Exceedence probabilities in a water body, even if it was located at the edge of the field, would likely be considerably smaller. Additional pesticide degradation and dilution may occur as the distance between the field and the water body increases. Figure 2 illustrates management practice effects on the probability of annual pesticide solution runoff to exceed each pesticide's MCL at the edge of the field. Click here for Figure 2. In some cases, this reduced tillage alternative may conflict with residue requirements that are in place for erosion control.
Erosion can lead to sediment which impacts both water quality and aquatic habitat.
The optimum solution for a particular ecosystem will change with different soils, climates and resource concerns. Three-tiered Pesticide Environmental Risk Screening is designed to help protect our natural resources. To be effective, water quality management practices must be differentially applied based on natural resource sensitivity.