Environmental Science Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States.
Department of Civil and Environmental Engineering, University of California, Los Angeles, CA, 90095, United States.
Environ Pollut. 2018 Dec;243(Pt A):573-581. doi: 10.1016/j.envpol.2018.09.018. Epub 2018 Sep 6.
Biodegradation of 1,4-dioxane was examined in packed quartz and soil column flow-through systems. The inhibitory effects of co-contaminants, specifically trichloroethene (TCE), 1,1-dichloroethene (1,1-DCE), and copper (Cu) ions, were investigated in the columns either with or without bioaugmentation with a 1,4-dioxane degrading bacterium Pseudonocardia dioxanivorans CB1190. Results indicate that CB1190 cells readily grew and colonized in the columns, leading to significant degradation of 1,4-dioxane under oxic conditions. Degradation of 1,4-dioxane was also observed in the native soil (without bioaugmentation), which had been previously subjected to enhanced reductive dechlorination treatment for co-contaminants TCE and 1,1-DCE. Bioaugmentation of the soil with CB1190 resulted in nearly complete degradation at influent concentrations of 3-10 mg L 1,4-dioxane and a residence reaction time of 40-80 h, but the presence of co-contaminants, 1,1-DCE and Cu ions (up to 10 mg L), partially inhibited 1,4-dioxane degradation in the untreated and bioaugmented soil columns. However, the inhibitory effects were much less severe in the column flow-through systems than those previously observed in planktonic cultures, which showed near complete inhibition at the same co-contaminant concentrations. These observations demonstrate a low susceptibility of soil microbes to the toxicity of 1,1-DCE and Cu in packed soil flow-through systems, and thus have important implications for predicting biodegradation potential and developing sustainable, cost-effective technologies for in situ remediation of 1,4-dioxane contaminated soils and groundwater.
1,4-二恶烷的生物降解在填充石英和土壤柱流通过系统中进行了研究。在没有或有生物增强的情况下，考察了共污染物（特别是三氯乙烯（TCE）、1,1-二氯乙烯（1,1-DCE）和铜（Cu）离子）对柱的抑制作用。用 1,4-二恶烷降解菌假诺卡氏菌（Pseudonocardia dioxanivorans）CB1190 进行生物增强。结果表明，CB1190 细胞在柱中容易生长和定殖，导致在好氧条件下 1,4-二恶烷的显著降解。在没有生物增强的原生土壤（未经增强的还原脱氯处理共污染物 TCE 和 1,1-DCE）中也观察到 1,4-二恶烷的降解。用 CB1190 对土壤进行生物增强，在 3-10 mg/L 1,4-二恶烷的入口浓度和 40-80 h 的停留反应时间下，几乎完全降解，但共污染物 1,1-DCE 和 Cu 离子（高达 10 mg/L）的存在部分抑制了未经处理和生物增强的土壤柱中 1,4-二恶烷的降解。然而，与在浮游培养物中观察到的抑制作用相比，在柱流通过系统中抑制作用要小得多，在相同的共污染物浓度下，抑制作用接近完全。这些观察结果表明，土壤微生物对 1,1-DCE 和 Cu 的毒性的敏感性较低，这对于预测生物降解潜力以及开发用于原位修复 1,4-二恶烷污染土壤和地下水的可持续、具有成本效益的技术具有重要意义。
