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首页> 外文期刊>Environmental Science & Technology >Environmental Influences on the Partitioning and Diffusion of Hydrophobic Organic Contaminants in Microbial Biofilms
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Environmental Influences on the Partitioning and Diffusion of Hydrophobic Organic Contaminants in Microbial Biofilms

机译：环境对微生物生物膜中疏水性有机污染物的分配和扩散的影响

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A biofilm reactor was used to investigate kinetic and thermodynamic aspects of the sorption of polycyclic aromatic hydrocarbons (PAH) as model compounds for hydrophobic organic contaminants (HOC) to intact microbial biofilms. Effective diffusion coefficients are in the range of 10~(-10) cm~2·s~(-1), resulting in equilibration times of more than 3 days for a biofilm of 100 μm thickness. Diffusion in the biofilm was strongly temperature-dependent and increased by a factor of 3 (phenanthrene) to 6 (fluoranthene, pyrene) between 5 and 35 ℃. Drying and rewetting of the biofilm as well as the inclusion of Ca~(2+) ions and of humic acids all strengthened the biofilm rigidity and slowed down the diffusion of PAH. The later two factors also influenced the thermodynamics of the process as they supported the partitioning of PAH into the biofilm. Humic acid inclusion from solution into the biofilm illustrates that a microbial biofilm can act as a primer allowing for the buildup of a paniculate organic phase from dissolved organic matter. PAH metabolites β-hydroxy-phenanthrene and 1 -hydroxy-2-naphthoic acid) showed lower partition coefficients as compared to their parent compounds and 3-hydroxy-phenanthrene also showed a higher diffusion constant, indicating that these transformation products would be easily released into the water phase upon formation during PAH biodegradation in a biofilm. These results allow the quantification of the influence of environmental conditions on a biofilm's function as a sink or as a diffusion barrier for PAH from aqueous solution, and they indicate the importance of kinetic aspects of this partitioning process.
机译：生物膜反应器用于研究多环芳烃（PAH）作为疏水性有机污染物（HOC）完整微生物生物膜的模型化合物吸附的动力学和热力学方面。有效扩散系数在10〜（-10）cm〜2·s〜（-1）范围内，对于100μm厚度的生物膜，平衡时间超过3天。在5到35℃之间，生物膜中的扩散强烈依赖于温度，并且增加了3（菲）至6（荧蒽，pyr）。生物膜的干燥和再润湿以及Ca〜（2+）离子和腐殖酸的加入均增强了生物膜的刚性，并减慢了PAH的扩散。后两个因素也支持该过程的热力学，因为它们支持了PAH在生物膜中的分配。溶液中的腐殖酸被包含在生物膜中，这说明微生物生物膜可以充当引物，从而允许从溶解的有机物中形成颗粒状的有机相。与母体化合物相比，PAH代谢物β-羟基菲和1-羟基-2-萘甲酸显示出较低的分配系数，而3-羟基菲也显示出较高的扩散常数，表明这些转化产物将易于释放到生物膜中PAH生物降解过程中形成时的水相。这些结果可以量化环境条件对生物膜作为PAH从水溶液中的沉陷或扩散屏障的功能的影响，并且它们表明了这种分配过程动力学方面的重要性。

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