Transport and fate of heavy metals in Onondaga Lake, New York.

Abstract

Lakes in the immediate vicinity of population centers provide extremely valuable resources for recreation. Industrialization, however, generally accompanies urbanization, and urban lakes particularly may be affected by pollutants of a wide variety, including toxic heavy metals, from cultural sources within the watershed. Onondaga Lake (Figure i) typifies this situation. Located at the northwest edge of the city of Syracuse, New York, for many years the lake has been the recipient of heavy metal inputs from the city, its suburbs, and approximately 140 industries which are located in its drainage basin (MURPHY 1978). Owing to broadly-supported efforts aimed at improving water quality in Onondaga Lake during the past decade, the concentration of nutrients and some heavy metals has decreased in the lake during that period (EFFLER et el. 1981; MURPHY 1978). Few quantitative data exist, however, concerning the fate of metals which enter Onondaga Lake or of the mechanisms which have permitted the observed reductions in concentration to occur. The sediments, nonetheless, are known to contain extremely high levels of several heavy metals compared to other lakes (EFFLER et el. 1980; RAND et el. 1977), which suggests that the transport to and permanent storage in the sediments may be important. In general the fate of heavy metals in aquatic systems depends on partitioning between soluble and settleablesolid phases and may be influenced by various interactions which include coagulation, adsorption, precipitation, coprecipitation, complexation, and biotic uptake (BURRELL 1974). These factors, in turn, are known to be affected hy environmental conditions, such as: pH, redox potential, metal concentrations, ionic strength, hioaccumulation, and type and concentration of complexing ligands (LECKIE & JAMES 1974). Superimposed on the aforementioned phenomena are kinetic factors which govern reaction rates, particle sedimentation, and hydrodynamics. With full appreciation of this multidimensional web of interactions, the present investigation was undertaken to develop a simple, nonsteady-state, deterministic model for prediction of the behavior of the metals Zn, Ni, and Cr in Onondaga Lake over a growing season.