When is groundwater contamination of particular concern for pesticide applicators?

Groundwater contamination is a significant concern for pesticide applicators primarily in areas where groundwater is close to the surface. This proximity increases the risk that pesticides, if not used properly, can leach into the groundwater, potentially affecting drinking water supplies and local ecosystems. When groundwater is shallow, any applied pesticides have less soil barrier to filter and degrade them before they reach the water table. Thus, when working in areas with high water tables, practitioners must exercise greater caution and implement strategies to minimize the risk of contamination.

Other scenarios, such as during heavy rainfall, may also pose risks by increasing surface runoff, but the immediate proximity of groundwater to the surface presents a more direct threat. This makes the scenario outlined in the chosen answer critical to consider for safe pesticide application practices.