Risk assessment of drinkable water sources using gross alpha and beta radioactivity levels and heavy metals

The increase in economic activities as a result of population surge in Dutsin-Ma has culminated into increase in waste and environmental quality degradation. Hence, this study examined the risk associated with different drinking water sources (dam water (DM), borehole water (BW), Hand dug well water (WW) and tap water (TW)) in Dutsin-Ma, Katsina using concentrations of gross alpha (alpha) and gross beta (beta) activity, and heavy metals cadmium (Cd) and lead (Pb) in the water. A total of Thirty six (36) samples were collected from the study area. Standard methods were deployed for the determination of pH, concentration of gross alpha and gross beta activity and concentrations of Cd and Pb in the water samples were done using chemical fraction method. The results of the pH showed values not within the recommended limits for drinking water quality with exception of 8.30 (WW). Also, the measured activity concentrations of gross alpha in all water samples are below 0.1 Bq/L with few exceptions, while the measured activity concentrations of gross beta in 50% of the total water samples collected are higher than 1.0 Bq/L permissible limit. The mean annual dose equivalent all the water sources is higher than 0.1 mSv recommended dose for radionuclides in water, hence the life cancer risk assessment showed higher values, indicating the water are unsafe for drinking. The results in this study showed that Cd and Pb in all the water fractions (mobile, dissolved, total and particulate) are above the WHO recommended limit of 0.003 and 0.01 mg/L in drinking water. Similarly, the hazard index (HI) for the water samples are greater than one (1), hence, a possible concern for potential carcinogenic effect for consumer of the water sources.