Indicators of sediment and biotic mercury contamination in a southern New England estuary

► We examined factors that affect estuarine sediment and biota Hg and MeHg content. ► Spatial patterns in sediment Hg and MeHg were governed by total organic carbon. ► Methylation of Hg was inversely correlated with bottom water dissolved oxygen. ► Accumulation of total Hg was elevated in benthic infauna and upper trophic biota. ► Biotic Hg accumulation was reduced in organic rich sediments and hypoxic waters.