ASTM D7535-09
(Test Method)Standard Test Method for Lead-210 in Water
Standard Test Method for Lead-210 in Water
SIGNIFICANCE AND USE
This test method was developed to measure the concentration of 210Pb in nonprocess water samples. This test method may be used to determine the concentration of 210Pb in environmental samples.
SCOPE
1.1 This test method covers the determination of radioactive 210Pb in environmental water samples (for example, drinking, non-process and effluent waters) in the range of 37 mBq/L (1.0 pCi/L) or greater.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information purposes only.
1.3 This method has been used successfully with tap water. It is the user's responsibility to ensure the validity of this test method for samples larger than 500 mL and for waters of untested matrices.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazards statements, see Section 9.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7535 − 09
StandardTest Method for
Lead-210 in Water
This standard is issued under the fixed designation D7535; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 This test method covers the determination of radioac-
tive Pb in environmental water samples (for example,
3. Terminology
drinking, non-process and effluent waters) in the range of 37
3.1 Definitions—For definitions of terms used in this test
mBq/L (1.0 pCi/L) or greater.
method, refer to Terminology D1129.
1.2 The values stated in SI units are to be regarded as
4. Summary of Test Method
standard. The values given in parentheses are provided for
information purposes only.
4.1 This test method is based on the utilization of solid
phase extraction of lead from water samples with detection of
1.3 This method has been used successfully with tap water.
It is the user’s responsibility to ensure the validity of this test theradioactiveleadbybetagasflowproportionalcounting.An
aliquotofthesampleismeasuredintoabeaker;ironcarrierand
method for samples larger than 500 mL and for waters of
untested matrices. lead carrier are added. Lead is scavenged by an iron hydroxide
precipitation. Lead is then selectively sorbed on a solid phase
1.4 This standard does not purport to address all of the
extraction column and eluted with water. Lead is precipitated
safety concerns, if any, associated with its use. It is the
asleadsulfateandiscollectedonafilterpaper.Theleadsulfate
responsibility of the user of this standard to establish appro-
precipitate is covered with aluminum foil and held for 5 days
priate safety and health practices and determine the applica-
or longer for Bi ingrowth. It is then counted for beta
bility of regulatory limitations prior to use. For specific
radiation on a gas flow proportional counter.
hazards statements, see Section 9.
5. Significance and Use
2. Referenced Documents
5.1 This test method was developed to measure the concen-
2.1 ASTM Standards:
tration of Pb in nonprocess water samples.This test method
D1129Terminology Relating to Water 210
may be used to determine the concentration of Pb in
D1193Specification for Reagent Water
environmental samples.
D2777Practice for Determination of Precision and Bias of
6. Interferences
Applicable Test Methods of Committee D19 on Water
D3370Practices for Sampling Water from Closed Conduits
6.1 Significant amounts of stable lead (>0.3 mg/L) present
D4448GuideforSamplingGround-WaterMonitoringWells
in the sample will interfere with the chemical yield
D5847Practice for Writing Quality Control Specifications
determination, leading to positive bias in the yield. If it is
for Standard Test Methods for Water Analysis
known or suspected that natural lead is present in the sample,
D6001Guide for Direct-Push Ground Water Sampling for
blanksamplealiquotstowhichnoleadcarriercontentisadded
Environmental Site Characterization
should be analyzed. The amount of natural lead contained in
D7282Practice for Set-up, Calibration, and Quality Control
the sample shall be used to correct the yield.
of Instruments Used for Radioactivity Measurements
6.2 In most cases measurable amounts of Pb will be
present in the Pb carrier used in Section 12.1. This additional
contribution to the measured sample activity must be deter-
This test method is under the jurisdiction ofASTM Committee D19 on Water
mined and treated as additional background activity. For each
andisthedirectresponsibilityofSubcommitteeD19.04onMethodsofRadiochemi-
new carrier solution, the inherent Pb in the carrier must be
cal Analysis.
