ͻ 0.02, respectively). 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 2,3,7,8substituted 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 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-observedeffect-level (NOEL) of 100 ng/kg and a lowest-observed-effect-level (LOEL) of 210 ng/kg TEQs WHO on a whole egg (wet weight basis) are suggested for bald eagle chicks. Keywords-Bald eagleEmbryotoxicity TCDD Non-ortho PCBs P450Chlorinated hydrocarbon effects on bald eagles Environ. Toxicol. Chem. 15, 1996 783 Environ. Toxicol. Chem. 15, 1996 J.E. Elliott et al. Environ. Toxicol. Chem. 15, 1996 J.E. Elliott et al.Council of Canada. This project was part of a Ph.D. project on toxicology of chlorinated hydrocarbons in British Columbia bald eagles.

Impact of 2,3,7,8-TCDD Exposure on Survival, Growth, and Behavior of Ospreys Breeding in Wisconsin, Usa

“…Levels of TCDD in osprey eggs collected at the CR/P during this study (geometric mean, 78 pg/g) were higher than levels reported in other avian studies (range, 15-37 pg/g [9,10,14,45,46]) with one exception (211 pg/g in great blue heron eggs [8]). Conversely, eggs from these other avian studies contained levels of coplanar PCBs that were higher than those from the CR/P (range, 31-63 pg/g TCDD-Eq).…”

Polychlorinated -dibenzo-p-dioxins/furans and -dioxin-like biphenyls in eggs of common terns from lime island, St. Mary's river, Michigan, USA

“…This trend is similar to the observations in common terns from many parts of the world. The observed TEQ values were greater than the Lowest-Observed-Effective-Level (LOEL) for eggs of chickens and wood ducks, and within the ranges of NOEL and LOEL observed for common tern embryos in an egg injection study, and bald eagle embryos in a field study [3,30,44] as shown in Fig. 2.…”

“…Several studies documented the association between various biological responses and effects with exposure to persistent organic contaminants (POCs) such as dioxin-like polychlorinated biphenyls (dioxin-like PCBs), 2,3,7,8-chlorine substituted polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) in fish-eating water birds [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Many species of terns (Sterna spp.)…”

“…Dioxin-like PCBs were within the range of 360-1230 ng/g wet wt. Great Toxic Equivalent Quantity (TEQ) contributions by 2, 3,7,2,3,4,7,2,3,7,1,2,3,7,, and dioxin-like PCBs such as CB-77, CB-126 and CB-105 are considered greatly due to their influence of poor embryo development and consequent damage of embryos of common terns in egg injection studies. However, other organochlorines, heavy metals, and/or synergistic effects also taken in to account.…”

Contamination and Biomarkers in the Great Blue Heron, an Indicator of the State of the St. Lawrence River

“…Murvoll et al (1999) found a borderline significant positive correlation between PCBs in lipid weight and plasma retinol in shag (Phalacrocorax aristotelis) hatchlings, at PCB levels lower than levels in the great blue heron from the St. Lawrence. Murk et al (1994) found increased plasma retinol levels with increasing PCB burden in common tern (Sterna hirundo) hatchlings, while Elliott et al (1996) found no difference in 1-day-old bald eagle chick's plasma retinol among colonies with various levels of dioxin and furan contamination. However, all these results are from very young birds in which absorption of the vitellus at hatching may influence circulating retinol levels.…”