Assessment of Integral Carryover of Long-Lived Radionuclides with Water Aerosols from Karachay Lake Based on the Analysis of Data on Soil Contamination in the Area of Its Location
In the initial period of Karachay Lake operation, monitoring of water contamination was performed occasionally and through the use of imperfect measurement techniques. As a result, no reliable estimates of integral activity carryover from the lake water area is available. Archive data have been analyzed on the density of soil contamination with <sup>137</sup>Cs, <sup>90</sup>Sr and with a total of Pu isotopes (ΣPu) using 20 samples taken in the vicinity of Karachay Lake in 1991. The analysis findings are presented. Radionuclide ratios were considered, and, for each sampling point, contribution of two main sources of radioactive contamination of soil in the lake location area was identified. The two main sources included: an accidental "one-time" wind carryover of dried out highly-active silts in April 1967 and a long-lasting spread of radioactivity with water aerosols from the Karachay Lake water area during the whole period of its previous operation (1951-1991). The obtained data helped evaluate and verify the calculation results of the total carryover of <sup>137</sup>Cs, <sup>90</sup>Sr and ΣPu from the lake water area for the whole period of its operation, and also get information required to implement activities on remediation of the contaminated area.