Relationships between the Partitioning of Trace Metals in Sediments and Their Accumulation in the Tissues of the Freshwater Mollusc Elliptio complanata in a Mining Area

Abstract

Surficial sediment samples and specimens of a benthic freshwater pelecypod, Elliptio complanata, were collected at eight sites located along a metal contamination gradient downstream from the mining and smelting complex in Rouyn–Noranda, Quebec. The molluscs were dissected, digested, and analysed for Cu, Pb, Zn, Fe, and Mn by flame atomic absorption spectrophotometry. Each sediment sample was wet sieved and the < 70-μm granulometric fraction was subjected to a sequential extraction procedure designed to determine the partitioning of the trace metals among various geochemical phases. Regression analysis indicates that Cu, Pb, and Zn levels in various tissues of E. complanata (or in the whole organism, without the shell) are best related, not to total metal concentrations in the adjacent sediment, but rather to one or more of the relatively easily extracted fractions. Accumulation of Cu, Pb, and Zn was also influenced by the protective or competitive effect of other sediment constituents, notably amorphous iron oxyhydroxides and, to a lesser degree, organic matter.