USGS-Branch of Quality Systems
PO Box 25046
DFC, Bldg 95, MS 401
Lakewood, CO 80225
|George Ritz||Branch Chiefemail@example.com||303-236-1835|
|Brooke Connor||LEP, LTMDLfirstname.lastname@example.org||303-236-1877|
|Mark Nilles||Acid Rain Projectemail@example.com||303-236-1878|
Sediment Laboratory Quality Assurance
To improve and assess data quality produced by the USGS and to enable comparison among laboratories, participation in the SLQA Project by USGS sediment laboratories and by laboratories contracted by the USGS is required. Results from the SLQA studies may be used to assess variability in environmental data and to improve laboratory performance.
National Field Quality Assurance
The National Field Quality Assurance Program (NFQA) was created in 1979 to provide quality-assurance reference samples to field personnel who make water quality field measurements. The program monitors the proficiency of alkalinity, pH, and specific conductance measurements determined by water quality field analysts.
Standard Reference Samples
Semiannually, BQS conducts an inter-laboratory comparison of inorganic analytes in water. This program provides a variety of Standard Reference Samples (SRSs) for laboratory quality assurance testing and are available to purchase for internal quality control. The majority of samples are prepared with water from Colorado streams.
Laboratory Evaluation Project
Analytical laboratories that provide chemical, radiochemical, and biological analyses to the U.S. Geological Survey, Water Resources Discipline (WRD) must be evaluated relative to the objectives of a project requiring analyses and approved for use for that specific project. Analysis of performance samples will provide the basis for the initial laboratory approval and the approved laboratory must continue to provide acceptable performance sample results during the life of the project.
Inorganic Blind Sample Project
Since 1981, the USGS has operated an independent, external, quality-assurance project called the Inorganic Blind Sample Project (IBSP). The purpose of the IBSP is to monitor and evaluate the quality of laboratory analytical results through the use of double-blind quality-control (QC) samples. The information provided by the IBSP assists the laboratories in detecting and correcting problems in the analytical procedures. The information also can aid laboratory users in estimating the extent that laboratory errors contribute to the overall errors in their environmental data.
Organic Blind Sample Project
The Organic Blind Sample Project (OBSP) of the Branch of Quality Systems (BQS) assesses the operational performance of organic analytical methods used for determining water-quality parameters for the USGS - National Water Quality Laboratory (NWQL) by means of blind submissions of Quality Assurance (QA) samples. The assessments identify not only the baseline performance capabilities of the methods in the Organic Chemistry Program, but also identify strengths and weaknesses in the current system of bench-level quality and process control. The information provided by the OBSP assists the NWQL in detecting and correcting problems in the analytical processes. The information also can aid the NWQL data user in interpreting their environmental data over time.
Long-term Method Detection Level
BQS submits double-blind samples to the National Water Quality Laboratory at concentrations near their detection levels to assess the laboratory's long-term method detection level (LT-MDL). An LT-MDL is used to identify the lower concentration limit of a method's ability to differentiate noise from analyte. The LT-MDL is derived by determining the standard deviation of ideally 24 low concentration spiked blind sample measurements collected over approximately one year. Alternatively, if an analytical method produces a reading for a blank (including negative values), blank data (rather than spikes) can be used to determine the LT-MDL. The LT-MDL controls false positive error (reporting that an analyte is present when it is not in the sample at a concentration equal to or greater than the reporting level). The chance of falsely reporting a concentration greater than or equal to the LT-MDL for a sample that did not contain the analyte is predicted to be less than or equal to 1 percent.
|National Atmospheric Deposition Program National Trends Network||National Water Quality Laboratory||Office of Water Quality|