Abstract
This paper presents the results of a radiological risk assessment arising from the presence of naturally occurring radionuclides in sand samples from three river-banks in Muzaffarabad. The mean values obtained for Th-232, Ra-226, and K-40 were found to be 44.58 +/- 3.34, 48.25 +/- 1.77, and 239.92 +/- 22.73 Bq kg(-1), respectively. To assess the uniformity of exposure, the radium equivalent activity (Ra-eq) was calculated and was found to be 130.47 +/- 8.29 Bq kg(-1). The current reported value for Ra-eq is lower than the maximum permissible value, that is, 370 Bq kg(-1) , and equivalent to a gamma dose of 1.5 mSv y(-1) . To investigate the possible contribution to health risks of alpha particle exposure, the radon exhalation rate (RER) from the sand samples was determined. The mean RER for all the samples was found to be 335 mBq m(-2) h(-1). About 43% of the samples were found to have an indoor excess lifetime cancer risk value slightly higher than recommended safety limit of 1, as proposed by the ICRP. A normalized parameter, the equivalent multiplicative factor, was defined and used to compare the current results with the findings of studies performed in other countries. Our findings are relevant to both human health and future environmental radiation monitoring.