What describes the process where pesticides move downward through soil layers potentially reaching groundwater?

Leaching is the process by which pesticides dissolve in water and move downward through the soil layers. When rainfall or irrigation occurs, the water can carry dissolved chemicals, including pesticides, through the soil profile, which may eventually lead to contamination of groundwater supplies. This movement depends on several factors, including the solubility of the pesticide, soil texture, and the presence of moisture.

Understanding this concept is crucial for managing pesticide use effectively, as it helps identify the risks associated with groundwater contamination. Awareness of leaching potential is essential for selecting appropriate pesticides and implementing practices that minimize adverse environmental impacts. Other processes like runoff, drift, and volatilization do not involve transport through the soil leading to groundwater; they pertain instead to surface movement, aerial dispersal, or gas emissions, respectively.