Which practice would best reduce the risk of water contamination from pesticides?

• A. Select pesticides that tightly adsorb to soil and are not persistent
• B. Use highly persistent pesticides
• C. Apply pesticides near bodies of water
• D. Apply pesticides during rain

Answer: (A)

The main idea is choosing pesticides that won’t move easily through soil and won’t linger in the environment. When a pesticide binds tightly to soil particles, it’s less likely to be leached down toward groundwater or carried away by runoff during rain or irrigation. If it also degrades rapidly, there’s less time for it to persist, migrate, or reach water bodies. Together, strong soil adsorption and quick breakdown substantially lower the chances of water contamination.

In contrast, pesticides that linger (high persistence) stay active longer and can travel with water through the soil or over the surface, increasing contamination risk. Applying near water or during rain further raises the chance of direct runoff or wash-off into streams, rivers, or ponds.