ARS | Publication request: MIXED-MODE SORPTION OF HYDROXYLATED ATRAZINE DEGRADATION PRODUCTS TO SOIL: A MECHANISM FOR BOUND RESIDUE

Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 7, 1997
Publication Date: N/A

Technical Abstract: This study tested the hypothesis that sorption of hydroxylated atrazine degradation products (HADP) [hydroxyatrazine (HA), deethylhydroxyatrazine (DEHA), and deisopropylhydroxyatrazine (DIHA)] to soils occurs by mixed-mode binding resulting from two simultaneous mechanisms: (1) cation exchange and (2) hydrophobic interaction. The objective of this research was to use liquid 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 atrazine residue. Based on differences between several soil extractants and solid-phase extraction (SPE) bonded-phases, the extent of HADP mixed-mode binding to soil or to SPE occurred in the order: HA > DIHA > DEHA. Mixed-mode extraction recovered 43% of bound atrazine residues from aged soil, and 88% 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. This sorption mechanism may also have relevance for other weakly basic, hydrophobic compounds.