Which statement about groundwater contamination and fumigation for pocket gophers is true?

• A. Fumigation does not affect groundwater
• B. Groundwater contamination is possible
• C. Groundwater becomes enriched with nutrients
• D. Groundwater is never affected

Answer: (B)

Groundwater movement is a real consideration with soil fumigation used to control pocket gophers. Fumigants are designed to move through the soil to reach buried pests, and they can travel as gases or dissolve in water and percolate downward. If the chemical moves through the soil profile and reaches groundwater or a water supply, contamination can occur, especially where the water table is shallow, soils are permeable, or there are gopher burrows that provide fast pathways. That’s why the statement that groundwater contamination is possible best reflects how these products behave in real-world conditions. The idea that fumigation does not affect groundwater isn’t accurate, because movement through soil and potential leaching or vapor migration can lead to groundwater exposure. Groundwater becoming enriched with nutrients isn’t how fumigants work, since they’re pesticides, not nutrient sources. And saying groundwater is never affected ignores the very mechanisms by which fumigants can move and reach underground water.