QADATA user's manual; an interactive computer program for the retrieval and analysis of the results from the external blind sample quality- assurance project of the U.S. Geological Survey

Abstract

The U.S. Geological Survey conducts an external blind sample qualityassurance project for its water-analysis laboratories in Denver, Colorado, and Ocala, Florida, based on the analysis of reference water samples. Reference samples containing selected inorganic and nutrient constituents are disguised as environmental samples and are sent periodically through Survey offices to each laboratory. The results of this blind sample project indicate the quality of analytical data produced by the laboratories. This report provides instructions for the use of QADATA, an interactive, menu-driven program that allows data users to retrieve the results of the blind sample quality-assurance project. The QADATA program, which is available through the U.S. Geological Survey's national computer network, accesses a blind sample data base that contains more than 50,000 determinations from the last five water years for approximately 40 constituents at various concentrations. The data can be retrieved from the database for any user-defined time period and for any or all available constituents. After the user defines the retrieval parameters, the program prepares statistical tables, control charts, and precision plots and generates a report which can be transferred to the user's office through the computer network. A discussion of the interpretation of the program output is also included in this report. This quality-assurance information will permit users to document the quality of the analytical results received from the laboratories. The blind sample data is entered into the database within weeks after being produced by the laboratories and can be retrieved to meet the needs of specific projects or programs.

Evaluation of quality assurance/quality control data collected by the US Geological Survey for water-quality activities at the Idaho National Engineering Laboratory, Idaho, 1994 through 1995

“…Lack of precision for analytical methods to determine the concentrations of aluminum and iron has been documented by the BTD&QS in the BSP. The information from the QADATA program that is available through the USGS computer network (Lucey, 1990) shows that 20 percent of the dissolved aluminum analyses and 12 percent of the WWR aluminum analyses were outside the two sigma control limits. The BTD&QS also has noted significant lack of precision for the WWR iron analyses at the NWQL (Ludtke, A., 1995; Ludtke A. and Woodworth, M., 1995, USGS, written communs.).…”

“…Only twelve replicate pairs were analyzed for aluminum; therefore, additional information from the BSP was used to support the conclusions. The information from the QADATA program that is available through the USGS computer network (Lucey, 1990) shows that the aluminum analyses of the BSP samples hav0: displayed high variability with 20 percent of the dissolved aluminum analyses and 12 percent of the WWR aluminum analyses outside the two sigma control limits. The BTD&QS has reset the contT)!…”

Water-quality, streamflow, and meteorological data for the Tualatin River Basin, Oregon, 1991-93

“…Quality-control practices employed by the USGS NWQL were reported by Pritt and Raese (1992). Results of the blind-sample program are available in the National Water Information System (NWIS) database (Lucey, 1990). These quality-assurance data were used to evaluate sample-collection and processing techniques, water-matrix affects, laboratory accuracy and precision, and the comparability of each laboratory's analytical results.…”

Chlorine-36 in water, snow, and mid-latitude glacial ice of North America; meteoric and weapons-tests production in the vicinity of the Idaho National Engineering and Environmental Laboratory, Idaho

“…The USGS Quality Assurance (QA) unit conducts a blind-sample program in which reference samples disguised as environmental samples are submitted to the laboratory for analyses (Maloney and others, 1993). These blind-sample program data are stored in the USGS data base (QADATA) and are accessible through the USGS computer system (Lucey, 1990). The statistical analyses generated through the QADATA program include equations generated by using linear-least-squares regression of a most probable value for a given analyte from the USGS's Standard Reference Water Sample program during the previous seven years compared to a corresponding concentration generated in the laboratory for an environmental sample.…”