Studies of Concentrations of Methyl Mercury in Sediments from the St. Clair System and Rate of biological Methylation in incubated Samples of Sediments

The levels of methyl mercury in lake and river sediment from the St. Clair system have been investigated in relation to total-mercury concentrations and to levels of ethyl-lead compounds which were detected during the work. The co-occcurrence of ethyl-lead and methyl mercury indicate a connection probably in the form of a chemical methylation of mercury from methyl groups among the ethyl ones in alky-lead. In the incubated river and lake sediment from the St. Clair system no biological methylation of mercury could be statistiaclly certified.