Assessment of water quality and associated human health risk of a tropical freshwater body in Edo State, Nigeria

Abstract

The quality of freshwater sources is a key factor in sustainable development. This study investigated the water quality suitability of  Ossiomo River for human consumption and the implications for public health. Water samples were collected and analysed from October  2021 to March 2022. Results indicated that the water physico-chemical parameters from sampled locations were within their respective  National Environmental Standards and Regulation Enforcement Agency (NESRA) permissible limits except for pH (< 6.5), dissolved oxygen  (< 6.0mg L⁻¹ ), cadmium (> 0.005m /L⁻¹ ), manganese (> 0.05mg L⁻¹ ) and total hydrocarbon content (>10mg L⁻¹ ).  Comprehensive pollution index (0.4–1.0) and water quality index (251.57–765.37) values indicate that the water body was slightly polluted and unsuitable for human consumption (WQI > 50). Health risk assessment showed that children and adults were predisposed to non- carcinogenic risk (HIoral > 1) and carcinogenic risk (ICR: 1.21E-02 and 2.84E-03) from heavy metals through oral exposure. Natural run-off  and anthropogenic activities were identified sources of heavy metals and hydrocarbons within the catchment. The study has provided  data for water resource quality monitoring and raised concerns as to the need for immediate action to safeguard the public health of  communities surrounding the Ossiomo River, through the provision of alternative sources of potable water.