Quality of Pesticide Data for Groundwater Analyzed for the National Water-Quality Assessment Project, 2013-18 [open pdf - 4MB]
From the Purpose and Scope: "The purpose of this report is to describe the quality of pesticide data for groundwater samples analyzed by S2437 for the National Water-Quality Assessment Project during 2013-18. The analysis objectives are to assess and document the quality of data by estimating (1) bias and (2) variability using data from field and laboratory QC [quality-control] samples, along with third-party performance assessment samples. When these samples indicate the potential for unacceptable bias or variability, likely contributing sources-- laboratory method performance and (or) one or more nonlaboratory factors--are identified. Given results of the data-quality assessment, implications for interpretation of S2437 results for groundwater samples also are described."
Scientific Investigations Report 2020-5072
USGS Publications Warehouse: https://pubs.er.usgs.gov/