HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Turin, H. J. Articles by Bowman, R. S. Search for Related Content PubMed Articles by Turin, H. J. Articles by Bowman, R. S. Agricola Articles by Turin, H. J. Articles by Bowman, R. S.

Sorption Behavior and Competition of Bromacil, Napropamide, and Prometryn

Los Alamos National Laboratory, Los Alamos, NM 87545;

R. S. Bowman

Department of Earth and Environmental Science and Geophysical Research Center, New Mexico Institute of Mining and Technology, Socorro, NM 87801.

^* Corresponding author (turin{at}lanl.gov).

ABSTRACT

Groundwater contamination by pesticides is a problem of major and increasing concern. Detailed field measurements reveal that leaching of pesticides from soils is often faster than predicted using simple models. This discrepancy is likely due to a combination of physical effects (e.g., preferential pathways) and complexities in the chemical sorption process. To address the issue of sorption complexity, a series of laboratory batch sorption studies have been conducted to determine the detailed sorption behavior of three herbicides, bromacil [5-bromo-6-methyl-3-(1-methylpropyl)-2,4(1H,3H)pyrimidinedione], napropamide [N,N-diethyl-2-(1-naphthalenyloxy)propanamide], and prometryn [N,N'-bis(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine], onto a sandy loam soil. The studies were designed to determine the extent of nonideal sorption behavior, specifically nonequilibrium, nonlinearity, sorption hysteresis, and solute-solute interactions. Results showed all three herbicides reached sorption equilibrium quickly, within 2 h. Both napropamide and prometryn were linearly sorbed, while bromacil sorption followed a Freundlich isotherm, with n = 0.92. All three herbicides displayed apparent sorption hysteresis. Bromacil and napropamide sorption decreased in the presence of the other herbicides, while prometryn sorption was unaffected. Contrary to most literature data, napropamide was more strongly sorbed than prometryn in these studies, due to the high pH of the soil. Results suggest that sorption nonlinearity and competition may increase field-scale transport velocities by 10% or more.

This article has been cited by other articles:

				M. Sander, Y. Lu, and J. J. Pignatello A Thermodynamically Based Method to Quantify True Sorption Hysteresis J. Environ. Qual., May 11, 2005; 34(3): 1063 - 1072. [Abstract] [Full Text] [PDF]