The bioconcentration and metabolism of chlorpyrifos by the eastern oyster, Crassostrea virginica

Eastern oysters (Crassostrea virginica) were exposed to [14C]chlorpyrifos (O,O‐diethyl‐O‐[3,5,6‐trichloro‐2‐pyridyl] phosphorothioate) at an average measured seawater concentration of 0.6 μg/L under flow‐through conditions for 28 d. The compound O,O‐diethyl‐O‐(3,5‐dichloro‐6‐methylthio‐2‐pyridyl)phosphorothioate (DMP) was extracted and identified as the single metabolite observed, and this metabolite constituted the majority of the total [14C] activity in the oyster at all sampling times. Once oysters were exposed to clean water, both chlorpyrifos and DMP residues cleared rapidly from whole oysters, with elimination half‐lives of