Potability and Health Risk Assessment of Some Potentially Toxic Elements in Groundwater Around Some Residential Areas in Ibadan Southwestern Nigeria

Abstract

Diseases worldwide are increasingly linked to consumption of contaminated water, necessitating safety assessment of domestic and drinking water in every locality. Consequently, this study aimed to assess the potability and possible health risk associated with the borehole water around Adegbayi, Celica, Iyana Agbala and Alakia residential areas in Ibadan, Southwestern Nigeria. Twenty borehole raw water samples were collected and examined for major cations and anions and other physicochemical parameters using standard procedures of flame photometry and spectrometry techniques. Selected potentially toxic elements such as lead (Pb), Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Cobalt (Co), Chromium (Cr), Nickel (Ni), and Cadmium (Cd) were analyzed by Atomic Absorption Spectrometry (AAS) method. All the physicochemical parameters were within the permissible limit of WHO for drinking water and the result of major cations and anions revealed a cations sequence of Ca> Mg> Na> K, while for the major anions HCO₃^- > SO₄^2- > Cl^- > NO₃^2-. The groundwater facies type is CaHCO₃. The calculated Average Daily Dose (ADD), Hazard Quotient (HQ), Total hazard index (HI) and Cancer Risk (CR) assessment of selected PTEs across different age groups (adults, children, and infants) revealed that Fe has the highest dose for all categories (0.1139 mg^-1kg^-1 day^-1 bodyweight^-1 in infants, 0.025 mg^-1kg^-1 day^-1 bodyweight^-1 in adults, and 0.07595 mg^-1 kg^-1 day^-1 bodyweight^-1). The estimated hazard quotients (HQ) obtained revealed that HQ of Cr for children (1.523) and infants (1.2025) was greater than 1 (HQ > 1) which signifies non carcinogenic adverse effects. However, the HQ values for Pb, Ni, Cd, Fe, Cu, and Zn were less than 1 (HQ < 1). The total hazard index (HI) for children (2.356) and infants (2.453) were greater than 1 (HI > 1). However, the HI for adults (0.546) was found to be less than 1 (HI < 1) this inferred a high health impact for children, and infants. The groundwater should be treated before consumption to avoid all associated health risks.