In a look at water-quality conditions of 20 of the country's largest and most important river basins, the U.S. Geological Survey announced today (June 28, 1999) that streams in areas with significant agricultural or urban development almost always contain complex mixtures of nutrients and pesticides.
The complex nature of those chemical mixtures and the lack of current human and aquatic health criteria to determine risk of exposure, make addressing these issues a top national priority.
Secretary of the Interior Bruce Babbitt said, "Over the last two decades, our nation has made great progress in improving water quality and, yet, as the USGS report points out, major challenges remain in protecting our aquatic resources.
"The widespread occurrence of pesticides and nutrients in water documented in the USGS report underscores the need to devote more attention to the quality of our waterways and the life that depends on them," Babbitt said.
The good news is that concentrations of individual pesticides in samples from wells and as annual averages in streams were almost always lower than current U.S. Environmental Protection Agency drinking-water standards and guidelines.
The USGS assessment results suggest that aquatic life may be more at risk than humans from these contaminants. More than one-half of agricultural and urban streams sampled had concentrations of at least one pesticide that exceeded a guideline for the protection of aquatic life.
The potential risk to people and to aquatic life can only be
partially addressed, based on available standards and guidelines. The
health picture is made more complex by the lack of standards or guidelines
for many pesticides and their "breakdown" products or metabolites. Adding
to the complexity is the fact that existing standards and guidelines were
developed for individual chemicals and do not take into account exposure t
Contact: Tim Miller
United States Geological Survey