Accumulation of metals and organochlorines in tissues of the oyster Crassostrea angulata from the Sado Estuary, Portugal.

Sixty-eight composite samples of selected tissues (mantle, gills, adductor muscle and other soft parts) of Crassostrea angulata oysters collected in the upper Sado Estuary from May 1985 to May 1987 were analyzed for Fe, Mn, Zn, Cu, Cd, Pb, Ni, Cr, Co, PCB and total DDT. Principal component analysis demonstrated that Cd, Ni, Zn, Cu and Mn were more closely associated with mantle and gills, and their accumulation seemed to be highly influenced by oyster metabolic alterations. In contrast, partitioning of Pb and Cr in C. angulata tissues was largely related to environmental changes. As both biological and environmental factors tend to have major influences at the same period on the accumulation of PCB and DDT, the major factor defining their temporal partition in oysters from this upper estuary could not be clearly discerned. PCB and DDT were principally accumulated in the mantle and visceral mass.