Browsing by Author "C, Chandy, P"

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    Investigation of the contributions of domestic sewage effluents to groundwater pollution in some selected parts of Dar es Salaam region- Tanzania
    (University of Dar es Salaam, 2001) C, Chandy, P
    The present study focuses on the investigation of the contributions of domestic sewage effluents to groundwater pollution and characterization of physicochemical conditions of groundwater in some selected parts of Dar es Salaam region. Water samples were taken from both shallow wells and boreholes in which selected bacteriological and physicochemical indicators were determined. The results of FC and FS are found to range from 3-312 counts/lOOml of water sample as detected by membrane filtration procedure in 73 to 67% of the wells sampled from the two wards. Groundwater is found to be free from heavy metals as determined by AAS method. Principal component analysis resulted in three factors in each ward. The first factor is highly loaded with Cl', TDS, Na+, Ca2\ Mg2+, K+, F for Ukonga and TDS, Ca2+, Mg2+, Na+, HC03\ Cl', S042' for Kigamboni indicating that the dissolution of minerals, natural saltwater and seawater could be the sources of salinity in the area. The second factor is highly dominated by FC, NO,', FS, S042', HC03' and N03', FC, FS for Ukonga and Kigamboni respectively implying groundwater pollution from domestic sewage effluents. The third factor is highly weighted with pH and K for Ukonga and pH, K, and F for Kigamboni indicating the hydrolysis of both potassium feldspar, potassium mica and biotite minerals. The sample clustering processes appeared to be influenced by salinity content of the groundwater. Thus the dissolution, hydrolysis, natural saltwater and seawater intrusion processes are found to influence the chemical characters of groundwater and thus affected the aesthetic quality of groundwater in the area as explained by the use of both various chemical molar ratios and factor analysis. Further analysis of the data leads to the conclusion that bacteriological groundwater pollution in the study area is predominately caused by uncontrolled release of domestic effluents. It is therefore recommended that improvement in handling domestic wastes by installation of sanitary sewage systems and remediation of polluted sites and/or abandoned polluted wells, should be undertaken.