Current through Register Vol. 49, No. 13, September 23, 2024
Subpart
1.
Scope.
This part applies to laboratories performing radiochemistry
testing on environmental samples. All requirements in this part must be
incorporated into the laboratory's standard operating procedures unless
otherwise directed by the approved method. The quality control requirements
specified by the laboratory's standard operating procedures manual must be
followed. All quality control measures must be assessed and evaluated on an
ongoing basis and quality control acceptance criteria must be used to determine
the validity of the data.
Subp.
2.
Method blanks.
A.
A laboratory must analyze at least one method blank per batch. The method blank
result must be evaluated according to the acceptance criteria in the
laboratory's standard operating procedures manual.
B. When the method blank acceptance criteria
are not met, a laboratory must take corrective action. The occurrence of a
failed method blank and the actions taken must be noted in the laboratory
report.
C. In the case of gamma
spectrometry where the sample matrix is simply aliquoted into a calibrated
counting geometry, the method blank must be of similar counting geometry that
is empty or filled to similar volume with ASTM Type II water to partially
simulate gamma attenuation due to the sample matrix.
D. A laboratory must not subtract results of
method blank analysis from the sample results in the associated batch unless
permitted by the approved method. This does not preclude the application of any
correction factor, such as instrument background, analyte presence in tracer,
reagent impurities, peak overlap, or calibration blank, to all analyzed
samples, both program- or project-submitted and internal quality control
samples. However, the correction factors must not depend on the required method
blank result in the associated analytical batch.
E. The method blank sample must be prepared
with similar aliquot size to that of the routine samples for analysis whenever
possible.
Subp. 3.
Laboratory control sample.
A.
Laboratory control samples must be performed at a frequency of one per batch.
The results of the analysis must be one of the quality control measures to be
used to assess the batch. The laboratory control sample result must be assessed
against the specific acceptance criteria specified in the laboratory standard
operating procedures manual. When the specified laboratory control sample
acceptance criteria are not met, the specified corrective action and
contingencies must be followed. The occurrence of a failed laboratory control
sample acceptance criterion and the actions taken must be noted in the
laboratory report.
B. The activity
of the laboratory control sample must:
(1) be
two to ten times the detection limit; or
(2) at a level comparable to that of routine
samples if the sample activities are expected to exceed ten times the detection
limit.
C. The laboratory
standards used to prepare the laboratory control sample must be from a source
independent of the laboratory standards used for instrument calibration, if
available.
D. The matrix spike must
be prepared by adding a known activity of target analyte. When a radiochemical
method, other than gamma spectroscopy, has more than one reportable analyte
isotope, such as plutonium, Pu 238 and Pu 239, using alpha spectrometry, only
one of the analyte isotopes need be included in the laboratory control sample.
When more than one analyte isotope is added to the laboratory control sample,
each isotope must be assessed against the specified acceptance
criteria.
Subp. 4.
Matrix spikes.
A. Matrix spikes
must be performed at a frequency of one per batch for those methods that do not
utilize an internal standard or carrier for which there is a chemical
separation process and when there is sufficient sample to do so. The exceptions
are gross alpha, gross beta, and tritium, which require matrix spikes for
aqueous samples. The results of the analysis must be one of the quality control
measures to be used to assess the sample results acceptance. The matrix spike
result must be assessed against the specific acceptance criteria specified in
the laboratory standard operating procedures manual. When the specified matrix
spike acceptance criterion is not met, the corrective actions specified in the
laboratory's standard operating procedures must be followed. The occurrence of
a failed matrix spike acceptance criterion and the actions taken must be noted
in the laboratory report. The lack of sufficient sample aliquot size to perform
a matrix spike must be noted in the laboratory report.
B. The activity of the analytes in the matrix
spike must be greater than ten times the detection limit.
C. The laboratory standards used to prepare
the matrix spike must be from a source independent of the laboratory standards
used for instrument calibration, if available.
D. The matrix spike must be prepared by
adding a known activity of target analyte. When a radiochemical method, other
than gamma spectroscopy, has more than one reportable analyte isotope, such as
plutonium, Pu 238 and Pu 239, using alpha spectrometry, only one of the analyte
isotopes need be included in the matrix spike sample. When more than one
analyte isotope is added to the matrix spike, each isotope must be assessed
against the specified acceptance criteria.
E. When gamma spectrometry is used to
identify and quantitate more than one analyte isotope, the laboratory control
sample and matrix spike must contain isotopes that represent the low
(americium-241), medium (cesium-137), and high (cobalt-60) energy range of the
analyzed gamma spectra. As indicated by these examples, the isotopes need not
exactly bracket the calibrated energy range or the range over which isotopes
are identified and quantitated.
F.
The matrix spike sample must be prepared with similar aliquot size to that of
the routine samples of analyses.
Subp. 5.
Tracer.
For those approved methods that allow or require the use of a
tracer, that is, internal standard, each sample result must have an associated
tracer recovery calculated and reported. The tracer recovery for each sample
result must be one of the quality control measures used to assess the
associated sample result acceptance. The tracer recovery must be assessed
against the specific acceptance criteria specified in the laboratory standard
operating procedures manual. When the specified tracer recovery acceptance
criteria are not met, corrective actions specified in the laboratory's standard
operating procedures must be followed. The occurrence of a failed tracer
recovery and the corrective actions taken must be noted in the laboratory
report.
