# 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-05-0452 

### 1.0 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.



### 2.0 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 si x 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 standard s to be “equally effective” as the approved ASTM methods cited in 40 CFR 141.25(a). The fo llowing table lists the currently approved ASTM methods under the Safe Drinking Water Act (SDW A) and the corresponding method revisions that were reviewed for approval.

Currently Approved

(40 CFR 141.25) ASTM Method Approved Method Title A STM 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 forHigh-Resolution GammaRay Spectrometry in Water D 3649-06 Standard Practice forHigh-Resolution GammaRay 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 Yes3 Office of Ground Water and Drinking Water January 4, 2010

MEMORANDUM

SUBJECT: Basis for Expedited Approval of Me thods 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 provi des 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 compar ison, 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 refe renced 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 su spended 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 standard ization instructions (Section 8.7.1) for the barium nitrate carrier solution.

 Section 8.13 was modified to add th e 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.4  Section 13.2 was modified to change the following concentration calculation terms; the calculation remains the same:

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

- C = net count rate was changed to R n

- 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 radi um-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 sta ndard uncertainty (CSU). This update is consistent with the U.S. Nuclear Regulat ory Commission , Multi-Agency Radiological Laboratory Anal ytical 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 R s

- B was changed to R b

- t G was changed to t s

 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 ba tch to be limited to 20 samples.

- Section 15.2 details detector e fficiency calibra tion verification.

- Section 15.3 describes the steps necessa ry for initial demonstration of the laboratory/instrument/analyst capability.

- Section 15.4 details laboratory contro l sample requirements in analytical batches.

- Section 15.5 provides for method blank re quirements 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 duplicat e error ratio calculation and acceptance criteria.

- Section 15.8 defines the requirements for quarterly verification of the quantitative value produced by the te st 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 an alytically 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 t hose cited in D 2460-97. Therefore, Method5 D 2460-07 is considered to be equally as e ffective as D 2460-97 for determining radium226 concentrations in drinking water.

2) ASTM International Method D 3454-05:

Method D 3454-97 was used as the basis for compar ison, 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 refere nced ASTM standards; Standard D 5847 was added.

 Section 7.5 was modified, for the de termination 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 incl ude the molarity of the hydrochloric acid solution.

 Section 8.16 was updated to include the we ight 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 mo larity of the sulf uric 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 R n ; the calculation remains the same.

 Section 10.17 was expanded to provid e additional calibration frequency requirements.

 Section 11.1.14 was modified to chan ge 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, AC 226Ra = concentration of Ra-226, Bq/L

- R n was previously changed in Section 10.16

- RY was previously changed in Section 11.1.14

- V was changed to V a = 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 sta ndard uncertainty (CSU). This update is consistent with MARLAP.

 Section 14 has been rewritten as noted below:

- Section 14.2 details calibration a nd calibration verification steps.

- Section 14.3 details detector efficiency verification.

- Section 14.4 describes the steps necessa ry for initial demonstration of the laboratory and instrument capabilities.6 - Section 14.5 details laboratory contro l sample requirements for analytical batches.

- Section 14.6 provides for method blank re quirements 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 duplicat e error ratio calculation and acceptance criteria.

- Section 14.9 defines the requirements for quarterly verification of the quantitative value produced by the te st 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 an alytically 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 ci ted in D 3454-97. Therefore, Method D 3454- 05 is considered to be equally as eff ective 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 comp arison, 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 a pplicability of the pr ocedure to nuclides emitting gamma-rays with energies great er than 45 keV versus those with energies greater than 20 keV as stipul ated 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 rela tive determinations of samples other than just tracers. References have also been updated in this section.

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

 Section 4.1 was expanded to include a ll the components in the gamma ray spectrometer signal chain.

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

 Section 4.4 was modified, because of ne wer 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 re move 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).7  Section 5.3 was modified to lower the di stance 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 re ference 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 pe r second, to minimize random summing.

 Section 6.4 was added to the method to disc uss 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 th e 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 calib ration 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 includ e 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-liv ed 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 th e verification of the energy calibration, from “During each day in which the spectro metry 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 en ergy calibration should be verified at a predetermined interval.” The daily or be fore-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; th e calculations are the same:

 

###  R t R

ne


###  f

Where :

ε f = full-energy peak efficiency (counts per gamma-ray emitted), R

net

= net gamma-ray count in the full-en ergy peak of interest (counts per second), and8 R

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

## R γ 

## = 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:



#   DF I V R AC net



###      Where : R

net = 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 term inology 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 (R net ) and the counting uncertainty [ u (R net )].

