Safety and quality of borehole water: a case of Dar Es Salaam region

MSc. Dissertation 2018

This study was conducted to assess the safety and quality of the borehole water consumed in Dar es Salaam based on depth and distance from the septic tank. It covered the three districts of Dar es Salaam namely Ilala, Kinondoni (including Ubungo) and Temeke (including Kigamboni). A Randomized Complete Block Design with two factors, depth (treatments) and distance to the septic tank (block) was used. Depth was studied at 4 levels, shallow (0-30 m), medium (31-50 m), deep (51-80 m), and very deep (>80 m) while the distance from the septic tank to the borehole was examined at two levels: less than 15 m and more than 15 m. This was replicated two times. A total of 48 samples of borehole water were collected and analyzed for physico-chemical (pH, B.O.D, total hardness and metal contaminants {copper (Cu) and lead (Pb)}) and microbiological qualities (for coliforma E.coli and C. perfringens) and analyzed according to standard procedures in the Water Development and Management Institute (WDMI) and Tanzania Bureau of Standards (TBS) laboratories. Results were compared to WHO (2011) and TBS (2008) standards. Data was analyzed using R- statistics for ANOVA and means were separated by Tukey‘s Honest at p <0.05. The results of pH, B.O.D and C. perfringens were significantly decreased as the depth increase while levels of total hardness, coliforms and E. coli were significantly higher in deep and very deep boreholes water. Also, the levels of B.O.D were significantly lower in boreholes which were located near the septic tank than those which were far. Microorganisms however, were significantly higher the boreholes located far from the septic tank compared to near. This was unexpected, however other factors were also considered. The distance between the septic tank and borehole did not affect significantly neither the pH nor the total hardness of water.