Po-210 and Pb-210 in water and fish from Taboshar uranium mining Pit Lake, Tajikistan

Polonium-210 in water and 210Pb and 210Po in different fish organs from 3 different fish species in Taboshar Pit Lake (n = 13), located in the uranium mining area in Tajikistan, and in Kairakkum Reservoir (reference lake, n = 3), have been determined as part of a Joint project between Norway, Kazakhstan, Kyrgyzstan and Tajikistan.The average activity concentration of 210Pb and 210Po in liver, muscle and bone of Carassius auratus was higher than the concentration in similar tissues of C. carpio and Sander lucioperca from the reference site. The accumulation of 210Po was higher than for 210Pb, and the accumulation of 210Po was highest in the liver of C. auratus (3673 ± 434 Bq kg−1 ww). Although the average activity concentration of 210Pb in liver and bones of C. auratus from Pit Lake were fairly similar, a huge variation in the liver activity concentrations (25–327 Bq kg−1 ww) was found. The results confirm direct uptake of unsupported 210Po into the liver, and that the distributions of 210Po and 210Pb in fish organs were different. The BCF (L/kg) for 210Po in bone, liver and muscle clearly demonstrates high accumulation of 210Po in C. auratus, especially in the liver. The average BCFs of liver, bone and muscle were >1.4 × 105, >2.5 × 104 and >1.4 × 104, respectively. All fish in the Pit Lake were found to be in the same trophic level, however, a linear correlation between log 210Po in liver and δ15N could indicate biomagnification of 210Po in liver of C. auratus.In regards to the recommended Annual Limit of Intake (ALI) for 210Po, the concentration of 210Po in muscle tissues of C. auratus is alarming, as there is a high probability for the local population at risk to exceed the recommended ALI through consumption of fish from Taboshar Pit Lake.