Water-quality assessment and spatial distribution of water-quality parameters of Dodoma Urban, Tanzania

Abstract

The study was conducted in 2022 in shallow wells and deep boreholes owned by residents, to investigate the water quality status in the  emerging developing area of Dodoma Urban municipality in central Tanzania. Eighteen boreholes and five shallow wells were assessed  using the water quality index (WQI), the inverse distance weighting (IDW) method under the ArcGIS environment, and the Euclidean  similarity index. The WQI classified the water samples into a good category class with a covered area of 42.5% and an excellent category  class with a covered area of 57.5%, indicating that most of the deep boreholes and shallow wells were suitable for residential purposes. The IDW revealed the spatial distribution of the physico-chemical parameters and WQI, indicating that water quality improved from west  to east within the study area. Yet, the Euclidean similarity index was dominated by nitrates, pH and heavy metals, with the highest  correlation coefficients. Despite the WQI being above the average class, water treatment technologies should be practiced to lower those  values of physico-chemical parameters existing above the threshold limits.