Document ID: EPA-HQ-OW-2010-0288-0023
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2010-06-08T04:00Z

Equivalency Assessment 

Revisions to Currently Approved 

ASTM Drinking Water Methods 

in 40 CFR 141.25

for 

Expedited EPA Method Approval Action 

 

FINAL (01/21/2010)

 

Prepared by:

Larry Umbaugh

Environmental Scientist Leader - Senior Radiochemist

Computer Sciences Corporation (CSC)

6101 Stevenson Avenue

Alexandria, VA 22304

Prepared in Support of 

EPA Work Assignment 4-21 under EPA Contract No. EP-C-05-045

Activity Description

CSC was directed, on 12/7/09, to review six updated ASTM methods and
provide recommendations as to whether they are suitable for approval in
an Expedited Method Approval action.  The review was conducted as a
comparison of the updated versions to the versions that are cited in 40
CFR 141.25(a).  The review evaluated any changes in the methods that may
impact the performance of the method.  

  

Evaluation Conclusions

Details of the evaluation of revisions to the six ASTM methods are
provided in the attached memo.  It was determined that the revisions, in
all six methods, did not change sample handling or the analytical
chemistry process.  It is recommended that Environmental Protection
Agency (EPA) considers the new versions of the ASTM standards to be
“equally effective” as the approved ASTM methods cited in 40 CFR
141.25(a).  The following table lists the currently approved ASTM
methods under the Safe Drinking Water Act (SDWA) and the corresponding
method revisions that were reviewed for approval.

Currently Approved (40 CFR 141.25) ASTM Method 	Approved Method Title	
ASTM Method Revision	Revised 

Method Title	Recommended for Approval?

D 2460-97	Standard Test Method for Alpha-Particle-Emitting Isotopes of
Radium in Water	D 2460-07	Standard Test Method for
Alpha-Particle-Emitting Isotopes of Radium in Water	Yes

D 3454-97	Standard Test Method for Radium-226 in Water	D 3454-05
Standard Test Method for Radium-226 in Water	Yes

D 3649-98a	Standard Practice for High-Resolution Gamma-Ray Spectrometry
in Water	D 3649-06	Standard Practice for High-Resolution Gamma-Ray
Spectrometry in Water	Yes

D 4107-98

(Reapproved 2002)	Standard Test Method for Tritium in Drinking Water	D
4107-08	Standard Test Method for Tritium in Drinking Water	Yes

D 4785-00a	Standard Test Method for Low-Level Iodine-131 in Water	D
4785-08	Standard Test Method for Low-Level Analysis of Iodine
Radioisotopes in Water	Yes

D 5147-02	Standard Test Method for Trace Uranium in Water by
Pulsed-Laser Phosphorimetry	D 5174-07	Standard Test Method for Trace
Uranium in Water by Pulsed-Laser Phosphorimetry	Yes

 Office of Ground Water and Drinking Water

January 4, 2010

MEMORANDUM

						

SUBJECT:	Basis for Expedited Approval of Methods from ASTM International

FROM:	Michella Karapondo, Chemist

			

		

TO:		The Record

	This memo documents the reviews that were conducted on new versions of
six methods issued by ASTM International.  It provides the background
information on why EPA is approving these methods using the expedited
method approval process.  Each method is discussed individually below:

1)  ASTM International Method D 2460-07:

Method D 2460-97 was used as the basis for comparison, because it is
currently promulgated in the drinking water regulations at 40 CFR
141.25(a) for determining alpha particle-emitting isotopes of radium in
water.  The following changes are included in the newer version:

Section 2.1 was modified to update referenced ASTM standards; Standards
D 4448, D 5847, and D 6001 were added.

Section 6, concerning interferences, was modified to add additional
discussions on:

Interferences from the presence of suspended solids or insoluble
precipitates that will bias the chemical yield high and lead to falsely
low sample results (Section 6.2).

Radium progeny in-growth and decay that will interfere with the total
alpha particle emission rate over time (Section 6.3).

Precipitate mass that will interfere with alpha particle detection
efficiency (Section 6.4).

Self-absorption interference effects that may be addressed during the
calibration process (Section 6.5).

Section 8.6 was modified to add the molarity of the ammonium hydroxide.

Section 8.7 was modified to add standardization instructions (Section
8.7.1) for the barium nitrate carrier solution.

