What does leaching refer to in the context of pesticide movement?

Leaching refers specifically to the movement of pesticides (and other chemicals) through the soil and into the groundwater. This process occurs when water, such as rainfall or irrigation, permeates the soil. As water moves downward, it can carry dissolved pesticides along with it, eventually leading to contamination of groundwater. Understanding leaching is crucial for environmental protection, as it can have significant impacts on water quality, especially in agricultural areas where pesticides are widely used.

While the other options describe different interactions between pesticides and the environment—such as bonding with soil, evaporating into the atmosphere, or being absorbed by plants—they do not accurately capture the essential concept of leaching. Leaching specifically involves the downward movement of substances through the soil profile, highlighting its role in potential groundwater contamination.