The University of Queensland, National Research Centre for Environmental Toxicology (Entox), Brisbane, QLD 4108, Australia.
Water Res. 2011 Aug;45(14):4227-37. doi: 10.1016/j.watres.2011.05.038. Epub 2011 Jun 7.
The interaction of organic micropollutants with dissolved organic carbon (DOC) can influence their transport, degradation and bioavailability. While this has been well established for natural organic carbon, very little is known regarding the influence of DOC on the fate of micropollutants during wastewater treatment and water recycling. Dissolved organic carbon-water partition coefficients (K(DOC)) for wastewater derived and reference DOC were measured for a range of micropollutants using a depletion method with polydimethylsiloxane disks. For micropollutants with an octanol-water partition coefficient (log K(OW)) greater than 4 there was a significant difference in K(DOC) between reference and wastewater derived DOC, with partitioning to wastewater derived DOC over 1000 times lower for the most hydrophobic micropollutants. The interaction of nonylphenol with wastewater derived DOC from different stages of a wastewater and advanced water treatment train was studied, but little difference in K(DOC) was observed. Organic carbon characterisation revealed that reference and wastewater derived DOC had very different properties due to their different origins. Consequently, the reduced sorption capacity of wastewater derived DOC may be related to their microbial origin which led to reduced aromaticity and lower molecular weight. This study suggests that for hydrophobic micropollutants (log K(OW) > 4) a higher concentration of freely dissolved and thus bioavailable micropollutants is expected in the presence of wastewater derived DOC than predicted using K(DOC) values quantified using reference DOC. The implication is that naturally derived DOC may not be an appropriate surrogate for wastewater derived DOC as a matrix for assessing the fate of micropollutants in engineered systems.
有机微量污染物与溶解有机碳 (DOC) 的相互作用会影响它们的迁移、降解和生物利用度。虽然这一点在天然有机碳中已经得到了很好的证实,但对于在废水处理和水再利用过程中 DOC 对微量污染物命运的影响,人们知之甚少。采用聚二甲基硅氧烷圆盘耗尽法,测定了一系列微量污染物与废水衍生和参比 DOC 的分配系数 (K(DOC))。对于辛醇-水分配系数 (log K(OW)) 大于 4 的微量污染物,参比 DOC 和废水衍生 DOC 之间的 K(DOC) 存在显著差异,最疏水的微量污染物对废水衍生 DOC 的分配系数要低 1000 多倍。研究了不同废水处理阶段和高级水处理工艺废水中衍生的 DOC 与壬基酚的相互作用,但观察到 K(DOC) 几乎没有差异。有机碳特征分析表明,由于来源不同,参比和废水衍生的 DOC 具有非常不同的性质。因此,废水衍生 DOC 的吸附容量降低可能与其微生物来源有关,这导致其芳香度降低和分子量降低。本研究表明,对于疏水性微量污染物 (log K(OW) > 4),在存在废水衍生的 DOC 时,预计自由溶解且生物利用度更高的微量污染物的浓度会高于使用参比 DOC 定量的 K(DOC) 值预测的浓度。这意味着天然衍生的 DOC 可能不适合作为评估工程系统中微量污染物命运的基质来替代废水衍生的 DOC。
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