Evaluating dissolved organic carbon-water partitioning using polyparameter linear free energy relationships: Implications for the fate of disinfection by-products

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• 作者：Peta A. Neale^a ; Beate I. Escher^a ; Kai-Uwe Goss^b ; ^c ; Satoshi Endo^b ; ^{satoshi.endo@ufz.de}
• 关键词：Fulvic acid ; Partition coefficient ; Polyparameter linear free energy relationship ; Dissolved organic carbon ; Disinfection by-products
• 刊名：Water Research
• 出版年：2012
• 出版时间：July, 2012
• 年：2012
• 卷：46
• 期：11
• 页码：3637-3645
• 全文大小：395 K

文摘

The partitioning of micropollutants to dissolved organic carbon (DOC) can influence their toxicity, degradation, and transport in aquatic systems. In this study carbon-normalized DOC-water partition coefficients (K_DOC-w) were measured for a range of non-polar and polar compounds with Suwannee River fulvic acid (FA) using headspace and solid-phase microextraction (SPME) methods. The studied chemicals were selected to represent a range of properties including van der Waal forces, cavity formation and hydrogen bonding interactions. The K_DOC-w values were used to calibrate a polyparameter linear free energy relationship (pp-LFER). The difference between experimental and pp-LFER calculated K_DOC-w values was generally less than 0.3 log units, indicating that the calibrated pp-LFER could provide a good indication of micropollutant interaction with FA, though statistical analysis suggested that more data would improve the predictive capacity of the model. A pp-LFER was also calibrated for Aldrich humic acid (HA) using K_DOC-w values collected from the literature. Both experimental and pp-LFER calculated K_DOC-w values for Aldrich HA were around one order of magnitude greater than Suwannee River FA. This difference can be explained by the higher cavity formation energy in Suwannee River FA. Experimental and pp-LFER calculated K_DOC-w values were compared for halogenated alkanes and alkenes, including trihalomethane disinfection by-products, with good agreement between the two approaches. Experimental and calculated values show that DOC-water partitioning is generally low; indicating that sorption to DOC is not an important fate process for these chemicals in the environment.