Photolytic Transformation of Organic Pollutants on Soil Surfaces-An Experimental Approach

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• 作者：Marianne E. Balmer ; Kai-Uwe Goss ; and René ; P. Schwarzenbach
• 刊名：Environmental Science & Technology
• 出版年：2000
• 出版时间：April 1, 2000
• 年：2000
• 卷：34
• 期：7
• 页码：1240 - 1245
• 全文大小：108K
• 年卷期：v.34,no.7(April 1, 2000)
• ISSN：1520-5851

文摘

Photolysis on soil surfaces is an important degradationpathway for many agrochemicals. Although the investigationof photochemical pesticide transformation on soil surfacesis required by registration authorities, knowledge of therelevant processes is limited. The quantification of photolysison soil surfaces is of higher complexity than it is insolutions. In experiments, carried out on soil layers, theobserved overall degradation rate is not only determined byphotolysis itself but is also a function of the layer thicknessand in many cases of transport processes. In this articlewe describe a theoretical framework to understand combinedeffects of these different processes, and we present anexperimental setup that allows a separate quantification ofactual photolysis and diffusive transport processes. Forthe two compounds p-nitroanisole and trifluralin we performedexperiments on kaolinite layers of variable thickness andevaluated the results using a mathematical model. Thus, wewere able to determine the actual photolysis rate constantswhich are independent of layer thickness and transportkinetics. The proposed theoretical and experimental conceptcontributes to the development of a standardized laboratorymethod.