Effects of urbanization on mercury deposition and accumulation in New England

Abstract We compare total mercury (Hg T ) loading and methylmercury (MeHg) accumulation in streams and lakes from an urbanized area (Boston, Massachusetts) to rural regions of southern New Hampshire and Maine. The maximum Hg T loading, as indicated by Hg T atmospheric deposition, Hg T emissions, and sediment Hg T concentrations, did not coincide with maximum MeHg concentrations in fish. Urbanized ecosystems were areas of high Hg T loading but had low MeHg concentrations in fish. Controls on MeHg production and accumulation appeared to be related primarily to Hg T loading in undeveloped areas, while ecosystem sensitivity to MeHg formation appeared to be more important in regulating accumulation of MeHg in the urban area.