Factors Contributing to Accumulation of 210Po in Freshwater Fishes in Dong Thai Lake, Vietnam and Radiological Hazard Assessment

²¹⁰Po (polonium), one of the most toxic naturally occurring radionuclides, is well-known as a common natural radionuclide in fish species. Human consumption of ²¹⁰Po-contaminated fish could result in a significant internal dose. This study determined by alpha spectrometry the ²¹⁰Po activity in sixteen selected fish species with different living behaviors (pelagic, demersal), trophic positions (herbivores, carnivores, omnivorous), and masses in Dong Thai Lake, Hanoi, Vietnam. The min, max, and average of the ²¹⁰Po concentration of sixteen fish species were 0.80 ± 0.44, 12.7 ± 0.20, and 3.54 ± 0.31 Bq kg⁻¹, respectively. Regarding the different living behaviors, trophic positions, and masses, the results showed trending of ²¹⁰Po_pelagic > ²¹⁰Po_demersal; ²¹⁰Po_herbivores < ²¹⁰Po_carnivores < ²¹⁰Po_omnivorous and ²¹⁰Po_<0.2 kg > ²¹⁰Po_0.2-1 kg > ²¹⁰Po_>1 kg, respectively. The ²¹⁰Po concentrations in muscle tissue were greater in fish species with a small mass, omnivorous trophic position, and pelagic living behavior relative to demersal fish with a larger mass that were herbivores or carnivores. In addition, the results showed an uneven distribution of ²¹⁰Po activities in atmospheric aerosols, terrestrial soils, surface waters, and lake sediments in the study area. The primary source of ²¹⁰Po could be supplied from atmospheric aerosols and/or terrestrial soils in the study area. The ²¹⁰Po annual effective dose for adults due to fish consumption has been calculated with a range from 20 to 400 µSv y⁻¹ and 111 µSv. y⁻¹ on average, and it is far below the allowable limits of 1000 µSv y⁻¹.