2018-01-102024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/657596摘要：重金屬汞因為具有高移動性、揮發性、生物有效性及神經毒性，被認為是最具有毒性危害之污染物之一。而人類在近數十年之工業活動所產生之工業廢水，已然使汞污染底泥在全球形成嚴重的污染議題，而我國亦有污染嚴重之底泥場址亟需整治。以傳統開挖法為基礎之離地整治技術為國際間常用之底泥整治技術，但由於鉅額成本與可能造成之二次污染，使底泥污染問題一直不具有可被完全接受之整治工法。近年來，國際間逐漸傾向以風險為基礎的管理架構進行底泥問題之管理，使現地整治工法得以發展。活性覆蓋法(active capping)為一具有經濟可行性之現地整治工法，以活性材料鋪設於底泥表面製造出薄層覆蓋層，降低污染物釋出至水體中，進而降低人體健康與生態風險。目前活性覆蓋法已廣泛使用於國外有機物污染場址之整治，而本研究團隊也於前期之研究計畫中，發現以活性碳為主要吸附材料之活性覆蓋層亦可用於抑制汞污染底泥釋出至水體，並發現能有效降低甲基汞(最具毒性之汞物種)釋放至水體中。 本期研究之實驗可分為兩大部分。第一部分為利用批次實驗探討汞封存機制之研究，將進行裝有不同參數之表水與活性覆蓋層的批次實驗。活性材料選用活性碳。二價硫[S2-]、溶解態有機物[DOM]及氯離子[Cl-]對於汞封存機制有重要影響，將針對此幾項水體環境因子進行其影響活性覆蓋法進行汞封存之機制探討。此外將藉由序列萃取技術(SEP)探討汞物種在進行活性覆蓋法前後之影響，其中汞污染底泥使用桃園灌溉渠道底泥(接續前期研究)、人工底泥和採自國內知名之汞污染場址海水池。第二部分為模擬真實場址中橫向水流之擬環境系統研究，在橫向水流下，不同組合之活性覆蓋層之穩定性、汞封存成效，以及汞物種變化和水質因子將在此部分中探討。本年期計畫之研究，將有助於了解環境因子對於活性覆蓋法成效之影響，此研究成果也預期將逐步解決目前活性覆蓋法在未來實場化過程所可能遇到之挑戰，並期望能更進一步實現活性覆蓋法應用於汞污染底泥實場整治的終極目標。 <br> Abstract: With high mobility, toxicity, volatility, and bioaccumulation ability, mercury is considered one of the most toxic heavy metal in the environment. Over decades of human industrial activities, wastewater has been discharged to river streams causing severe pollution problems across the globe. In Taiwan, a highly mercury-contaminated sediment site has lured marked public attention, and proper remediation actions should be taken immediately. Ex-situ site remediation based on traditional dredging is a common solution for sediment problem. However, disadvantages of ex-situ remediation were noticed due to its high cost and possibility to cause secondary contamination; thus, other feasible solutions for sediment remediation are still highly needed. In recent years, risk-based management approach is an approved paradigm for sediment issues across the globe; thus in favor the development of in-situ remediation. Active capping is an economically-feasible in-situ method for sediment remediation, by using activated material to form a thin-layer caps to reduce contaminants release from sediment to overlying water, subsequently reducing human health and ecological risks. While active capping has been proven effective in sediments contaminated by organic compounds, it potentially reduced mercury and methylmercury species released to overlying water based on several previous research. The proposed research can be divided into two parts. The first part involves studies on understanding the mercury sequestration mechanisms by batch experiments. The batches containing overlying water, active caps, and sediment will be examined. Mercury contaminated sediment will be collected from an irrigating canal and a well-known mercury contaminated estuarine site in Southern Taiwan. Artificial sediment will also be used. Activated carbon will be examined as the active material. Water quality factors including divalent sulfur [S2-], dissolved organic matter [DOM], and chloride [Cl-] are chosen to study mercury sequestration mechanisms for active capping method. In addition, sequential extraction procedure (SEP) will be used to discuss the mercury species mobility before and after active capping. The second part of the proposed research involves in using microcosms to simulate the pattern of horizontal flows in real contaminated sites. The capping stability of different active caps and their ability of sequestration for mercury species influenced by the water quality factors will be further discussed. The obtained results are anticipated to resolve future challenges during scale up approaches to achieve the ultimate goal of introducing active capping technology into remediate mercury contamination sediment in actual site practices.活性覆蓋法活性碳汞甲基汞底泥active cappingactivated carbonmercurymethylmercurysediment