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United States Department of Agriculture

Agricultural Research Service

Title: Complexation of Herbicides with Soluble Humic Substances

Authors
item Clapp, Charles
item Hayes, Michael - UNIVERSITY OF BIRMINGHAM
item Mingelgrin, Uri - ARO BET DAGAN ISR

Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 1997
Publication Date: N/A

Technical Abstract: Complexation of herbicides with humic substances in soils and waters of natural environments may influence the efficiency and movement of herbicides. It has been recognized that organic matter content is the major factor controlling herbicide sorption in soil/water systems, both on the immobile solid phase and on colloids. Humic and fulvic acids are the most active fractions of soil and water organic materials. Complexation with soluble acids may have a marked effect on the apparent solubility and mobility of slightly-soluble herbicides. Humic acids from different sources displayed widely different complexation affinities, possibly due to variations in chemical structure of the acids. Fulvic acids appeared to form much weaker complexes than humic acids. An equilibrium dialysis method was considered to be the most quantitative method for determining extent of interaction. Our data show that complexation of herbicides with soluble humic substances was strongly influenced by the properties of both herbicide and acids.

Last Modified: 11/27/2014
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