Summary of the MeHg Panels of the 2004 CalFed Science Conference

Mercury (Hg) can become an environmental problem when sulfate-reducing anaerobic bacteria, in the presence of organic substrates, form methylmercury (MeHg), a highly toxic compound that endangers wildlife and people by accumulating in their food.

The spatial and temporal variation in MeHg production is mainly a function of the availability of inorganic mercury to methylating bacteria. Typically only a small percentage (e.g. < 5 %) of total inorganic mercury is available for methylation. The amount of MeHg that actually becomes available for bioaccumulation depends on many environmental factors operating at different spatial scales, from watersheds to microbes. Scientists are working to prioritize these factors for management actions.