Health Risk Implications of Heavy Metals Contamination on Drinking Water in Densely Populated Markets of Abeokuta, Nigeria.

Abstract

Background: Access to safe drinking water is vital for public health; issues like water quality aberrations and pollution continue to affect urban dwellers, calling for an evaluation of health risks and pollution levels in water resources. Objectives: The study aimed at presenting an aggregate assessment of the pollution index and health risk of physical, chemical, and heavy metal constituents in drinking water resources across the markets of Abeokuta metropolis. Methodology: Three densely populated markets, including Kuto, Lafenwa, and Osiele, were selected for monitoring over three months during the wet season. Five hand-dug wells were sampled from each market and evaluated for groundwater quality parameters including pH, Temperature, Electrical conductivity (EC), Total Dissolved Solids (TDS), Sodium (Na), Potassium (K), Cadmium (Cd), Lead (Pb), Nickel (Ni), and Zinc (Zn). The data obtained were subjected to descriptive (mean and standard deviation) and inferential statistics (Pearson’s Correlation matrix and linear regression). Heavy Metal Pollution Index (HPI) and Health Risk Assessment (HRA) were estimated in the water samples. Results: Significantly, high levels of TDS and EC were observed in drinking water from Lafenwa, while high Pb, Ni, and Cd were observed in the water samples from Kuto, Lafenwa, and Osiele. The HPI revealed higher metal contamination at Lafenwa, but the value was generally below the critical index. The HRA showed high Pb, Cd, and Ni hazard quotients in adults, children, and infants, indicating non-carcinogenic adverse health effects. In contrast, cancer risk assessment showed elevated cancer risk. Conclusion: The drinking water from hand-dug wells at Kuto, Lafenwa, and Osiele markets of Abeokuta is contaminated and poses significant threats to human health upon consumption. Recommendations: The study advises the local health authorities to implement a regular monitoring programme for groundwater quality within the Abeokuta metropolis, especially in densely populated areas, to ensure safety and compliance with health standards. They can also launch educational campaigns to raise residents' awareness of the potential health risks associated with contaminated drinking water. Information on the importance of water quality testing can empower communities to proactively manage their health risks and advocate for improvements in water safety.