Physical-Chemical and Bacterial Contamination Levels in Mzinga River Catchments of the Southern Dar es Salaam City, Tanzania: Public Health Implications

Abstract

Water is an appreciated natural resource for the survival of all living organisms. Management of the quality of this precious resource is therefore of special importance. In this study Mzinga River and its tributaries water samples were collected at a weekly interval from 2 nd November 2014 to 6 th December 2014 and analyzed for physicochemical and bacteriological evaluation of pollutants. Total and faecal bacteria were analyzed using membrane techniques while physical chemical parameters were analyzed using specified standard methods. The water pH was found to range from 6.09±0.08 to 7.05±0.06 which is slightly acidic though it is within the acceptable WHO limits of 6.5-8.5. The mean values of ammonium and phosphate varied between 4.50±0.03 mg/l to 6.50±0.04 and 7.18±0.27 to 9.70±0.12 respectively. Both of these are higher than Tanzania acceptable limits (2mg/l and 5mg/l respectively). The mean result of the analysis of the water samples for total coliform ranges from 14.17±4.06 CFU/100ml to 486.80±102.32 CFU/100ml, while faecal coliform ranges from 2.78±1.03 CFU/100ml to 120.36±4.50 CFU/100ml. The bacteriological contamination was due to the fact that Mzinga river is passing through a populated urban area thereby more exposed to direct sewage disposal and incoming industrial effluents. These results implicate the probability of people around these areas being prone to water-borne infections such as diarrhea or cholera.