| 摘要: | 本研究採集台灣台南縣二仁溪南萣橋上下游流域之2處底泥與河
水，建立底泥環境模擬箱以模擬環境中含氯芳香族化合物之脫氯情形。
研究分為三部份，第一部份實驗為改良式通透性管柱( Modified
Permeable Column, MPC )之初步測試，在MPC中添加HCB、2,3,4-
三氯聯苯( 2,3,4-trichlorobiphenyls,2,3,4-CBp )及2,3,4,5-四氯聯苯(2,3,4,
-tetrachlorobiphenyl,2,3,4,5-TeCB)，置放在模擬箱中進行培養。60天後
發現HCB有脫氯作用發生，並產生QCB, 1,2,3,5- TeCB, 1,2,4-TCB 和
1,3,5-TCB等脫氯產物。2,3,4-CBp的濃度則有明顯降低並有外移情形。
至於添加2,3,4,5-CBp的管柱中，2,3,4,5-CBp濃度只有些微下降，並且
也有外移現象。
第二部份實驗為模擬表層底泥之含氯芳香族脫氯狀況測試，在玻璃
杯中添加含六氯苯( Hexachlorobenzene,HCB )、1,2,3,4-四氯苯( 1,2,3,4-
tetrachlorobiphenyl,1,2,3,4- TeCB)之底泥，置放在模擬箱中進行培養。經
過13個月後發現1cm~4cm深度之土壤層在有添加YE之組別中HCB
濃度比率明顯低於無添加YE之組別HCB，並產生QCB, 1,2,3,5- TeCB,
1,2,4-TCB 和 1,3,5-TCB等產物。1,2,3,4- TeCB之玻璃杯實驗中1cm~
4cm土壤層在經過4個月後，添加YE組別之1,2,3,4-TeCB濃度比率明
顯降低，並產生1,2,4-TCB 之脫氯產物。無添加YE之1,2,3,4- TeCB濃
度比率還是很高，產物出現的濃度比率也很低。
第三部份實驗為利用MPC測試HCB及其脫氯產物的移動，在MPC
最內層中置入含HCB 5ppm之底泥，中外層則置入無污染之底泥置放在
模擬箱中培養，經過30天後內層底泥即有脫氯作用發生，90天後HCB
濃度已降至1ppm以下，然而在培養其間HCB有些微擴散至管柱中層
(M/B)~管柱外層(O/L)的部份。脫氯的產物有QCB,1,2,3,5-TeCB, 1,2,4-
TCB和1,3,5-TCB，至於產物則沒有明顯外移或殘留在中外層底泥的現
象。綜合以上結果顯示，二仁溪底泥中固有之微生物具有HCB和2,3,4-
CBp之脫氯作用能力，而對於2,3,4,5-CBp則脫氯活性並不顯著，顯示
脫氯作用是具有專一性的，然而HCB和2,3,4-CBp分別屬於氯苯類及多
氯聯苯，其結構並不相同，但皆能在天然底泥中進行降解，說明不分種
類含氯污染化合物環境復育是極具可能性的，因此仍須投入更多嘗試，
設法提升並改善多氯聯苯等含氯芳香族的自然降解效率，建立有效且確
實可行之環境污染的復育策略。
The main objective of this study was to determine the environmental dechlorination of hexachlorobenzene (HCB) in a simulated anaerobic condition within an aquarium box contained natural river sediments and waters. Three successive experiments were conducted, the first experiment was the primary test of Modified Permeable Column-Simulated Aquarium Box system (MPC-SAB), the second experiment was a test of Cup-SAB system, and the third one was the application of MPC-SAB system in the evaluation of HCB dechlorination and the movement of HCB and its dechlorination products.
In the first experiment, sediment samples used in the Modified Permeable Column-Simulated Aquarium Box system (MPC-SAB). were amended with 5 ppm of HCB, 2,3,4-CBp or 2,3,4,5-CBp, individually. After 60 days of incubation, the results showed that HCB was dechlorinated and HCB moved outward as well. After 120days, 2,3,4-CBp and 2,3,4,5-CBp dechlorination was both observed.
In the second experiment, dozens of 70 mm tall glass cups were fill with sediment samples that spiked with 5 ppm of HCB or 20 ppm of 1,2,3,4- TeCB. After 13 months, the level of HCB in the sediment with YE was significantly lower than that without YE. And HCB dechlorination products, such as QCB, 1,2,3,5- TeCB were also found in sediment with YE. For sediments mixed with 1,2,3,4-TeCB, sediment with YE showed the decrease of 1,2,3,4- TeCB and the products of 1,2,4-TCB.
In the third experiment, sediment samples with 5 ppm of HCB were applied in the Modified Permeable Column-Simulated Aquarium Box system (MPC-SAB). It was found that HCB dechlorination could be initiated within 30days and after that HCB could be transported to the middle and outer layer. HCB dechlorination products, QCB, 1,2,3,5-TeCB, 1,2,4-TCB, and 1,3,5-TCB were found in the core part, but never been visualized in the middle and outside layer.
The results suggested that Sediment microbes in Er-Jen River possessed HCB and PCBs dechlorination ability. HCB was easier to be degraded than PCBs showed the differentia of HCB-dechlorination consortium to PCBs’. However, this study revealed that the environmental remediation of HCB and PCBs was possible. It need more researches to promote the inherent dechlorinating activity of sediment microbes, especially for the dechlorination of PCBs. |
