Spatial Distribution and Health Implications of Trace Elements in the Groundwater of Ado-Ekiti, Southwestern Nigeria

Abstract The spatial variations, potential origin and associated health risks of some trace elements in groundwater of Ado-Ekiti southwestern Nigeria were evaluated. Sixty groundwater samples were evaluated for the concentration of some selected trace elements which includes Mn, Fe, Pb, Zn, Cu and Cr. The results were presented as spatial distribution maps with respect to the world health organization and the Nigerian standards for drinking water. The result showed that the mean concentrations of some of the trace elements exceeded the threshold values stipulated by the world health organization and the Nigerian standard for drinking water in several sampling locations. However, all of the sampled wells recorded Pb concentration below both standards. The weathering of underlying bedrocks are key sources to some of the trace elements in the groundwater of the study area. A health risk assessment was undertaken using hazard quotient (HQ) and hazard index (HI). The HI values imply that the risk of contamination through oral ingestion pathway is from low through medium to high levels for both adults and children as the trace elements show mean HI values more than unity. The health risk assessment also indicates that the children are more susceptible to the non-carcinogenic risks than adults in the study area. Hence, some urgent proactive steps should be taken to avert the consequences of this health risk.