Which statement about the movement of pesticides from the application site is true?

• A. Runoff and erosion are sources of surface water contamination by pesticides
• B. Pesticides never contaminate surface water
• C. Contamination only occurs in groundwater
• D. Pesticides move only by vapor phase

Answer: (A)

Pesticide movement from the application site happens through several pathways, with surface water contamination mainly occurring via runoff and erosion. When rain or irrigation occurs, pesticides that remain on plant surfaces or in the soil can be washed off and carried into nearby streams or rivers. Erosion can also move contaminated soil particles into water bodies. These processes are common and directly link field practices to surface water contamination. Pesticides can also reach groundwater through leaching or move through the air by evaporation or drift, but they are not limited to any single route. The statement about runoff and erosion captures a primary way surface water becomes contaminated, whereas the other options either deny surface water involvement or misstate how pesticides move.