| Summary: | 碩士 === 嘉南藥理大學 === 環境工程與科學系 === 102 === This research is dedicated to investigate the resolution of 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene(p,p’-DDE) contamination in Environments. p,p’-DDE is a major intermediates of Dichloro-Diphenyl-Trichloroethane(DDT) in environmental degradation. After 30 years of extensive use in pest control, DDT had made a tremendous contribution in keeping human healthy but also caused a severe pollution. As an extremely hydrophobic chemical, DDT is both persistent and bioaccumulated in natural environment. It had been distributed to all kinds of animals by food chain system, even human being was suffered.
Nowadays, DDT has been banned in most countries, only few countries still use it for protection children from diseases. During recent decades, environmental DDT gradually degraded and the contamination of DDT seemingly fading away. However, researchers found that the environmental degradation did not transform DDT, this hazardous chemical to completely harmless intermediates, instead, one of the major products, p,p’-DDE, another hazardous chemical was produced and accumulated. p,p’-DDE does not possessed the potential to kill pests, but it is harmful to mammals including human being. Especially to the pre-mature mammals, p,p’-DDE will induce the hypoplasia, nervous system insufficiency, and even deformity. Wherefore, to diminish and deplete p,p’-DDE in natural environment is critical in sustained a balanced global ecosystem.
In this research, anaerobic microorganisms from Er-Ren River sediments were applied in the reductive dechlorination of p,p’-DDE. This bioderadation technology has been proved to be effective in environmental remediation of the chlorinated aromatics pollution, not only because it is economic but also much more environmental friendly. The whole research has three individuals, various environmental conditions and chemical additives were applied within to invest a group of parameters to create a suitable environment condition for p,p’-DDE degradation. Most of experiments were tested in a designed aquatic system, the Simulated Aquarium Boxes equipped with Modified Permeable Columns (MPC-SAB). This system was used to provide a simulated natural condition for p,p’-DDE environmental remediation. The results showed that anaerobes from different sites of Er-ren River were all able to degrade p,p’-DDE. The p,p’-DDE dechlorination varied by different treatments, the addition of surfactants usually showed positive effects, but ordinary contaminants in river water like Nonylphenol and bis(2-ethylhexyl) phthalate showed negative results. This research revealed the potential of river sediments in depleting p,p’-DDE, and contribute valuable information in the environmental remediation of DDT and its families. In case of re-open of the use of DDT in the near future in certain region, the results can reduced the damage of DDT to human being and the ecosystem.
|
|---|
