Groundwater-quality and select quality-control data from the National Water-Quality Assessment Project, January 2017 through December 2019

First posted March 29, 2021 For additional information, contact: Director, Lower Mississippi-Gulf Water Science Center U.S. Geological Survey640 Grassmere Park Drive Nashville, TN 37211 Groundwater-quality environmental data were collected from 983 wells as part of the National Water-Quality Assessment Project Survey Quality Program and are included in this report. The six types well networks: principal aquifer study networks, which used to assess quality groundwater for public water supply; land-use effects on shallow quality; major domestic enhanced trends evaluate time scales during changes; vertical flow-path changes deeper depths; modeling support studies, provide modeling. Groundwater samples analyzed many water-quality indicators constituents, including ions, nutrients, trace elements, volatile organic compounds, pesticides, radionuclides, microbiological indicators, some constituents special interest (arsenic speciation, hexavalent chromium [chromium (VI)], perchlorate). These groundwater-quality data, along with quality-control samples, tabulated report an associated release. Data 2016 companion