Toxicity of natural radioactivity in water samples from a gold mine in Gauteng Province, South Africa

A radiological toxicity assessment of natural radioactivity in water samples from a gold mine in the Gauteng Province of South Africa was evaluated. In this study, 29 water samples were collected from the mine and 5 were collected from a control area. A broad energy germanium detector was used to measure the activity concentrations of Uranium-238, Thorium-232, and Potassium-40. Their activity concentrations were then used to calculate radiological hazard parameters in water for the area. The average value of the Radium Equivalent Activity (Ra-eq) in water samples from the mining area and from the control area was found to he lower than the allowable limit of 370 Bq.L-1. The Annual Effective Dose Equivalent (AEDE) was found to be equal to 1.29x10(-3) mSv.y(-1), a value below worldwide average of 2.4 mSv.y(-1) for natural radiation. The external hazard (H-ex) and internal hazard (H-in) index for water samples from the mining area were less than unity, making water samples safe to the population in the area.