Glyphosate and aminomethylphosphonic acid (AMPA) in National Water Quality Network Streams and Rivers in the U.S., Water Years 2015-2017

The U.S. Geological Survey (USGS) National Water Quality Network - Rivers and Streams (NWQN) is comprised of 110 surface-water monitoring sites designed to track ambient water-quality conditions across the nation. Although numerous constituents, including pesticides, have been collected at many of these sites since 1991, glyphosate and its metabolite aminomethylphosphonic acid (AMPA) were not routinely measured in NWQN water samples prior to 2014. Because of the widespread use of glyphosate for agricultural and nonagricultural applications, in 2014, these two compounds were added to the NWQN. This dataset includes concentrations of glyphosate and AMPA from water samples collected from 2015 through 2017 at 70 NWQN sites that passed screening criteria. It is a companion to the larger work (Medalie and others, 2019, in press) which characterizes the regional distribution of glyphosate and AMPA detection frequencies and concentrations in water and examines their association with watershed size and land use. This dataset is comprised of 5 tables: Table1.NWQN.SiteInformation.txt, Table2.Glyphosate.AMPA.SampleConc.txt, Table3.Glyphosate.AMPA.AnnualData.txt, Table4.GlyphosateAgUse.txt, and Table5.LandUseClass.txt