Pesticides in Surface Waters
U.S Geological Survey Fact Sheet FS-039-97
Current Understanding of Distribution and Major Influences
This report summarizes a comprehensive analysis of existing
information on national and regional patterns of pesticide occurrence in
surface waters of the United States and the major influences on the
sources and transport of pesticides. It is one of a four-part series that
synthesizes current knowledge and understanding of pesticides in the
nation's water resources as part of the National Water Quality
Assessment Program.
Bibliography of Studies Reviewed -
511 References
Highlights
- Low levels of pesticides have been widespread in the nation's surface
waters for several decades.
- Pesticide concentrations in surface waters follow strong seasonal
patterns that result from the timing of pesticide applications and runoff
conditions.
- Many pesticides are rarely detected in surface waters because of
relatively low use, how they are applied, chemical properties, or
elevated detection limits.
- In many streams, some pesticides exceed water-quality criteria for
seasonal periods each year, but annual average concentrations seldom
exceed regulatory standards for drinking water.
- Potential effects of pesticides on humans and aquatic ecosystems
are difficult to evaluate because of inadequate information on effects
of low-level mixtures, transformation products, and seasonal exposure.
- Improved information is needed on long-term trends, pesticides and
transformation products that have not been widely measured, and biological
effects of typical exposure patterns.
Pesticides in Surface Waters
U.S. Department of the Interior | U.S. Geological Survey
