Assessment of the Suitability of Groundwater in Kigamboni, Tanzania for Domestic and Irrigation Purposes Using Multivariate and Water Quality Index Analyses

Groundwater is a critical water source supporting over 2.5 billion people globally and accounting for 43% of water used for irrigation worldwide. In this study, the suitability of groundwater quality in Kigamboni, Dar es Salaam, Tanzania for drinking and irrigation purposes was assessed. Groundwater samples were collected from 25 boreholes and analyzed for physical chemical, and bacteriological parameters. Water quality index (WQI), sodium adsorption ratio (SAR), percentage of sodium (Na %), magnesium hazard (MH) and permeability index (PI) were used to evaluate groundwater suitability for drinking and irrigation purposes. Also, Pearson correlation coefficient, Piper diagram, Multivariate analysis were used to assess the groundwater quality. Results indicated that groundwater in the study area is characterized by concentration of cations in the order of Na+ > Ca2+ > Mg2+ > K+ and anions Cl- > CO32- > HCO3- > SO42-. Groundwater in the study area is predominantly characterized by Na-K-Cl water type signifying influence of seawater intrusion. Furthermore, 44% and 12% of the groundwater samples were considered unsafe for drinking and irrigation purposes, respectively. This study recommends that groundwater in the study area can be used for drinking purposes with minimal treatment at household level and be used for irrigation purposes to support plant growth.