Biomonitoring ²¹°Po and ²¹°Pb in marine brachyuran crabs collected along the coast of Kudankulam, Gulf of Mannar (GOM), India

Activities of ²¹⁰Po and ²¹⁰Pb in whole-body and in various tissues of brachyuran crabs collected along the Kudankulam coast were studied. A non-uniform distribution of these radionuclides was observed between the various tissues. Of all the tissues, ²¹⁰Po and ²¹⁰Pb were found to accumulate more in the hepatopancreas and intestine. Among the crabs studied, Charybdis lucifera registered higher ²¹⁰Po and ²¹⁰Pb activity. Muscle tissue in all the species registered lower activity. The ²¹⁰Po/²¹⁰Pb activity ratio was found to be greater than unity. The biological concentration factor for organs varied between ~ 10⁴ and 10⁶ for ²¹⁰Po and ~10² and 10⁴ for ²¹⁰Pb. A significant variation in the accumulation of ²¹⁰Po and ²¹⁰Pb was noted between species and between seasons (p < 0.05). The mean whole-body internal dose ranged from 1.42 to 6.86 μGy h⁻¹ for ²¹⁰Po and from 3.0 × 10⁻³ to 8.0 × 10⁻³ μGy h⁻¹ for ²¹⁰Pb. The external dose for ²¹⁰Po and ²¹⁰Pb was 2.41 × 10⁻⁶ to 5.76 × 10⁻⁶ μGy h⁻¹ and 4.14 × 10⁻⁵ to 8.26 × 10⁻⁵ μGy h⁻¹, respectively. The activity levels recorded are in agreement with values recorded in related organisms in other parts of the world. The total committed effective dose due to the intake of both radionuclides ranged from 80.3 to 871.7 μSv y⁻¹. The median dose calculated due to ²¹⁰Po and ²¹⁰Pb in certain crabs in Kudankulam is less and would not pose any significant radiological impact on health or a cancer risk to the public, and the seafood is considered safe for human consumption.