Pennsylvania Code
Title 25 - ENVIRONMENTAL PROTECTION
Part I - Department of Environmental Protection
Subpart D - Environmental Health and Safety
Article VI - General Health and Safety
Chapter 252 - ENVIRONMENTAL LABORATORY ACCREDITATION
Subchapter D - QUALITY ASSURANCE AND QUALITY CONTROL REQUIREMENTS
Section 252.405 - Essential quality control requirement-radiochemistry

Universal Citation: 25 PA Code § 252.405

Current through Register Vol. 54, No. 44, November 2, 2024

(a) In addition to the requirements of § 252.401 (relating to basic requirements), laboratories performing testing or analysis of environmental samples in the area of radiochemistry shall comply with this section.

(b) When the method selected by an environmental laboratory in accordance with § 252.307 (relating to methodology) contains more stringent requirements than the requirements of this section, the environmental laboratory shall follow the more stringent requirements contained in the method.

(1) An environmental laboratory shall follow the initial calibration requirements of the method or regulation.

(2) Initial calibrations shall be performed using calibration standards that have the same general characteristics as the associated environmental samples, for example geometry, homogeneity and density.

(3) The initial calibration must include, when applicable, determination of instrument background, efficiency, mass attenuation and energy calibration.

(4) The results of testing or analysis of environmental samples shall be determined from an initial calibration that is not more than 12 months old and may not be determined from any continuing calibration verification, unless otherwise required by regulation, method or program.

(5) The details of the initial calibration procedures including calculations, integrations, acceptance criteria and associated statistics shall be included or referenced in the laboratory's standard operating procedures.

(6) Raw data records shall be retained to permit reconstruction of the initial calibration.

(d) The requirements for an instrument suitability verification are as follows:

(1) An instrument suitability verification standard shall be analyzed at the beginning of each analysis day, unless a higher frequency is required in the method or regulation.

(2) The instrument suitability verification standard shall be a check source that provides adequate counting statistics for a relatively short count time and is sealed or encapsulated to prevent loss of activity and contamination of the instrument and laboratory personnel.

(3) For alpha and gamma spectroscopy systems, the instrument suitability verification standard must include determination of instrument counting efficiency, energy calibration and peak resolution.

(4) For gas-proportional and liquid scintillation counters, the instrument suitability verification standard must include determination of instrument counting efficiency.

(5) For scintillation counters, the instrument suitability verification standard must include determination of instrument counting efficiency.

(6) Details of the instrument suitability verification procedure including calculations, integrations, acceptance criteria and associated statistics shall be included or referenced in the laboratory's standard operating procedures.

(7) Raw data records shall be retained to permit reconstruction of the instrument suitability verification.

(8) Acceptance criteria for instrument suitability verification standards in the method or regulation shall be followed. When there are no established criteria in the method or regulation, an environmental laboratory shall determine internal criteria and document the procedure used to establish the criteria.

(9) If an instrument suitability verification standard fails the acceptance criteria, an environmental laboratory shall initiate corrective actions.

(10) Environmental samples not bracketed by acceptable instrument suitability verification standards shall be reanalyzed.

(e) The requirements for an instrument background measurement are as follows:

(1) An instrument background check shall be analyzed every analysis day.

(2) Instrument background values shall be subtracted from the total measured activity in the determination of the sample activity.

(3) Each individual background check shall be compared to the acceptance criteria in the method or regulation. When there are no established criteria in the method or regulation, an environmental laboratory shall determine internal criteria and document the procedure used to establish the limits.

(4) Environmental samples associated with an out of control instrument background check shall be reprocessed and reanalyzed from the beginning of the method or the results reported with the appropriate data qualifiers.

(f) The requirements for a method blank are as follows:

(1) A method blank shall be processed along with and under the same conditions as the associated samples including all steps of the preparation and analytical procedure.

(2) A method blank shall be analyzed at a minimum of one per preparation batch. When no separate preparation method is used, such as gamma analysis in water, the batch shall be defined as no more than 20 environmental samples that are analyzed together using the same method, personnel and lots of reagents.

(3) A method blank must consist of a matrix that is similar to the associated environmental samples and is free of the isotopes of interest. When a matrix that is similar to the associated environmental samples that is free of the analytes of interest does not exist and cannot be prepared, reagent water or an artificial or simulated matrix may be used.

(4) When an environmental sample is analyzed by gamma spectrometry by placing the sample matrix into a calibrated counting geometry, the method blank must consist of a similar counting geometry that is filled to a similar volume with reagent water to partially simulate gamma attenuation due to a sample matrix.

(5) The method blank result may not be subtracted from the sample results in the associated preparation or analytical batch unless permitted by the method or regulation.

(6) The method blank shall be prepared with similar aliquot size to that of the routine samples for analysis. The method blank result and acceptance criteria shall be calculated in a manner that compensates for sample results based upon differing aliquot size.

(7) If a contaminant is detected in the method blank, the source of contamination shall be investigated and measures shall be taken to minimize or eliminate the contamination. A method blank is considered contaminated if one of the following applies:

(i) The activity of a target isotope in the method blank is at or above the reporting limit established by the method or by regulation.

(ii) The contamination in the method blank otherwise affects the environmental sample results as described in the method, regulation or in individual project data quality objectives.

