A pesticide that is persistent in the soil and binds tightly to soil particles is most associated with which type of drift?

• A. Particle drift
• B. Leaching
• C. Runoff
• D. Spray drift

Answer: (A)

A pesticide that stays in the soil and sticks tightly to soil particles tends to move with soil or dust rather than as a liquid or droplet in the air. When it is bound to soil particles, it can be carried away by wind as soil dust or by erosion, which is what particle drift describes. This contrasts with leaching, which is movement down through the soil with water; runoff, which is surface flow with water; or spray drift, which involves droplets or vapors moving through the air during application. So, the best association is with particle drift because the pesticide travels attached to soil particles rather than as a free droplet or dissolved chemical.