Predicting Soil-Water Partitioning of Polycyclic Aromatic Hydrocarbons and Polychlorinated Biphenyls by Desorption with Methanol-Water Mixtures at Different Temperatures
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- 作者：Martin Krauss and Wolfgang Wilcke
- 刊名：Environmental Science & Technology
- 出版年：2001
- 出版时间：June 1, 2001
- 年：2001
- 卷：35
- 期：11
- 页码：2319 - 2325
- 全文大小：106K
- 年卷期：v.35,no.11(June 1, 2001)
- ISSN：1520-5851
文摘
We evaluated a method to determine organic carbon-normalized soil-water partition coefficients (KOC) of 20 PAHsand 12 PCBs by desorption in the presence of a cosolvent(methanol fractions of 0.1-0.9) and at different temperatures(20-80 
C). The KOC values, the deviation factor from idealsorption 
, and the desorption enthalpies 
Hdes wereestimated by nonlinear regression of log KOC on the methanolfractions and on T. The KOC values of individual compoundsvaried up to a factor of 100 among the studied 11 urbansoils. The calculated and Hdes of individual compoundsvaried considerably among the soils (coefficients ofvariation 5-20% and 20-30%, respectively), increasedwith increasing hydrophobicity of the compounds. A sequentialextraction with four temperature/methanol fractioncombinations followed by a nonlinear regression allowedfor the direct determination of the KOC, , and Hdes. The useof less temperature/methanol fraction combinationsrequires a suitable estimation of and Hdes, as theirchoice may change the obtained KOC values by up to a factorof 10. The proposed method is suitable for a routinedetermination of KOC values of PAHs and PCBs for smallsoil samples (2-6 g) and low concentrations (down to 0.3mg kg-1 of 
20 PAHs and 1.2 
g kg-1 of 12 PCBs).
C). The KOC values, the deviation factor from idealsorption , and the desorption enthalpies Hdes wereestimated by nonlinear regression of log KOC on the methanolfractions and on T. The KOC values of individual compoundsvaried up to a factor of 100 among the studied 11 urbansoils. The calculated and Hdes of individual compoundsvaried considerably among the soils (coefficients ofvariation 5-20% and 20-30%, respectively), increasedwith increasing hydrophobicity of the compounds. A sequentialextraction with four temperature/methanol fractioncombinations followed by a nonlinear regression allowedfor the direct determination of the KOC, , and Hdes. The useof less temperature/methanol fraction combinationsrequires a suitable estimation of and Hdes, as theirchoice may change the obtained KOC values by up to a factorof 10. The proposed method is suitable for a routinedetermination of KOC values of PAHs and PCBs for smallsoil samples (2-6 g) and low concentrations (down to 0.3mg kg-1 of 20 PAHs and 1.2 g kg-1 of 12 PCBs).