Spatio-temporal Variations and Potential Health Risks of Heavy Metals in Water from River Manafwa, Uganda

The epicenter of flash flood inundations and landslides in Uganda has been areas around Mt. Elgon. By implication, it has led to the loss of lives and food and water insecurity. This study assessed the seasonal variations in physiochemical parameters and heavy metals (HMs) water content from River Manafwa (R. Manafwa), the major water source used around Mt. Elgon. Potential insidious human health risks associated with consumption and dermal contact with water from the river were assessed using target hazard quotient and incremental lifetime cancer risk methods. Results of atomic absorption spectrometry analysis showed that the concentrations of the HMs in the wet and dry seasons ranged from below the detection limit to 1.407 ± 0.001 mg/L, which were below WHO limits. Health risk assessments indicated that there are discernable non-carcinogenic health risks from the ingestion of water from R. Manafwa, as the total target hazard quotients were above 1 for some of the samples. Cancer risk values indicated that there are no potential cancer risks from ingestion of water from the river. This study recommends that regulatory authorities should intervene to mitigate the pollution of R. Manafwa by strengthening restrictions on sand mining and dumping of wastes into the river.