Natural radioactivity in cephalopod molluscs from Kerala coast: baseline concentrations and health risk implications

The study examined natural radionuclide levels in edible muscles of cephalopod species consumed in Kerala. Uranium (²³⁸U) concentrations ranged from 1.14 ± 0.06 to 1.72 ± 0.07 Bq kg^-1, while thorium (²³²Th) levels were between 0.08 ± 0.02 and 0.66 ± 0.04 Bq kg^-1. Polonium (²¹⁰Po) showed higher concentrations, ranging from 4.7 ± 0.9 to 27.2 ± 3.3 Bq kg^-1, and lead (²¹⁰Pb) levels varied from 3.8 ± 0.9 to 24.6 ± 6.8 Bq kg^-1. Squids, being pelagic, accumulated higher amounts of ²³⁸U and ²¹⁰Po, whereas cuttlefishes, being benthic, showed greater levels of ²³²Th and ²¹⁰Pb. Statistical analysis revealed significant differences in radionuclide concentrations among and within cephalopod species, influenced by habitat and taxonomy (p < 0.05). The annual committed effective dose (ACED) for coastal residents consuming these cephalopods was assessed. ²¹⁰Po was the main contributor to radiation dose, comprising over 80% of the total dose from all radioisotopes analyzed. Despite this significant contribution, the study concluded that health risks from consuming these cephalopods were within acceptable safety limits.