Pesticide datasets from the National Water Quality Laboratory: a review of recent practices of censoring scenarios for select groundwater and surfacewater results, 2001-2015

This data release includes all pesticide results from selected batches of water samples analyzed by the U.S Geological Survey National Water Quality Laboratory (NWQL). Samples were analyzed using gas chromatography/mass spectrometry (GCMS) or liquid chromatography/mass spectrometry (LCMS) methods. Eight datasets are included in this data release; 1) all environmental and field quality control (QC) results for 11 pesticide compounds from 70 selected batches of GCMS data from schedules 2001, 2003, 2032, and 2033 (Sandstrom and others, 2001; Zaugg and others, 1995) from May 2001-June 2015, 2) all environmental and field QC results for 10 pesticide compounds from 43 selected batches of LCMS data from schedule 2060 (Furlong and others, 2001) from October 2001-July 2015, 3) All available GCMS set blank results from January 2001-May 2016, 4) All available LCMS set blank results from May 2001-August 2015, 5 and 6) All available blind-blank GCMS and LCMS results from the NWQL from 2004 and from the USGS Branch of Quality systems from 2007 through 2012, and 7 and 8) Blind-spike results from the USGS Organic Blind Sample Project from 2001 through 2016 for the 11 GCMS and 10 LCMS compounds that were investigated in the larger work cited in this metadata record. In addition to the pesticide data originally analyzed and published by the NWQL, a reevaluation of the data in the first two datasets listed in this abstract was performed using current 2017 identification practices. NWQL standard operating procedures have evolved over the 15 years encompassed by this study to provide more specific guidance on the application of identification rules for determining detections. In addition, technology advances were implemented at the NWQL that resulted in improvements in method performance and sample analysis over time. In the data reevaluation process, NWQL reevaluated every result from the 70 GCMS batches and 43 LCMS batches of samples using current 2017 operating procedures and consistently applied criteria for the qualitative identification of pesticides as described in the methods documents (Sandstrom and others, 2001; Zaugg and others, 1995; Furlong and others, 2001). This data release supports the following publication: Medalie, L., Sandstrom, M.W., Toccalino, P.L., Foreman, W.T., ReVello, R.C., Bexfield, L.M., and Riskin, M.L., 2019, Use of set blanks in reporting pesticide results at the U.S. Geological Survey National Water Quality Laboratory, 2001-15: U.S. Geological Survey Scientific Investigations Report 2019-5055, 147 p., https://doi.org/10.3133/sir20195055. References: Furlong, E.T., Anderson, B.D., Werner, S.L., Soliven, P.P., Coffey, L.J., and Burkhardt, M.R., 2001, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of pesticides in water by graphitized carbon-based solid-phase extraction and high-performance liquid chromatography/mass spectrometry: U.S. Geological Survey Water-Resources Investigations Report 01-4134, 73 p. [Also available at https://doi.org/10.3133/wri014134.] Sandstrom, M.W., Stroppel, M.E., Foreman, W.T., and Schroeder, M.P., 2001, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of moderate-use pesticides and selected degradates in water by C-18 solid-phase extraction and gas chromatography/mass spectrometry: U.S. Geological Survey Water-Resources Investigations Report 01-4098, 70 p. [Also available at https://nwql.usgs.gov/Public/pubs/WRIR/WRIR-01-4098.pdf.] Zaugg, S.D., Sandstrom, M.W., Smith, S.G., and Fehlberg, K.M., 1995, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring: U.S. Geological Survey Open-File Report 95-181, 49 p. [Also available at https://doi.org/10.3133/ofr95181.]