Physical controls on total and methylmercury concentrations in streams and lakes of the northeastern USA

摘要: The physical factors controlling total mercury (HgT) and methylmercury (MeHg) concentrations in lakes streams of northeastern USA were assessed a regional data set containing 693 HgT 385 corresponding MeHg surface waters. Multiple regression models using watershed characteristics climatic variables explained 38% or less the variance MeHg. Land cover percentages soil permeability generally provided modest predictive power. Percent wetlands alone 19% at low-flow, it was only significant (p < 0.02) predictor for lakes, albeit explaining 7% variance. When stream discharge added as variable became dominant streams, improving model r2 from 0.19 to 0.38. Stream improved more modestly, 0.25 0.33. Methylation efficiency (MeHg/HgT) modeled well (r2 0.78) when seasonal term incorporated (sine wave with annual period). Physical 18% fish Hg 134 55% 20 reservoirs. Our results highlight important role seasonality short-term hydrologic changes delivery water bodies.