Assessment of radioactivity and heavy metals in water sources from Artisanal mining areas of Anka, Northwest Nigeria

Abstract

This study assessed the health risk associated with water sources in the artisanal and local mining areas of Anka, Northwest Nigeria. The evaluation of radioactivity concentration was carried out using a gas flow proportional counter while the carcinogenic and non-carcinogenic risks of heavy metals exposure were also evaluated. The concentrations of Cd, Co, Cu, Fe, Hg, Ni, Pb and Zn were measured using the microwave plasma atomic emission spectrometer. The mean annual effective dose for α- and β- emitters for children were 10.12 and 14.63 µSvy−1, respectively and those of adults were 22.94 and 30.51 µSvy−1 for α- and β- emitters, respectively. The mean values of lifetime cancer risk for children and adults were 2.73 × 10−4 and 1.26 × 10−4, respectively. The mean concentrations of heavy metals in descending order show the trend as Pb > Fe > Zn > Hg > Cu > Ni > Co > Cd > Cr. The mean concentrations of Fe, Hg, and Cd were above the WHO permissible limits of 0.200, 0.100 and 0.003 mgL−1, respectively. The hazard index of heavy metal evaluated in this study for children was 7.43 while that of adults was 1.27, which are higher than the limit of 1. The cancer risk due to heavy metal was 1.55 × 10−3 for children and 2.65 × 10−4 for adults; these values are higher than USEPA safe limits. The carcinogenic and non-carcinogenic risks from heavy metal are of concern and should be considered for continuous monitoring and remediation.

Keywords

• Carcinogenic risk
• Heavy metal
• Hazard index
• Mining
• Radioactivity
• Water