Department of Biology/Clarkson Center for the Environment,
Clarkson University, Potsdam, New York 13699, USA

Summary

   The historical record of reliable analytical measurements of trace metal concentrations in the water column of Lake Erie dates back only 15 years to the publication of the first measurements made using stringent trace metal clean sampling protocols. The results of these and later efforts revealed that the concentrations of dissolved trace metals were much lower than previously thought to have existed in these waters - accordingly, the perceived role that these elements play in Lake Erie has radically changed. Plankton are widely considered to be the most important factor controlling the residence time of trace metals in the water column. Evidence suggests that some metals (Zn, Fe) may at times be low enough to cause physiological adaptations in plankton; the influence of other metals has not yet been examined. The Lake Erie trace metal data set is limited to primarily total dissolved concentrations. Measurements are available for Cd, Cr, Co, Cu, Cs, Fe, Hg, Pb, Ni, Tl, and Zn. Important information regarding chemical speciation of most of these elements is lacking, yet needed. In addition, the data set represents measurements made almost exclusively during the summer months ? hence, the current restricted view of trace metal biogeochemistry in the lake cannot allow proper risk assessment. Determinations of the chemical speciation of several bioactive trace metals (Cd, Co, Ni, Cu, Zn, Fe, Mn) will provide important information regarding the interaction of these elements with plankton.