ABSTRACT
Accidental releases as farm-specific point sources in hydrogeologically vulnerable areas or near man-made conduits have resulted in the direct entry of chemicals to ground water at relatively high concentrations in short periods of time. While research has shown that under normal agronomic use some more mobile chemicals can leach downward to ground water, it is important to note that this is only one mechanism of movement. Field inspections of areas where agricultural chemicals have been reportedly detected in ground water commonly result in nonleaching explanations for the findings. Natural modes of entry refer to natural fissures or cracks or channels that develop in the soil as a result of pedogenic processes or as the result of soil flora and/or fauna activities. Domestic wells also can provide direct entry for chemicals to reach ground water. Wells situated topographically lower and located near the chemical mixing/loading areas can provide pathways for surface-water runoff to impact ground water quality.
