The potential for pesticides to leach into groundwater increases with?

The potential for pesticides to leach into groundwater increases significantly with rainfall. When rainfall occurs, the water can saturate the soil and create conditions that allow for movement of water downward through the soil layers. This movement can carry dissolved pesticides with it, especially in situations where the soil is not able to retain the pesticide molecules or where groundwater is close to the surface.

Heavy or prolonged rainfall can lead to runoff but also provides enough water to push pesticides deeper into the soil profile. If the pesticide properties, such as solubility and soil adsorption, are appropriate, this can result in contaminants reaching groundwater sources. Understanding this process is crucial for effective water resource management and pesticide application strategies.

In contrast, factors like soil erosion may remove topsoil where pesticides might be more concentrated but do not inherently cause more pesticides to move into groundwater. High temperatures and low humidity typically affect evaporation rates and pesticide degradation rather than directly influencing leaching dynamics. Rainfall, therefore, plays a pivotal role in the leaching process, making it a key factor in evaluating pesticide environmental impacts.