Reanalysis of Experiments To Quantify Irreversibility of Pesticide Sorption鈥揇esorption in Soil

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• 作者：Laura A. Suddaby ; Sabine Beulke ; Wendy van Beinum ; Rafael Celis ; William C. Koskinen ; Colin D. Brown
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2013
• 出版时间：March 6, 2013
• 年：2013
• 卷：61
• 期：9
• 页码：2033-2038
• 全文大小：294K
• 年卷期：v.61,no.9(March 6, 2013)
• ISSN：1520-5118

文摘

Previously published research used an isotope-exchange technique to measure irreversibility of pesticide sorption鈥揹esorption in soil. Results indicated significant irreversibility (6鈥?1%) in sorption in five pesticide鈥搒oil systems measured over 72 h. Here, we propose a three-site model to reanalyze the experimental data. The model adds a slow but reversible binding on nonequilibrium sorption sites in addition to instantaneously reversible sites and irreversible sites. The model was able to match experimental data very closely, but only if irreversible sorption was assumed to be absent. Observed asymmetry in the binding of ¹²C- and ¹⁴C-pesticide was explained on the basis of nonattainment of sorption equilibrium over the study period. Results suggest that irreversible sorption may be less significant than previously considered with important implications for understanding the fate of pesticides applied to soil.

Keywords:

irreversible sorption; three-site model; pesticide; soil; isotope exchange