Kim Han S, Weber Walter J
Department of Chemical Engineering, Energy and Environment Program, The University of Michigan, Ann Arbor, Michigan 48109-2099, USA.
Environ Toxicol Chem. 2005 Feb;24(2):268-76. doi: 10.1897/04-219r.1.
The effects of an ethoxylated sorbitan fatty ester nonionic surfactant (Tween 80) on the bioavailability of polycyclic aromatic hydrocarbons (PAHs) were examined by using soil-free and dense-slurry (67% solids content, by wt) systems containing a creosote-contaminated field soil. The dispersed-micelle-phase PAHs in soil-free systems were not readily bioavailable to the mixed consortium of microbes indigenous to the creosote-contaminated soil. Instead, the microbes partially and preferentially utilized readily available portions of the surfactant as carbon sources (16-18% of the initial surfactant dose). This selective microbial attack resulted in destabilization of dispersed-phase micelles and significant decreases in molar solubilization ratio and micelle-water partition coefficient values. Remarkably high dosages (>20 g/L) of Tween 80 were required to enhance mobilization of the sorbed PAHs via micelle association because of the sorption of Tween 80 to the soil employed. The PAHs released from the destabilized micelles in soil-slurry systems either associated with sorbed-phase surfactants or readsorbed to soil organic matter too rapidly to be biologically accessed, even by the acclimated PAH-degrading microbes present. The work provides important new information and practical insights to surfactant solubilization and mobilization technology applications for the bioremediation of PAH-contaminated soils and sediments.
通过使用含有杂酚油污染的田间土壤的无土和浓浆（固体含量67%，重量）体系，研究了一种乙氧基化山梨糖醇脂肪酸酯非离子表面活性剂（吐温80）对多环芳烃（PAHs）生物有效性的影响。在无土体系中，分散胶束相的多环芳烃对于杂酚油污染土壤中的混合微生物群落而言不易被生物利用。相反，微生物部分且优先利用表面活性剂中易于利用的部分作为碳源（占初始表面活性剂剂量的16 - 18%）。这种选择性的微生物攻击导致分散相胶束不稳定，摩尔增溶比和胶束 - 水分配系数值显著降低。由于吐温80被所用土壤吸附，需要相当高剂量（>20 g/L）的吐温80才能通过胶束缔合增强吸附态多环芳烃的迁移。在土壤 - 泥浆体系中，从不稳定胶束中释放的多环芳烃要么与吸附相表面活性剂结合，要么太快重新吸附到土壤有机质上，以至于即使是存在的适应多环芳烃降解的微生物也无法对其进行生物利用。这项工作为表面活性剂增溶和迁移技术在多环芳烃污染土壤和沉积物生物修复中的应用提供了重要的新信息和实用见解。
