Fate and Transport of Pesticides through Soils
Collaborators: Jorge Jerez (Washington State University)
Pesticide contamination of groundwater resources is of major concern in many
areas of the United States, and in particular in the Palouse and Columbia Basin
of Washington State. Pesticides have been found to move faster than anticipated
through soil profiles. For example, our lab has recently documented movement of a hydrophobic pesticide to $>$ 1 m depth in Palouse soil during the first few months following pesticide application. We hypothesize that one important reason for this accelerated movement is facilitated transport via carbonaceous (non-carbonate, carbon-containing) colloidal particles, such as humic acids and combustion/pyrolysis residues.
While previous research has shown that dissolved organic matter can enhance the transport of pesticides, it is not clear which fractions of carbonaceous colloids are mainly responsible for colloid-facilitated transport.
The objective of the proposed research is to elucidate the role of carbonaceous
colloids in facilitated transport of pesticides through porous media, with special emphasis given to the physical and chemical properties of the colloidal material.
Specifically, we address the following objectives:
-
Fractionate and characterize carbonaceous colloids in terms of composition and colloidal properties.
- Study sorption of a model pesticide (atrazine) to carbonaceous colloids that vary in structure and composition.
- Investigate the transport of atrazine as facilitated by the various well-characterized carbonaceous colloids.
- Develop a conceptual model for colloid-facilitated pesticide transport with data from well-controlled experiments.
Publications
- Guo, L., W.A. Jury, R.J. Wagenet, and M. Flury, Dependence of pesticide
degradation on sorption: nonequilibrium model and application to soil
reactors, J. Contam. Hydrol., 43, 45-62, 2000.
- Flury, M., and W.A. Jury, Solute transport with resident-time-dependent
sink/source reaction coefficients, Water Resour. Res., 35, 1933-1938, 1999.
- Fortin, J., M. Flury, W.A. Jury, and T. Streck, Rate-limited sorption of
simazine in saturated soil columns, J. Contam. Hydrol., 25, 219-234, 1997.
- Flury, M., Experimental evidence of transport of pesticides through field
soils-A review, J. Environ. Qual., 25, 25-45, 1996.
- Flury, M., J. Leuenberger, B. Studer, and H. Flühler, Transport of anions
and herbicides in a loamy and a sandy field soil, Water Resour. Res.,
31, 823-835, 1995.
- Flury, M., H. Flühler, W. A. Jury, and J. Leuenberger, Susceptibility of
soils to preferential flow of water: A field study, Water Resour.
Res., 30, 1945-1954, 1994.
- Buchan, G.D., and M. Flury, Pathogen transport by water, in Encyclopedia of Water Science, edited by B.A. Stewart, and T.A.
Howell, doi: 10.1081/E-EWS 120021169, Marcel Dekker, New York, 2004.
-
Flury, M., and T. Gimmi, Solute diffusion, in Methods of Soil
Analysis, Part 4, Physical Methods, edited by J. H. Dane, and G. C. Topp,
pp. 1323-1351, Soil Science Society of America, Madison, WI, 2002.
- Hendrickx, J.M.H., and M. Flury, Uniform and preferential flow mechanisms in
the vadose zone, in Conceptual Models of Flow and Transport in the
Fractured Vadose Zone, edited by National Research Council,
pp. 149-187, National Academy Press, Washington DC, 2001.
- Flury, M., W.A. Jury, and E.J. Kladivko, Field-scale solute transport in the
vadose zone: Experimental observations and interpretation, in Physical Nonequilibrium in Soils: Modeling and Application, edited by H.M. Selim, and L. Ma, pp. 349-369, Ann Arbor Press, Chelsea, MI,
1998.
- Flury, M., Sampling efficiency for mass recovery calculations, in Soil
Monitoring, edited by R. Schulin, A. Desaules, R. Webster, and B. von
Steiger, pp. 187-199, Birkhäuser, Basel, 1993.
Markus Flury 
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