Modeling methylmercury in Maine's tribal meres

Abstract

Methylmercury (MeHg) concentrations in the fish of twenty Maine lakes were projected for the year 2035 under three different policy scenarios. A mechanistic model of Hg fate and transport was calibrated for Maine's environment using four parameters: volumetric outflow rate, settling velocity, burial velocity, and Hg(II) biotic solids partitioning coefficient. The model was evaluated through comparison with measured results from the year 1993. The model results showed that the strictest global Hg regulations will lead to the greatest decreases in MeHg concentration. No piscivore will be safe for frequent consumption, even under the strictest regulations in the cleanest lakes. The Wabanaki traditional-subsistence diet will continue to entail unsafe MeHg exposures.