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United States Department of Agriculture

Agricultural Research Service

Title: Mixed-Mode Sorption of Hydroxylated Atrazine Degradation Products in Soil: a Mechanism for Bound Residue

Authors
item Lerch, Robert
item Thurman, E - USGS
item Kruger, Ellen - IOWA STATE UNIV

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 30, 1997
Publication Date: N/A

Technical Abstract: This study tested the hypothesis that sorption of hydroxylated atrazine degradation products [HADPs; hydroxyatrazine (HA), deethylhydroxyatrazine (DEHA), and deisopropylhydroxyatrazine (DIHA)] to soils occurs by mixed mode binding resulting from two mechanisms occurring simultaneously: 1) cation exchange; and 2) hydrophobic partitioning. The objective was to use eliquid chromatography and soil extraction experiments to show that mixed mode binding is the mechanism controlling HADP sorption to soils and is also a mechanism for bound residue. Overall, HADP binding to solid-phase extraction (SPE) sorbents occurred in the order: cation exchange >> octadecyl(C18) >> cyanopropyl. Binding to cation exchange SPE and to a high-performance liquid chromatography octyl (C8) column showed evidence for mixed-mode binding. Based on differences between extractants, the extent of HADP mixed-mode binding to soil occurred in the order: HA > DIHA > DEHA. Mixed-mode extraction recovered 42.8% of bound atrazine residues from aged soil, and the majority of this fraction was identified as HADPs. Thus, a significant portion of bound atrazine residues in soils is sorbed by the mixed-mode binding mechanisms.

Last Modified: 11/23/2014
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