Assessment of Groundwater Quality Using Physicochemical Parameters inHodan District, Mogadishu, Somalia

Abstract

Groundwater is the principal source of domestic water supply in Hodan District, Mogadishu, Somalia, yet rapid urbanization, unplanned settlement growth, and inadequate sanitation infrastructure have raised concerns over its quality and safety for human consumption. This study evaluated groundwater quality in Hodan District using seven physicochemical parameters: pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), chloride (Cl−), nitrate (NO3−), and fluoride (F−) obtained from eight boreholes (Heydar, Buruj Tower, Rer M. Shekh, Gorgor, Umu Batula, Ciise Qodax, Soonikia/Digfer, and Tarabuuna/Umu Caisha) distributed across the district. Laboratory-derived hydrochemical data were compiled, statistically summarized, and compared against World Health Organization (WHO) drinking-water guideline values, while spatial distribution patterns were mapped using Geographic Information System (GIS)-based Inverse Distance Weighting (IDW) interpolation. Results show that the groundwater is alkaline (pH 7.6–8.9) and very hard, with mean EC (2.42 mS/cm), TDS (2274.0 mg/L), and chloride (526.6 mg/L) values exceeding WHO permissible limits at most or all sampling points, indicating pervasive salinization consistent with seawater intrusion in this coastal aquifer. Nitrate concentrations were highly variable (4.3–146.6 mg/L), with three boreholes exceeding the WHO limit of 50 mg/L, pointing to localized anthropogenic contamination from onsite sanitation systems. Fluoride was the only parameter within safe limits at every borehole (0.28–0.60 mg/L). The findings indicate that groundwater in Hodan District is largely unsuitable for direct consumption without treatment, primarily due to salinity and localized nitrate pollution, and highlight the need for routine water-quality monitoring, sanitary protection of wellheads, and appropriate household-level treatment.