USGS - science for a changing world

USGS Washington Water Science Center

Skip Navigation
Message From Our Water Science Center Director Newsroom Seminar Schedule Outreach and Education Water Science Center Information Employment and Volunteer Opportunities Directions and Locations Map Our Customers
graphic line

News Release

U.S. Department of the Interior
U.S. Geological Survey

Release: June 25, 1997
Luis A. Fusté, Information Officer

Model Used to Predict Where Ground Water is Most Vulnerable to Nitrate

Low concentrations of pesticides were found in small urban and agricultural stre ams in the Puget Sound region, according to a fact sheet jointly authored by the U.S. Geological Survey (USGS) and the Washington State Department of Ecology (W DOE).

None of the concentrations exceeded drinking-water standards or guidelines, but concentrations of four pesticides exceeded maximum levels recommended for the pr otection of aquatic life. More pesticides were detected in urban than agricultur al streams. This is because the total amount of pesticides used in urban areas in the populated Puget Sound region is about three times greater than the amount used in agricultural areas, say the investigators.

"The amounts of pesticides used in urban areas and on crops explains much of wha t we found in streams, " said Gil Bortleson, USGS hydrologist and the principal author of the fact sheet. "The most commonly detected pesticides were among the most heavily applied in the basin," added co-author Dale Davis of the WDOE. Lo w levels of older-generation pesticides such as DDT were not found in water, but were found in streambed sediments. This is not surprising, according to the aut hors, because many studies nationwide report that older pesticides currently ban ned in the U.S. can still be found in sediments.

The four-page color fact sheet is a product of the USGS National Water-Quality A ssessment Program. The program is designed to assess current water-quality condi tions, describe how water quality is changing, and improve understanding of the natural and human factors that affect water quality.

Copies of Fact Sheet 067-97, "Pesticides in selected small streams in the Puget Sound Basin, 1987-95," by Gilbert C. Bortleson and Dale A. Davis, are available free from the U.S. Geological Survey, 1200 Pacific Avenue, Suite 600, Tacoma, WA , telephone (253) 593-6510, and the Washington State Department of Ecology, Publ ic Distribution Office, (360) 407-7472, or by email at Copies may be viewed on the World Wide Web at qa.html and are available at most area libraries.

* * * USGS * * *

Note to editors: For additional technical information, contact Jim Ebbert, Project Chief, Puget Sound NAWQA, telephone (253) 593-6530 ext. 234, or email to

Accessibility FOIA Privacy Policies and Notices logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: webmaster
Page Last Modified: Thursday, 15-Dec-2016 12:49:00 EST