Environmental radioactivity,magnetic measurements and mineral analysis of major South Indian river sediments

The activity concentrations of 238u,232th and 40k have been determined by gamma ray spectrometer with nai (tl) detector in sediments of palar river,tamilnadu,india. the mean values of 238u,232th and 40k are 9.81±0.3,36.49±2.4 and 742.46±26.5 bqkg-1. the absorbed dose rate,radium equivalent concentration,external (hex) and internal (hin) hazardous indices are calculated and compared with the world average. the radioactive heat production rate (rhp) and excess lifetime cancer risk (elcr) are also calculated. the observed dose rate from erdm (environmental radiation dosi meter) at 1m above the ground level are measured and correlated with calculated absorbed dose rate. the distribution of quartz,feldspar,magnetic susceptibility and weight of the magnetic minerals are correlated with radioactivity results. from the observations,the weight of the magnetic minerals is an index to select the sediments of low or high radiological risk. the mean activity concentrations and the values obtained from the criteria formula is slightly greater than the world average.