Organochlorine contaminants and biomarker response in double-crested cormorants nesting in Green Bay and Lake Michigan, Wisconsin, USA

Archives of Environmental Contamination and Toxicology
By: , and 



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 μg/g wet weight in eggs from three Wisconsin colonies compared to 0.9 μg/g PCBs from reference locations. Double-crested cormorant chicks accumulated on average 33–66 μg PCBs/day and 7–12 μg p,p′-DDE/day in the Wisconsin colonies compared to 0 μg PCBs/day and 1 μg 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.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Organochlorine contaminants and biomarker response in double-crested cormorants nesting in Green Bay and Lake Michigan, Wisconsin, USA
Series title Archives of Environmental Contamination and Toxicology
DOI 10.1007/s002440010151
Volume 40
Issue 1
Year Published 2001
Language English
Publisher Springer
Contributing office(s) Patuxent Wildlife Research Center, Upper Midwest Environmental Sciences Center
Description 12 p.
First page 89
Last page 100
Country United States
State Minnesota, South Dakota, Wisconsin
County Big Stone County, Brown County, Door County, Marshall County
Other Geospatial Cat Island, Hat Island, Spider Island, Lake Michigan, Piyas Lake, Marsh lake
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