Synoptic study of glyphosate, neonicotinoids, and selected other pesticides in streams draining to Lake Champlain from urban and agricultural sources near Burlington, Vermont, 2021

A study designed to measure concentrations of glyphosate, aminomethylphosphonic acid (AMPA, a product of glyphosate degradation in the environment), and several neonicotinoids in selected urban and agricultural streams located in the Lake Champlain Basin of Vermont was conducted in the spring, summer, and fall of 2021. These pesticides are of concern due to their widespread use (Baker, 2018) and potentially adverse ecological and human-health effects (Hladik and others, 2018; Medalie and others, 2020).  Water samples were collected from Rock River near Highgate Center, Vt; Stevens Brook near St. Albans, Vt; Englesby Brook in Burlington, Vt; Potash Brook in Burlington, Vt; and the City of Burlington, Vt wastewater treatment plant (Burlington WWTP). Jewett Brook near St. Albans, Vt also was selected as a sampling site but was dry during the extent of the sampling period.  Based on the 2019 National Land Cover Database (Dewitz, 2021) the watersheds of Englesby Brook and Potash Brook are predominantly urban, those of Rock River and Jewett Brook are predominantly agricultural, and that of Stevens Brook is more equally split between urban and agricultural, or "mixed."
The study was designed, in part, to target high-flow events during the agricultural growing season, but the study region (Chittenden and Franklin County, Vermont) experienced "abnormally dry" to "moderate drought" conditions (National Drought Mitigation Center, University of Nebraska-Lincoln, 2022). As a result, samples were more representative of low-flow conditions. 
All data, including quality-control results, are in table “VT_GLYPH1_RESULTS.txt.”  Metadata for the table can be found in “VT_GLYPH1_RESULTS.xml.”  A detailed description of each column in the results table is given in the separate data dictionary “VT_GLYPH1_DataDictionary.txt.”  Environmental data are also available for download from the National Water Information System (NWIS) at https://nwis.waterdata.usgs.gov/usa/nwis/qwdata.
References
Baker, N.T., 2018, Estimated annual agricultural pesticide use by major crop or crop group for states of the conterminous United States, 1992–2016: U.S. Geological Survey data release, https://doi.org/10.5066/F7NP22KM.
Dewitz, J., and U.S. Geological Survey, 2021, National Land Cover Database (NLCD) 2019 Products (ver. 2.0., June 2021): U.S. Geological Survey data release, https://doi.org/10.5066/P9KZCM54.
Hladik, M. L., Main, A.R., and Goulson, D., 2018, Environmental risks and challenges associated with neonicotinoid insecticides: Environmental Science and Technology 52, pp3329-3335. DOI: 10.1021/acs.est.7b06388.
Medalie , L., Baker,  N.T., Shoda, M.E., Stone, W.W., Meyer,  M.T., Stets, E.G., and Wilson, M., 2020, Influence of land use and region on glyphosate and aminomethylphosphonic acid in streams in the USA: Science of the Total Environment 707, pp. 136008. DOI: https://doi.org/10.1016/j.scitotenv.2019.136008.
National Drought Mitigation Center, University of Nebraska-Lincoln, 2022, Percent Area in U.S. Drought Monitor Categories, accessed May 27, 2022,
https://droughtmonitor.unl.edu/DmData/DataTables.aspx

Tags: biota, glyphosate, herbicide, lake-champlain-basin, neonicotinoid, pesticide, usgs-627954a8d34e8d45aa6e3c0a, vermont, water-quality
Organization: Department of the Interior