The Dynamics of Metals in the American Oyster, Crassostrea virginica. II. Environmental Effects

Abstract

The dynamics of Mn, Fe, Zn, Cu and Cd in the shell and soft tissues of the American oyster,Crassostrea virginica, were observed in oysters exposedin situ to a metal-contaiminated environment from September, 1972 until August, 1973. Zn and Cu accumulated in soft tissues of exposed oysters reaching levels of 4100 μg Zn/gm and 450 μg Cu/gm compared to 1700 μg Zn/gm and 60 μg Cu/gm for controls (dry weight basis). The relative enhancement of metals in oyster soft tissues exposed to the contaminated environment over controls reflected the pattern of metal contamination in sediments. Although growth of the oysters, as measured by soft tissue dry weight and shell dimension, was identical, shells of exposed oysters were significantly thinner than controls (16%). Trace metal incorporation into shell was affected with Mn deposition surpressed and Fe, Zn and Cu slightly increased. Uptake of metals by oyster soft tissues was seasonally dependent with rapid uptake occurring in the summer and fall but delayed uptake occurring in the early spring.