Spatial distribution of gamma radioactivity levels and radiological hazard indices in the East Coastal sediments of Tamilnadu, India with statistical approach

摘要

Natural and artificial radionuclide pollutants of the marine environment have been recognized as a serious environmental concern. The natural radioactivity levels in beach sediment samples collected from Thazhankuda (Cuddalore) to Kodiyakkarai along East Coast of Tamilnadu have been determined. Sediment sample were collected by a Peterson grab sampler from 10 m water depths parallel to the shore line. The grab sampler collects 10 cm thick bottom sediment layer from the seabed along the 20 stations. The radioactivities of 20 samples have been measured with a Nal(Tl) detector. The average specific activities for ~(238)U, ~(232)Th, and ~(40)K were found to be 3.67, 37.23 and 387.17 Bq kg~(-1) respectively. The results have been compared with other radioactivity measurements in different countries. It shows that the average activity of ~(238)U and ~(40)K is lower whereas ~(232)Th is slightly greater than the compared worldwide average value. The radiation hazard due to the total natural radioactivity in the study area was estimated by different approaches such as the radium equivalent activity (Ra_(eq)), absorbed dose rate (D_R), hazard indices, the annual gonadal dose equivalent (AGDE) and annual effective dose equivalent (AEDE) are compared with the international recommended values. Multivariate Statistical analyses (Pearson Correlation, Cluster and Factor analysis) were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclide.