Pathways of pesticide spread in the environment

Macropore flow - rapid passage of pesticides to groundwater

Rainwater can rapidly be transported down through the soil profile via wormholes, cracks and root channels and reach the groundwater. This phenomenon is known as macropore flow and means that any pesticides accompanying water in its downward movement can reach the groundwater fairly quickly without having been broken down chemically or biologically. The most crack-filled soils are clayey soils that can swell and shrink.

By dyeing water applied to the surface, it is possible to monitor water movements in the soil. The red streaks in the soil profile show the macropores in this soil. Photo: Nick Jarvis, SLU.