Water Cycle Research Center, National Agenda Research Division, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea; Department of Earth and Environmental Sciences, Korea University, Seoul, 136-701, South Korea.
Water Cycle Research Center, National Agenda Research Division, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea.
Chemosphere. 2022 Sep;302:134804. doi: 10.1016/j.chemosphere.2022.134804. Epub 2022 May 6.
The natural attenuation potential of a vadose zone against diesel is critical for optimizing remedial actions and determining groundwater vulnerability to contamination. Here, diesel attenuation in unsaturated soils was systematically examined to develop a qualitative relationship between physical soil properties and the natural attenuation capacity of a vadose zone against diesel. The uniformity coefficient (C) and water saturation (S, %) were considered as the proxies reflecting the degree of effects by porous network and water content in different soils, respectively. These, in turn, are related to the primary diesel attenuation mechanisms of volatilization and biodegradation. The volatilization of diesel was inversely proportional to C and S, which could be attributed to effective pore channels facilitating gas transport. Conversely, biodegradation was highly proportional to C under unsaturated conditions (S = 35-71%), owing to nutrients typically associated with fine soil particles. The microbial community in unsaturated soils was affected by S rather than C. The overall diesel attenuation including volatilization and biodegradation was optimized at S = 35% for all tested soils.
包气带中柴油的自然衰减潜力对于优化补救措施和确定地下水对污染的脆弱性至关重要。在这里，系统地研究了非饱和土壤中柴油的衰减作用，以建立物理土壤特性与包气带对柴油的自然衰减能力之间的定性关系。均匀系数 (C) 和水饱和度 (S，%) 分别被视为反映多孔网络和不同土壤中含水量影响程度的指标。这反过来又与柴油的主要挥发和生物降解衰减机制有关。柴油的挥发与 C 和 S 呈反比，这可归因于有效孔隙通道有利于气体传输。相反，在非饱和条件下（S = 35-71%），生物降解与 C 呈高度正相关，这是由于与细颗粒土壤相关的营养物质。非饱和土壤中的微生物群落受 S 而不是 C 的影响。对于所有测试的土壤，在 S = 35%时，包括挥发和生物降解在内的整体柴油衰减达到最佳状态。
