Analysis of groundwater contamination on selected areas of Asmara, Eritrea

Water is indispensable for all living organisms, and its safety is critical for public health. The Water Safety Plan framework enables communities to evaluate the purity and safety of water sources; however, groundwater remains highly vulnerable to pollution from domestic waste, industrial effluents, oil spills, and seepages. In this study, 12 groundwater samples from nine sites—collected exclusively from hand-dug wells—were analyzed for 20 physicochemical parameters: pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, temperature, turbidity, total alkalinity, total hardness, calcium hardness, magnesium hardness, sodium (Na), potassium (K), phosphate, sulfate, nitrate, chloride, bicarbonates, chemical oxygen demand (COD), and biochemical oxygen demand (BOD). The results were compared with World Health Organization (WHO) drinking water guidelines. Analysis revealed that six wells exceeded the permissible limit for TDS, 11 wells had elevated total hardness, and four wells exceeded the limit for calcium and magnesium hardness. Sulfate concentrations in GW08 (474 mg/L) and GW12 (531 mg/L) were above WHO permissible limits, while nitrate concentrations in GW03 (350 mg/L), GW07 (140 mg/L), GW09 (113 mg/L), and GW12 (350 mg/L) exceeded permissible limits. Notably, GW03, GW11, and GW12 exceeded multiple parameter limits, with GW03 identified as the most contaminated source.