measured. A brief description of this additional background
Current edition approved Oct. 1, 2009. Published October 2009. DOI: 10.1520/
D7535-09.
calibration is given in Section 11.2.Accurate determination of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
thecombinedstandarduncertaintyandtheminimumdetectable
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
concentration should include this additional activity in the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. method background count rate.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7535 − 09
6.3 Previous experimental data suggests that barium con- 8.2 Purity of water—Unless otherwise indicated, reference
centrations of approximately 30 ppm can be a source of towatershallbeunderstoodtomeanreagentwaterconforming
interference,leadingtochemicalyielddeterminationsthatmay to Specification D1193, Type III.
be non-representative and outside normal acceptance criteria.
8.3 Ammonium hydroxide—15MNH OH, (concentrated
reagent).
7. Apparatus
8.4 Iron carrier (20 mg/mL)—Dissolve 9.6 g of ferric
7.1 Analytical Balance, 0.0001 g.
chloride (FeCl ·6H O) in 70 mL of 0.5 M HCl and dilute to
3 2
NOTE 1—A thickness of aluminum of approximately 0.003 in. (areal
100 mL with 0.5 M HCl.
density of approximately 0.02 mg/cm ) is needed to effectively eliminate
210 3
8.5 Nitric acid, 16 M HNO —(concentrated reagent) (sp gr
the 60 keV beta particles from Pb. The thickness of aluminum foil
used during calibration of the detector and measurement samples must be
1.42).
210 210
held constant to maintain self-absorption of Pb and Bi beta particles
8.5.1 Nitric acid,8MHNO —Add 500 mLof concentrated
at a constant level.
nitric acid to 400 mL water. Dilute to 1 L with water and mix
7.2 Aluminum foil.
well.
8.5.2 Nitric acid,1MHNO —Add 63 mL of concentrated
7.3 Centrifuge.
nitric acid to 800 mL water. Dilute to 1 L with water and mix
7.4 Centrifuge tubes (50 mL plastic).
well.
7.5 Filters, 25 mm polypropylene , 0.1 µm, with polycar-
8.5.3 Nitric acid, 0.1 M HNO —Add 6.4 mL of concen-
bonate base and metal screen.
tratednitricacidto600mLwater.Diluteto1Lwithwaterand
mix well.
7.6 Filter apparatus, polysulfone funnel and 100 mL poly-
propylene flask.
8.6 Lead Carrier (10 grams Pb/L)—Dissolve 1.60 g of lead
nitrate in water and dilute to 100 mL with water.
7.7 Beta Gas Flow Proportional Counting System, (<1.0
cpm beta), low background.
8.7 Lead Extraction Chromatography column, 2-mL bed
volume, 100–150 µm particle size.
7.8 Glass stir rods.
8.8 Pb-210 Standardizing Solution—Traceable to a national
7.9 Glass beakers.
standardizinglaboratorysuchasNationalInstituteofStandards
7.10 Hot plate.
and Technology, Gaithersburg, MD, USA (NIST) or National
7.11 Petri dish.
Physical Laboratory, Teddington, Middlesex, UK, (NPL) with
less than 0.1 mg of stable lead per mL of final solution with a
7.12 Planchets, stainless steel, flat, with diameter large
typical Pb concentration range from 85 to 125 Bq/mL.
enough to hold the 25 mm filter.
The Pb calibration source should be in equilibrium with its
7.13 Tweezers. 210
progeny Bi.
7.14 Watch glass.
8.9 Sulfuric Acid, 18 M H SO —concentratedreagent(spgr
2 4
1.84).