Section 8.13 was modified to add the molarity of the sulfuric acid.

Section 10.1 was modified to add additional ASTM reference Standards D
4448 and D 6001 for the collection of non-drinking water samples.

Section 11 was modified by splitting Section 11.1 into 3 separate
sections; the text remains the same. 

Section 13.2 was modified to change the following concentration
calculation terms; the calculation remains the same:

D was changed to, AC226Ra = concentration of Ra-226, Bq/L

C = net count rate was changed to Rn

F was changed to, IF = correction for the ingrowth of descendants
between the time of separation and the time of counting.

Table 1 was updated to expand the correction factor range for in-growth
of alpha activity into initially pure radium-226, from 72 hours to 720
hours.

Figure 1 was updated to expand the range of the in-growth and decay
curves from the time of separation, to 30 days versus 7 days in D
2460-97.

Figure 2 was added to provide information on the typical alpha particle
efficiency as a function of time and precipitate mass.

Section 13.4 was modified to update the terminology for the calculation
of the analysis uncertainty from the older, total propagated uncertainty
(TPU), in D 2460-97, to the currently used combined standard uncertainty
(CSU).  This update is consistent with the U.S. Nuclear Regulatory
Commission, Multi-Agency Radiological Laboratory Analytical Protocols
Manual, NUREG-1576 EPA 402-B-04-001A, July 2004, (MARLAP).

Section 13.4.1 was modified to change the following one-sigma
uncertainty calculation terms; the calculation remains the same:

G was changed to Rs

B was changed to Rb

tG was changed to ts

Section 13.5 was modified to update the calculation of the a priori
minimum detectable concentration (MDC) to be consistent with MARLAP.

Section 15 has been rewritten to include detailed instructions:

Section 15.1 defines the quality control (QC) program for the instrument
and details the size of an analytical batch to be limited to 20 samples.

Section 15.2 details detector efficiency calibration verification.

Section 15.3 describes the steps necessary for initial demonstration of
the laboratory/instrument/analyst capability.

Section 15.4 details laboratory control sample requirements in
analytical batches.

Section 15.5 provides for method blank requirements in an analytical
batch.

Section 15.6 describes the requirements for analytical batch matrix
spikes.

Section 15.7 presents the requirements for duplicates in the batch
analysis.  It also delineates the duplicate error ratio calculation and
acceptance criteria.

Section 15.8 defines the requirements for quarterly verification of the
quantitative value produced by the test method by analyzing independent
reference material that has been submitted on at least a single-blind
basis.

The two methods are identical with respect to drinking water sample
collection/handling protocols and sample preparation, and are
analytically equivalent.  The calculation of radium-226 concentrations
has been updated to capture the uncertainty determinations outlined in
MARLAP; precision and bias are unchanged.  The QC requirements in D
2460-07 are far more detailed compared to those cited in D 2460-97. 
Therefore, Method D 2460-07 is considered to be equally as effective as
D 2460-97 for determining radium-226 concentrations in drinking water.

2)  ASTM International Method D 3454-05:

Method D 3454-97 was used as the basis for comparison, because it is
currently promulgated in the drinking water regulations at 40 CFR
141.25(a) for determining radium-226 in water.  The following changes
are included in the newer version: 

Section 2.1 was modified to update referenced ASTM standards; Standard D
5847 was added.

Section 7.5 was modified, for the determination of acceptable background
counting rate, from 0.00 to 0.03 counts per minute (cpm) to 0.00 to
0.0005 counts per second (cps).

Sections 8.13 and 8.14 were updated to include the molarity of the
hydrochloric acid solution.

Section 8.16 was updated to include the weight percent of the hydrogen
peroxide.

Section 8.19 was modified to update known suppliers.

Section 8.20 was modified to update known suppliers.

Section 8.22 was updated to include the molarity of the sulfuric acid
solution.

Section 10.16 was modified to change the following term in the
calculation for the cell calibration constant:

C = net count rate was changed to Rn; the calculation remains the same.

Section 10.17 was expanded to provide additional calibration frequency
requirements.

Section 11.1.14 was modified to change the sample yield term from Y to
RY.

Section 11.12.10 was revised to eliminate repeated verbiage from Section
11.12.9.

