Abstract
This study shows the assessment of radiation hazard parameters due to terrestrial radionuclides in the soil around artisanal gold mining for addressing the issue of natural radioactivity in mining areas. Hence, the levels U-238, Th-232, K-40 and Ra-226 in soil (using gamma spectrometry), Rn-222 in soil and Rn-222 in air were determined. Radiation hazard parameters were then computed. These include absorbed dose D, annual effective dose E, radium equivalent activity Ra-eq, external hazard H (ex), annual gonadal dose equivalent hazard index AGDE and excess lifetime cancer risk ELCR due to the inhalation of radon (Rn-222) and consumption of radium (Ra-226) in vegetation. Uranium (U-238), thorium (Th-232) and potassium (K-40) averages were, respectively, 26, 36 and 685 Becquerel per kilogram (Bq kg(-1)). Soil radon (4671 Bq m(-3)) and radon in air (14.77 Bq m(-3)) were found to be less than worldwide data. Nevertheless, the average K-40 concentration was 685 Bq kg(-1). This is slightly higher than the United Nations Scientific Committee on the Effects of Atomic Radiation average value of 412 Bq kg(-1). The obtained result indicates that some of the radiation hazard parameters seem unsavory. The mean value of absorbed dose rate (62.49 nGy h(-1)) was slightly higher than average value of 57 nGy h(-1) (similar to 45% from K-40), and that of AGDE (444 mu Sv year(-1)) was higher than worldwide average reported value (300 mu Sv year(-1)). This study highlights the necessity to launch extensive nationwide radiation protection program in the mining areas for regulatory control.