8. Reagents and Materials
8.1 Purity of Reagents—Reagent grade chemicals shall be
9. Hazards
used in all tests. Unless otherwise indicated, it is intended that
9.1 Use extreme caution when handling all acids. They are
all reagents shall conform to the specifications of the Commit-
extremely corrosive, and skin contact could result in severe
tee onAnalytical Reagents of theAmerican Chemical Society,
burns.
where such specifications are available. Other grades may be
used, provided that the reagent is of sufficiently high purity to
9.2 When diluting concentrated acids, always use safety
permit its use without increasing the background of the
glasses and protective clothing, and add the acid to the water.
measurement. Some reagents, even those of high purity, may
contain naturally occurring radioactivity, such as isotopes of 10. Sampling
uranium, radium, actinium, thorium, rare earths and potassium
10.1 CollectasampleinaccordancewithGuidesD4448and
compounds and/or artificially produced radionuclides. Conse-
D6001 and Practice D3370, or other documented procedure as
quently, when such reagents are used in the analysis of
appropriate.
low-radioactivity samples, the activity of the reagents shall be
determined under analytical conditions that are identical to
11. Calibration
those used for the sample. The activity contributed by the
11.1 Detection Effıciency Calibration (see also Practice
reagents may be considered to be a component of background
D7282):
and applied as a correction when calculating the test sample
result.Thisincreasedbackgroundreducesthesensitivityofthe
measurement.
Resin available in bulk form and in prepacked columns or cartridges from
Eichrom Technologies LLC, Lisle, IL 60532. If you are aware of alternative
Radiological Health Handbook, Revised Editions January 1970, Compiled and suppliers, please provide this information to ASTM International Headquarters.
Edited by the Bureau of Radiological Health and the Training Institute Environ- Your comments will receive careful consideration at a meeting of the responsible
mental Control Administration, US Department of Health, Education and Welfare. technical committee, which you may attend.
D7535 − 09
where u(·) denotes standard uncertainty; for example, u(V ) is
11.1.1 Prepare a set of three working calibration sources
s
the standard uncertainty of V .
according to the calibration procedure outlined in the subse- s
quent steps.
11.1.8.1 Eq 2 omits the uncertainties due to the activity
11.1.2 Pipet 1.0 mL of lead carrier into a small beaker.
concentration of the calibration standard solution, c , and the
s
11.1.3 Add 1.0 mL of Pb standardizing solution to the
concentration of the carrier solution, c . These uncertainty
c
beaker and evaporate to near dryness on a hot plate at a low
components are accounted for when the average efficiency is
setting.
determined (below).
11.1.4 Redissolve the residue in 10 mL of1MHNO .
11.1.8.2 The procedure requires an average of (at least)
11.1.5 Follow the steps described in 12.9 through 12.28.
three efficiencies (N = 3) measured using three calibration
11.1.6 Count to amass at least 10 000 counts. Record the
sources on each detector. For this purpose, calculate ´ , ϵ , ´
1 2 3
time and date of the midpoint of this counting period as t .
m
for each source, and use Eq 3 to calculate the weighted
11.1.7 Detection Effıciency Calculation—Calculate the de-
average:
tectionefficiencyfor Biforeachcalibrationsourceandeach
N
detector using Eq 1.
H
ϵ 5 ϵ (3)
Bi ( i
N
i51
R 2 R
a b
ϵ 5 (1)
Bi
c 3V 3DF 3IF 3Y 11.1.8.3 To calculate the uncertainty of the average, includ-
s s Pb
ing uncertainty components due to systematic errors, Eq 4 is
where:
used:
´ = detection efficiency for Bi,
Bi
–1
N
2 2
R = total count rate (s ) for calibration source, (counts
1 u ~c ! u ~c !
a
s c
2 2
H H
u~ϵ ! 5Œ u ~ϵ !1ϵ 3 1 (4)
2 S 2 2 D
Bi ( c i Bi
divided by count time (s))
N c c
i51
s c
–1
R = count rate (s ) for blank or background source,
b
11.2 Determination of Inherent Pb in Pb Carrier:
(counts divided by count time (s))
210 210
IF = correction factor for ingrowth of Bi from Pb 11.2.1 AsnotedinSection6.2,incaseswherethePbcarrier
between the time of the bismuth separation to the used in this procedure has not been determined to be free
210 210
2λ ~t 2t !
