Accumulation and mobilization of organochlorine contaminants in wintering greater scaup

Analyses for chlorinated pesticides (α-BHC, Aldrin, DDD, DDE, DDT, Dieldrin, Endrin, and Hexachlorobenzene) and polychlorinated biphenyls (PCBs) of abdominal fat pad (AFP) and breast muscle tissue were performed on 112 adult male greater scaup (Aythya marila) wintering in Long Island Sound. The AFP weight decreased significantly later in the wintering period. Based on tissue wet-weights there was an increase in residues (ppm wet-wt) of all contaminants in breast muscle over time, but no significant change in the concentrations within the AFP. However, when the residues were normalized for tissue percent lipid, contaminant concentrations increased over time for both tissues. The decrease in the weight and percent lipid of the AFP corresponded to increasing concentrations of the contaminants in the fat pad as well as the breast muscle tissue. Normalizing for the percent lipid may reflect changes in concentrations of lipophilic compounds that may not be evident based upon wet-weight analysis. The role of organochlorine contaminants in waterfowl food webs, reproduction, and human consumption may be underestimated when reported by traditional methods. Therefore, the use of lipid-weight reporting procedures may be more appropriate for analyzing temporal trends in lipophilic contaminant accumulation.