INTERSTITIAL SOIL SOLUTIONS IN TRANSPORT OF 137CS, 90SR, 239, 240PU, AND 241AM

Abstract

The inflow of 137Cs, 90Sr, 239,240Pu, and 241Am to interstitial solutions was studied in organic and mineral soils that are abundant in the region of Belarus subjected to the consequences of the Chernobyl accident. The exclusive role of interstitial solutions of soils in the processes of the geochemical and biological transport of radionuclides is emphasized. The interphaseous distribution coefficient of a radionuclide is used as a measure of the transport ability of radionuclides in systems whose viability is a significant function of mass transfer of trace elements in interstitial soil solutions (directly along soil profiles or in soil-plant, soil-surface water, soil-groundwater, and other systems). The distribution coefficients of the radionuclides between the solid and liquid soil phases were determined for the condition of ultimate water saturation and for lower water contents of soils. Among the key parameters that control the 137Cs, 90Sr, 239,240Pu, and 241Am abundances in the soil solutions of interest and that are significant for the intensity of the subsequent transport of these radionuclides in biogeocenoses, the following were recognized: the reserve of mobile species of the radionuclides; the water capacity and water content of the soil; the abundances of calcium, potassium, and water-soluble organic components in the interstitial solutions; and the solution pH. It is stressed that a systematic approach is essential for the development of measures to decrease (or increase) the mobility of various radionuclides present simultaneously in the soil.