Chemical contaminants in harbor porpoise (Phocoena phocoena) from the North Atlantic coast: Tissue concentrations and intra- and inter-organ distribution

Concentrations of chlorinated hydrocarbons (CHs), such as polychlorinated biphenyls (PCBs), were measured in subsamples taken from different anatomical locations of blubber and liver of three apparently healthy harbor porpoises (Phocoena phocoena) incidentally caught in a gill-net fishery along the northwest Atlantic coast; selected elements (e.g., mercury) were measured in subsamples of liver. The vertical distribution (skin to muscle) of contaminants within blubber was also determined. Additionally, the concentrations of CHs and elements were determined in individual samples of brain, lung, kidney, and testis to assess how the disposition of toxic chemicals may be dependent on the physiological characteristics of a specific organ. Statistical analyses of the results showed that the anatomical location of the blubber or liver sample had no significant effect on concentrations of either CHs in blubber and liver, or of selected elements in liver. However, there were statistical differences between strata of blubber (skin to muscle) for the concentrations of CHs. As expected, the results showed that the CH concentrations, based on wet weight, were considerably higher in the blubber than in the other tissues; however, the concentrations of CHs in the different tissues were more comparable when values were based on total lipid weight with the exception of the brain where lipid normalized concentrations were than in all other tissues. This low relative accumulation of lipophilic contaminants in the brain tissue may be due to the presence of the blood-brain barrier, or due to a lower proportion of neutral lipids, such as triglycerides, as analysis for percent lipid and for the proportion of specific lipid classes showed.