Benthic Macroinvertebrates Modify Copper and Zinc Partitioning in FreshwaterSediment Microcosms

The effects of bioturbation on metal dynamics in freshwater–sediment systems were examined. In general, benthic macroinvertebrates caused significant changes in Cu and Zn partitioning among physicochemical forms in the sediment. The proportion of cation-exchangeable and specifically adsorbed Cu observed in Chub Lake (Muskoka–Haliburton) microcosms colonized by chironomids and chaoborids was greater than that for uncolonized sediment. The same …