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A Mercury Transport and Fate Model for Mass Budget Assessment of Mercury Cycling in Lake Michigan
Citation:
ZHANG, X., K. R. RYGWELSKI, R. ROSSMANN, AND R. G. KREIS. A Mercury Transport and Fate Model for Mass Budget Assessment of Mercury Cycling in Lake Michigan . Presented at 52nd Annual Conference on Great Lakes Research, Toledo, OH, May 18 - 22, 2009.
Impact/Purpose:
A mercury mass balance model was developed to describe and evaluate the fate, transport, and biogeochemical transformations of mercury in Lake Michigan.
Description:
A mercury mass balance model was developed to describe and evaluate the fate, transport, and biogeochemical transformations of mercury in Lake Michigan. Coupling with total suspendable solids (TSS) and dissolved organic carbon (DOC), the mercury transport and fate model simulates total mercury and three mercury species including elemental mercury, divalent mercury, and methylmercury. The model was designed to have enough sophistication in overall model conceptualization to capture key processes but at the same time maintain simplicity of speciation processes where permitted. Comparing model output with observed data generated during the Lake Michigan Mass Balance project, model calibration was performed for each state variable. Using this calibrated model, mass budget analysis was applied to assess mercury cycling in Lake Michigan. Model-derived mass flow rates within a mass budget assessment helped to quantitatively identify key environmental transport and fate processes controlling the concentrations of mercury species in both the water and sediments of the lake. The relative magnitude of these model-derived mass flow rates were also compared to measured mercury load contributions to the lake.