[show abstract][hide abstract] ABSTRACT: Cormorants (Phalacrocorax carbo sinensis) breeding in the heavily contaminated sedimentation area of the rivers Rhine and Meuse have a severely reduced breeding success as compared to several other Dutch colonies. A detailed analysis of reproductive performance in combination with chemical analysis of eggs and food from colonies in differently contaminated aquatic habitats is presented. The differences in breeding success between colonies are caused mainly in the egg-stage of breeding. Eggshell thinning and increased embryonic mortality cause the differences in hatching success. The observed effects seem to be related to chlorinated hydrocarbons. Significant correlations are found for concentrations of DDE with eggshell thinning and for concentrations of PCBs with hatching and breeding success. The correlations between concentrations of chlorinated hydrocarbons in eggs and biological effects measured in the field are established both on colony and individual clutch level.
[show abstract][hide abstract] ABSTRACT: The hepatic microsomal ethoxyresorufin O-deethylase (EROD)-inducing potency in ovo of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was determined in the domestic chicken (Gallus gallus), domestic pigeon (Columba livia), great blue heron, and double-crested cormorant. Dose-response curves were produced by injecting various doses of [3H]TCDD into the air sac of developing eggs during the latter third part of incubation. Hepatic EROD activities were measured in day-old hatchlings. Liver, yolk, and whole blood were analyzed for [3H]TCDD; no distributional differences among species were found. The ED50 for EROD induction was between one and two orders of magnitude lower in the chick (0.1 microgram/kg egg) than in the heron and cormorant (3-10 micrograms/kg egg). Consistent with this, the apparent affinity of TCDD for the hepatic cytosolic Ah receptor was about 15 times higher in the domestic chick (Kd = 0.75-1.6) than in the other avian species (pigeon, Kd = 11-14; heron, Kd = 10-20; cormorant, Kd = 12-16). Receptor binding affinities in the pigeon, heron, and cormorant were of the same order of magnitude as that reported for human placenta (D.K. Manchester, S.K. Gordon, C.L. Golas, E.A. Roberts, and A.B. Okey, 1987, Cancer Res. 47, 4861-4868). Subcutaneous edema was observed in TCDD-treated hatchlings of the chick, heron, and cormorant, but not of the pigeon, within the dose range examined. The laboratory dose-response relationships demonstrated that the heron and cormorant hatchlings that were exposed to TCDD and related chemicals in the Strait of Georgia (J.T. Sanderson, R.J. Norstrom, J.E. Elliott, L.E. Hart, K.M. Cheng, and G.D. Bellward (1994b) J. Toxicol. Environ. Health 41, 245-263; and J.T. Sanderson, J.E. Elliott, R.J. Norstrom, P.E. Whitehead, L.E. Hart, K.M. Cheng, and G.D. Bellward (1994a) J. Toxicol. Environ. Health 41, 435-450) had hepatic EROD activities at the lower end of the linear part of their respective dose-response curves. A further increase in levels of TCDD and related compounds in the environment would lead to a large increase in EROD activity and further increases in TCDD-induced toxicities, such as body weight loss and subcutaneous edema.
Toxicology and Applied Pharmacology 06/1995; 132(1):131-45. · 3.98 Impact Factor
[show abstract][hide abstract] ABSTRACT: Double-crested cormorant (Phalacrocorax auritus) eggs at pipping and sibling 10-day-old chicks were collected from two colonies in Green Bay, WI, one colony in Lake Michigan, WI, and reference colonies in South Dakota and Minnesota. Egg contents and chicks were analyzed for organochlorine contaminants including polychlorinated biphenyl (PCB) congeners. Livers of embryos and chicks were assayed for hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity. Eggshell thickness and the physical dimensions of embryo brains were measured. Concentrations of organochlorines, including p,p'-DDE (p,p'-dichlorodiphenyldichloroethylene), PCBs, and PCB congeners were generally an order of magnitude higher in eggs and chicks from Wisconsin than from reference locations. Total PCBs averaged 10-13 microg/g wet weight in eggs from three Wisconsin colonies compared to 0.9 microg/g PCBs from reference locations. Double-crested cormorant chicks accumulated on average 33-66 microg PCBs/day and 7-12 microg p,p'-DDE/day in the Wisconsin colonies compared to 0 microg PCBs/day and 1 microg p,p'-DDE/day in the reference colonies. At pipping, EROD activity in the livers of cormorant embryos was significantly higher in the Wisconsin colonies and significantly correlated with PCBs and the toxic equivalents (TEQs) of aryl hydrocarbon-active PCB congeners relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin. However, in 10-day-old chicks EROD activity was not consistently different among colonies and was not correlated with PCBs or TEQs. A significant negative relationship between embryo brain asymmetry and the size of the egg suggested that physical constraint might be an important factor influencing the response of this bioindicator. Thinner eggshells in two colonies located near Door County, Wisconsin, suggested that historic p,p'-DDE residues associated with orchards are still an important source of p,p'-DDE in the local environment.
Archives of Environmental Contamination and Toxicology 02/2001; 40(1):89-100. · 2.01 Impact Factor
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