Shallow Groundwater Quality and Human Health Risk Assessment in Holte, a Town in Southern Ethiopia

Abstract

Groundwater quality and human health risk assessment are critical for the long-term usage of household water supplies. The purpose of this study was to evaluate groundwater quality and human health risk in Holte, a town in the Derashe Special Woreda in southern Ethiopia. Water samples from seven shallow groundwater wells were taken and examined for hydrogeochemical properties. The Water Quality Index (WQI) was developed to assess the suitabilityof groundwater for drinking. Groundwater hydrochemistry types and evolutionary processes were investigated. The results suggested that the typical pH of groundwater samples had an average pH of 7.99. The values of electrical conductivity (EC), bicarbonate (HCO3) and total dissolved solid (TDS) in all samples were above the recommended upper limit of World Health Organization (WHO) for drinking water. Based on the hydrochemical findings, the orders of cationic abundance and anionic abundance in the groundwater were Ca²⁺ < Mg²⁺ < K⁺ < Na⁺ and F⁻ < SO₄²⁻ < Cl⁻< HCO₃⁻, respectively. According to the Piper Tri-linear Diagram, the majority of groundwater samples were found to have Mixed Ca-Na-HCO3. The Gibbs fields results showed that evaporation dominated groundwater quality, whereas chemical weathering of rock-forming minerals dominated the remaining samples. The calculated WQI result showed that 57.1% (4 handpumps) of groundwater samples from the town had acceptable water quality, but 42.9% (3 handpumps) had poor water quality. The finding of this study suggests that groundwater quality parameters should be tested and monitored on handpumps at sample locations 1, 2, and 3 in the town to minimize human health risks and ensure long-term socioeconomic development.