1、Designation: D5072 09 (Reapproved 2016)Standard Test Method forRadon in Drinking Water1This standard is issued under the fixed designation D5072; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number i
2、n parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of radon indrinking water in concentrations above 2 Bq/L.1.2 This test method may be used for absolute
3、measure-ments by calibrating with a226Ra standard or for relativemeasurements by comparing the measurements made witheach other.1.3 This test method is used successfully with drinkingwater samples and Type III reagent water conforming toSpecification D1193. It is the users responsibility to ensure t
4、hevalidity of this test method for waters of untested matrices.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is t
5、heresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practic
6、e for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD7902 Terminology for Radiochemical AnalysesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis2.2 Oth
7、er Documents:Multi-Agency Radiological Laboratory Analytical ProtocolsManual EPA402-B-04-001A, NUREG1576, NTISPB2004-105421, July 20043. Terminology3.1 Definitions:3.2 For definitions of terms used in this standard, refer firstto Terminology D7902 and second to Terminology D1129. Forterms not define
8、d in this standard, or in Terminologies D7902or D1129, reference may be made to other published glossa-ries.4. Summary of Test Method4.1 This test method is based on the scintillation countingof222Rn and its progeny.4.2 In a glass liquid scintillation vial, an aliquot of unaeratedwater is drawn into
9、 a syringe then gently injected beneath 10mL of a suitable liquid scintillation cocktail that does notcontain an emulsifier. The vials are capped, shaken, andallowed to stand 3 hours prior to counting to permit darkadaptation and buildup of short-lived radon progeny. Radon-222 contained in the sampl
10、e is selectively partitioned into thescintillation cocktail. The sample is counted using a liquidscintillation counting system optimized for detection of222Rnactivity.5. Significance and Use5.1 The most prevalent of the radon isotopes in groundwater is222Rn. This isotope presents the greatest health
11、 riskcompared to the other naturally occurring radon isotopes ifingested via the water pathway.6. Interferences6.1 Other radionuclides soluble in the scintillation cocktailmay interfere. High energy beta/gamma emitters, even thoughthey are not soluble in the scintillation mix, may also interfere.The
12、se interferences will cause a high bias if present in asignificant quantity. These interferences would be rare indrinking water samples but may be observed in some cases.6.2 A reduced or increased counting efficiency may result ifsample quenching is significantly different than that of thecalibratio
13、n standard.6.3 Scintillation stock cocktails and sample cocktail mixesmust be dark-adapted to prevent artificial excitation of fluors1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemi-cal Analysis
14、.Current edition approved Feb. 1, 2016. Published February 2016. Originallyapproved in 1992. Last previous edition approved in 2009 as D5072 091. DOI:10.1520/D5072-09R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annu
15、al Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1which may lead to falsely elevated count rates which couldcompromise data qua
16、lity.7. Apparatus7.1 Sampling Funnel.7.2 Tube, with standard faucet fitting.7.3 Disposable Syringe, 12 mL capacity, with 20 gauge, 38mm hypodermic needle.7.4 Glass Liquid Scintillation Vials, 20 mL capacity withpolyethylene inner seal cap liners.7.5 Liquid Scintillation Counter.8. Reagents and Mater
17、ials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades
18、 may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean conforming to Specifi-cation D1193, Type III
19、.48.3 Radioactive Purity of ReagentsRadioactive purityshall be such that the measured radioactivity of blank samplesdoes not exceed the calculated probable error of measurements.8.4 Radium-226 Solution Standard, traceable to a nationalstandards laboratory such as the National Institute of Standardsa
20、nd Technology (NIST) or the National Physical Laboratory(NPL).8.5 Scintillation Cocktail Mix, without emulsifier. Toluenebased mix is acceptable.9. Safety9.1 Some scintillation cocktails can pose a significant healthhazard if handled improperly. Refer to manufacturer instruc-tions for the safe use o