(8) Environmental samples associated with a contaminated method blank shall be reprocessed for analysis or the results reported with the appropriate data qualifiers.

(g) The requirements for a laboratory control sample are as follows:

(1) A laboratory control sample must be processed along with and under the same conditions as the associated environmental samples, including all steps of the preparation and analytical procedure.

(2) The laboratory control sample must consist of a defined matrix containing known and verified activities of isotopes. When a matrix that is similar to the associated environmental samples that is free of the analytes of interest is not available, reagent water or an artificial or simulated matrix may be used.

(3) A laboratory control sample must be analyzed at a minimum of one per preparation batch. When no separate preparation method is used, such as gamma analysis in water, the batch shall be defined as no more than 20 environmental samples that are analyzed together with the same method, personnel and lots of reagents.

(4) The activity of the laboratory control sample must be within the calibration range of the method and one of the following:

(i) Two to ten times the detection limit.

(ii) At an activity level comparable to that of the environmental samples being tested or analyzed, if the sample activities are expected to exceed ten times the detection limit.

(5) The standard used to prepare the laboratory control sample must be from a source independent of the standards used for initial calibration.

(6) When a radiochemical method, other than gamma spectroscopy, has more than one reportable isotope, for example, plutonium, Pu 238 and Pu 239, using alpha spectrometry, only one of the isotopes shall be included in the laboratory control sample. When more than one isotope is present above the specified detection limit, each isotope shall be assessed against the acceptance criteria.

(7) When gamma spectrometry is used to identify and quantitate more than one isotope, the laboratory control sample must contain isotopes that represent the low, for example americium-241, medium, for example cesium-137, and high, for example cobalt-60, energy range of the analyzed gamma spectra. The isotopes need not exactly bracket the calibrated energy range or the range over which isotopes are identified and quantitated.

(8) Each individual laboratory control sample must be compared to the acceptance criteria in the method or regulation. When there are no established criteria in the method or regulation, an environmental laboratory shall determine internal criteria and document the procedure used to establish the limits.

(9) Environmental samples associated with an out of control laboratory control sample shall be reprocessed and reanalyzed from the beginning of the method or the results reported with the appropriate data qualifiers.

(h) The requirements for sample duplicates are as follows:

(1) A sample duplicate shall be analyzed at a minimum of one per preparation batch. When no separate preparation method is used, for example gamma analysis in water, the batch shall be defined as no more than 20 environmental samples that are analyzed together using the same method, personnel and lots of reagents.

(2) An environmental laboratory shall document the calculations used for determining the relative percent difference or other statistical method for evaluation of the sample duplicate pairs.

(3) Each sample duplicate relative percent difference shall be compared to the acceptance criteria in the method or regulation. When there are no established criteria in the method or regulation, an environmental laboratory shall determine internal criteria and document the procedure used to establish the acceptance limits.

(4) For sample duplicate results outside established criteria, corrective action shall be documented and the affected data reported with appropriate data qualifiers.

(i) Tracer requirements are as follows:

(1) For those methods that utilize a tracer or internal standard, each sample result must have an associated tracer or internal standard recovery calculated and reported.

(2) The tracer or internal standard recovery shall be assessed against the acceptance criteria specified in the method or regulation. When there are no established criteria in the method or regulation, an environmental laboratory shall determine internal criteria and document the procedure used to establish the acceptance limits.

(3) For tracer or internal standard recovery outside established criteria, corrective action shall be documented and the data reported with appropriate data qualifiers.

(j) Carrier requirements are as follows:

(1) For those methods that utilize a carrier, each sample must have an associated carrier recovery calculated and reported.

(2) The carrier recovery for each sample shall be assessed against the acceptance criteria specified in the method or regulation. When there are no established criteria in the method or regulation, an environmental laboratory shall determine internal criteria and document the procedure used to establish the acceptance limits.

(3) For carrier recovery outside established criteria, corrective action shall be documented and the data reported with appropriate data qualifiers.

(k) The requirements for detection limits are as follows:

(1) A detection limit shall be determined by the protocol in the method or regulation. If the protocol for determining detection limits is not specified in the method or regulation, the environmental laboratory shall select a procedure that reflects instrument limitations and the intended application of the method.

(2) A detection limit shall be initially determined for the isotopes of interest in each method in a matrix in which neither the target isotope nor interferences are at a concentration that would impact the results. The detection limit shall be determined in the matrix of interest.

(3) A detection limit shall be determined each time there is a change in the method that affects how the test is performed or that affects the sensitivity of the analysis.

(4) The sample processing steps of the method shall be included in the determination of the detection limit.

(5) Supporting data shall be retained to permit reconstruction of the detection limit determination.

(6) An environmental laboratory shall have a written procedure to relate detection limits with quantitation limits.

(7) The method's lower limit of quantitation shall be established and must be above the detection limit.

(l) Each result shall be reported with the associated measurement uncertainty. The procedures for determining the measurement uncertainty shall be documented and be consistent with the method and regulation.

(m) Records of all equipment, reference materials, reagents, and supplies shall be maintained in accordance with § 252.306 (relating to equipment, supplies and reference materials).

The provisions of this §252.405 amended under 27 Pa.C.S. §§ 4103(a), 4104 and 4105; and section 1920-A of The Administrative Code of 1929 (71 P. S. § 510-20).

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