Chemo dynamics of pesticides in soil at some hotspots in ten regions and in atmospheric matrices in kibaha Tanzania

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University of Dar es Salaam
This thesis reports on the chemodynamics of pesticides in soil at contaminated sites in ten regions and in atmospheric matrices in Kibaha, Tanzania. Soil samples were extracted using an accelerated solvent extractor with n-hexane:acetone while rainwater samples were extracted by liquid-liquid extraction with dichloromethane. Labelled internal standards were used. Clean-up of extracts of samples was performed by using silica gel and aluminium oxide with 3% water followed by C18 sorbents. Instrumental analysis of extracts was performed by use of a high resolution GC-MS. Very high concentrations of persistent bioaccumulative and toxic organochlorine pesticides and degradation products (e.g. DDT, DDD, DDE, HCHs, endosulfans, dieldrin, aldrin, endrin, hexachlorobenzene, heptachlor and chlordane) have been found in samples from almost all sites and they were widely distributed. The concentrations of the dominant contaminants (e.g. DDT) were up to 560000 mg/kg dw in soil and 3200 μg/l in rainwater samples. The compositions of the contaminants indicated aged compounds in most cases but which have not been significantly degraded in most of the studied areas. The contaminants were evenly distributed among the sampling depths at most sites while there were significant differences in the concentrations of the compounds among the sampling depths in soil at the most contaminated sites. The highest concentrations of the compounds were found at points located within the most affected areas and the concentrations decreased with increase in distance from those points. The concentrations of the compounds in rainwater samples indicated a slight decrease in emissions with time. The findings indicate risk and concern to public health and the environment and thus point out to the urgent need for remedial actions at the most affected areas.
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Pesticides, Kibaha, Tanzania
Marco, J.A.M (2011)Chemo dynamics of pesticides in soil at some hotspots in ten regions and in atmospheric matrices in kibaha Tanzania master dissertation, University of Dar es Salaam, Available at