Health Risk Assessment of Selected Heavy Metals along the Ethiope River in Delta State, Nigeria

Abstract

Human activities and processes degrade water quality. Early detection of threats from contaminated water can protect all aspects of life and habitat degradation. The concentration and health risk assessment of selected heavy metals (Cu, As, Ni, Cr, Pb, Hg, and Cd) were investigated in the surface water samples of River Ethiope. Water samples were collected along its banks at the following towns; Umuaja (SWI), Ebedie (SW2), Abraka (SW3), Sapele (SW4) and Ughara (SW5) axis during the rainy season; June to October, 2023. The heavy metal contents, heavy metal pollution index (HPI) and risk assessment were determined using standard methods of analysis. Descriptive analysis and analysis of variance were employed for data 
interpretation of the results. The results revealed that the mean concentration values of Cu, Pb and Cr ranged from 0.012 mg/l to 0.020 mg/l, 0.004 mg/l to 0.008 mg/l and 0.004 mg/l to 0.008 mg/l respectively. The observed highest concentrations of Cu (0.0133 mg/l), Pb (0.007mg/l) at locations SW4, SW5 and SW3 may be attributed to the anthropogenic activities including domestic and mainly industrial wastewater discharges and runoff. All metals analyzed were within the WHO permissible limits for portable water. Heavy metal pollution index (HPI) was computed for stations SW3, SW4 and SW5, however, none for SW1 and SW2 as the parameters of interest were not detected. The HPI values 5.612, 10.750 and 7.796 for stations SW3, SW4 and SW5 respectively were below 100 which showed a low level of heavy metal contamination and will not adversely affect health. Estimated human health risk from each metal contamination from adsorption and drinking the water of River Ethiope gave each of the hazard quotient (HQ) and hazard index (HI) values of < 1. It is therefore obvious from the results that the observed values were below the safe limit of one, suggesting that there was no potential adverse risk in water sampled via direct ingestion or dermal 
adsorption to the inhabitants.