Occurrence, spatial distribution, and health risk assessment of heavy metals in groundwater from parts of the Kassena Nankana area, Ghana

摘要

Abstract In the absence of treated pipe-borne water supply to some local communities, groundwater can readily serve demands for agricultural and drinking purposes. Nonetheless, natural and anthropogenic activities can impact groundwater quality and render it unsafe for human consumption. Most communities in the Kassena Nankana district depend on water from boreholes for domestic use. The quality of groundwater in the area, particularly the heavy metals content, therefore needs to be assessed. In this study, the occurrence, spatial distribution, and human health risks due to exposure to heavy metals from groundwater in the area were assessed. The water samples were subjected to acid digestion (HNO3?+?H2O2?+?H2SO4) and analyzed for Zn, Pb, Ni, Mn, Fe, Cr, Co, and Cu using Atomic Absorption Spectrometer. The health risks due to heavy metals were computed using risk indices. Spatial maps were created with the aid of ArcMap and statistical analyses were done with SPSS. Concentrations of Pb and Cr were above the WHO limits for drinking water in 40 and 56 of the samples, respectively. The heavy metals showed a complex distribution pattern in space with high concentrations observed mostly in the northern parts of the study area. The sources of heavy metals in the groundwater were potentially from both the aquifer material and anthropogenic inputs. Total hazard index (HItotal) showed potential non-carcinogenic health effects in 61.04 and 62.34 of samples for adults and children, respectively, and the total cancer risk (CRtotal) showed potential carcinogenic health effects in 64.94 of samples for both groups. Risks of heavy metals exposure were higher in children than adults with Cr posing the highest threat. Constant quality monitoring, implementation of environmental management strategies, and treatment of groundwater before drinking are recommended to protect the groundwater and safeguard the health of inhabitants.