Sorption of radioactive contaminants by sediment from the Kara Sea

The purpose of this study is to quantify some of the parameters needed to p erform near-field modelling of sites in the Kara Sea that were impacted by the disposal of radioactive waste. The parameters of interest are: the dist ribution coefficients (Kd) for several important radionuclides, the mineral ogy of the sediment, and the relationship of Kit to liquid-to-solid ratio. Sediment from the Kara Sea (location: 73 degrees 00'N, 58 degrees 00'E) was sampled from a depth of 287 m on August 23/24, 1992. Analysis of the mater ial included mineralogy, grain size and total organic carbon (TOC). Uptake kinetics were determined for Sr-85, Cs-137, Am-241, Tc-99, I-125, U-232 and Pb-210 and distribution coefficients (Kd) were determined for these radion uclides using batch type experiments. Sorption isotherms, developed for Cs- 137, Sr-85 and Tc-99, were linear in each case. Increasing the liquid-to-so lid ratio strongly increased uptake of Cs-137 and moderately increased upta ke of Tc-99. Analysis for anthropogenic radionuclides indicated the presenc e only of Pu-239/240 in the sediment with the highest activity (at the top section of the core) being 0.420 Bq kg(-1). Other anthropogenic radionuclid es were below detection limits. (C) 2001 Elsevier Science Ltd. All rights r eserved.