Section 12.1 was modified to change the following concentration
calculation terms; the calculation remains the same:

D was changed to, AC226Ra = concentration of Ra-226, Bq/L

Rn was previously changed in Section 10.16

RY was previously changed in Section 11.1.14

V was changed to Va = volume of sample used, L

Section 12.2 was modified to update the terminology for the calculation
of the analysis uncertainty from the older, total propagated uncertainty
(TPU), in D 3454-97, to the currently used combined standard uncertainty
(CSU).  This update is consistent with MARLAP.

Section 14 has been rewritten as noted below:

Section 14.2 details calibration and calibration verification steps.

Section 14.3 details detector efficiency verification.

Section 14.4 describes the steps necessary for initial demonstration of
the laboratory and instrument capabilities.

Section 14.5 details laboratory control sample requirements for
analytical batches.

Section 14.6 provides for method blank requirements in an analytical
batch.

Section 14.7 describes the requirements for analytical batch matrix
spikes.

Section 14.8 presents the requirements for duplicates in the batch
analysis.  It also delineates the duplicate error ratio calculation and
acceptance criteria.

Section 14.9 defines the requirements for quarterly verification of the
quantitative value produced by the test method by analyzing independent
reference material that has been submitted on at least a single-blind
basis.

The two methods are identical with respect to drinking water sample
collection/handling protocols and sample preparation, and are
analytically equivalent.  The calculation of radium-226 concentration
has been updated to capture the uncertainty determinations outlined in
MARLAP.  The precision and bias are unchanged.  The QC requirements in D
3454-05 are far more detailed than those cited in D 3454-97.  Therefore,
Method D 3454-05 is considered to be equally as effective as D 3454-97
for determining radium-226 concentrations in drinking water.

3)  ASTM International Method D 3649-06:

Method D 3946-98a was used as the basis for comparison, because it is
currently promulgated in the drinking water regulations at 40 CFR
141.25(a) for determining gamma emitters in water.  The following
changes are included in the newer version:

Section 1.1 was modified to change the applicability of the procedure to
nuclides emitting gamma-rays with energies greater than 45 keV versus
those with energies greater than 20 keV as stipulated in D 3946-98a. 
The increase of the lower end energy is more appropriate to match
typical low energy calibration standards.  New technology (digital
signal processors) was also included to accommodate high count rate
samples.

Section 1.2 was modified to allow for relative determinations of samples
other than just tracers.  References have also been updated in this
section.

Section 2.1 was modified to update referenced ASTM standards; the
discontinued ASTM Standard D 3085 was deleted, and Standard D 4488 was
added.

Section 4.1 was expanded to include all the components in the gamma ray
spectrometer signal chain.

Section 4.2 was modified to remove antiquated lithium-drifted germanium,
Ge(Li), detectors.  New technology (electromechanical cooling) was added
as an alternative to liquid nitrogen cooling.

Section 4.4 was modified, because of newer computer technology, to
expand the system memory from 2000 channels to 4000 channels to fully
utilize a germanium detector’s energy resolution.

Section 4.6 was modified to remove cathode-ray tube (CRT).

Section 4.7 was modified to remove 1 keV per channel, which is
appropriate only if 2000 channels are used (see Section 4.4).

Section 5.3 was modified to lower the distance for high activity samples
from the detector to 10 centimeters instead of 1 meter.

Section 5.4 was modified to simplify the gross count rate determination
from 100,000 counts per minute to 2,000 counts per second, to eliminate
electronic problems,.

Section 6.1 was modified to remove reference to a method of predicting
the gamma-ray resolution of a detector.

Section 6.3 was modified to increase the acceptable counting rate from
1,000 counts per second to 2,000 counts per second, to minimize random
summing.

Section 6.4 was added to the method to discuss sample density as being a
factor that can affect quantitative results.

Section 7 apparatus was updated to reflect current technology upgrades
in gamma ray spectrometer system components.

Section 8.1 was revised to include the following updates:  D 1066
Practice for Sampling Steam and D 4448 Guide for Sampling Ground-Water
Monitoring Wells for additional sample collection criteria.

Section 10.1 was modified to raise the calibration source activity to a
range of 1 to 1000 k Becquerel (Bq), to reflect better electronics in
current gamma ray spectrometry systems.

Section 10.2.1.2 was modified to add a statement on cascade and random
summing interferences that should be considered during calibration.

