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Monitoring and risk assessment of polychlorinated biphenyls (PCBs) levels in soil contaminated by oil spillages from transformers in South Africa

A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Environmental Sciences
Johannesburg, 2017. / PCBs are chemical compounds which were synthesised in the laboratory in the 1920s. They are classified under the category of POPs. They were mainly used in electrical equipments and transformers as the insulating material. PCBs were released to the environment in the form of oil spillages, combustion of PCB-containing equipments and others. Its production was banned in the 1970s after its toxic, persistent, bioaccumulative and carcinogenic behaviour was discovered. This study was conducted to determine and monitor the level of PCB in soil contaminated by oil spillages from pole mounted transformers in Polokwane, Limpopo, South Africa after sites have been remediated. Seventy eight soil samples were collected from five sites. The QuEChERS extraction method and GC-MS was used to extract and analyse PCBs. The PCB congeners targeted in this study are PCB-180, PCB-158 and PCB-101. The concentration of PCB-180 ranges between 10.02 and 78.30 μg kg -1, PCB-158 ranges between 3.89 and 45.36 μg kg -1 and PCB-101 ranges between 2.42 and 39.12 μg kg -1. The PCB congener with the highest concentration at all sites is PCB-180 followed by PCB-158 while PCB-101 has the least concentration; this order is consistent in all sampling sites. PCB concentrations after bioremediation were found to be extremely higher than concentrations before bioremediation which suggest that the bioremediation process was not efficient including actual analytical methods used. In comparison to the range of the PCB levels reported in literature, the PCB concentration determined from this study is found within a higher range. The PCBs concentration at all five sites was found to be below the legal limits. / LG2018

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/25121
Date January 2017
CreatorsRampjapedi, Maria Tebogo
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
FormatOnline resource (x, 69 leaves), application/pdf

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