Accumulation of radionuclides in the Caspian bivalves

Due to the increase in oil production, there is an increased accumulation of natural radionuclides in molluscs, brought to the surface with formation waters when drilling wells. It is established that the accumulation of radionuclides in mollusks occurs both during life and after their death. In the process of work the features of accumulation were revealed and the coefficients of biological accumulation (KBA) of 238U and 232Th in the shells of bivalves of the Caspian sea were determined. The content of 238U и 232Th was determined by radiochemical method using ion exchange columns with anionite EDE-10P and subsequent colorimetry with arsenazo III on the photoelectric colorimeter KFK-2MP. The biological accumulation rate of uranium ranges from 10 to 78. The variability of uranium concentrations in shells depends on the individual characteristics of the mollusks, their age and the nature of the soil. KBA thorium in the shells of molluscs of the Caspian from 76 to 626, the concentration of thorium in the shells depends on torinosette food material. The unique structure of the crystal lattice of aragonite shells forms stable compounds with 238U, which is one of the factors of increased accumulation of this radionuclide in Didacna. Our results on uranium content in mollusk shells are consistent with the concept of primary biochemical accumulation of 238U in the organic matter of living organisms. Data on the accumulation of 238U and 232Th in the external skeleton of Bivalvia living near oil production sites can be used in monitoring.