21、f these materials.10. SamplingNOTE 1Refer to Practices D3370 for applicable sampling instructions.Also see U.S. Environmental Protection Agency reports EPA 5205andEPA 600.610.1 Attach the sampling funnel and tube to a faucet withthe standard faucet fitting.10.2 Slowly turn on the water and allow a s
22、teady stream toflow out of the funnel for approximately 2 min. This purges thetube and ensures a fresh sample.10.3 Reduce the flow of water and invert the funnel. Theflow should be adjusted to a level that does not causeturbulence in the pool of water contained in the funnel. Allowexcess water to sp
23、ill over one edge of the funnel.10.4 Examine the hose connection and tubing for airbubbles or pockets. If these are visible, raise or lower thefunnel until they are removed.11. Calibration and Standardization11.1 Add a known quantity of traceable226Ra standardsolution to a known volume of water.11.2
24、 Prepare three222Rn calibration standards by combininga 10 mL aliquot of the226Ra standard solution with 10 mL ofscintillation cocktail in a 20 mL glass scintillation vial.Securely cap each vial and shake to mix the contents.11.3 In liquid scintillation vials, prepare three backgroundsamples contain
25、ing 10 mLof Type III reagent water and 10 mLof scintillation solution. Cap the vials and shake to mix thecontents.11.4 Allow approximately 30 days for buildup of radon (thatis, secular equilibrium with226Ra).11.5 Shake vial to transfer nearly all the radon to thescintillation mix phase (radon is hig
26、hly soluble in the scintil-lation mix). The226Ra remains in the aqueous phase and,therefore, does not contribute significantly to the count rate.11.6 Allow for the buildup of short-lived radon progeny andfor dark-adapting by waiting 3 hours before counting.11.7 Count the standard samples for a count
27、ing periodsufficiently long to obtain a relative counting uncertainty of 1% (10 000 net counts minimum). Count background samples atleast as long as the test samples.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing
28、 of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.4If this water is not aerated or degassified prior/
29、subsequent to demineralization,radon background may be substantial. This can happen if the lab uses RO, EDI oronly deminerialization resins for purification of their water.5EPA520/583027 Methods and Results of EPAs Study of Radon in DrinkingWater. Published December 1983. Available from U.S. Governm
30、ent Printing OfficeSuperintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE,Washington, DC 20401, http:/www.access.gpo.gov.6EPA 600/287/082 Two Test Procedures for Radon in Drinking Water.Published March 1989. Available from U.S. Government Printing Office Superin-tendent of Documents, 73
31、2 N. Capitol St., NW, Mail Stop: SDE, Washington, DC20401, http:/www.access.gpo.gov.D5072 09 (2016)211.8 Calculate the calibration factor (CF) as in accordancewith 13.1.12. Procedure12.1 Clean scintillation vials with alcohol and add 10 mL ofscintillation cocktail.12.2 Collect unaerated sample in ac
32、cordance with Section10.12.3 Place the tip of the hypodermic needle approximately 3cm under the surface of the water in the funnel and withdrawa few millilitres of water and eject this water. Using thisprocedure, rinse the syringe and hypodermic needle two orthree more times.12.4 Again, place the ti
33、p of the needle approximately 3 cmbelow the surface of the water and withdraw approximately 12mL.NOTE 2The water should be pulled into the syringe slowly to avoidextreme turbulence and collection of air bubbles. If large air bubbles arenoticed in the syringe, the sample should be rejected and redraw
34、n.12.5 Invert the syringe and slowly eject any small airbubbles and extra water. Retain precisely 10 mLof water in thesyringe.12.6 Remove the cap from a vial and carefully place the tipof the needle into the bottom of the liquid scintillation solution.Slowly eject the water from the syringe into the
35、 vial.NOTE 3Water is injected under the liquid scintillation solution toprevent loss of radon from the sample. If the water is forced out of thesyringe with much pressure, it will cause turbulence in the solution andcould result in loss of radon.12.7 Carefully withdraw the hypodermic needle from the
