Trace metal bioaccumulation in marine fish from Senegal: influence of trophic ecology.

Aside from natural sources, marine ecosystems can be subjected to metal contamination due to urban effluents and industrial activities. Part of this metal exposition involves marine sediments, making the interface between water and sediment a gateway for contamination of marine organisms. In this study, the influence of trophic pathways on metallic contamination was assessed in the fish community from Senegal. Trace metals levels were determined in various fish species at two stations presumed to be differently impacted by effluents, and their diets were measured using stable isotope signatures and fatty acid composition. The hypothesis was made that fish feeding on the water/sediments interface were more exposed to trace metal contamination.
At the most impacted station, the results revealed that trace metal levels were highly correlated to benthic biomarkers, suggesting that prey living at the water/sediments interface are the main contamination vector for fish.
However, at the less impacted station, trace metals distribution within the fish community is less determined by the relationship with sediments, since various elements are correlated with plankton biomarkers as well as with benthic ones.
This study highlighted the impact of anthropogenic activities on an oceanic interface and how the trophic link to a habitat can determine metal contamination in organisms.