Analysis of organic contaminants in New Zealand marine mammals

1. Chlorinated organic contaminants were analysed in samples of blubber collected from New Zealand's Hector's dolphin (Cephalorhynchus hectori ) and dusky dolphins (Lagenorhynchus obscurus ). 2. Polychlorinated biphenyl (PCB) congeners were detected in all samples analysed. Total PCB concentrations measured in these samples were lower than those detected in cetaceans from other countries. 3. Polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners were also detected in many of the samples. These compounds were more common and present at higher concentrations in Hector's dolphins than in the dusky dolphin. 4. Data from this study will be used to perform pattern recognition analysis of the contaminants detected. Using these methods we hope to be able to better identify source areas for these contaminants. 5. It is difficult to predict adverse effects of contaminants on the dolphins at the level of the individual or population level. The fact that contaminant concentrations detected in New Zealand dolphins are consider ably lower than concentrations in northern hemisphere cetaceans suggests some margin of safety.