Custer, T. W., Custer, C. M., and Stromborg, K. L., 1997, Distribution of
organochlorine contaminants in double-crested cormorant eggs and sibling
embryos: Environmental Toxicology and Chemistry, v. 16, no. 8, p. 1646-1649.

Abstract

Double-crested cormorant (Phalacrocorax auritus) fresh eggs and sibling
embryos at pipping were collected from a polychlorinated biphenyl (PCB)-
contaminated colony in Green Bay, Wisconsin, USA. Egg contents were
analyzed for organochlorine (OC) contaminants, including 15 arylhydrocarbon-
active PCB congeners. In order to determine the significance of tissue removal
on the subsequent estimate of contaminant burden, embryos were decapitated
and the heads, yolk sac, liver, fecal sac (allantois), and carcass remainder were
analyzed separately. The distribution of contaminant concentration in the
embryos was yolk sac > liver > carcass > head > fecal sac. The distribution of
contaminant mass in the embryos was yolk sac > carcass > liver > head > fecal
sac. For example, mass of total PCBs (TPCB) was yolk sac = 58%, carcass =
31%, liver = 5%, head = 3%, and fecal sac = 1%. Eighteen additional OCs,
including 13 PCB congeners, had distribution patterns similar to that of TPCB
concentration and mass. Excluding the head of the embryo from the chemical
analysis overestimated TPCB concentrations by 15% (16 vs 14 mu g/g). In
contrast, excluding the liver from the chemical analysis underestimated TPCB
concentration by only 4% (13.5 vs 14 mu g/g). Mean concentrations of OCs
were not significantly different between fresh eggs and sibling embryos.

Keywords

 organochlorines, double-crested cormorant, PCB congeners, contaminants,
sample egg method, crowned night-herons, metabolism, exposure, residues