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

摘要

Polonium-210 in water and ~(210)Pb and ~(210)Po 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 ~(210)Pb and ~(210)Po 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 ~(210)Po was higher than for ~(210)Pb, and the accumulation of ~(210)Po was highest in the liver of C. auratus (3673 ± 434 Bq kg~(-1) ww). Although the average activity concentration of ~(210)Pb 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 ~(210)Po into the liver, and that the distributions of ~(210)Po and ~(210)Pb in fish organs were different. The BCF (L/kg) for ~(210)Po in bone, liver and muscle clearly demonstrates high accumulation of ~(210)Po in C. auratus, especially in the liver. The average BCFs of liver, bone and muscle were >1.4 × 10~5, >2.5 × 10~4 and >1.4 × 10~4, respectively. All fish in the Pit Lake were found to be in the same trophic level, however, a linear correlation between log ~(210)Po in liver and δ~(15)N could indicate biomagnification of ~(210)Po in liver of C. auratus. In regards to the recommended Annual Limit of Intake (AL1) for ~(210)Po, the concentration of ~(210)Po 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.