Which surface type is likely to prevent pesticide infiltration into groundwater?

Hard surfaces such as asphalt are effective at preventing pesticide infiltration into groundwater because they are non-porous. Unlike porous surfaces, which allow water and contaminants to percolate through them, hard surfaces create a barrier that limits the movement of liquids. This means that any pesticide application on these surfaces is likely to remain on the surface and evaporate or wash away rather than seep down into the ground where it could contaminate groundwater supplies.

In contrast, porous surfaces like soil and sandy soils in agricultural fields can absorb water and dissolved substances, including pesticides, which can lead to contamination of groundwater. Grassy areas also tend to have some permeability, allowing for infiltration. Thus, asphalt and other similar hard surfaces serve as a protective layer against such infiltration, making them a crucial consideration in pesticide application practices to safeguard water quality.