What is the term for pesticides being carried horizontally over the ground surface by water?

The term that describes pesticides being carried horizontally over the ground surface by water is runoff. Runoff occurs when water—often from rain, irrigation, or snowmelt—flows across the soil surface and transports any dissolved or suspended substances, including pesticides, along with it. This phenomenon is important to understand because it can lead to contamination of nearby water bodies and can significantly affect local ecosystems.

Leaching, while related to the movement of pesticides, refers specifically to the downward movement of these substances through the soil profile and into groundwater, rather than horizontal movement across the surface. Drift relates to the airborne dispersal of pesticide particles, which can occur during application and lead to unintended exposure of non-target areas. Volatilization describes the process in which pesticides change from liquid to gas and enter the atmosphere, which does not involve water movement across the ground. Understanding these distinctions is crucial for effective pesticide management and environmental protection.