Transport of Commercial Endosulfan through a Column of Aggregated Vineyard Soil by a Water Flux Simulating Field Conditions
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- 作者：M. Carmen Ló ; pez-Blanco ; Beatriz Cancho-Grande ; Jesú ; s Simal-Gá ; ndara ; Eugenio Ló ; pez-Periago ; and Manuel Arias-Esté ; vez
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：August 24, 2005
- 年：2005
- 卷：53
- 期：17
- 页码：6738 - 6743
- 全文大小：123K
- 年卷期：v.53,no.17(August 24, 2005)
- ISSN：1520-5118
文摘
Endosulfan is a potentially harmful, degradation resistant pesticide that is found in soils where it hasbeen used. Despite being hydrophobic and having high affinity for soil matrix components, it hasalso been found in groundwater. To investigate this behavior, we studied the passage of a commercialemulsified formulation through a column of aggregated vineyard soil under simulated light rain.Breakthrough data were obtained using gas chromatography with electron capture detection todetermine the concentration of endosulfan in samples extracted from the column periodically at severaldepths. These data, and analogous data obtained previously for the passage of bromide, wereanalyzed using the program CXTFIT v.2. Analysis of the bromide data strongly suggested the existenceof preferential flow paths in the column. The endosulfan data were adequately accounted for by amodel in which the preferential flow and nonpreferential flow regions are almost isolated from eachother. These regions differ also as regards both the partition of endosulfan between soil and soilsolution and the rate at which reversibly adsorbed endosulfan is transformed into irreversibly adsorbedendosulfan. The "irreversibility" sink term accounts also for biological and chemical degradation ofendosulfan. The findings imply that soil humidity favors the transport of commercial endosulfan bythe formation and maintenance of preferential flow paths in soil, controlling both the presence ofendosulfan in groundwater and its high persistence in soil.Keywords: Soil transport; environmental fate; endosulfan; gas chromatography-electron capturedetection