Application of the regional mercury cycling model (RMCM) to predict the fate and remediation of mercury in Onondaga Lake, New York

Onondaga Lake exhibits elevated concentrations of total mercury (Hg(T)) and methyl-mercury (MeHg) in the water Column, sediments and fish tissue due to industrial inputs, wastewater discharge and urban runoff. The steady- state Regional Mercury Cycling Model (RMCM) was calibrated to Onondaga Lake and applied to evaluate various remediation scenarios. Because of detailed data available for onondaga Lake, the RMCM was effectively calibrated. Model predictions of water column and fish concentrations of rig generally agreed with measured values. The model underestimated concentrations of Hg in sediments. Mass balance calculations show that inputs of Hg(T) largely originate from tributary and wastewater inflows to the lake. In contrast, MeHg is largely derived from internal production. Model calculations suggest that elimination of Hg inputs from wastewater effluent and of drainage from a former chlor-alkali facility could greatly decrease Hg concentrations in fish tissue.