Hydrogeochemical Assessment of Groundwater Quality in Salima and Nkhotakota Districts, Malawi

This paper investigated the hydrogeochemical characteristics influencing water quality, and assessed the groundwater quality for domestic and irrigation purposes in two districts of Salima and Nkhotakota in Malawi. Data was compiled from water quality surveillance reports of water sources constructed by sponsorship from WaterAid Malawi programme. A water quality index (WQI) was used to measure suitability of groundwater for domestic purposes. Electrical conductivity, total dissolved solids and various indices were used to measure quality of water for irrigation. Anion chemistry showed a general dominance of, while Ca2+ was the dominant cation. The pH of groundwater in Salima was neutral and of Ca-HCO3/Na type, while in Nkhotakota it was slightly acidic and of Ca-Na/Mg type. It was determined that Ca2+, Mg2+, and originated from release of carbonates (calcite or dolomite) in both districts and from gypsum in Salima district only. Although turbidity, pH and EC exceeded drinking water standards, the WQI showed the water to be suitable for consumption. It was therefore recommended to educate communities on household water treatment methods. Continual monitoring of these water sources with unacceptable standards was also proposed to be a priority.