| 摘要: | 本研究主要在於測試當p,p’-DDE被釋放到環境中之後的解決方案，p,p’-DDE屬於DDT之衍生物質，DDT在過去的數十年中被大量的使用在抑制病媒蚊的散播，對於當時的環境衛生有重大的功勞，然而DDT在使用前並未做足風險評估的規劃，因此在使用多年之後才逐漸被發現對環境有嚴重的危害，因DDT屬於脂溶性化學物質，同時又具有持久性而難以在環境中分解之特質，因此當大量釋放到自然環境之後，隨著食物鏈傳遞，嚴重破壞整個地球的生物圈。然而，隨著時間的推移，DDT在環境中還是可以逐漸慢慢的被降解轉化，以致目前尚有少數國家因為衛生原因仍持續的使用DDT抑制病媒蚊，但對於整個地球來說其負面影響已不如之前那樣的嚴重，但當人們逐漸忘記DDT的污染歷史存在時，開始有部分的學者發現，環境中的DDT在經過各種方式降解之後，並非完全消失或轉化為無害物，其所產生之衍生物質p,p’-DDE開始出現在整個地球的生物圈中，同樣是隨著食物鏈進入到地球生物圈內，而p,p’-DDE不但不具有抑制病媒蚊的功效，同時對哺乳類動物的內分泌有非常強的影響力，尤其是對於未成年之哺乳類動物有嚴重的影響，會使其發育不全、神經受損甚至畸形，因此如何處理環境中之p,p’-DDE避免其透過食物鏈進入生物圈將是一個非常重要的議題。 研究中利用二仁溪河川之底泥厭氧微生物對p,p’-滴滴依（p,p’-DDE）進行還原性脫氯作用降解研究，因滴滴涕（DDT）在過去是大量被散佈在環境中，因此要以人為工程方式進行處理則成本過於龐大，如果能夠利用自然環境本身的條件來進行降解將是最好的方式。本研究p,p’-DDE進行脫氯降解測試共分為三部分，在每一部分的實驗過程中採用不同處理條件進行測試，藉由各項模擬環境參數之設計來推測p,p’-DDE降解之環境條件，實驗中採用配備改良型通透性管柱之底泥環境模擬槽以進行自然環境之污染復育模擬實驗。研究結果顯示，二仁溪底泥當中具有能夠降解p,p’-DDE之厭氧微生物，而且會因環境的條件以及添加的化學物質不同而有不同的降解情況，藉由實驗結果可以推導出適合降解 p,p’-DDE之環境，尤其在厭氧環境下添加界面活性劑降解效率最好，但是添加環境常見污染物如壬基酚或鄰苯二甲酸二酯卻往往有抑制及遲緩的現象發生。研究結果可以促進二仁溪底泥中之厭氧微生物降解p,p’-DDE之效率，用在處理現存之DDT與其衍生物之染之環境復育，此外未來如果因為某些特殊原因在某些特定地點需要再次使用DDT時，也可做為避免DDT及其家族對於生態系統危害之參考。
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. |
