Hydrocarbon biomarkers responses in the bivalve, Tivela mactroides, exposed to polluted sediments.

The objective of this work was to evaluate the potential use of the bivalve Tivela mactroides, as a Caribbean sentinel species. Organisms were collected from a relatively clean sandy beach, and were exposed to a gradient of petroleum hydrocarbon-polluted sediments for periods of 3, 4 and 6 days, after which their activity levels of biotransformation enzymes were measured. NADPH-cytochrome c reductase, glutathione transferase and cytochrome b5 activities increased according to total hydrocarbon concentration, whereas NADH-cytochrome ferricyanide reductase activity decreased. Catalase activity was constant while superoxide dismutase activity was inhibited. The results indicated that T. mactroides may serve as a sentinel species. However, further studies are recommended on the influence of biotic and abiotic variables on basal activities of enzymes, and their responses to other pollutants.