Section 10.3.1 was modified to include a new Table 1 that lists some
commercially available nuclides suitable for energy calibrations.

Section 10.3.1.1 was revised to delete the following sentence:  “The
radionuclide purity of the standards should be verified periodically to
ensure against accidental contamination or the presence of long-lived
impurities by comparing the observed spectra published in the literature
(8).”  The deletion of this sentence is appropriate because routine QC
checks, using the calibration standards, will verify potential
contamination and/or impurity issues.

Section 10.3.2 has been modified, for the verification of the energy
calibration, from “During each day in which the spectrometry system is
being used to analyze samples, the above sequence of operation shall be
repeated using at least two different gamma-ray energies” to “The
energy calibration should be verified at a predetermined interval.” 
The daily or before-use requirement has been moved to Section 14.2.

Efficiency calibration equation terms included in Section 10.4.2 have
been modified to those below; the calculations are the same: 

 

Where:

εf 	=  full-energy peak efficiency (counts per gamma-ray emitted),

Rnet	=  net gamma-ray count in the full-energy peak of interest (counts
per second), and

Rγ	= gamma-ray emission rate (gamma rays per second).  If the standard
source is calibrated as to activity, the gamma-ray emission rate is
given by:

		Rγ = A × I

Where:

A = activity in becquerels (Bq), and

I = absolute gamma intensity for the specific gamma-ray emission.

Section 12.4 has been modified to remove the nuclear decay data table
and the user is referred to References 6, 7, and 8 for such data.

Section 12.5 has been revised to modify the calculation terms to those
below; the calculation is the same:

 

Where:

Rnet	= net count rate (s-1),	

V	= test specimen volume (L),

ε 	= detector efficiency factor,

I	= absolute gamma intensity, and

DF	= radionuclide decay correction factor (correction for radioactive
decay).

Section 12.6 was added to update the terminology for calculation of the
analysis uncertainty from the older total propagated uncertainty (TPU,
in D 3649-98a), to the currently used combined standard uncertainty
(CSU).  This update is consistent with MARLAP.

Section 12.7 was added to provide clarification for calculation of the
net count rate  (Rnet) and the counting uncertainty [u(Rnet)].

Section 12.9 was added to reference ASTM D 3648, Standards for the
Measurement of Radioactivity, for detailed discussion on minimum
detectable concentration concepts.

The two methods are identical with respect to drinking water sample
collection/handling protocols and sample preparation, and are
analytically equivalent.  The calculation of gamma-ray emitting nuclide
concentrations has been updated to capture the uncertainty
determinations outlined in MARLAP.  The precision and bias are
unchanged.  Therefore, Method D 3649-06 is considered to be equally as
effective as D 3649-98a for determining gamma-ray emitting nuclide
concentrations in drinking water.

4)  ASTM International Method D 4107-08:

Method D 4107-98 (Reapproved 2002) was used as the basis for comparison,
because it is currently promulgated in the drinking water regulations at
40 CFR 141.25(a) for determining tritium in water.  The following
changes are included in the newer version:

Section 2.1 was modified to update referenced ASTM standards.

Section 8.6 was added to include the NIST traceable tritium standard as
a reagent and material.

Section 10.1.1 was modified to define that 17 disintegrations/second are
equal to 17 Becquerel.  The acronym RWTS was added for raw water tritium
standard.

Section 10.1.1 was modified by moving the last sentence in Section
10.1.1 to the first sentence in 10.1.1.1.  The acronym DWTS was added
for distilled water tritium standard.

Section 10.1.2 was modified to add the acronym DRWTS for distilled raw
water tritium standard.

Section 11.1 was modified by taking the last 2 sentences in the Note and
making them Section 11.2.  The remaining sections (11.3 through 11.5)
were then incremented by one number, ending at Section 11.16.

Section 12.1 was modified to update the calculation for detection
efficiency to reflect the previously defined acronyms.  The detection
efficiency calculation was updated to add the standard uncertainty for
the activity of the DWTS.  This update is consistent with MARLAP.

Section 12.2 was updated to reflect the previously defined acronyms for
the recovery correction factor calculation.

Section 12.3 was updated to include the half-life correction in the
tritium activity calculation.

