| Summary: | The hepatic body-burdens of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were integrated with fatty acid levels in four fish species from Sabine Lake (TX), namely: bull shark (Carcharhinus leucas), alligator gar (Atractosteus spatula), red drum (Sciaenops ocellatus) and gafftopsail catfish (Bagre marinus). Fatty acids were used as tracers of dietary preferences, and as PAHs and PCBs bio-accumulate, it was anticipated that dietary preference may delineate the source of pollutant exposure. Results showed unique PAH and PCB profiles in fish. Specifically, PAH profiles indicated mainly petrogenic sources of exposure. The multivariate analysis of pollutant hepatic body-burdens indicated bull sharks to have a distinct profile relative to the other fish species. This trend was confirmed by the observation that bull sharks also exhibited a significantly higher body-burden of PCBs relative to the other fish species. The risk assessment of the high PCB body-burden in bull sharks was also reflected in a high toxic equivalent (TEQ) value. The TEQ level in bull sharks was above the upper limits of toxicity thresholds reported for fish and aquatic mammals. The size range of bull sharks indicated young-of-the-year (YoY) life stages. Therefore, a unique exposure history for YoY bull sharks is postulated, and implicates a role of maternal transfer. The analysis of fatty acid profiles in fish showed elevated levels (45x higher) of nervonic acid (24:1n9) (indicator of calanoid copepods and soil filamentous fungi), in gafftopsail catfish and red drum vs. alligator gar and bull shark. This indicated that the feeding ecology of catfish and red drum was ‘closer’ to the base of the marine food web. The correlational analysis of pollutant body-burdens with fatty acids indicated no clear distinction or preference of pollutant correlation with any particular type of fatty acid. My results suggest that pollutant bioaccumulation is unlikely to be associated with the specific fatty acid composition of lipids. ...
|
|---|