This study characterises high-fluoride groundwater in the aquifer system on the flanks of Mount Meru, focusing on parts of the flanks that were only partially or not at all covered by previous research. Additionally, we analyse the impact of rainwater recharge on groundwater chemistry by monitoring spring discharges during water sampling. The results show that the main groundwater type in the study area is NaHCO3 alkaline groundwater (average pH = 7.8). High F− values were recorded: in 175 groundwater samples, the concentrations range from 0.15 to 301 mg/L (mean: 21.89 mg/L, median: 9.67 mg/L), with 91% of the samples containing F− values above the WHO health-based guideline for drinking water (1.5 mg/L), whereas 39% of the samples have Na+ concentrations above the WHO taste-based guideline of 200 mg/L. The temporal variability in F− concentrations between different seasons is due to the impact of the local groundwater recharge. We recommend that a detailed ecohydrological study should be carried out for the low-fluoride springs from the high-altitude recharge areas on the eastern and northwestern flanks of Mount Meru inside Arusha National Park. These springs are extracted for drinking purposes. An ecohydrological study is required for the management of these springs and their potential enhanced exploitation to ensure the sustainability of this water extraction practice. Another strategy for obtaining safe drinking water could be to use a large-scale filtering system to remove F− from the groundwater.

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A study was conducted to benchmark the ground water quality parameters and its spatial variation from Makutopora boreholes which are found 32 km from Dodoma town. A total of 90 samples (from both deep and shallow wells) were collected and analyzed for various quality parameters. The analysis results were interpolated using statistics and Inverse Distance Weighting tool in a Geographical Information System (GIS) environment to determine their spatial variation. The results indicated that all samples were within the permissible Tanzanian standards, except for two unused production boreholes which showed higher levels of total hardness, Electrical conductivity and total dissolved solids. However, gross pollution was found in community shallow wells of Chihanga and Veyula that showed high levels of nitrate (78-82 mg/l), Manganese (1.05 mg/l), low pH (5.98) and E. coli. (52/100 ml). It is quite clear from this study that the ground water supplied to Dodoma is still meeting the set drinking water standards in Tanzania although aquifer deterioration was noticed which demands an urgent innovative ground water management. The results obtained in this study will therefore be helpful for future monitoring and sustainable ground water quality management in the Makutopora sub basin.

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