1991 Quality Assurance Report, NADP/NTN Deposition Monitoring: Laboratory Operations, Central Analytical Laboratory, January 1991 through December 1991

Abstract

In August 1991, the Central Analytical Laboratory (CAL) of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) received and analyzed its 100,000th wet deposition sample. Analysis of precipitation samples began in the summer 1978 and has continued to the present time making the NADP/NTN "... the longest-running, national-scale, atmospheric wet deposition monitoring network in the world."(1).

From the beginning, the laboratory has operated with a strict system of quality control (QC), which has enabled its analysts to produce well documented and dependable data. A Quality Assurance Plan (2) prescribes the methods used to conduct and document the chemical and physical analyses of each sample. These analyses are then verified mathematically using ion balance and specific conductance calculations. Voluntary participation in national and international interlaboratory comparison studies ensures the comparability of CAL results with those of its peers throughout the world and finally the U.S. Geological Survey (USGS) acts as the official external auditing agency of the NADP/NTN laboratory program.

Annual reports (3-10) describe the development of the quality assurance program and document the daily, weekly, monthly, semi-annual, and annual procedures followed at the CAL. The format of this report is the same as that of the 1989 and 1990 reports.

Quality Assurance Reports of Laboratory Operations for the previous years (1978-1990) are available from the Illinois State Water Survey or the Program Coordinator's Office at Colorado State University. The quality assurance data summarized in these reports are additionally available in tabular form upon request from the CAL.