36、vial and replace the cap. The cap should be tightly secured toprevent leakage. Shake the vial to mix the contents.12.8 Repeat the previous steps to obtain two separatealiquots from each sample.12.9 Load the samples into the liquid-scintillation countingsystem and after waiting for 3 h, count at leas
37、t 50 minutes.12.10 After dark-adapting them, count a backgroundsample, consisting of 10 mLof water and 10 mLof scintillationsolution, and a standard radium-226 solution sample for 50 minat the beginning of counting and after every ten drinking watersamples.13. Calculation13.1 Calibration Factor, CF:
38、CF 5CCS2 CB!ACS(1)where:CCS= calibration standard count rate, counts per second(s1) (as prepared in 11.2),CB= average background sample count rate (s1) (as pre-pared in 11.3), andACS= calibration standard226Ra activity, Bq.13.2 Sample Activity, ACCalculate the radon activity con-centration in the sa
39、mple as follows. First calculate the net countrate in counts per second:Rn5 Ra2 Rb(2)Then calculate the activity concentration of radon in thesample, in becquerels per litre (Bq/L), using the followingequation:AC 5RnCF 3D 3Va(3)where:AC = activity concentration of222Rn (Bq/L),Ra= Sample count rate (
40、s1),Rb= background count rate (s1),Rn= net count rate (s1),CF = calibration factor calculated as in Eq 1,D = decay correction factor D=eln(2) T/t,Va= volume of sample analyzed (0.010 L),T = time in days from collection time to midpoint ofcounting time, andt= half-life of222Rn, 3.82 d.13.3 Estimate t
41、he square of the standard uncertainty of Rnasfollows:u2Rn! 55J 3Rn12Rbt, if Rn.0Ra1Rbt, if Rn#0(4)where:t = counting time of the sample and background (s), andJ = index of dispersion for the net counts produced by222Rnand its progeny.7If the counting time t is 3000 s, then J is approximately equalto
42、 1.83 if the counter is configured to count alpha radiationonly and J is approximately equal to 2.78 if it is configured tocount both alpha and beta radiation. For longer count timesestimate J as follows:J 5c51(i503cie2it1 2 e20t(5)where the decay constants 0through 3are given by:0= 2.098 106s1,1= 0
43、.003 727 s1,2= 0.000 431 s1, and3= 0.000 581 s1.and where the coefficients c0through c5are given either by:c0= 3.0060503c1= 0.00038339968c2= 0.026908241c3= 0.015190995c4=0c5= 2.99394977Lucas, H.F., Jr., and D.A. Woodward, Journal of Applied Physics, Vol. 35, pg.452, 1964.D5072 09 (2016)3if the count
44、er is configured to count alpha radiation only, or by:c0= 5.0106487c1= 0.00020574781c2= 0.036387727c3= 0.015296013c4=0c5= 4.9893513if the counter is configured to count both alpha and betaradiation.13.4 The combined standard uncertainty of the radon activ-ity concentration can be estimated as follow
45、s:ucAC! 5=u2Rn!1Rn23 ur2CF!1ur2Va!1ur2D!CF 3D 3Va(6)where:uc(AC) = combined standard uncertainty of the radon activ-ity concentration (Bq/L),ur(CF) = relative standard uncertainty of the calibrationfactor CF,8Va= volume of sample analyzed (0.010 L),ur(Va) = relative standard uncertainty of the volum
46、e (0.010L) of sample analyzed, andur(D) = relative standard uncertainty of the decay correc-tion D.13.5 The a priori minimum detectable radon activity con-centration (MDC) can be estimated by the following equation:MDC 52.71 3Jt14.65RbtCF 3D 3Va(7)where:MDC = minimum detectable radon activity concen
47、tration(Bq/L).13.6 The critical level Lcfor radon activity concentrationcan be calculated by the following equation:Lc52.33RbtCF 3D 3Va(8)where:Lc= critical level radon activity concentration (Bq/L).14. Precision and Bias914.1 The collaborative test conducted on this test methodincluded 15 laborator
48、ies each with one operator. Three activitylevels between 60 Bq/L and 2454 Bq/L were tested with threereplicates per level.The determination of the precision and biasstatements were made in accordance with Practice D2777.14.2 These collaborative test data were obtained usingreagent grade water. For o
49、ther matrices, these data may notapply.14.3 The overall and single operator precision have beenfound to vary with level in a manner according to Table 1.14.4 The bias of this test method, based upon the collab-orative test data, was found to vary with level according toTable 2.15. Quality Control15.1 In order to provide reasonable assurance that theanalytical results obtained using this method are valid andaccurate within the confidence limits of the method, QualityControl (QC) samples are analyzed with each batch of samplesun
