Replicate surface water and groundwater data analyzed by USGS National Water Quality Laboratory schedule 2437, 2013-15

Replicate water-quality samples are collected and prepared in the field and analyzed in the laboratory in identical ways so that they are considered to be the same in composition and analysis (Mueller and others, 2015). This data set includes one table of duplicate National Water-Quality Assessment Project (NAWQA) surface water and groundwater samples collected between October 1, 2012 and September 30, 2015 and analyzed by the USGS National Water Quality Laboratory (NWQL) using direct aqueous-injection liquid chromatography-tandem mass spectrometry (Schedule 2437; Sandstrom and others, 2015) for the determination of 225 pesticides at 288 sites. Mueller, D.K., Schertz, T.L., Martin, J.D., and Sandstrom, M.W., 2015, Design, analysis, and interpretation of field quality-control data for water-sampling projects: U.S. Geological Survey Techniques and Methods, book 4, chap. C4, 54 p., https://dx.doi.org/10.3133/tm4C4 Sandstrom, M.W., Kanagy, L.K., Anderson, C.A., Kanagy, C.J., 2015, Determination of pesticides and pesticide degradates in filtered water by direct aqueous-injection liquid chromatography-tandem mass spectrometry: U.S. Geological Survey Techniques and Methods, book 5, chap. B11, 54 p., https://dx.doi.org/10.3133/tm5B11