Determination of gamma ray exposure rate in soils of Yelagiri Hills, Tamil Nadu

Anthropogenically enhanced naturally occurring radionuclides such as ²³⁸U, ²³²Th and ⁴⁰K have been determined in soil of Yelagiri Hills, Tamilnadu using gamma ray spectrometry. The activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K range from £2.17 to 53.23 ± 7.07Bqkg^-1, 13.54 ± 5.23 to 114.75 ± 9.21Bqkg^-1 and 261.11 ± 33.06 to 2207.3 ± 50.53 Bqkg^-1 respectively. The results show that the mean activity of ²³⁸U is lower whereas that of ²³²Th and ⁴⁰K are 1.38 and 2.86 times higher than worldwide average value given by UNSCEAR, 2000. To evaluate the environmental radiological hazards in soils, exposure rate (ER) has been calculated and this exposure rate varies from 181.03 to 565.77 µRhr^-1 with an average of 379.20 µRhr^-1. This average exposure rate was below the world average value of 600 µRhr^-1 given by UNSCEAR, 2000. Multivariate statistical techniques such as Pearson's correlation, Principal component, and cluster analysis were performed for radioactivity data to know the exiting relation between them. The results of this study show that the soils of Yelagiri Hills do not possess any radiological hazards and are safe for construction purpose. (author)