Potential health risk and levels of heavy metals in water resources of lead–zinc mining communities of Abakaliki, southeast Nigeria

Abstract

Heavy metals are potential health risk, especially in mining sites where they deteriorate from sulfide-rich ore bodies. Lead, cadmium, arsenic and mercury are very carcinogenic, while others are toxic. The assessment of the levels of these metals in water resources of the lead–zinc mining communities of Enyigba, Mkpuma Akpatakpa, Ameka, Amorie, Amanchara and Alibaruhu was carried out, and the potential health risk has been investigated. These areas make up the main mining communities of Abakaliki, where active and abandoned mines are located. One hundred and six water samples were analyzed in two seasons using atomic absorption spectrophotometric and ultra-violet/visible spectroscopy. Result indicates levels of Pb 2+ > Hg 2+ > As 2+ > Cd 2+ > Mn 2+ > Ag 2+ > Se 2+ > Ni 2+ > Cr 2+ > Cu 2+ in water sources. High levels of Mn 2+(63.45 mg/L), Pb 2+(11.42 mg/L), Cr 3+(14.60 mg/L), Ni 2+(1.260), Cd 2+(15.67 mg/L), Ag+(6.06 mg/L), Hg 2+(2.60 mg/L), As(4.13 mg/L), Se 2+(2.68 mg/L), Zn 2+(10.53 mg/L) and Co 2+(0.9 mg/L) above the WHO recommended standard for drinking water were observed. Only Cu 2+ recorded safe concentrations in 100% samples analyzed. Levels of associated metals including Pb 2+, As, Hg 2+, Se 2+ and Cd 2+ are higher in groundwater especially in areas close to the active mines; this is due to mineralization in the area. Seasonal analysis shows a decreased concentration of chemical constituents in the rainy season relative to the dry season. Potential health risk is associated with accumulation of toxic heavy metals in tissues including Parkinson disease, arsenicosis, acrodynia, selenoises, Alzheimer’s disease, hair loss, mental imbalance and abortion in women abound in the areas. Alternative water supply sources and sensitization on the potential health risk are highly advocated in these communities.