Long-Term Dynamics of the Concentrations of Organochlorine Compounds and Mercury in the Bottom Sediments of the Chernorechenskoe Reservoir

Resumo

The accumulation of organochlorine compounds (OCs) and mercury in the bottom sediments of the Chernorechenskoe Reservoir since the mid-1960s to 2008 has been studied. Sedimentation rate and accumulation chronology of recovered sediments were reconstructed by the method of radioisotope dating . The sedimentation rate in the reservoir has been found to vary because of changes in reservoir volume and area in the late 1980s. Historical reconstruction of the input of OCs and mercury into the reservoir sediments in the recent 50 years has been performed. The period of 1950–1960 has been found to show considerable pollution of reservoir sediment by DDT and mercury. The spatial distribution of OCs and mercury has been determined in the top 5-cm layer of bottom sediments in the Chernorechenskoe Reservoir. The deposition rates of OCs and total mercury into bottom sediments in 2008 have been evaluated.