Polychlorinated biphenyls (PCBs) from the commercial mixture Aroclor 1268 were released into the Turtle-Brunswick River Estuary (TBRE, southeastern Georgia, USA). Sum PCB concentrations in blubber samples from TBRE bottlenose dolphins (Tursiops truncatus) have been reported more than 10-fold those observed in adjacent regional estuaries and adverse effects have been suspected. Availability of toxicity data specific to Aroclor 1268 that are applicable to marine mammals are limited. Predicting toxic effects of Aroclor 1268 is uncertain due it's unique congener profile and associated physiochemical characteristics, such that data from other PCB mixtures may not be applicable. American mink were chosen as a surrogate model for cetaceans to develop mammalian PCB toxicity benchmarks. Mink are a suitable surrogate species for cetaceans in toxicity studies because of similarities in diet and taxonomic class. The mink's greater sensitivity to PCBs, compared to other mammals, allows for the application of mink toxicology data to provide a level of safety for cross-species extrapolations. A variety of ecologically-relevant effects in Aroclor 1268-exposed mink were assessed to support development of toxicity reference values for Aroclor 1268. Mink were exposed to Aroclor 1268 in diet at concentrations that ranged from 1.8 to 29 micrograms Aroclor 1268/gram feed wet weight, and the positive control contained 0.0009 to 0.0013 micrograms PCB 126/gram feed wet weight.
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