Water Quality in Selected Shallow Wells in Dar es Salaam

Abstract

Majority of Dar es Salaam residents depend mostly on ground water fortheir domestic use because, they are not connected to the city water supply system,or the supply system is not reliable. Due to widespread use of groundwater (shallowand deep wells), the scientific determination of quality of this mass consumedproduct is essential. In this study the water quality parameters: physical, chemicaland biological contaminants on the shallow wells were investigated around Dar esSalaam City.Except for Total Dissolved Solids (TDS) and Total Hardness, other physicalparameters tested were within the WHO acceptable range. Levels of phosphate insamples from Temeke district ranges from 0.42 – 1.20 ppm, while samples fromIlala ranges from 0.16 – 0.36. Meanwhile chloride levels in samples from Temekeranges between 158.40 – 624.14 ppm and Ilala ranges between 142.34 – 359.52ppm. This could be due to human activities such as small industries and unplanned waste dumping sites close to water source.All water samples were contaminated with both Total Coliform (TC) and Fecal Coliform (FC). The highest TC and FC levels were detected in the sample from Vikunai Village in Temeke municipality (2160/100ml and 67/100ml respectively).This was due to proximity of pit latrines and runoff during rainfall because shallowwells are neither covered nor built up above ground level to create barriers againststorm water inflow.Generally, water from shallow wells in Dar es Salaam City is bacteriologically and chemically contaminated. The source of contamination is on-site waste disposal andpoor hygiene education. It is recommended that water from wells must be treatedprior to consumption in order to prevent potential infections. Residents ought to beprovided with water quality management education so that they could know how totreat, store and maintain the quality of drinking water.

Key words: shallow well, phosphate, water quality, nitrate, faecal coliform,chloride.