Potential health risk and level of heavy metal in groundwater in the highly-dense area of Akure, Southwestern Nigeria

Abstract

The drinking water quality of Akure, in the Ondo State area of southwestern Nigeria, was assessed. 21 groundwater samples were collected and tested for physicochemical characteristics such as pH, main ions, and heavy metals from motorized boreholes and hand-dug wells. From the hydrogeochemical modeling, it shows 77.3% of the samples are of the geochemical zone of 4 (strong acids exceed weak acids) while 22.7% of the samples are of the geochemical zone of 3 (weak acids exceed strong acids) with a hydrogeochemical trend of Mg > Na + K > HCO3 > Cl > SO4 > Ca. WQI results revealed that groundwater needs proper treatment before it can be fit for different purposes. Contamination Factor results showed minimal contamination, Metal Pollution Index revealed that 80.6 percent of the samples had values more than 6, suggesting that they were severely contaminated. Pollution Load Index values in the area were less than 1 showing there isn't any pollution. Geoaccumulation Index results showed that 47.6% of the samples are respectable contamination while 47.6% of the samples are modestly dirty. Principal Component Analysis results indicated loadings of variables within the PCI, PC2, and PC3 while the Correlation Matrix results indicated that there exists weak correlation amongst elements and the majority of the elements. From statistical approach of health risk assessment, it was observed that traceable absorption of poisonous heavy metals have resulted to diarrhea, typhoid fever, cholera, hepatits A and dysentery commonly found in children and youths in the study area. The results of the Hazard index showed that children were more prone to heavy metal hazards. Regular monitoring of the groundwater sources is highly recommended.