Conceptualization of Pollution of Groundwater Resources in Ilaje Area, Nigeria, West Africa: Contribution From Hydrogeochemical and Numerical Index Techniques

Abstract

Ilaje is a coastal settlement in Nigeria with a large number of its population depending on groundwater, through hand-dug wells, for domestic and irrigation use. Due to the vulnerability of coastal aquifers to contamination, for this study, 29 groundwater samples were analyzed for physicochemical parameters, major ions and trace elements to appraise the quality, pollution status and health risks of Ilaje water sources. Hydrogeochemical analysis revealed cationic, anionic and trace metals concentrations in these orders: Na+>K+>Mg2+>Ca2+, HCO3->Cl->SO42->NO3-, and Fe2+> Co2+>Pb2+> Ni2+> Mn2+ respectively and prevalence of Na-Cl facies suggesting imprints of saline-water intrusion. The results from the pollution evaluation and irrigation index methods revealed that the groundwater has significant trace metal pollution and has low to no suitability for irrigation. Furthermore, in this study, the carcinogenic and non-carcinogenic health risks posed by ingestion of the water to adults and children were determined using Probability of Cancer Risk, Chronic Daily Intake, Health hazard Quotient and Indices. It was discovered that upon exposure to the water for a long period of time, residents are prone to illnesses such as kidney disfunction, brain damage, diabetes and cancer. The pollution of the shallow groundwater resources hinges on the highly porous and permeable nature of the alluvial aquifer system of the area. This work recommends solutions like proper monitoring system and treatment plants installation to control the problem of groundwater pollution in the area.