Standard procedures and quality-control practices for the U.S. Geological Survey National Field Quality Assurance Program from 1982 through 1993

The U.S. Geological Survey operates the National Field Quality Assurance Program to provide quality- assurance reference samples to field personnel who make water-quality field measurements. The program monitors the accuracy and precision of pH, specific conductance, and alkalinity field measurements. This report documents the operational procedures and quality-control techniques used in operating the quality-assurance program.