Reduction of herbicide contamination in flowing waters

A brief survey of potential pathways of herbicide transport in flowing waters is given. For a small watershed in Hesse (central Germany) during 4 spraying periods (spring and autumn 1995 and 1996) all point and non-point sources were measured. It was proved that faulty spray practice occurred in 60% of 260 applications. However this source caused no evident herbicide contamination in running Caters. More than 90% of the total herbicide load has been detected as point sources originating from the 40 farms connected to a sewage plant. Compared to these point sources, the pesticide pollution originating from run off and subsurface drainage was not significant. An example is given describing how advisory measures in pesticide handling can reduce :the loads by 80%.