Research Article published by Springer
Arusha aquifers have been exploited intensively serving as the main source of domestic water supply in the city. But the
quality of groundwater is not clearly documented for future planning and management. Hydrogeochemical assessment was
carried out to establish groundwater quality and its spatial distribution with the aid of geostatistical techniques. Groundwater
samples were collected and analyzed for major cations and anions using conventional methods of water analysis. Well
lithology and geological map were considered for hydrogeological interpretation of the area. The results of piper diagram
revealed Na–K–HCO3 water type with sodium and bicarbonate ions dominating in all samples. High fluoride concentrations
and general groundwater chemistry are mainly controlled by aquifer lithology than anthropogenic activities. The levels
of anthropogenic pollution indicators such as nitrate, chloride and sulfate in deep wells are generally low and most likely
coming from natural sources. The geological sections indicate two potential aquifers (volcanic sediment and weathered/
fractured formation) both yield water containing significant concentration of fluoride. Fluoride concentrations were higher
than WHO guidelines (1.5 mg/l) and Tanzanian standards (4.0 mg/l) by 82 and 36% of the analyzed groundwater samples,
respectively. The southern part of the study area yields groundwater of better quality for human consumption than northern
zones which is at high elevation on the foot of Mt. Meru. With exception of fluoride, the quality of groundwater in the study
area is generally suitable for drinking purpose and other socioeconomic uses.