Spatial distribution of natural radionuclides and the assessment of radiation indices in the coastal environs of Kovalam, southwest coast of India

Abstract An investigation on the natural radioactivity levels in the coastal areas of Kovalam beach was conducted using a 3ʺ ×3ʺ flat-type NaI (Tl) detector. The activity concentration of 40 K, 226 Ra, and 232 Th ranges from 1489 ± 20 to 1511 ± 16 Bqkg −1 , 3228 ± 200 to 3246 ± 186 Bqkg −1 , and 19,190 ± 760 to 19,210 ± 746 Bqkg −1 , respectively. The radiological parameters, namely radium equivalent activity, absorbed dose, and annual effective dose, were calculated, and all those values significantly exceed the world average values recommended by the UNSCEAR 2000. The study concludes that the enhanced level of natural radioactivity is mainly due to the presence of monazite-bearing black sand present in the study area.