How do pesticides get into ground and surface water?
Water solubility and adsorption to soil are important in determining a pesticide s tendency to move through the soil profile with infiltrating water, and over the soil with runoff. Most pesticides that have low water solubility also tend to sorb strongly to soil, but there are exceptions. The more strongly a pesticide sorbs to soil, the lower the tendency to move with infiltrating water. Soil properties are also important, as each soil has a characteristic ability to adsorb pesticides. Soils high in clay and organic matter sorb pesticides better than sandy soils low in organic matter. Soil structure also is important as it determines the infiltration rate. Rapidly infiltrating water may move pesticides on the surface deeper into the soil as they have less time for sorption. Soils that weakly adsorb pesticides and have a rapid infiltration rate are more sensitive to groundwater pollution than soils that strongly adsorb pesticides and have a slow infiltration rate. Soil sorption and infi