Bi m s
midpoint of counting, 12e , where: of Pb, the Pb content inherent in the lead carrier used in
210 –6 –1
thismethodmustbeevaluated.Eachnewcarriersolutionmust
λ = decay constant for Bi, (1.60 × 10 s ),
Bi
210 210
t = date and time of Bi separation, and
be measured for Pb prior to use. Once the Pb content of
s
t =midpointofcountofcalibrationmount(dateand
m the lead carrier is known, the Pb count rate from the
time).
recovered lead carrier can be calculated for each sample
DF = correction factor for decay of Pb in the carrier
analyzed. The following step provides a protocol to determine
solutionfromthecarrieractivityreferencedatetothe
the inherent Pb in the lead carrier and Section 13 provides
2λ ~t 2t !
Pb s r
time of the bismuth separation,e , where:
the equations needed to correct for the Pb inherent in the
210 −10 −1
λ = decay constant for Pb, (9.85 × 10 s ),
Pb
lead carrier. The specific number of samples, as well as
t = reference date and time of Pb calibration of
r
acceptancecriteriaforthedataandstatisticalteststodetermine
lead carrier, and
detectable Pb in the lead carrier, should be specified in the
t = date and time of Bi separation.
s
laboratory’s Quality Systems Manual.
c = activity concentration (or massic activity) of the
s
calibration standard solution (Bq/unit), 11.2.2 To a minimum of five 50 mLcentrifuge tubes, add 1
V = volume(ormass)ofstandardsolutionused(mLorg),
mL of the Pb carrier solution.
s
Y = chemical yield of lead (see Sections 13.1 and 13.2);
Pb
11.2.3 Add 20 mL of water and 4 mL concentrated sulfuric
Y 5m /~c 3V ! , where:
Pb s c c
acid to each centrifuge tube.
m = net mass (mg) of lead sulfate found in the
s
11.2.4 Continue with the normal sample preparation, begin-
source, equal to m −m , where m is the total
F+P F F+P
ning at Section 12.16.
mass of the filter plus precipitate and m is the tare
F
mass (filter only),
11.2.5 After counting, calculate for each sample the Pb
c = mass concentration (mg/mL) of lead (as sulfate)
c concentration and associated uncertainty according to Section
in the carrier solution (see Eq 5), and
13.Calculatetheweightedaverage aˆ andstandarduncertainty
c
V = volume of carrier solution added (mL).
c 210
210 u(aˆ)ofthe Pb concentration using the calculated sample
c
Eq 1 assumes that any Pb activity contamination in the Pb
results from the data set using the equations in Section 13.3.
carrierisinsignificantcomparedtotheamountof Pbactivity
in the calibration source spike.
12. Procedure
11.1.8 Thevarianceinthe Bidetectorefficiency, ϵ ,(not
Bi
NOTE 2—See Fig. 1 for a diagram of the procedure.
the average) is calculated by Eq 2:
2 2 2 2 12.1 Add 1.0 mL of lead carrier and 1.0 mL of iron carrier
u R 1u R R 2 R u m
~ ! ~ ! ~ !
a b a b s
2 2 ˆ 2
u ~ϵ ! 5 1 3 1u ~F ! 3DF
S S D D
c Bi 2 2 2 c c to a maximum 500 mL of sample. Acidify sample with nitric
m 3IF m 3IF m
s s s
acid to pH 2.
2 2 2 2 2 2
c 3V u ~c ! u ~V ! u ~c ! u ~V !
c c s s c c
3 1ϵ 3 1 1 1
S D
2 2 2 Bi 2 2 2 2
c 3V 3DF c V c V
12.2 Cover beaker with a watch glass and heat at near
s s s s c c
(2) boiling
...
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