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United States Department of Agriculture

Agricultural Research Service

Title: Role of Humic Substances in Drainage Waters in the Transport of Anthropogenic Organic Chemicals: It Is a Myth?

Authors
item Hayes, Thomas - UNIV OF BIRMINGHAM
item Hayes, Michael - UNIV OF BIRMINGHAM
item Clapp, Charles

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 29, 1995
Publication Date: N/A

Technical Abstract: Taking account of pH and salt, studies were carried out of the maximum solubility enhancements of **14C-labelled atrazine, DDT, napropamide, isoproturon, trifluralin, imazaquin, and simazine by humic acids (HA), fulvic acids (FA), and XAD-4 acids isolated from the drainage waters of two soils. The HA solutions (20 to 100 ppm) had no effect on the solubilities of atrazine (pH 6 and 4, and no salt), simazine (pH 6 and 4, salt and no salt), isoproturon (pH 6, no salt), trifluralin (pH 6 and 4, no salt), napropamide, (pH 6 and 4, no salt), and DDT (pH 6, no salt). The HA solution inhibited solubilization of isoproturon (pH 4, no salt), imazaquin, (pH 4, salt and no salt), and DDT (pH 4, no salt). Except in the case of imazaquin, in a salt background at pH 6, solubilities were enhanced in all other instances. The FA solutions did not affect the solubilities of trifluralin, simazine, napropamide, and atrazine under some conditions, and enhanced solubilities of isoproturon, trifluralin, napropamide, DDT and imazaquin. Humic substances may not play a major role in solubilizing pesticides.

Last Modified: 10/25/2014