Assessment of Natural Radioactivity Levels in Surface Waters within Proximity to a Proposed New Mine Site at Ahafo North, Ghana

Abstract

This study investigates the natural radioactivity levels, in surface waters close to a proposed mining area in Ahafo North of Ghana by analyzing the presence of uranium 238 and thorium 232 among elements in 16 water samples through gamma and alpha spectrometry methods. It was found that uranium 238 levels varied from < 0.01 to 22.3 Bq/L, with an average concentration of 5.24 ± 0.26 Bq/L and the highest levels were observed in sample CSw26. Thorium 232 levels peaked at 56.5 Bq/L in the sample; meanwhile potassium-40 levels fluctuated between 0.1 to 189 Bq/L on average of 44.8 ± 2.98 Bq/L. Polonium 210 showed variation, in its levels from < 0.01 to 65.5 Bq/kg, with an average of 17.5 ± 0.8 Bq/kg. The higher end of this spectrum correlates with discoveries in areas abundant in phosphates but surpasses the usual concentrations observed in non-mined regions globally indicating geological factors affecting polonium levels in these water bodies Analysis of gross alpha and beta activity revealed alpha values ranging from 0.00358 and 0.0053 Bq/L and beta activity ranging from 0.0345 to 0.0488 Bq/L. Even though the levels detected were lower, than the standards set by the WHO (with 0.5 Bq/L for alpha and 1 Bq/l for beta) 23% of the samples surpassed the recommended threshold for thorium content, in water sources that people rely on – emphasizing the importance of monitoring to ensure radiation protection and safety.