Characterization of Leachate and sludge for pollutants that pose health risks to the Pugu Kinyamwezi area in Dar es Salaam
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Date
2013
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Publisher
University of Dar Es Salaam
Abstract
Characterization of leachate, soil and sludge for Hg, Pb and Cd was carried out. Stannous chloride (SnCl2) aided COLD VAPOR test using model Hg-201 Semi-Automated analyzer was employed to determine Hg-levels in matrices. The concentrations of Pb and Cd were determined using Flame-AAS according to U.S.EPA SW-846 Method 3050A. Results show that all three types of environmental samples contain high values of Hg, Pb and Cd whereby Pb; 7.858mg/l (leachate), 18,150.751mg/kg (sludge) and 153.113mg/kg (soil) is the principal contaminant. Two tests for the hypotheses were tested to verify for metal content and environmental intoxication. A parametric t-test was employed to prove the first hypothesis using analyte values in sludge. The second hypothesis was verified using paired t-test and readings from proxy batches of soil collected far away and close to the dumpsite. At 5 per cent level of significance metals were found to exceed standard limits: 0.3μg/kg (Hg), 0.6mg/kg (Pb), 0.42mg/kg (Cd); and have contaminated the surrounding environment. On the average 2.35kg (Hg), 225302.7kg (Pb) and 85.86kg (Cd) are released into the study area per hectare per year. Accordingly, these results far exceed EPA regulatory limits of 0.85kg/ha/yr (Hg), 15kg/ha/yr (Pb) and 1.9kg/ha/yr (Cd). Thus, further studies on groundwater and surface water, flora and fauna to determine the extent of heavy metal pollution, formulation of policies to address treatment and deposition problems of hazardous wastes; and development of a sanitary landfill are recommended.
Description
Available in print form, East Wilbert Africana Collection, Dr. Wilbert Chagula Library, Class mark (THS EAF TD767.T34M36)
Keywords
Sewage sludge, Characterization, Leachate, Pollutants, Health risks, Pugu Kinyamwezi, Dar es Salaam
Citation
Mangasini, F(2013)