Data Series 667
Water-quality samples were collected from April through December 2010 from four streams in Idaho and analyzed for a suite of pesticides, including fungicides, by the U.S. Geological Survey. Water samples were collected from two agricultural and two nonagricultural (control) streams approximately biweekly from the beginning of the growing season (April) through the end of the calendar year (December). Samples were analyzed for 90 pesticides using gas chromatography/mass spectrometry. Twenty-three pesticides, including 8 fungicides, 10 herbicides, 3 insecticides, and 2 pesticide degradates, were detected in 45 water samples. The most frequently detected compounds in the two agricultural streams and their detection frequencies were metolachlor, 96 percent; azoxystrobin, 79 percent; boscalid, 79 percent; atrazine, 46 percent; pendimethalin, 33 percent; and trifluralin, 33 percent. Dissolved-pesticide concentrations ranged from below instrumental limits of detection (0.5–1.0 nanograms per liter) to 771 nanograms per liter (hexazinone). The total number of pesticides detected in any given water sample ranged from 0 to 11. Only three pesticides (atrazine, fipronil, and simazine) were detected in samples from the control streams during the sampling period.
First posted May 21, 2012
Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.
Reilly, T.J., Smalling, K.L., Wilson, E.R., and Battaglin, W.A., 2012, Dissolved pesticides, dissolved organic carbon, and water-quality characteristics in selected Idaho streams, April–December 2010: U.S. Geological Survey Data Series 667, 17 p.
Purpose and Scope
Description of Sampling Sites and Watershed Characteristics
Methods of Study
Watershed Delineation and Land-Use Characterization
Analysis of Dissolved Pesticides
Quality Assurance/Quality Control
Method Detection Limits
Analysis of Dissolved Organic Carbon
Dissolved Pesticides in Streams
Dissolved Organic Carbon and Water-Quality Characteristics in Streams