Development and application of WARMF to track mercury species in river basins from atmospheric deposition to fish tissue

摘要

A CIS based watershed model (WARMF) was enhanced to track mercury species from atmospheric deposition through watershed compartments to fish tissue. It was applied to St. Louis River, Nemadji River, and North Coast Rivers of Minnesota that drain to Lake Superior. Preliminary results show that WARMF simulated hydrology and concentrations of mercury species in various river sections comparable to the observed data. Predicted fish tissue concentrations of methylmercury were in the range of scattered data. The new atmospheric deposition and legacy mercury accumulated in soil contribute nonpoint source mercury to rivers and lakes. Reduction of atmospheric deposition and soil erosion may lower mercury concentrations in rivers and in fish tissue, very slowly.