Effect of boiling time on radionuclide concentration in seafood

To reveal the effect of boiling time on radionuclide concentrations in seafood by investigating boiling-represented cooking practices, in order to fill the knowledge gap on how boiling time affects human radiation exposure. A total of 13 seafood species of four categories (fish, crustacean, mollusk and algae) were collected from the coastal areas of China and analyzed for radionuclide contents left after boiling at 5, 10, 20 and 40 ​min under 100°C. Gross α and β, 40 K, 226 Ra, 232 Th, 137 Cs were measured using the low background α and β counter and the gamma-spectrometer. The contents of radionuclides decreased significantly with the increasing boiling time. The average retention rate of α-emitting radionuclide in in fish, crustacean, mollusk, and algae decreased to 64.47%, 53.34%, 84.12% and 62.63% after 5 ​min of boiling, respectively, and then to 15.46%, 14.21%, 71.94%, and 27.27% after 40 ​min, respectively. The average retention rate of β-emitting radionuclide in in fish, crustacean, mollusk, and algae decreased to 64.89%, 43.43%, 66.55% and 63.30% after 5 ​min, respectively, and then to 47.90%, 29.01%, 45.96%, and 53.24% after 40 ​min. The greatest loss of solubility was observed for 40 K with the average retention rate of 47.16% after 10 ​min, and higher retention rate of 87.86% and 90.03% in 226 Ra and 232 Th, respectively. Boiling is effective in reducing the radionuclide content, with the committed effective dose (CED) reduction of 44.6% achieved by boiling for 10 ​min, mainly due to the reduction in 40 K. A full assessment will also be needed to incorporate more radionuclides ( 210 Po, 210 Pb, 228 Ra) into the calculations.