 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.9 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 re gulations at 40 CFR 141.25(a) for determining tritium in water. The following change s 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 th at 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 la st 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 la st 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 ca lculation for detection efficiency to reflect the previously defined acronyms. The detection efficiency calculation was updated to add the standard uncertainty fo r 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 hal f-life correction in the tritium activity calculation.

 Section 12.3.1 was replaced with Se ction 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 Secti on 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 L c . This update is consistent with MARLAP.

 Section 12.7 was added to provi de the calcula tion 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 nece ssary for initial demonstration of laboratory and instrument quality.

- Section 13.3 details laboratory contro l sample requirements in analytical batches.

- Section 13.4 provides for method blank re quirements in an analytical batch.10 - 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 duplicat e error ratio calculation and acceptance criteria.

- Section 13.7 defines the requirements for quarterly verification of the quantitative value produced by the te st 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 uncerta inty 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 concentr ations in dr inking water.

5) ASTM International Method D 4785-08:

Method D 4785-00a was used as the basis for comp arison, because it is currently promulgated in the drinking water regulations at 40 CFR 141.25(a) for determining ra dioactive iodine in water. The following changes are incl uded 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 rem ove specificity for iodine-131( 131 I) and replace it with radioactive iodine in water.

 Section 2.1 was modified to update refere nced ASTM standards; Standard D 5847 was added.

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

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

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

 Section 8.20 was added to include calibrati on 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 ga mma-ray spectroscopy system. The rewrite is very comprehensive in compar ison 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. Ta ble 1 provides the gamma energy, gamma11 fraction, and half-life for the radioactive iodine isotopes ( 121 I, 123 I, 124 I, 125 I, 126 I,
129 I, 130 I, 131 I, 132 I, 133 I, and 135 I) applicable to the method.

 Section 14 was re-written to incorporate MARLAP calcu lations as noted below:

- Section 14.1calculates the net count rate and stan dard uncertainty of each photopeak.

- Section 14.2 was updated for the activity calculation to include the gamma emission probability I γ for the iodine isotope s listed in Table 1.

- Section 14.3 calculates the uncertainty due to counting statistics.

- Section 14.4 calculates the CSU to incl ude the standard counting uncertainty, relative standard uncertainty of th e measured quantity, and the relative standard uncertainty due to ot her 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 th e calculation of the critical activity concentration ( L c ).

- Section 14.7 replaces Section 14.5 (i n 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 th e instrument and details the size of an analytical batch to be limited to 20 samples.

- Section 15.2 describes the carrier recove ry acceptance criteria for the internal stable iodide standard used in the dete rmination of radioiodine in each sample.

- Section 15.3 details calibration a nd calibration verification steps.

- Section 15.4 describes the steps necessa ry for initial demonstration of the laboratory/instrument/analyst capability.

- Section 15.5 details laboratory contro l sample requirements in analytical batches.

- Section 15.6 provides for method blank re quirements 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 duplicat e error ratio calculation and acceptance criteria.

- Section 15.9 defines the requirements for quarterly verification of the quantitative value produced by the te st 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 a ddition 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 an alytically equivalent. The calculation of iodine concentrations has been updated to capture the uncertainty dete rminations outlined in MARLAP. The precision and bias are unchanged for iodine-131. The QC requirements in D 4785-08 are far more deta iled 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 concentr ations in drinking water.12 6) ASTM International Method D 5174-07:

Method D 5174-02 was used as the basis for compar ison, 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 include d 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 refe renced 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 mola rity of the nitric acid used (0.8 M) for diluting samples if they exceed the calibration range.

 Section 6.7 was added to further explai n how to minimize the effects of interferences by diluting the sa mple 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 chan ge the precision statement, from “The precision of repetitive measurements mu st be within 15% relative standard deviation (R.S.D.) .” to “ The precision of repetitive measurements sufficient to obtain a relative standard d eviation of less than 15% at the low points of the calibration curve.”

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

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

 Section 12 has been rewritten to a dd 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 de lineation of the calibration verification concentration ranges, which were not present in D 5174-02.

 Section 14.6.1 was modified, for method blank acceptance criteria, from “ The concentration of analyte f ound in the blank should be less than half the MDC .” to

“ The concentration of the analyte found in the blank should be less than the reporting limit.”

 Section 14.7.3 was modified to clarify that 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 th e acceptance criteria for matrix spike recovery from  50% of the expected value to a range of 50% to 150% of the expected value.13 The two methods are identical with respect to drinking water sample collection/handling protocols and sample preparation, and are analy tically equivalent. Th e calculation of uranium concentrations has been updated to expand dete rmination 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 cons idered to be equally as effective as D 5147-02 for determining uranium concentrations in drinking water.