Surface-Water Monitoring for Pesticides in Wyoming

In 2006, the U.S. Geological Survey (USGS), in cooperation with the Wyoming Department of Agriculture, conducted a one-year surface-water sampling project at two sites in the North Platte Basin and three sites in the Big Horn Basin.  The purpose of the study was to determine the occurrence of pesticides in the basins and evaluate the seasonality of any pesticide detections.

Bighorn River at Basin, Wyoming

Three synoptic sample events were conducted during March, May, and September, 2006.  The sample events corresponded with pre-application of pesticides, post-application of pesticides, and the end of the growing season.  The analytical methods used determined the presence and concentration of 125 different pesticides.  In addition to pesticide analyses, temperature, pH, specific conductance, dissolved oxygen, and discharge were measured at each site.

Results

• Samples collected from all five sites and all three sampling dates contained pesticides.
• The most commonly detected pesticide in the Bighorn River Basin was MCPA (trade names Solve1 and MCP1).
• The most commonly detected pesticide in the North Platte Basin was atrazine (trade name AAtrex1). 
• Atrazine was detected in all samples collected in the Big Horn Basin.
• In the two river basins, additional pesticides (with trade name¹ in italics) detected include:
• aldicarb (Temik) degradation product
• atrazine (Aatrex) degradation products
• bentazon (Bentzone)
• bromoxynil (Buctril)
• carbofuran (Furadan)
• cycloate (Ro-Neet)
• 2,4-D
• EPTC (Eptam)
• MCPA (Solve)
• hexazinone (Velpar)
• metolachlor (Dual)
• metribuzin (Sencor)
• prometon (Pramitol)
• simazine (Princep)
• trifluralin (Treflan)

¹The use of trade, product, industry, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government

Products

All data were published in the 2006 USGS Water Data Report for Wyoming in early 2007, in addition to being available on the USGS NWIS-Web site (http://wwwnwis.er.usgs.gov/index.html).  A fact sheet describing the results is now available.

U.S. Department of the Interior | U.S. Geological Survey
URL: http://wy.water.usgs.gov/projects/pesticide/index.htm
Page Contact Information: Wyoming Webmaster
Page Last Modified: April 10, 2007