ROLE OF THE BENTHOS IN Cu AND Zn DYNAMICS IN FRESHWATER MICROCOSMS.
Abstract
Microcosm studies were designed to determine whether benthic macroinvertebrates (BMI's) could effect Cu and Zn speciation in the sediment and release to overlying waters. BMI's caused significant changes in Cu and Zn partitioning in freshwater sediments. Greater proportions of cation-exchangeable and specifically adsorbed Cu and Zn were observed in systems colonized by tubificid worms or by chironomids and chaoborids. The role of bioturbation in metal speciation and toxicity was considered and an extrapolation of microcosm results to the natural environment indicated the potential for macroinvertebrates to affect metal cycling in aquatic ecosystems.