摘要
This paper presents the results of a radiological risk assessment arising from the presence of naturally occurring radionuclides in sand samples from three riverbanks in Muzaffarabad.The mean values obtained for 232 Th,226 Ra,and 40 K 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(Raeq) was calculated and was found to be130.47 ± 8.29 Bqkg^(-1).The current reported value for Raeqis lower than the maximum permissible value,that is,370 Bq kg^(-1),and equivalent to a gamma dose of1.5 m Svy^(-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 be335 m Bq 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.
This paper presents the results of a radiological risk assessment arising from the presence of naturally occurring radionuclides in sand samples from three riverbanks in Muzaffarabad. The mean values obtained for 232^Th, ^226Ra, and ^40K 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 （Raeq） was calculated and was found to be 130.47±8.29 Bq kg^-1. The current reported value for Raeq 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 multi- plicative factor, was defined and used to compare the current results with the findings of studies performed inother countries. Our findings are relevant to both human health and future environmental radiation monitoring.
