Methylmercury in lake bed soils during re-flooding of an Appalachian reservoir in the northeastern USA

Mercury methylation, where inorganic mercury (Hg) is converted to methylmercury (MeHg), can increase in soils when flooded. While effects of the initial flooding on MeHg production have been well studied, less known about impacts re-flooding production. Lake Perez, an impounded recreational reservoir Appalachian Highlands, was completely drained then re-filled 7 years later. We use a combination chemical, soil physical, and microbial data quantify changes before after lakebed. Portions that were transiently saturated due pluvial had highest pre-flooded concentrations. When lake re-flooded, concentrations subaqueous increased by factor 2.74 (+174%) average. Substantial variability observed among sampling sites, with smaller increases at sites subjected seasonal during periods drained. The lower this study compared studies evaluated flooding, indicating former bed caused response terrestrial land. This advances understanding environmental impact reservoirs.