What term refers to surface movement of water away from the treated site?

• A. Drift
• B. Leaching
• C. Runoff
• D. Volatilization

Answer: (C)

Runoff is the surface movement of water away from the treated site. After a pesticide is applied, rain or irrigation can flow across the soil surface and pick up residues, carrying them off the site into nearby water bodies or drainage paths. This is different from drift (pesticide moving through the air before it lands), leaching (water moving downward through the soil), and volatilization (pesticide turning into vapor and moving with air). Understanding runoff helps explain why avoiding application before heavy rain, incorporating products when appropriate, and using buffers and proper soil and slope management are important to protect water quality and non-target organisms.