Assessments of radioactivity concentration of natural radionuclides and radiological hazard indices in sediment samples from the East coast of Tamilnadu, India with statistical approach

This paper reports on the distribution of three natural radionuclides U-238, Th-232 and K-40 in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10 m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a Nal(TI) detector based gamma-spectrometry. The mean activity concentration is <= 2.21, 14.29 and 360.23 Bq kg(-1) for U-238, Th-232 and K-40, respectively. The average activity of Th-232, U-238 and K-40 is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of U-238, Th-232 and K-40 to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Ra-eq), absorbed gamma dose rates in air (D-R), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (H-ex) internal hazard index (H-in), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended values. Therefore, coastal sediments do not to pose any significant radiological health risk to the people living in nearby areas along East coast of Tamilnadu. The data obtained in this study will serve as a baseline data in natural radionuclide concentration in sediments along the coastal East coast of Tamilnadu. (C) 2015 Elsevier Ltd. All rights reserved.