Natural radioactivity measurement and radiological hazard evaluation in surface soils in a gold mining area and surrounding regions in Bolikhamxay province, Laos

Measurement of natural radioactivity in surface soils in a gold mining area and surrounding regions in Bolikhamxay province, Laos has been conducted using an HPGe detector. Soil samples were collected at 65 locations distributed widely in Bolikhamxay province, including 25 samples in the gold mining area in Khamkheut district. The average activity concentrations of Ra-226, Th-232 and K-40 are obtained as 44.4 +/- 3.2, 63.3 +/- 5.2 and 523 +/- 18 Bq kg(-1), respectively. The calculated average radium equivalent activity is 175 +/- 20 Bq kg(-1). Radiological hazard indices in the gold mining area are higher than the average values in the province by 15-20%.