Human Health Risks from Exposure to Heavy Metals in Water from Great Ruaha River Serving Domestic Purpose in Pawaga Division

Abstract

River water and banks could be very busy with varied activities ranging from farming to small industrial activities and other domestic household activities. The present study aimed at investigating the potential human health risks from selected heavy metal contaminants in Ruaha River water at the Kilolo division. To assess potential human health risks the concentration data for six heavy metals (Fe, Mn, Cu, Pb, Zn, and Cd) during the wet and dry seasons from four (4) villages were analyzed using Atomic Absorption Spectrophotometer. The observed mean concentration of heavy metals during the wet season is in the following order: Fe > Zn > Cu > Mn > Pb > Cd > Al. During dry season is in the following order: Fe > Cu > Zn > Mn > Al > Cd= Pb. The HQing of Cd ranges from 0.000 – 9.000 while Pb ranges from 2.143 – 32.143. The maximum carcinogenic risk (CR) from ingestion of Cd was 9.429 × 10-4 and Pb was 4.714 × 10-3. According to risk assessment standard these values are in grade five and six respectively. About 54.2% of the analyzed samples are at grade seven which is extremely high-risk position, while the rest are at high-risk side. Though most levels did not exceed critical values for human health risk from heavy metals, there is still a potential human health risk from chronic exposure to low heavy metal concentrations due to long-term exposure and potential metal interactions. Results of this study inform water pollution remediation and management efforts designed to protect public health in polluted urban area waterways common in rapidly developing regions.