Distribution of Dissolved Pesticides and Other Water Quality Constituents in Small Streams, and Their Relation to Land Use, in T
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Cover photographs: Upper left—Filbert orchard near Mount Angel, Oregon, during spring, 1993. Upper right—Irrigated cornfield near Albany, Oregon, during summer, 1994. Center left—Road near Amity, Oregon, during spring 1996. The shoulder of the road has been treated with herbicide to prevent weed growth. Center right—Little Pudding River near Brooks, Oregon, during spring, 1993. Lower left—Fields of oats and wheat near Junction City, Oregon, during summer, 1994. (Photographs by Dennis A. Wentz, U.S. Geological Survey.) Distribution of Dissolved Pesticides and Other Water Quality Constituents in Small Streams, and their Relation to Land Use, in the Willamette River Basin, Oregon, 1996 By CHAUNCEY W. ANDERSON, TAMARA M. WOOD, and JENNIFER L. MORACE U.S. Department of the Interior U.S. Geological Survey Water-Resources Investigations Report 97–4268 Prepared in cooperation with the Oregon Department of Environmental Quality and Oregon Association of Clean Water Agencies Portland, Oregon 1997 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Mark Schaefer, Acting Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For additional information write to: Copies of this report can be purchased from: U.S. Geological Survey District Chief Information Services U.S. Geological Survey Box 25286 10615 SE Cherry Blossom Drive Federal Center Portland, Oregon 97216 Denver, CO 80225 E-mail: [email protected] CONTENTS Abstract .....................................................................................................................................................................1 Introduction ................................................................................................................................................................3 Study Background ..........................................................................................................................................3 Purpose and Scope..........................................................................................................................................6 Methods......................................................................................................................................................................7 Streamflow ....................................................................................................................................................7 Sample Collection and Laboratory Analysis ..................................................................................................7 Pesticides and Conventional Constituents ..........................................................................................7 Immunoassay ....................................................................................................................................12 Laboratory Analysis .............................................................................................................12 Data Analysis........................................................................................................................ 13 Quality Assurance ............................................................................................................................ 13 Statistical Methods ...................................................................................................................................... 16 Site Selection ................................................................................................................................................17 Crop Type and Pesticide Use Determination ...............................................................................................17 Agricultural Fields ............................................................................................................................17 Pesticide Application Rates .............................................................................................................18 Land Use ..................................................................................................................................................................21 Site Selection ...............................................................................................................................................21 Agricultural Crop Surveys ...........................................................................................................................22 Pesticide Applications ..................................................................................................................................25 General water quality findings .................................................................................................................................30 Water Quality Criteria and Standards, and Toxicological Significance of Detected Pesticides ..................35 Pesticide Detections and Concentrations......................................................................................................30 Conventional Constituents ...............................................................................................................38 Pesticides ..........................................................................................................................................39 Relation of pesticide occurrence to land use............................................................................................................40 Pesticide Occurrence Relative to Urban and Agricultural Land Uses..........................................................44 Pesticide Occurrence Relative to Different Types of Agricultural Land Uses.............................................46 Correlations with Estimated Application Rates ...........................................................................................47 Other Correlations ........................................................................................................................................51 Seasonal distribution of pesticides ...............................................................................................................55 Summary .................................................................................................................................................................58 References Cited ......................................................................................................................................................63 Appendixes 1. Quality Assurance Data and Figures...............................................................................................67 2.Toxicological Reference Data.........................................................................................................73 3. Data Presentation ...........................................................................................................................79 COMPACT DISK (CD-ROM) [CD-ROM is in pocket] FIGURES Figure 1. Map Showing Willamette River Basin, Oregon.......................................................................................5 Figure 2. Graph showing comparison of immunoassay and gas chromatography/mass spectrometry (GC/MS) results for atrazine and metolachlor concentrations, Willamette Phase III, Oregon, 1996 ..................14 Figure 3. Map showing location of subbasins sampled in the Willamette River Basin, Oregon, during 1996.....23 Figure 4. Diagram showing examples of agricultural study subbasins with diverse and nondiverse crop types, Willamette River Basin, Oregon, during 1996 .....................................................................................26 Figure 5. Graph showing relation between the percentage of the basin devoted to agricultural land use 1 and the percentage of the basin planted in grass seed crops for 16 agricultural subbasins, Willamette Basin, Oregon, 1996...........................................................................................................27 Figure 6. Graph showing concentrations of all compounds detected with 10% or greater frequency in the Willamette Valley during 1996 that had significant differences in concentration between urban and agricultural land uses ...........................................................................................................45 Figure 7. Graph showing concentrations of compounds detected with 10% or greater frequency at 16 agricultural sites in the Willamette Basin during 1996 that had significant differences in concentration between the northern and southern sites ........................................................................46 Figure 8. Graph showing relation between the concentration of four pesticides and their estimated seasonal application to 16 agricultural subbasins in the Willamette River Basin during 1996............50 Figure 9. Graph showing comparison of atrazine concentrations with concentrations of metolachlor, bromacil, and pronamide in samples collected from 16 agricultural sites in the Willamette Basin during 1996 ......................................................................................................................................................53 Figure 10. Graph showing short-term temporal variability of atrazine and metolachlor concentration at Senecal Creek in October 1996 and Lake Creek in November 1996 ...............................................54