Yards for Kids
A Community Health Education Program Aiming to Significantly Reduce the Use of Lawn Pesticides in Iowa
Excerpts from USGS Fact Sheet 097-99
April 1999
Pesticides Detected in Urban Streams During Rainstorms and Relations
to Retail Sales of Pesticides in King County, Washington
According to studies conducted in the Puget Sound Basin from 1987 to 1995 and summarized by Bortleson and Davis (1997), more types of pesticides were detected in urban streams than in agricultural streams. As well, in Puget Sound Basin, more pounds of pesticides were applied in urban than in agricultural areas (Tetra Tech Incorporated, 1988). To provide some insight about sources of pesticides found in urban streams, the U.S. Geological Survey (USGS), the Washington State Department of Ecology, and King County collaborated to study and compar types of pesticides found in urban stream water with pesticide information sales from large home and garden stores.
Findings
Twenty-three pesticides were detected in water from urban streams during rainstorms,
and the concentrations of five of these pesticides exceeded limits set to protect aquatic life.
During rainstorms, 23 of 98 pesticides sampled for were detected in water samples from 12 study sites in 10 urban watersheds. Concentrations of five insecticides exceeded maximum concentrations set by the National Academy of Sciences and National Academy of Engineering (NAS/NAE) (1973). In a few samples, concentrations of Diazonon, carbaryl, and Lindane exceeded the U.S. Environmental Protection Agency (USEPA) and other chronic aquatic-life criteria.
Pesticides used on lawns and gardens contribute to the occurrence of several pesticides in urban streams.
According to 1997 sales data from home and garden stores, of the pesticides sampled for, Diazonon, 2,4-D, and MCPP are the most frequently purchased pesticides purchased by residents of King County. MCPP and 2,4-P are also among those pesticides used by professional applicators for pest control in residential, recreational, and industrial areas. The presence of these pesticides in water samples from all of the 12 study sites shows that their widespread application impacts water quality in urban streams. Also, residents purchased and applied four of the five pesticides that exceeded recommended maximum concentrations set by the NAS/NAE (Diazonon, carbaryl, Malathion, and chlorpyrifos).
Many pesticides found in urban streams might be the result of nonresidential applications.
Almost half of the 23 pesticides detected in stream water had no retail sale according to a 1997 survey of pesticide sales from home and garden stores in King County. Two of these pesticides (atrazine and simazine) were found at more than 60 percent of the study sites. This indicates that these pesticides are being applied to nonresidential areas in urban watersheds such as right-of-way, parks, and recreational areas.
References
Bortleson, G.C., and Davis, D.A., 1997, Pesticides in selected small streams in the Puget Sound Basin, 1987-1995: U.S. Geological Survey Fact Sheet 067-97, 4p.
National Academy of Sciences and National Academy of Engineering, 1973, Water quality criteria, 1972, a report of the committee on water quality criteria: Washington, D.C., Environmental Studies Board, National Academy of Sciences, National Academy of Engineering, 594p.
Tetra Tech Incorporated, 1988, Pesticides of concern in the Puget Sound Basin--a review of contemporary pesticide usage: Seattle, Wash., prepared for U.S. Environmental Protection Agency, Region 10, contract TC3338-32, 97p.
For further information:
WWW: http://wa.water.usgs.gov/ps.nawqa.html