Bioavailability assessment of PAHs in sediment at aerobic/anaerobic environment with solid phase microextraction

國內外對於河川底泥中PAHs的流佈調查已有基礎發研究，生物有效性的概念也已完備；但對於使用固相微萃取技術（Solidphasemicro-extraction,SPME）評估實場底泥中多環芳香烴化合物（Polycyclicaromatichydrocarbons,PAHs）的適用性尚未完備。 故本研究以PAHs中的二環分子—萘（naphthalene,Nap）、三環分子—菲（phenanthrene,PA）為目標污染物，以二仁溪實場底泥在有機質含量不同、單一/雙重污染以及好氧/厭氧條件下，以生物降解52天，探討污染物之生物有效性，並使用固相微萃取技術評估污染物於不同特性下的生物有效性，再與實際生物降解量比較，以期能提供SPME於實場底泥使用上的適用性評估。 由生物降解實驗結果可以發現，不論好氧或厭氧條件，隨著底泥有機質含量的增加，萘與菲在底泥中的分配作用則越強，污染物在底泥之脫附成為速率限制因子，使得生物降解量與降解速率均隨之降低；而微生物降解菲出現二階段趨勢（快速降解-緩慢降解）。而厭氧下且雙重污染時，微生物首先均會分解環數較低的二環萘其次才是環數較高的三環菲且萘的存在會促進菲的微生物降解作用，產生生物刺激的效果。 就固相微萃取技術之評估值與實際微生物降解量的相關性而言，會發現SPME技術對於整體評估量較低估，但是如果針對快速降解期來比較，SPME能準確評估生物有效性。SPME技術對於雙重污染下的實際生物降解量有低估的現象，因為SPME無法評估出微生物在雙重污染下會產生促進降解的現象。但是SPME能準確地評估單一污染下的實際生物降解量，受到有機質含量、污染物共存與否與氧濃度高低的影響較低。這表示SPME技術在特定條件下仍有良好的評估指標。In this study, naphthalene（Nap）and phenanthrene（PA）were used as target contaminants to investigate the bioavailability of contaminants in sediments with different organic contents under aerobic or anaerobic conditions. The actually total amount of Nap or PA biodegaded was used to compare the total amount of Nap and PA estimated by SPME process with different operating conditions in realistic sediments. Results showed that an increase in the organic contents in sediment increased the partitioning of naphthalene and phenanthrene into the organic matters in the aerobic and anaerobic condition. Desorption of target contaminants was the rate limiting factor which decreased the degradation rate and the amount of Nap and PA biodegraded. In the multi-contaminants experiment, naphthalene would be preferentially biodegraded in comparison with phenanthrene. The experiment results indicated that the presence of Nap could enhance the biodegradation of PA in the anaerobic condition. For the assessment of Nap biodegradation, SPME could more preeiously estimate its biodegradation potential. However, the LMW PAHs, such as PA, SPME might underestimate its biodegradation protential. The biodegradation of naphthalene, SPME could provide the better assessment and was not affected by sediment organic content or aerobic and anaerobic condition. It implied that desorption rate and biodegradation rate affected the SPME assessment. Therefore, SPME could not preciously predict the bioavailability of Nap or PA in sediment, especially, when the system contained multi-contaminate with various biodegradability.第一章 前言 - 1 - 1-1研究緣起 - 1 - 1-2研究目的 - 2 - 第二章 文獻回顧 - 3 - 2-1多環芳香族碳氫化合物 - 3 - 2-2多環芳香族碳氫化合物之生物降解 - 9 - 2-3整治技術 - 19 - 2-4吸持作用與污染物的生物降解關係 - 24 - 2-5生物有效性 - 29 - 2-6固相微萃取 - 43 - 第三章 材料與方法 - 49 - 3-1研究架構 - 49 - 3-2實驗儀器設備 - 51 - 3-3底泥樣品 - 55 - 3-4底泥萃取條件與檢量線之建立 - 58 - 3-5固相微萃取條件與檢量線之建立 - 61 - 3-6生物降解批次實驗 - 66 - 第四章 結果與討論 - 71 - 4-1確認實驗 - 71 - 4-2好氧狀態對於底泥中之生物降解批次實驗 - 75 - 4-3厭氧狀態於底泥中之生物降解批次實驗 - 85 - 4-4SPME 技術評估底泥中 PAHS 之生物有效性 - 94 - 4-5SPME 技術之應用性- 108 - 第五章 結論與建議 - 115 - 5-1結論 115 5-2建議 - 117 - 第六章參考文獻 - 118