Section 12.3.1 was replaced with Section 12.4.  The update includes the
calculation of the combined standard uncertainty (CSU) of the tritium
concentration in the sample due to counting statistics.  This update is
consistent with MARLAP.

Section 12.4 was replaced with Section 12.5 which updates the
terminology for calculation of the analysis uncertainty from the older,
total propagated uncertainty (TPU, in D 4707-98), to the currently used
combined standard uncertainty (CSU).  This update is consistent with
MARLAP.

Section 12.6 was added to calculate the critical activity concentration
Lc.  This update is consistent with MARLAP.

Section 12.7 was added to provide the calculation of the a priori
minimum detectable activity concentration (MDC).  This addition is
consistent with MARLAP.

Section 13 has been rewritten as noted below:

Section 13.2 describes the steps necessary for initial demonstration of
laboratory and instrument quality.

Section 13.3 details laboratory control sample requirements in
analytical batches.

Section 13.4 provides for method blank requirements in an analytical
batch.

Section 13.5 describes the requirements for analytical batch matrix
spikes.

Section 13.6 presents the requirements for duplicates in the batch
analysis.  It also delineates the duplicate error ratio calculation and
acceptance criteria.

Section 13.7 defines the requirements for quarterly verification of the
quantitative value produced by the test method by analyzing independent
reference material that has been submitted on at least a single-blind
basis.

The two methods are identical with respect to drinking water sample
collection/handling protocols and sample preparation, and are
analytically equivalent.  The calculation of tritium concentration has
been updated to capture the uncertainty determinations outlined in
MARLAP.  The QC requirements in D 4107-08 are far more detailed than
those cited in D 4107-98.  Therefore, Method D 4107-08 is considered to
be equally as effective as D 4107-98 for determining tritium
concentrations in drinking water.

5)  ASTM International Method D 4785-08:

Method D 4785-00a was used as the basis for comparison, because it is
currently promulgated in the drinking water regulations at 40 CFR
141.25(a) for determining radioactive iodine in water.  The following
changes are included in the newer version:

The method title was changed to Standard Test Method for Low-Level
Analysis of Iodine Radioisotopes in Water.

Section 1.1 was modified to remove specificity for iodine-131(131I) and
replace it with radioactive iodine in water.

Section 2.1 was modified to update referenced ASTM standards; Standard D
5847 was added.

Section 5.1 was modified to add the capability of analyzing additional
isotopes of iodine (in addition to 131I).  However, it also states that
other iodine isotopes have not been tested according to ASTM Standard D
2777 and that the user must determine the precision and bias for
radioactive isotopes of iodine other than 131I.

Section 5.2 was added to address the method’s applicability to
analysis of iodine radioisotopes with half-lives greater than 2 hours,
which include 121I, 123I, 124I, 125I, 126I, 129I, 130I, 131I, 132I,
133I, and 135I.

Section 6.2 was added to inform the user that, due to X-ray
interferences at and below 33.6 keV, only discreet gamma energy lines at
and above 35.5 keV should be used for identification and quantification
of iodine radioisotopes.

Section 8.20 was added to include calibration standards in the listing
of reagents and materials.

Section 11 was re-written to fully detail calibration and acceptance
criteria requirements for the high-resolution gamma-ray spectroscopy
system.  The re-write is very comprehensive in comparison to the
calibration section in D 4785-00a.

Section 13.3.6 was updated to include a new table (Table 1) for iodine
radioisotope nuclear decay data.  Table 1 provides the gamma energy,
gamma fraction, and half-life for the radioactive iodine isotopes (121I,
123I, 124I, 125I, 126I, 129I, 130I, 131I, 132I, 133I, and 135I)
applicable to the method.

Section 14 was re-written to incorporate MARLAP calculations as noted
below:

Section 14.1calculates the net count rate and standard uncertainty of
each photopeak.

γ for the iodine isotopes listed in Table 1.

Section 14.3 calculates the uncertainty due to counting statistics.

Section 14.4 calculates the CSU to include the standard counting
uncertainty, relative standard uncertainty of the measured quantity, and
the relative standard uncertainty due to other causes identified by the
user.

Section 14.4 was updated to replace the expanded uncertainty with
Section 14.5, which updates the calculation to MARLAP.

Section 14.6 was added to provide for the calculation of the critical
activity concentration (Lc).

