Assessment of naturally occurring radionuclides in the coastal sediment with statistical analysis of radiological risk parameters

Abstract

This study reports on the spatial distributions of naturally occurring 238U, 232Th, 40K, 222Rn, and 220Rn from sediments across the coastal zone of the Bay of Bengal (BoB). The mean values of 238U, 232Th, and 40K activity are 23.42, 80.95, and 292.49 Bq kg-1, and the 220Rn surface mass exhalation rate value of 1,225.33 was calculated by 2.54 mBq kg-1 h-1. The radionuclide concentration range in all the samples estimated in the coastal region was 220Rn > 40K > 232Th > 238U and the radiological risk parameters (Ra<inf>eq</inf>, D<inf>R</inf>, AEDE, AGDE, I<inf>γr</inf>, AUI, H<inf>ex</inf>, H<inf>in</inf>, and ELCR) were higher in the Kanyakumari region and lower in the Puducherry region of the BoB. The radionuclide levels of 232Th, 238U, and 220Rn displayed a strong step of positive association with all parameters of radiological hazards through constants of r > 0.75. This showed that radiation risks were correlated with, and regulated by, 238U and 232Th concentrations. Therefore, coastline sediments do not pose any serious hazard, and the statistics obtained from this analysis will serve as the reference data for the activity of natural radionuclides in sediments across the coastal zone of the BoB. © 2025 The Authors.