Radioactive contamination distribution in the bottom sediments and water of the Mishelyak River

Joint Russian-American field studies have been conducted within the framewo rk of a Memorandum of Cooperation between the Ministry of Atomic Energy for the Russian Federation and the U.S. Department of Energy and managed by th e Joint Coordinating Committee on Environmental Restoration and Waste Manag ement (JCCEM). We conducted the field studies discussed in this report in 1 996 near the Mayak Production Association in the South Urals, Russia. The p rimary purpose of the research was to apply new methods to study the distri bution of a containment plume originating from Lake Karachai an unlined rad ioactive waste repository, which is currently migrating into the Mishelyak River valley. This research was conducted within the frontal part of the co ntaminant water plume. The studies from this work include: surface water an d soil moisture sampling with in situ radiometric measurements. The data fr om the radiometric measurements obtained in the field were then compared to laboratory measurements of field samples. Due to the possible inflow of th e radionuclides from the groundwater to the Mishelyak River, this paper als o describes the study of river bottom sediments and water contamination.