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Laboratory Detection and Reporting Limits for Beryllium Samples

Detection and reporting limits for Be samples. Subject matter is controversial and open to wide debate.Affects many different laboratory processes:Environmental samplesRCRA waste characterizationIndustrial Hygiene air samplesArea assessment samples (e.g surface smears for beryllium). Detection

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Laboratory Detection and Reporting Limits for Beryllium Samples

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    1. Laboratory Detection and Reporting Limits for Beryllium Samples T. J. Oatts Y-12 National Security Complex Analytical Chemistry Organization B&W Y-12

    2. Detection and reporting limits for Be samples Subject matter is controversial and open to wide debate. Affects many different laboratory processes: Environmental samples RCRA waste characterization Industrial Hygiene air samples Area assessment samples (e.g surface smears for beryllium)

    3. Detection and reporting limits for Be samples There are many terms that have similar definitions/meanings: Instrument Detection Limit (IDL) Method Detection Limit (MDL) Practical Quantitation Limit (PQL) Contract Required Detection Limit (CRDL) Minimum Level of Quantitation (ML) Reporting Limit (RL) Are you confused yet? Just wait!

    4. Detection and reporting limits for Be samples Instrument Detection Limit (IDL) The equivalent concentration of an analyte that produces a signal three times the standard deviation for the measurement of the blank. As concentrations approach the IDL, the precision and accuracy of the measurement is poor.

    5. Detection and reporting limits for Be samples Method Detection Limit (MDL) The minimum concentration of a substance that can be measured and reported with 99% confidence that the analyte concentration is greater than zero. The MDL is determined from analysis of a sample (standard) in a given matrix containing analyte which has been processed through the preparative procedure. (from Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846, 3rd Edition, Environmental Protection Agency, also from 40 CFR Part 136, appendix B)

    6. Detection and reporting limits for Be samples Practical Quantitation Limit (PQL) The lowest concentration of an analyte that can reliably measured within specified limits of precision and accuracy during routine laboratory operation conditions. (52 FR 25690, July 8, 1987)

    7. Detection and reporting limits for Be samples Contract Required Detection Limit (CRDL) The minimum level of detection acceptable under the EPA Superfund Contract Laboratory Program Statement of Work. These concentration levels are consensus standards among analytical chemists about realistically achievable detection in commercial laboratories. (USEPA Contract Laboratory Program Statement of Work for Inorganic Analysis, ILM04.0)

    8. Detection and reporting limits for Be samples Minimum Level of Quantitation (ML) The lowest level at which the entire analytical system must give a recognizable signal and acceptable calibration point for the analyte. Used predominately in the organic analysis methods (GC, GC/MS) (44 FR 69463, December 5, 1979)

    9. Detection and reporting limits for Be samples Reporting Limit (RL) The minimum concentration established between the laboratory and customer, that meets the programmatic needs of the customer. For Y-12 beryllium samples, current reporting limit is 0.01 µg-Be/sample.

    10. Detection and reporting limits for Be samples

    11. Detection and reporting limits for Be samples The DOE Beryllium Rule, 10 CFR 850, establishes the need to sample the workplace air and surfaces for beryllium contamination. Action levels established for worker protection and release of materials from defined beryllium areas Air limit = 0.2 µg/m3 Surface limit = 0.2 µg/100 cm2

    12. Detection and reporting limits for Be samples To establish the reporting limit, the lab looks at: Sample matrix Known interferences Analytical capabilities Accuracy/precision needs of customer

    13. Detection and reporting limits for Be samples Advantages of reporting limits Consistent data across program. Few false positives. Allows for some matrix complexities to be minimized or accommodated. Simplifies lab operations.

    14. Detection and reporting limits for Be samples Disadvantages of reporting limits Makes statistical assessments difficult or impossible when many, or majority of, data points are “less than” values. May cause need for excessive sampling (See initial bullet) Often misinterpreted as “undetectable” or absence of an analyte. May introduce false negatives.

    15. Detection and reporting limits for Be samples The issue of which limit to use is still being discussed. - The EPA is using a Federal Advisory Committee to modify and revise the MDL definition and procedure. - The Beryllium Health & Safety Committee is reviewing the problem of data censoring, and its impacts to statistical assessment of large data sets.

    16. Detection and reporting limits for Be samples Conclusions There is a need for consolidation of terms, and commonality of data reporting approaches. The end use of the data needs to drive the data reporting needs.

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