Organochlorine bioaccumulation and risk for whales in a northwest Atlantic food web

The poor recovery of multiple whale populations raises concern for the integrity of the US marine environment. Fifty organochlorines were measured in samples of pilot whales, white-sided dolphins, endangered right whales and their prey. As expected from their high trophic position and proximity to land-based sources, the bioaccumulation of 4,4′-DDE, several chlordanes and polychlorinated biphenyl (PCB) congeners was substantial (ppm) in squid and the stranded odontocetes. Concentrations in fish and right whale biopsies were one to two orders of magnitude less than in odontocetes. Although the prevalent pesticides were different between odontocetes and balaenopterids, the magnitude of pesticide concentrations was similar across species. PCB concentrations were higher in the Gulf of Maine dolphins than pilot and right whales. Gender and tissue type were the important characteristics contributing to the bioaccumulation patterns observed in dolphins. Season of sample collection and exposure to different prey seemed critical for the bioaccumulation observed in right and pilot whales. Dolphin and pilot whale organs contained ample concentrations of specific compounds, notably 4,4′-DDE, that have been shown to alter endocrine function.