Hydrogeochemical characteristics and quality assessment of surface and groundwater around Adudu-Abuni lead-zinc minefields, Northcentral Nigeria

ABSTRACTThis study aims to evaluate the effects of contaminants on the surface and groundwater resources in the mining communities of Adudu-Abuni, Central-Nigeria. Thirty-one (31) water samples including 21 surface (streams) and 10 groundwater were analyzed for physicochemical parameters (major cations, anions, and heavy metals) using the APHA (2011) and (ICP-MS) standard methods. Physicochemical analysis showed that the concentration of heavy metal for both surface and groundwater of the area in the following order of abundance Fe>Pb>Zn>Cu>Cr>Cd>As and Fe>Zn>Pb>Cu>Cr>Cd>As, respectively. High concentrations of the heavy metals in the surface and groundwater are attributed to anthropogenic activities; improper channeling of mine effluents into the environments, these effluents reacted via oxidation and dissolution process, making solutions (contaminants) infiltrate into the aquifer system. Results showed for both surface (67%) and groundwater (70%) waterfall within the rock weathering dominance for both anions and cations, with few exceptions who fall into the precipitation dominance, suggesting that rock–water interface is the primary influencer for both surface and groundwater chemistry. This deduced that rock weathering and precipitations are the principal factors controlling the water chemistry in the study areas. WQI analysis for groundwater shows that the northern axis of the area depicts poor water quality while the southern regions are good for drinking. Whereas surface water source from the southern zones is unsuitable for drinking, while those in the northern region are good. This is attributed to the proximity of Pb-Zn mines to the southern region because streams within this zone serve as repositories for mine effluents