Bench-scale biodegradation tests to assess natural attenuation potential of 1,4-dioxane at three sites in California
Bench-scale biodegradation tests to assess natural attenuation potential of 1,4-dioxane at three sites in California
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DOI：
10.1007/s10532-014-9714-1
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发表时间：
2015-02-01
期刊：
影响因子：
3.6
通讯作者：
Alvarez, Pedro J.
中科院分区：
文献类型：
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作者：
Li, Mengyan;van Orden, E. Tess;Alvarez, Pedro J.
1，4-二氧六环(二恶烷)对生物降解相对较难，其物理化学性质使其无法通过挥发或吸附从受污染的地下水中有效去除。通过这个微观研究，我们评估了二恶烷在加利福尼亚州三个地点的生物降解潜力。在每个地点的不同地点收集了地下水和沉积物样本，包括假定的源区、羽流的中间和前缘。总共采集了16口监测井的样本，以准备微观世界。在模拟自然衰减的16个微宇宙中，有12个在28周内观察到二恶烷的生物降解。在含有痕量二恶烷(以10A/L为初始浓度)的微观世界中，从高达3449+/-A459A/L/周到低至0.3A/-A0.1A/L/周。微宇宙中加入了C-14标记的二恶烷，以评估二恶烷的命运。结合残留物的生物氧化剂-液体闪烁分析表明，C-14-二恶烷只在表现出显着生物降解性的微宇宙中被同化到细胞质中。在(CO2)-C-14回收过程中也观察到矿化(在28周的孵化过程中，降解量的44%)。降解和矿化活性随着与污染源区域距离的增加而显著降低(p<；0.05)，这可能是由于较少的适应所致。此外，利用场地1的源区样品制备的重复和重复的微观世界都证实了二恶烷的相对较快的降解(即在20周内100%地去除)。这些结果表明，这三个地点存在能够降解二恶烷的本土微生物，并表明监测的自然衰减应被视为一种补救反应。
1,4-Dioxane (dioxane) is relatively recalcitrant to biodegradation, and its physicochemical properties preclude effective removal from contaminated groundwater by volatilization or adsorption. Through this microcosm study, we assessed the biodegradation potential of dioxane for three sites in California. Groundwater and sediment samples were collected at various locations at each site, including the presumed source zone, middle and leading edge of the plume. A total of 16 monitoring wells were sampled to prepare the microcosms. Biodegradation of dioxane was observed in 12 of 16 microcosms mimicking natural attenuation within 28 weeks. Rates varied from as high as 3,449 +/- A 459 A mu g/L/week in source-zone microcosms to a low of 0.3 +/- A 0.1 A mu g/L/week in microcosms with trace level of dioxane (< 10 A mu g/L as initial concentration). The microcosms were spiked with C-14-labeled dioxane to assess the fate of dioxane. Biological oxidizer-liquid scintillation analysis of bound residue infers that C-14-dioxane was assimilated into cell material only in microcosms exhibiting significant dioxane biodegradation. Mineralization was also observed per (CO2)-C-14 recovery (up to 44 % of the amount degraded in 28 weeks of incubation). Degradation and mineralization activity significantly decreased with increasing distance from the contaminant source area (p < 0.05), possibly due to less acclimation. Furthermore, both respiked and repeated microcosms prepared with source-zone samples from Site 1 confirmed relatively rapid dioxane degradation (i.e., 100 % removal by 20 weeks). These results show that indigenous microorganisms capable of degrading dioxane are present at these three sites, and suggest that monitored natural attenuation should be considered as a remedial response.