GSI Environmental Inc., Houston, TX, USA.
Scissortail Environmental Solutions LLC., Ada, OK, USA.
J Hazard Mater. 2022 Feb 15;424(Pt D):127736. doi: 10.1016/j.jhazmat.2021.127736. Epub 2021 Nov 12.
Options for remediating 1,4-dioxane at groundwater sites are limited due to the physical-chemical properties of this compound. The relevance of natural attenuation processes for 1,4-dioxane was investigated through data from field, lab, and modeling efforts. The objectives were to use multiple lines of evidence for 1,4-dioxane biodegradation to understand the prevalence of this activity and evaluate convergence between lines of evidence. A C-1,4-dioxane assay confirmed 1,4-dioxane biodegradation at 9 of 10 sites (median rate constant of 0.0105 yr across wells). Site-wide rate constants were established using a calibrated fate and transport model at 8 sites (median = 0.075 yr). The C assay constants are likely more conservative, and variability in rates suggested that biodegradation at sites may be localized. Stable isotope fractionation was observed at 7 of 10 sites and served as another direct line of evidence of in situ biodegradation of 1,4-dioxane. This includes sites where indirect lines of evidence, including geochemical conditions or genetic biomarkers for degradation, would not necessarily have been supportive. This highlights the importance of collecting multiple lines of evidence to document 1,4-dioxane natural attenuation, and the widespread prevalence of biodegradation suggests that this process should be part of long-term management decisions.
由于 1,4-二恶烷的物理化学性质，地下水场地修复 1,4-二恶烷的选择有限。通过现场、实验室和建模工作的数据，研究了自然衰减过程对 1,4-二恶烷的相关性。目的是使用 1,4-二恶烷生物降解的多种证据来了解这种活动的普遍性，并评估证据之间的收敛性。C-1,4-二恶烷测定法在 10 个地点中的 9 个地点（跨井的中位数速率常数为 0.0105 年）证实了 1,4-二恶烷的生物降解。在 8 个地点使用经过校准的命运和运输模型建立了全站点速率常数（中位数= 0.075 年）。C 测定法常数可能更保守，并且速率的可变性表明，站点处的生物降解可能是局部的。在 10 个地点中的 7 个地点观察到稳定同位素分馏，这是 1,4-二恶烷原位生物降解的另一个直接证据。这包括在间接证据（包括地球化学条件或降解的遗传生物标志物）不一定支持的情况下的地点。这强调了收集多种证据来记录 1,4-二恶烷自然衰减的重要性，并且生物降解的广泛普遍性表明，该过程应该是长期管理决策的一部分。
