Browsing by Author "Nziku, Adreherm Joseph"

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    A study on heavy metal pollution in the receiving environment of the university of Dar es Salaam waste stabilization ponds, Dar es Salaam -Tanzania
    (University of Dar es salaam, 2010) Nziku, Adreherm Joseph
    The main objective of this study was to examine the availability and concentrations of mercury (Hg), cadmium (Cd), Lead (Pb), Zinc (Zn) and Molybdenum (Mo) in water, sediments and analyze their accumulation pattern in fish found in the receiving environment of the University of Dar es Salaam main campus waste stabilization ponds.Hg, Cd, Pb, Zn and Mo were analyzed in water, sediment and fish tissues (liver, gills and dorsal muscles) of Oreochromis niloticus (Tillapia) and Clarias gariepinus (Catfish) species from the receiving environment of the University of Dar es Salaam main campus waste stabilization ponds in September, 2009 - March 2010. Samples were analyzed using Inductively Coupled Plasma and the data were processed using ANOVA, Chi square, t-test and Correlation tests.The concentration of heavy metals varied significantly between water, sediment and fish. The variation was also noted between fish species and type of tissues analyzed. Hg, Cd, Zn and Mo concentrations in water and sediment were within safe limits with exception of Pb in water. Cadmium, Lead and Zinc in sediments were found to be appreciably above WHO recommended standards (p<0.05).The concentration levels for Cd, Pb and Zn were above acceptable levels in Oreochromis niloticus while Hg was found to be within safe limits in both species (p<0.05), Mo was below detection limit in Oreochromis niloticus. Pb, Zn and Mo appeared to be accumulated in Clarias gariepinus (p<0.05) while Cd was not detected. Heavy metals entering fish are distributed into different tissues in a varied proportion depending on the affinity. Oreochromis niloticus accumulated metals in the increasing order from dorsal muscles < gills < liver while Clarias gariepinus accumulated metals in the decreasing order from dorsal muscle < gills < liver.The study recommends sensitization of the public so that people become aware and well informed of the dangers to which they are exposed through consuming fish and other products from such polluted environment.