Contamination of groundwater sources in emerging African towns: the case of Babati town, Tanzania

Abstract

Assessment of groundwater contamination potential was carried out in Babati, Manyara, Tanzania. Diazotization, cadmium reduction, ascorbic acid, ion selective electrode and membrane filtration analytical methods were used, respectively, for nitrite, nitrate, phosphate, fluoride and microbial investigations. Fecal coliforms (FC) and high NO3 concentrations were present in wells less than 30 m deep. The maximum FC level was 280 CFU/100 ml, and the nitrate (NO3) ranged from 1.1 to 357.7 mg-NO3/l. In boreholes, nitrate concentrations ranged from 2.3 to 32.6 mg-NO3/l, below both national and WHO standards, and were all free of fecal coliform. Other parameters were all within recommended limits for all wells tested. Evaluation of the potential contamination pathways revealed that the shallow well depths ranged from 1.2 to 26.67 m – median 9 m (N ¼ 366): 70% were unlined and 19% were uncovered. About 74% of the wells were within 30 m of sanitation facilities, of which 60% were traditional pit latrines. The findings revealed that most shallow wells (64%) are polluted and could cause health problems for users. Therefore, it is prudent that the community avoids relying on shallow wells. Boiling of domestic water before use is highly recommended.