Subp. 6.
Carrier.
For those approved methods that allow or require the use of a
carrier, each sample must have an associated carrier recovery calculated and
reported. The carrier recovery for each sample must be one of the quality
control measures used to assess the associated sample result acceptance. The
carrier recovery must be assessed against the specific acceptance criteria
specified in the laboratory standard operating procedures manual. When the
specified carrier recovery acceptance criteria are not met, the corrective
actions specified in the laboratory's quality assurance manual must be
followed. The occurrence of failed carrier recovery acceptance criteria and the
actions taken must be noted in the laboratory report.
Subp. 7.
Analytical variability;
reproducibility for radiochemistry testing.
A. A laboratory must analyze replicate
samples at least once per batch when there is sufficient sample to do so. The
results of the analysis must be one of the quality control measures used to
assess sample results acceptance. The replicate result must be assessed against
the specific acceptance criteria specified in the laboratory's standard
operating procedures manual.
B.
When the specified replicate acceptance criteria are not met, the corrective
actions specified in the laboratory's standard operating procedures manual must
be followed. The occurrence of failed replicate acceptance criteria and the
actions taken must be noted in the laboratory test results.
C. If sample concentrations are expected to
contain analytes of interest below three times the detection limit, a
laboratory may substitute replicate laboratory control samples or replicate
matrix spiked samples for replicate samples in item A. The replicate result
must be assessed against the specific acceptance criteria specified in the
laboratory's standard operating procedures manual. When the specified replicate
acceptance criteria are not met, the corrective actions specified in the
laboratory's standard operating procedures manual must be followed. The
occurrence of failed replicate acceptance criteria and the actions taken must
be noted in the laboratory test results.
Subp. 8.
Instrument calibration.
A. Radiochemistry analytical instruments must
be calibrated prior to first use in sample analysis.
B. Calibration must be verified when:
(1) the instrument is serviced;
(2) the instrument is moved; and
(3) the instrument settings have been
changed.
C. The
standards used for calibration must have the same general characteristics, that
is, geometry, homogeneity, and density, as the associated samples.
D. The calibration must be described in the
laboratory's standard operating procedures manual.
Subp. 9.
Continuing calibration
verification.
A. Calibration
verification checks must be performed using appropriate check standards and
monitored with control charts or tolerance charts to ensure that the instrument
is operating properly and that the calibration has not changed.
B. The same check standards used in the
preparation of the tolerance chart or control chart at the time of calibration
must be used in the calibration verification of the instrument.
C. The check standards must provide adequate
counting statistics for a relatively short count time. The sources must be
sealed or encapsulated to prevent leakage and contamination of the instrument
and laboratory personnel.
D. For
alpha and gamma spectroscopy systems, the instrument calibration verification
must include checks on the counting efficiency and the relationship between
channel number and alpha or gamma ray energy.
E. For gamma spectroscopy systems, the
calibration verification checks for efficiency and energy must be performed at
least weekly along with performance checks on peak resolution.
F. For alpha spectroscopy systems, the
calibration verification check for energy must be performed at least weekly and
the performance check for counting efficiency must be performed at least
monthly for each day the instrument is used for sample analysis.
G. For gas-proportional and scintillation
counters, the calibration verification check for counting efficiency must be
performed each day of use.
Subp.
10.
Background radiation measurement.
A. Background radiation measurements must be
made on a regular basis and monitored using control charts or tolerance charts
to ensure that a laboratory maintains its capability to meet required data
quality objectives.
B. Background
radiation measurement values must be subtracted from the total measured
activity in the determination of the sample activity.
C. For gamma spectroscopy systems, background
radiation measurements must be performed at least monthly.
D. For alpha spectroscopy systems, background
radiation measurements must be performed at least monthly.
E. For gas-proportional counters, background
radiation measurements must be performed at least weekly.
F. For scintillation counters, background
radiation measurements must be performed each day of use.
Subp. 11.
Instrument contamination
monitoring.
A laboratory must have a written procedure for monitoring
radiation measurement instrumentation for radioactive contamination. The
procedure must indicate the frequency of the monitoring and must indicate
criteria that initiate corrective action.
Subp. 12.
Detection limits.
A. Detection limits must be determined before
sample analysis and must be redetermined each time there is a significant
change in the test method or instrument type.
B. The procedures employed must be documented
and consistent with published references.
Subp. 13.
Quality of standards and
reagents.
A. The quality assurance
manual must describe the procurement, use, and storage of radioisotope
standards.
B. Reference standards
that are used in a radiochemical laboratory must be obtained from the National
Institute of Standards and Technology (NIST), EPA, suppliers of NIST standards
or NIST traceable radioisotopes, or suppliers located outside of the United
States. Reference standards must be traceable back to the appropriate country's
national standards laboratory.
C.
Reference standards must be accompanied with a certificate of calibration that
describes traceability to NIST or another country's national standards
laboratory, when appropriate.
D.
Laboratories must consult with the supplier if the laboratory's assessment of
the activity of the reference traceable standard indicates a noticeable
deviation from the certified value. The laboratory must not use a value other
than the decay-corrected certified value.
E. All reagents used must be analytical
reagent grade or better.
Statutory Authority: MS s
144.97;
144.98
