Distribution of natural radioactivity and their radiological significance in beach sediments of Tamil Nadu, East Coast of India

Abstract

This study examines the distribution of natural radionuclides in sediment samples from the Tamil Nadu coastline, east coast of India. The activity concentrations ranged from 12.15 to 138.56 Bq kg⁻1 with an average of 34.33 Bq kg⁻1 for 238U, 15.08–173.03 Bq kg⁻1 with an average of 51.55 Bq kg⁻1 for 232Th, and 131.56–438.20 Bq kg⁻1 with an average of 282.59 Bq kg⁻1 for 40K. The mean value of 232Th activity was 1.7 times higher than the world mean value, whereas the mean value of 238U and 40K activity were lower than the world mean value. The activity concentrations in the study area was compared with other countries in world, and various locations in India and previous research work along the Tamil Nadu coastline were also discussed. The radiological indices included radium equivalent activity (129.8 Bq kg⁻1), absorbed dose rate (110.9 nGyh^(-1)), annual effective dose equivalent (0.14 mSvy^(-1)), internal hazard index (0.44), external index (0.35), representative level index (0.93), activity utilization index (0.96), annual gonadal dose equivalent (410.3 〖µSvy〗^(-1)), alpha index (0.17), gamma index (0.47) were calculated which were well within safety limits. The mean Gamma and alpha indices values be less than unity and show no exceedance beyond the recommended level. Our findings provide baseline data on radioactivity levels in beach sediment samples along the Tamil Nadu coastline, east coast of India, and confirm that these sediments do not pose a significant radiological risk to the public.