Assessment of heavy metal pollution of drinking water sources and staple food cultivars around artisanal mining site in Igade-Mashegu, Niger State, Nigeria

Abstract

Ecotoxicological studies have been carried out on the precarious effects of heavy metal pollution and exposure attributed to anthropogenic practices such as mining, industrial and agricultural activities, which poses serious health challenges. This study investigated ten (10) heavy metals namely As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb and Zn in one hundred and fifteen samples from water sources and staple food cultivars around Igade mining site in Mashegu Local Government Area of Niger State, North-Central Nigeria, using Atomic Absorption Spectrophotometer (AAS). The result revealed the concentrations of heavy metals in staple food cultivars consumed at Igade to be within the recommended maximum levels as stipulated by WHO/FAO, but As2+ and Cd2+ were higher in legumes (1.510 ± 0.169 mg/kg) and vegetables (1.666 ± 0.154 mg/kg); and cereals (0.328 ± 0.012 mg/kg) and tubers (0.421 ± 0.176 mg/kg) respectively. This implies that the artisanal mining contributed to the exogenous bioaccumulation of these metals in staple food cultivars following the pattern: Fe > Zn > Cu > As > Pb > Cr > Cd > Hg which could accumulate and destroy vital organs thereby affecting human health upon consumption. Also, the mean concentration of the heavy metals in various water sources at Igade mining site decreased in the order Zn > Fe > Cr > Cu > As > Hg > Pb > Cd > Ni. Levels of As, Hg, Pb, Fe, and partly Cr in water sources were observed to be higher than the WHO and NSDWQ recommended standards for drinking water. Thus, their continuous consumption poses potential health risk to inhabitants, and therefore, there is need for the provision of safe alternative water sources; proper sensitization and monitoring of the mining activities to curb health risks and the extent of heavy metal contamination.