Which movement is a route for pesticides into surface water?

• A. Runoff
• B. Leaching
• C. Evaporation
• D. Adsorption

Answer: (A)

When pesticides end up in surface water, the primary route is overland flow: water from rain or irrigation moves across the land and carries pesticide residues with it into streams, rivers, or ponds. This runoff picks up pesticides from the soil surface or plant material and transports them to surface water bodies, especially when rainfall is intense or soon after application and ground cover is limited.

Leaching, by contrast, is movement downward through the soil toward groundwater, not into surface water. Evaporation involves pesticides moving from surfaces into the air, not into water bodies. Adsorption is the binding of pesticides to soil particles, which tends to slow or limit movement and does not describe a transport route into surface water.