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Full-Text Articles in Physical Sciences and Mathematics

Modeling Transport Of Colloid-Bound Herbicides And Heavy Metals To Groundwater, Anastasios D. Karathanasis, R. E. Phillips, A. K. Seta Jun 1996

Modeling Transport Of Colloid-Bound Herbicides And Heavy Metals To Groundwater, Anastasios D. Karathanasis, R. E. Phillips, A. K. Seta

KWRRI Research Reports

Recent studies have suggested that contaminant transport to groundwater may be enhanced by association with colloidal particles. This study evaluated the role of water dispersible colloids with diverse mineralogical composition in co-transporting selected herbicides and heavy metals through intact soil columns. Colloid recovery in the eluents ranged from 45-90% for the herbicides and 10-60% for the heavy metals. The presence of colloids enhanced the transport of atrazine by 2-18%, and metolachlor by 8-30%. The corresponding increase for Cu and Zn was 2-150 and 5-30 times, respectively. For Pb, there was essentially no elution in the absence of colloids, suggesting nearly …


Formulation Enhanced Transport Of A Soil Applied Herbicide, V. P. Evangelou, Louis M. Mcdonald, Sandra Prima Jun 1996

Formulation Enhanced Transport Of A Soil Applied Herbicide, V. P. Evangelou, Louis M. Mcdonald, Sandra Prima

KWRRI Research Reports

Because pesticides are applied as formulated particles and the affinity of the active ingredient for the formulation is higher than for the bulk water, we hypothesized that a formulation complex could affect active ingredient transport. Our objectives were to investigate the nature and extent of surfactant-atrazine-clay/oxide surface interactions. When atrazine and an anionic surfactant were dried onto plain or Fe-coated sand and leached, atrazine concentrations in the initial leachate were lower in the Fe-coated sand treatment. This was likely due to an electrostatic attraction between the sand and surfactant. When a nonionic surfactant was used, atrazine concentration in the initial …


Potential For Crop Residue To Restrict Herbicide Movement In Surface From Water Corn And Soybean Fields, William W. Witt Jan 1996

Potential For Crop Residue To Restrict Herbicide Movement In Surface From Water Corn And Soybean Fields, William W. Witt

KWRRI Research Reports

As no-tillage and other conservation tillage practices continue to increase, it is important to have knowledge of herbicide adsorption on crop residue with regard to the potential for the herbicide to be removed from the residue and move with runoff water from the field into nearby surface waters. Previous research had compared herbicide adsorption to various residues, but it was difficult to make comparisons among these studies because the residues were from different crops or the amount of residue decomposition was different. The amount of "weathering" or "aging" of the residue at the time of herbicide treatment could alter the …