The quality of our nation's waters: Nutrients and pesticides

This report is the first in a series of nontechnical publications, 'The quality of our nation's waters,' designed to describe major findings of the National Water-Quality Assessment Program regarding water-quality issues of regional and national concern. Sources, seasonal and geographic patterns of occurrence, and long-term trends are evaluated for nutrients and pesticides in streams and ground water and for pesticides in bed sediment and fish tissue from 20 major river basins and (or) aquifer systems across the conterminous United States. Implications of these national findings relative to water policies and strategies are presented. Issues discussed include relationships of nutrients and pesticides to natural features, land and chemical use, and resource-management practices; effects on human and aquatic health; considerations for development of water-quality standards; and approaches to modeling.