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Gamma spectroscopy was performed to determine the concentrations of 226 Ra, 232 Th and 40 K in sediment samples collected from Periyakalapet to Parangaipettai, East coast of Tamilnadu. The activity concentrations were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA). The average activity concentrations of the corresponding nuclides were 30.81 Bq kg −1 for 226 Ra, 85.67 Bq kg −1 for 232 Th and 425.72 Bq kg −1 for 40 K. The average activity concentration of 232 Th and 40 K are slightly higher and 226 Ra is lower than world average values. The radiation hazard indices namely Radium Equivalent Activity (Ra eq ) Absorbed Gamma Dose Rate (D R ), Annual Effective Dose Rate (H R ), Representative Level Index (RLI), Annual Gonadal Dose Equivalent (AGDE) , Internal Hazard Index (H in ) and External Hazard index (H ex ) are calculated and compared with the previously reported data. The extracted values are comparable to the recommended values and they all fall within the safety limits. Hence harmful radiation effects are not posed to the public and tourists going to the beaches for recreation or to the fishermen involved in their activities in the area as a result of the natural radioactivity of sediments. Multivariate Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclides. [ABSTRACT FROM AUTHOR]

Selected heavy metals (Cr, Co, Ni, Cu, Zn, As, and Pb) in sediments from Periyakalapattu to Parangipettai of east coast of Tamil Nadu were determined to assess the contamination status and potential ecological risk. The pollution indices such as enrichment factor (EF), contamination factor (CF), geoaccumulation index (Igeo), and pollution load index (PLI) were calculated to determine the contamination level and enrichment of metals in sediments. EF analysis suggested that anthropogenic influence on the environment has been significant in case of Cr. The values of CF indicate that the sediments are not contaminated with these heavy metals. Igeo results reveal that the study area is not contaminated with respect to Cr, Co, Ni, Cu, Zn, As, and Pb. This results of Igeo are in good agreement with PLI. Based on the sediment quality guidelines, it is observed that Cr and Ni would be a concern for the ecotoxicological risk in study area. [ABSTRACT FROM AUTHOR]