Linkages between water quality and chemical
chemicals that are found in streams and ground water are closely
linked to the chemicals used in each watershed. Sometimes, these
connections show up quickly.
For example, a 1992-96 NAWQA study in the White River Basin, Indiana,
showed that concentrations of acetochlor increased and alachlor
concentrations decreased in streams within 1-2
years after acetochlor partially replaced alachlor as an herbicide
used on corn.
Reducing the amount of chemicals used and applying these chemicals
more efficiently can help reduce contaminant levels in both urban
and agricultural areas. Currently, however, we don't have enough
information on chemical use, particularly in urban areas. Improved
tracking of chemical use is needed to support water-resource management
Localities and states recognize the need for tracking
In King County, Washington, a USGS study found 23 of 98
pesticides in streams in 10 urban and suburban watersheds. Homeowner
use was indicated as the source of some insecticides, such as diazinon,
and some herbicides, such as 2,4-D, which are commonly sold in home
and garden stores.
To encourage homeowners to use fewer pesticides, the county uses
Fact Sheet 067-97 Pesticides
in Selected Small Streams in the Puget Sound Basin, 1987-1995.
Almost half of the pesticides found in the streams had no retail
sales within Seattle or the surrounding area, indicating that these
pesticides came from commercial applications, such as along road
rights-of-way. This information helps local officials to manage
USGS detected many pesticides in agricultural and urban streams
in the Willamette Basin, Oregon. Many of the compounds occurred
at elevated concentrations, often exceeding guidelines to protect
aquatic life. Lack of information on pesticide use, however, made
it difficult to assess the source of the pesticides and how they
were transported to the water.
Concerned Oregon citizens and stakeholders used these findings
to support a law that requires pesticide use to be reported. The
Oregon House and Senate passed the bill by wide margins, and it
was supported by both environmentalists and pesticide users.
Three states--Oregon, California, and New York-now require pesticide-use
tracking. Oregon's law is unique in its provision for reporting
pesticide use in urban areas, including home and garden use.