Mechanisms of Pesticide Transport to Surface Water and the Field Scale in the Palouse Loess

The goal of the proposed project is to determine the pathways by which pesticides enter surface water in this region.  An important contribution of this study is that it focuses on quantifying the components of mass discharge for a particular field, which will allow the relative importance transport pathways to be determined.   This cannot be determined by surveying stream water quality.  The pesticide selected for study is triallate, the herbicide applied in the largest amount in this region.  The specific objectives of the project are:

• to determine the triallate mass discharge attributable to surface versus subsurface transport pathways at the field scale;

• to determine the effect of these two mass discharges on the mass discharge in surface water over time; and

• to determine the effect of turbidity on transport by surface runoff.

These objectives will be met through the analysis of triallate concentrations and water discharges in surface runoff, drainage ditchwater, soil solution and tile drain water for a particular field at regular intervals throughout the spring and summer.  Because the study focuses on the processes which control transport, the information gained will provide insights on the fate of other chemicals with similar physicochemical properties.  We anticipate that the study will help to transform the conceptual model for chemical transport in the shallow subsurface in this region.   The results of this quantitative and hypothesis-driven study will be publishable in an internationally recognized journal, such as the Journal of Contaminant Hydrology.

Principal Investigators:

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Last modified Friday, March 24, 2000