Lifetime cancer risk due to gamma radioactivity in soils from Tudor Shaft mine environs, South Africa

AbstractThis study is aimed to evaluate the soil radionuclides' activity concentrations and environmental outdoor gamma dose rates in Tudor Shaft mine environs, South Africa. The excess lifetime cancer risks are also calculated. Outdoor gamma dose rates were determined in 45 soil samples taken from 9 locations. The maximum and minimum average outdoor gamma dose rate taken 1 m above ground was 202.74 ± 14.18 and 131.09 ± 5.43 nGy/h, respectively. Also, the maximum and minimum mean annual effective gamma dose of Tudor Shaft mine environs was 2.49 × 10−1 and 1.61 × 10−1 mSv/y, respectively and the excess lifetime cancer risk from the average values of the outdoor gamma dose from nine areas of 1.03 × 10−3 was observed. Soil samples were analysed by gamma spectroscopy and the average 238U, 232Th, and 40K activities were 271.96 ± 3.59 Bq/kg, 47.65 ± 3.69 Bq/kg and 87.17 ± 5.19 Bq/kg, respectively. The average soil radionuclides' concentrations of Tudor Shaft mine environs were above the worldwide range and some extreme values had been determined. Annual effective gamma doses and the excess lifetime risks of cancer were higher than the world's average