PCB uptake and accumulation by oysters (Crassostrea virginica) exposed via a contaminated algal diet.

Reproductively active oysters were fed daily with 0.2 g algal paste containing 0, 0.1, and 1.0 microgram polychlorinated biphenyls (PCBs) (1:1:1 mixture of Aroclor 1242, 1254 and 1260) for either 15 or 30 days, and accumulation of PCBs in different organ tissues and eggs assessed. The effects of PCB exposure on lipid content, lipid class and fatty acid composition were also evaluated. PCBs were accumulated by the oysters and transferred to the eggs. PCB accumulation in oysters was dose, time and tissue dependent. Mean PCB contents were 3150, 1970, and 250 ng/g dry wt., respectively, in the visceral mass, gills + mantle and muscle of oysters fed algal paste containing 1.0 microgram PCBs for 30 days. The PCBs in the eggs from the same oysters reached 671 ng PCBs/g dry wt. Feeding oysters with PCB-sorbed algal paste for 30 days significantly increased phospholipid and free fatty acid contents in gills + mantle tissue compared to the same tissues in the undosed control.

Effects of PCBs sorbed to algal paste and sediments on the stress protein response (HSP70 family) in the eastern oyster, Crassostrea virginica.

This study examined the stress protein response (HSP70 family) of reproductively inactive oysters fed 0.7 g algal paste containing 0, 0.35 and 3.5 micrograms polychlorinated biphenyls (PCBs) daily. A second set of treatment groups investigated the combined effect of PCBs and sediments (0.3 g sediments daily per oyster) on HSP70 response. After 8 weeks of PCB exposure, oyster tissues (mantle and gill) were sampled and analyzed for HSP70. Preliminary results did not show a significant effect in HSP70 response in oysters fed PCB sorbed to algal paste, albeit PCBs accumulated up to 1342 ng/g dry weight in the mantle, and up to 180 ng/g dry weight in gill tissues. However, the addition of sediments caused a significant increase in HSP70 levels of gills and mantle, although the mantle was less sensitive to the sediments.