Impact of radioactive discharges of Siberian Chemical Plant (SCP) and Pilot-demonstration energy complex (PDEC) on aquatic biota inhabiting in the SCP 30-km zone

Radiation doses to aquatic biota exposed to Siberian Chemical Plant (SCP, Tomsk) radioactive discharges, and Pilot-demonstration energy complex (PDEC) forecasting radiation doses from designed radioactive discharges were estimated. Doses to the biota in the habitat in the existing radiation situation were assessed with the use of measurements of water and bottom sediments samples collected during environmental monitoring of airborne radioactivity in 2017. Designed radioactivity discharges were assumed from normally operated PDEC modules for fabrication and refabrication and fuel reprocessing and reactor BREST-OD-300. It was found that the esti-mated highest radiation doses to biota were: for freshwater mammals – 24 μGy/day, it is 40 times below the reference levels; for fish – 7 μGy/day, it is 140 times below reference levels; for aquatic plants and mollusks – 1.2 μGy/day, it is about 10000 times below the reference levels. Anticipated radiation doses to the aquatic biota exposed to radiation discharged by PDEC were formed in the Lake Chernoe (Black Lake). The highest doses to fresh water mammals, fish and birds are 0.3 μGy/day, for aquatic plants and mollusks – 0.05 μGy/day. The main contributor to anticipated radiation doses to aquatic biota and birds is tritium, 3H.