Pesticides in Agricultural Waters: The Role of Water Quality Guidelines

Water of good quality is of primary importance to modern agriculture in determining the productivity of crops and the health and marketability of livestock. The quality of water used in agricultural operations can be affected by numerous factors, including pesticide usage. This paper focuses on the relationship between the use of pesticides in Canadian agriculture and the hazards associated with the quality of agricultural waters used in irrigation and livestock watering. The extent and complexity of this problem is assessed initially by examining the overlap between pesticide use and agricultural water use in Canada. The inherent properties of selected pesticides used in Canadian agriculture are highlighted and related to their potential for release to agricultural water supplies. Field and laboratory investigations as related to agricultural water uses are reviewed and a discussion of pesticide water quality guidelines to ensure protection of agricultural water supplies is provided.