Quality-assurance Data for Routine Water Analyses by the U.s. Geological Survey Laboratory in Troy, New York? July 2003 Through June 2005

The laboratory for analysis of low-ionic-strength water at the U. S. Geological Survey (USGS) Water Science Center in Troy, N. Y., analyzes samples collected by USGS projects throughout the Northeast. The laboratory?s quality-assurance program is based on internal and interlaboratory quality-assurance samples and quality-control procedures that were developed to ensure proper sample collection, processing, and analysis. The quality-assurance and quality-control data were stored in the laboratory?s Lab Master data-management system, which provides efficient review, compilation, and plotting of data. This report presents and discusses results of quality-assurance and quality control samples analyzed from July 2003 through June 2005.