Accumulation of artificial and natural radionuclides in hydrobionts of the Konoplyanka River (Kamianske City, Dnipropetrovsk region)

Purpose. To determine the radiation state of the ecosystem in the technologically modified Konoplyanka River in the area of ​​radioactive waste tailings dump and the mouth of the river (at the siteof confluence with the Zaporizhzhya (Dnipro) Reservoir), by analyzing the coefficients of radionuclides accumulation of natural and artificial origin in hydrobionts. Methodology. Classical sampling methods were used to determine natural (226Ra, 232Th, 40K) and artificial (137Cs, 90Sr) radionuclides in hydrobionts. The contents of radionuclides were determined in a certified laboratory at the “Dnipropetrovsk Regional Center for Disease Control and Prevention of the Ministry of Health of Ukraine” by the method of selective isolation of radionuclides based on the measurement of radiation on a scintillation beta spectrometer SEB - 0.XX and spectrum processing with the AK-1 software package. The measurement range of the beta spectrometer covers from 0.1 Bq to 10-4 Bq, which allows ensuring the control of artificial radionuclides in environmental objects in accordance with the regulatory documents of the “Permissible levels of radionuclides 137Cs and 90Sr in food and drinking water” (PLR–2006) and “Radiation Safety Standards of Ukraine–97” (RSSU–97) Findings. The study of the current radiation status of the Konoplyanka River in the summer-autumn period showed that the contents of artificial radionuclides in the water were significantly lower compared to normative data: the content of 137Cs was 15–19 times lower; 90Sr was 28–50 times lower. Among the different sampling sites, the highest content of 137Cs was recorded at site No3 (Konoplyanka River, old channel) and No1 (Konoplyanka River, top of the tailings dump). The study of artificial radionuclides in fish showed that their content did not exceed the normative values ​​for fish as food objects (137Cs content in fish was lower by 17–50 times, 90Sr by 16–62 times). By fish species, the highest content of artificial radionuclides was accumulated by benthic slow-moving fish (round goby) and the lowest by pelagic mobile fish (roach, bleak, bitterling). The difference in the contents of these fishes was 62% for 137Cs and 75% for 90Sr. At different sampling sites, the content of artificial radionuclides in fish did not differ significantly. The content of natural radionuclides in different fish species did not have general patterns, that is, each fish species selectively accumulated individual natural radionuclides. The accumulation coefficients of artificial radionuclides were the highest in demersal fish, which are characterized by a sedentary lifestyle and feed on benthic invertebrates (round goby), the accumulation coefficient of artificial radionuclides in planktonophagous fish was 40-69% lower. The coefficients of natural radionuclides accumulation were higher in planktonophagous fish (bleak, stone moroko) by 36–53% compared to benthophagous fish (roach, round goby). Originality. For the first time, data on the content of natural and artificial radionuclides in the hydrobionts from the Konoplyanka River at the conditions of technogenic influence in the industrial zone of the metallurgical and chemical industry were obtained. Practical Value. The results of the conducted research can be used to assess and monitor the radiation status of the Konoplyanka River, radioactive waste tailing dumps and develop a strategic program for the restoration of the ecosystem of techno-altered rivers with heavy techno-anthropogenic load. Keywords. Konoplyanka River, radionuclides, hydrobionts, molluscs, fish, tailings dumps.