The most off-site movement of pesticides in water is by evaporation.

• A. True
• B. False
• C. By Runoff
• D. By Plant Uptake

Answer: (B)

The main way pesticides move off-site into water is not evaporation. Evaporation involves water turning into vapor at the surface, and while some pesticides can volatilize, most pesticides have low volatility, so they don’t ride off with water vapor into new water bodies. The primary pathways bringing pesticides into water elsewhere are runoff, where rain or irrigation washes dissolved or sorbed pesticides from the field into streams and lakes, and to a lesser extent leaching, where water moves downward through soil and can reach groundwater that may discharge into surface water. Plant uptake reduces residues but does not transport them off-site in water. So the statement is false because evaporation is not the leading mechanism for off-site pesticide movement in water.