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

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Beigel, C. Articles by Di Pietro, L. Search for Related Content PubMed Articles by Beigel, C. Articles by Di Pietro, L. GeoRef GeoRef Citation Agricola Articles by Beigel, C. Articles by Di Pietro, L.

DIVISION S-1-SOIL PHYSICS

Transport of Triticonazole in Homogeneous Soil Columns

Influence of Nonequilibrium Sorption

^a Unité de Science du Sol, I.N.R.A., Domaine St Paul, Site Agroparc, 84914 Avignon Cedex 9, France

lili{at}avignon.inra.fr

Nonequilibrium sorption of pesticides is frequently reported to greatly affect their transport and dissipation in soil. This study was aimed at evaluating the performances of equilibrium and two site–two region nonequilibrium convective–dispersive models for describing the sorption and decay characteristics during transport of triticonazole systemic fungicide in water-saturated homogeneous soil. Chloride and ¹⁴C-triticonazole column displacement experiments were carried out in a loamy clay soil under steady-state water flow at high pore water velocities. The symmetrical breakthrough curves (BTC) obtained with the conservative tracer showed no significant physical nonequilibrium and were used to estimate a dispersivity of 0.06 cm. Compared with chloride, the ¹⁴C-triticonazole BTC was strongly asymmetrical and shifted to the right, with a broad, extended tailing characteristic of sorption nonequilibrium. Chemical analysis of the soil after elution showed that bound residues were rapidly formed during transport. These bound residues were accounted for as decayed in the models. The two-site model correctly described the first part of the tailing, with an estimated partition coefficient K_d of 1.5 L kg^-1 for instantaneous sorption, and it predicted high values in the range of 58 d^-1, and 7 d^-1 for the sorption and decay first-order rates, respectively. However, the model failed to describe the slower, extended release of ¹⁴C-triticonazole. Nonequilibrium sorption and formation of bound residues of triticonazole were attributed to the rate-limiting diffusive process. It was thus concluded that use of a single first-order rate constant for description and prediction of both nonequilibrium sorption and dissipation of triticonazole in soil is not appropriate.

Abbreviations: BTC, breakthrough curves • CDE, convective–dispersive equation • CDeq, CXTFIT 2.0 deterministic equilibrium CDE model • CDnoneq, CXTFIT 2.0 deterministic two-site, two-region nonequilibrium model • HOC, hydrophobic organic compounds • LEA, local equilibrium for solute adsorption • LSC, liquid scintillation counting • OM, organic matter • STD, standard deviation

This article has been cited by other articles:

				Y.-q. Tao, X. Jiang, Y.-r. Bian, X.-l. Yang, and F. Wang Transport of Malathion in Homogeneous Soil Liquid Chromatographic Columns: Influence of Nonequilibrium Sorption Vadose Zone J., February 1, 2009; 8(1): 42 - 51. [Abstract] [Full Text] [PDF]

				F. Prata, F. Prata, A. Lavorenti, J. Vanderborght, P. Burauel, and H. Vereecken Miscible Displacement, Sorption and Desorption of Atrazine in a Brazilian Oxisol Vadose Zone J., November 1, 2003; 2(4): 728 - 738. [Abstract] [Full Text] [PDF]