Toxicity and bioaccumulation of the booster biocide copper pyrithione, copper 2-pyridinethiol-1-oxide, in gill tissues ofSalvelinus fontinalis(brook trout)

This investigation studied the acute effects of copper pyrithione (CuPT) exposure on juvenile brook trout, Salvelinus fontinalis. Morphologic changes, copper bioaccumulation, and markers of oxidative stress in gill tissue were studied. Juvenile brook trout were treated with one of six experimental doses of CuPT (2-64 microg/L) for 2 hours. A seventh group served as a control population. Inductively coupled plasma atomic absorbance spectrophotometry (ICPAAS) analysis demonstrates significantly increased levels of copper in gill tissue (p < 0.001). Results from scanning electron microscopy and histological analysis demonstrate the formation of club-shaped lamella, edema, fusion of secondary lamella, loss of microridge structures and epithelial exfoliation. Transmission electron microscopy revealed altered morphology of chloride cells, including the swollen appearance of mitochondria with disruption of internal cristae and lipid membrane disruption. Thiobarbituric acid reactive substance (TBARS) assays demonstrated increased levels of lipid peroxidation products in gill tissue. Assays for the total antioxidant capacity of gill tissue revealed significantly lowered antioxidant levels. This data indicates that CuPT is potentially harmful to nontarget aquatic organisms at environmentally relevant doses.