Technical Review of 1,4-Dioxane: Occurrence, Characterization and Aerobic Biodegradation in Groundwater

1,4-環氧己烷的存在、表徵及地下水中好氧性生物降解技術回顧

蔣曉雲(Dora Sheau-Yun Chiang) ； Rebecca Mora

《土壤及地下水污染整治》 1卷2期 (2014/10) Pp. 179-207

https://doi.org/10.6499/JSGR.2014.0102.006

摘要

1,4-環氧己烷為人類可能致癌物，主要作為氯化溶劑如1,1,1-三氯乙烷(TCA)的穩定劑。過去生產、儲存、使用及處置造成土壤及地下水廣泛地被溶劑及其穩定劑大規模的污染。在1970年間，查覺到1,1,1-TCA毒性較低，更由於市場供需及價格因素，三氯乙烯(TCE)與1,1,1-TCA交互替代使用，其導致地下水含水層中發現1,4-環氧己烷的污染常混合著TCE、1,1,1-TCA及其降解產物順-1,2-二氯乙烯(DCE)及1,1-DCE。由於其在水中的溶解性高，不易在自然條件被生物降解，再加上一般針對氯化溶劑有效的處理技術並不適用於1,4-環氧己烷，其污染範圍極可能大於含氯溶劑污染。雖然美國環保署尚未制定國家級1,4-環氧己烷最高污染含量(MCLs)，但在美國許多州卻有明確的整治標準。常見的含氯溶劑整治技術(如：還原脫氯及空氣氣提法)，對處理1,4-環氧己烷是無效的，更導致未處理之1,4-環氧己烷由處理系統中排出，再度污染環境。本文說明1,4-環氧己烷在環境中最新的調查概況，如何利用生物整治技術作為整治地下水中1,4-環氧己烷之策略，及美國針對環境中1,4-環氧己烷潛在來源之法規趨勢。本文並針對1,4-環氧己烷不同的好氧性生物降解做明確說明，並經由案例研究，提出好氧性共同代謝地下水中1,4-環氧己烷現場的處理方式。此外，本文並討論如何利用最新的環境分子診斷技術来監測1,4-環氧己烷生物降解，並評估其在現場的實際應用。最後，本文並提供1,4-環氧己烷生物降解相關研究之後續發展方向。

關鍵字

1,4-環氧己烷 ； 環境分子診斷 ； 穩定性同位素偵測 ； 生物標記 ； 共代謝生物降解

並列摘要

1,4-Dioxane, a likely human carcinogen, is primarily used as a stabilizer of chlorinated solvents such as 1,1,1-trichloroethane (TCA). Historical practices of production, storage, usage, and disposal have resulted in widespread soil and groundwater pollution by solvents and their stabilizers. The alternating use of trichloroethylene (TCE) and TCA in the 1970's, in response to the perceived lower toxicity of TCA, as well as issues of market availability and pricing, have resulted in 1,4-dioxane commingling with TCE, TCA and their breakdown products, cis-1,2-dichloroethene (DCE) and 1,1-DCE in groundwater aquifers. Due to not being readily biodegradable under natural conditions, high solubility in water, and ineffective removal by technologies applicable for chlorinated solvents, 1,4-dioxane plumes potentially extend beyond chlorinated solvents plumes. Although no USEPA MCL is available for 1,4-dioxane, it is regulated in many states in the US. The common remediation technologies for chlorinated solvents (e.g., reductive dechlorination or air stripping) are ineffective with regard to treating 1,4-dioxane, resulting in 1,4-dioxane escaping untreated from existing treatment systems. This article provides an overview of the latest understanding of 1,4-dioxane in the environment, as well as a state-of-the practice summary of bioremediation as a remedial strategy for treating 1,4-dioxane in groundwater. A summary of regulatory trends for 1,4-dioxane in the US is provided as well as an overview of potential sources for 1,4-dioxane in the environment. Following a description of the different aerobic biodegradation mechanisms for 1,4-dioxane, a detailed case study is presented for implementing aerobic cometabolic biodegradation at a field site to treat 1,4-dioxane in groundwater. Significant recent advancements related to environmental molecular diagnostic tools for monitoring 1,4-dioxane biodegradation in the field are presented, along with details of case studies on recent applications to evaluate their use. Finally, a summary of future research needs related to biodegradation of 1,4-dioxane is provided.

並列關鍵字

1,4-dioxane ； environmental molecular diagnostics ； stable isotope probing ； biomarker ； cometabolic biodegradation