Pesticide concentrations have declined over the past decade in several salmon-bearing streams in Washington, report the Washington State departments of agriculture and ecology.
When detected, researchers found that most pesticides showed up at concentrations below levels of concern for aquatic species.
"This is certainly the direction we would have wanted to see," says Washington State Department of Agriculture Director Dan Newhouse. "This monitoring program is unique in that it provides growers with real-world data on the potential impact pesticide use could have on local streams and creeks, which in turn allows farmers to apply pesticides wisely and continue these efforts to protect salmon and the environment."
The Surface Water Monitoring program is one of the most intensive pesticide management efforts in the nation for streams and other surface waters. The program began in 2003 as a means of measuring how much of the pesticides used in agricultural areas finds its way to the surface.
Urban water runoff is also monitored.
State and federal agencies use the information to evaluate the effectiveness of existing regulations, and to determine whether more stringent rules are necessary. By the proactive farm action to reduce pesticides, producers can fend off new regulatory actions.
Two watershed areas were initially monitored: one agricultural and one urban. Later, four watershed areas were added. Ag areas monitored for the 2009-2011 report include the Lower Skagit-Samish, Lower Yakima, Wenatchee ad Entiat watershed areas.
From March to September, collections include weekly sampling and test for 170 pesticides and related compounds, issuing brief annual reports and longer comprehensive reports every three years.
The most recent report, "Surface Water Monitoring for Pesticides in Salmon-Bearing Streams, 2009-2011 Triennial Report: A Cooperative Study by the Washington State Departments of Ecology and Agriculture," is the first which has allowed researchers to see trends in data for several of the study areas.
A full report is available here.