Principal Investigator Harold Hemond
The extreme toxicity of mercury in many natural waters has led to the closing or restriction of many freshwater fisheries, a severe hardship and health threat to people who rely on fishing to supply their protein needs. This toxicity is due to the formation of methylmercury by natural microbial populations, especially sulfate-reducing bacteria. However, the extent of mercury methylation varies greatly from lake to lake, and no satisfactory explanation is yet available. We are examining the hypothesis that mercury-polysulfide complexes may alter the availability of inorganic mercury to the methylating organisms, thus accounting for some of the observed contrasts in methylation rates among water bodies.