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United States Department of Agriculture

Agricultural Research Service

Title: Fate and Transport of Propachlor and Thiosulfate

Authors
item Yates, Scott
item Papiernik, S

Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2003
Publication Date: March 20, 2003
Citation: Yates, S.R., Papiernik, S.K. 2003. Fate and transport of propachlor and thiosulfate`. American Chemical Society Abstracts 225:U94-U94 0024-AGRO Part 1, March 2003.

Interpretive Summary: Previous research has shown that several classes of pesticides will react with thiosulfate following a second-order rate law. Several mathematical methods have been developed to describe the transport process, and are tested using experimental data obtained in a saturated soil column. The transport behavior of propachlor in the presence of thiosulfate was found to be relatively complex compared to traditional conservative or single-constituent tracers. The transport of compounds undergoing second-order chemical reaction can yield unusual concentration profiles. Under certain circumstances, a bi-modal concentration curve may occur. A comparison is presented between model and experimental concentration measurements in the soil column. This research has implications for using thiosulfate to reduce the emissions of pesticides at the soil surface and as a soil remediation methodology.

Technical Abstract: Previous research has shown that several classes of pesticides will react with thiosulfate following a second-order rate law. Several mathematical methods have been developed to describe the transport process, and are tested using experimental data obtained in a saturated soil column. The transport behavior of propachlor in the presence of thiosulfate was found to be relatively complex compared to traditional conservative or single-constituent tracers. The transport of compounds undergoing second-order chemical reaction can yield unusual concentration profiles. Under certain circumstances, a bi-modal concentration curve may occur. A comparison is presented between model and experimental concentration measurements in the soil column. This research has implications for using thiosulfate to reduce the emissions of pesticides at the soil surface and as a soil remediation methodology.

Last Modified: 7/30/2014
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