Section 14.7 replaces Section 14.5 (in D 4785-00a) for the calculation
of minimum detectable concentration (MDC).  The new calculation is
consistent with MARLAP.  

 Section 15 has been rewritten as noted below:

Section 15.1 defines the QC program for the instrument and details the
size of an analytical batch to be limited to 20 samples.

Section 15.2 describes the carrier recovery acceptance criteria for the
internal stable iodide standard used in the determination of radioiodine
in each sample.

Section 15.3 details calibration and calibration verification steps.

Section 15.4 describes the steps necessary for initial demonstration of
the laboratory/instrument/analyst capability.

Section 15.5 details laboratory control sample requirements in
analytical batches.

Section 15.6 provides for method blank requirements in an analytical
batch.

Section 15.7 describes the requirements for analytical batch matrix
spikes.

Section 15.8 presents the requirements for duplicates in the batch
analysis.  It also delineates the duplicate error ratio calculation and
acceptance criteria.

Section 15.9 defines the requirements for quarterly verification of the
quantitative value produced by the test method by analyzing independent
reference material that has been submitted on at least a single-blind
basis.

Section 16.4 was updated to reflect the addition of the new Table 1 in
Section 13.3.6; the table in Section 16.4 is now Table 2.

The two methods are identical with respect to drinking water sample
collection/handling protocols and sample preparation, and are
analytically equivalent.  The calculation of iodine concentrations has
been updated to capture the uncertainty determinations outlined in
MARLAP.  The precision and bias are unchanged for iodine-131.  The QC
requirements in D 4785-08 are far more detailed than those cited in D
4785-00a.  Therefore, Method D 4785-08 is considered to be equally as
effective as D 4785-00a for determining iodine concentrations in
drinking water.

6)  ASTM International Method D 5174-07:

Method D 5174-02 was used as the basis for comparison, because it is
currently promulgated in the drinking water regulations at 40 CFR
141.25(a) for determining uranium in water.  The following changes are
included in the newer version:

Section 1.1 was modified to change the lower end of the calibration
range from 0.05 ppb or greater to 0.1µg/L (0.1 ppb) or greater.

Section 2.1 was modified to update referenced ASTM standards; Standards
D 4448 and D 6001 were added.

Section 6.4 was modified to remove Fluran as a complexation agent. 
Uraplex is the only remaining polyphosphate.

Section 6.6 was modified to specify the molarity of the nitric acid used
(0.8 M) for diluting samples if they exceed the calibration range.

Section 6.7 was added to further explain how to minimize the effects of
interferences by diluting the sample with 0.8 M nitric acid.

Section 7.1.1 was changed to raise the method detection limit (MDL) from
0.05 µg/Liter to 0.1 µg/Liter.

Section 7.1.3 was modified, to change the precision statement,
from“The precision of repetitive measurements must be within 15%
relative standard deviation (R.S.D.).” to “The precision of
repetitive measurements sufficient to obtain a relative standard
deviation of less than 15% at the low points of the calibration
curve.” 

Section 10.1 was modified to add reference to ASTM Standards D 4448 and
D 6001 for the collection of non-drinking water samples.

Section 11.6 was modified with the addition of Note 4, which elaborates
on how to minimize interference quenching effects by diluting the sample
with 0.8 M nitric acid when lifetime values are below 200 micro seconds.

Section 12 has been rewritten to add and expand details on the
following:

Performing and calculating the MDL on a periodic basis.

Determining the reporting limit (RL).

Reporting analytical results.

Section 14.2.2 was expanded to include delineation of the calibration
verification concentration ranges, which were not present in D 5174-02.

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the matrix spike recovery calculation is in percent recovery.  The
calculation terms were changed, but the calculation remains the same.

Section 14.7.4 was modified to change the acceptance criteria for matrix
spike recovery from (50% of the expected value to a range of 50% to 150%
of the expected value.

The two methods are identical with respect to drinking water sample
collection/handling protocols and sample preparation, and are
analytically equivalent.  The calculation of uranium concentrations has
been updated to expand determination of the MDL and RL.  The precision
and bias are unchanged.  The QC requirements in D 5174-07 are more
detailed than those cited in D 5147-00a.  Therefore, Method D 5147-07 is
considered to be equally as effective as D 5147-02 for determining
uranium concentrations in drinking water.

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