Toxicity and bioaccumulation of tributyltin in tissues of Urolophus jamaicensis (Yellow stingray)

Tributyltin oxide (TBTO) is the main constituent of tin based antifouling marine paint used on the hulls of ships to prevent the growth of fouling organisms. TBTO has been shown to be hazardous to non-target organisms. Urolophus jamaicensis represents the ideal study organism for the toxic effects of TBTO to elasmobranchs. This study investigates the toxicity and accumulation of tin in the gill tissue of the stingray U. jamaicensis after acute exposure to TBTO. This work demonstrates the alterations in the morphological architecture of the gill using electron and light microscopy, the induction of stress proteins, and peroxidative damage in response to TBT exposure. A captured population of U. jamaicensis was housed in isolated, static tank systems. After a minimum 30 day acclimation period, the animals were exposed to one of five experimental doses of TBTO (4ug/L, 2ug/L, 1ug/L, .5ug/L or .05ug/L). A sixth group was exposed to a chronic dose of .005ug/L for 28 days. A seventh group served as a control population. Three hours following treatment animals were sacrificed, gill tissue extracted, processed and stored for analysis. Results indicate that U. jamaicensis is hypersensitive to TBTO exposure. The elasmobranch gill showed a distorted, swollen epithelium with exfoliation following acute exposure to as little as .05ug/l TBTO for 3 hours. GFAAS results indicate that gill, brain, and blood tissue of treated animals contained a significantly increased tin concentration as compared to controls. Western Blot analysis demonstrates the induction of the stress proteins Hsp70 and HO1. 4HNE adduct formation determined by Western blot analysis provides further evidence that observed membrane degradation is a result of lipid peroxidation.