Weed management impact on the abiotic environment in particular on water and air quality

Chemical weed control unintentionally leads to a contamination of water and air. Surface waters in agricultural areas are polluted due to runoff subsurface drains, sewage effluents and interflow. Concentrations are highest during the spraying season and are usually <1 mu g/l. Ground water concentrations sometimes exceed the 0.1 mu g/l threshold level of the European Union. For air contamination not much information is available on volatilization under real field conditions but rain water may be polluted, especially during the spraying season, with average concentrations for single compounds of 0.1 mu g/l. Negative impacts on water and air are not to be expected because of the prevailing low concentrations, though ground and surface water often need special treatment if used as drinking water. Several strategies for minimizing water and air pollution are outlined, and a justification is given why a broad spectrum of herbicides is desirable in order to minimize contamination of the environment.