A pesticide that is soluble in water is most associated with which loss process?

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

Answer: (B)

When a pesticide dissolves readily in water, its mobility in water makes it more likely to be carried away with moving water. Runoff is the process where water from rainfall or irrigation flows across the soil surface and can pick up dissolved pesticide, transporting it into ditches, streams, or other water bodies. This makes runoff the most likely loss pathway for water-soluble pesticides.

Spray drift and vapor drift involve movement through air and are influenced by droplet size, wind, and the chemical’s volatility rather than how soluble it is in water. Leaching refers to downward movement through the soil with percolating water, which is indeed related to water solubility, but the question emphasizes the surface transport that occurs with rainfall or irrigation runoff, which is why runoff is the best single association.