The role of dissolved organic matter in pesticide transport through soil

Soil derived dissolved organic matter (DOM) can complex with pesticides and facilitate their transport through soil. Soil column leaching experiments showed that, in the absence of preferential flow, the herbicide napropmaide was present in the initial leachate. A stable, non-retarded, complex formed between napropamide and DOM that was capable of transport through soil columns. The presence of a napropamide - DOM complex in the leachate was confirmed using an equilibrium dialysis technique. Batch equilibrium adsorption techniques qualitatively predicted the transport of napropamide in soil. The formation of the napropamide - DOM complex was dependent on a drying event where napropamide was applied to the soil and allowed to dry prior to water application.