The efficacies ofsoil extraction methods, namely, Soxhlet, sonication, agitation, alkaline digestion
and the ethyl acetate micro-method, for monitoring soil bioremediation were evaluated using three
soil types, Swartland, Rensburg and Hutton, encompassing the mineralogical range prevalent in Kwa
Zulu Natal. Phenol, atrazine and the BTEX component of petrol were the molecules used in this
study and were extracted under different spiking concentrations, after prolonged ageing times up
to 21 days and after changing the composition of the spiking solution. It was concluded that
extraction methods must be validated for the specific conditions under which they would be used,
taking into consideration, soil type, spiking solutions, moisture content, weathering times and the
analyte(s) in question. A preliminary appraisal of atrazine degradation in a Hutton soil was then
made under the conditions of sterilized, fertilized/non-fertilized and non-sterilized, fertilized/nonfertilized
soils. The predominant pathway of atrazine degradation was deemed to be
chemically/abiotically mediated due to the soil pH and the presence of iron and aluminium oxides
as well as the high levels of manganese in the soil. The results obtained prompted further study into
atrazinecatabolism using soil-slurry reactors, under the conditions of carbon-limitation, nitrogen
limitation, carbon/nitrogen non-limitation and carbon/nitrogen limitation. A comparison was made
between inoculated and non-inoculated bioreactors. The ability of the indigenous microbial
population to return the Hutton soil to its original pristine state was confirmed. The expense of
inoculation and culture maintenance could be avoided since carbon and nitrogen supplementation
would be as equally effective as inoculation. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2002.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/4908 |
| Date | January 2002 |
| Creators | Khan, Fatima. |
| Contributors | Wallis, Frederick Malcolm. |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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