Methylmercury in Estuarine Sediments

Abstract

INDUSTRIAL mercury discharges into natural waters have been effectively reduced during the past several years in the United States. In areas such as Mobile Bay, which previously received sufficient quantities of anthropogenic mercury effluents to require a ban on commercial fisheries, it is now critical to determine if the residual contaminated sediments are a reservoir of mercury compounds which could be detrimental to the fishery on a long term basis. It is well established that mercury accumulates in particulate material1,2 and may subsequently be transferred from sediment to fish3. Laboratory studies4 suggest that diagenetic processes in natural sediments can transform inorganic mercury to mono and dimethylmercury, increasing the pollution hazard. The methylated forms of mercury have been found to be more toxic to organisms than inorganic or phenyl mercury compounds5,6. Here we report the first published results on the concentration and distribution of methylmercury compounds in natural sediments from polluted and unpolluted coastal environments.