Mercury Circulation in Aquatic Environment. Part 3: Mercury Transformations in Sediments

Two types of sediments, one of them highly polluted by the pulp and chemical industry and the other one polluted by the urban type of sewage, have been analysed for their content of methylmercury and inorganic mercury. The rate of the formation of methylmercury in sediment from inorganic mercury (II) and the decomposition of methylmercury and phenylmercury have been investigated using ²⁰³mercury compounds. It has been found that the rates of both processes depend on the experimental conditions. The quickest formation of methylmercury has been observed under the Procedure C which simulates the natural conditions. The lower the rate of demethylation of methylmercury the higher the equilibrium concentration of methylmercury which has been found in sediments.