1、Designation: D7283 17Standard Test Method forAlpha and Beta Activity in Water By Liquid ScintillationCounting1This standard is issued under the fixed designation D7283; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in 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 grossalpha- and beta- activity concentrations in a homogeneouswater sample. I
3、t is applicable to alpha emitters with activityconcentration levels above 0.11 Bq/L (3 pCi/L) and betaemitters with activity concentration levels above 0.15 Bq/L (4pCi/L). This test method is not applicable to samples contain-ing radionuclides that are volatile under conditions of theanalysis.1.2 Th
4、is test method may also be used for the directmeasurement of gross alpha- and beta- activity concentrationsin homogeneous water samples with alpha emitter activityconcentration levels above 1.8 Bq/L (50 pCi/L) and betaemitter activity concentration levels above 3.7 Bq/L (100pCi/L).1.3 This test meth
5、od was tested using single-operatortests.2,3Acollaborative study following the U.S. EPA“Protocolfor the Evaluation of Alternate Test Procedures for AnalyzingRadioactive Contaminants in Drinking Water” was performed.The results of this study are on file at ASTM Headquarters.41.4 The values stated in
6、SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to pCi/L that are provided for information onlyand are not considered standard. An exception is noted inSection 14.1.5 This standard does not purport to address all of thesafety concerns, if any, asso
7、ciated with its use. It is theresponsibility 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.1.6 This international standard was developed in accor-dance with internationally recognized princip
8、les on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:5D1129 Terminology Relating to Wate
9、rD1125 Test Methods for Electrical Conductivity and Resis-tivity of WaterD1193 Specification for Reagent WaterD1890 Test Method for Beta Particle Radioactivity of WaterD1943 Test Method for Alpha Particle Radioactivity ofWaterD3370 Practices for Sampling Water from Closed ConduitsD3648 Practices for
10、 the Measurement of RadioactivityD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD4448 Guide for Sampling Ground-Water Monitoring WellsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD6001 Guide for Direct-Push Ground
11、water Sampling forEnvironmental Site CharacterizationD7902 Terminology for Radiochemical AnalysesE177 Practice for Use of the Terms Precision and Bias inASTM Test Methods1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.04
12、on Methods of Radiochemi-cal Analysis.Current edition approved June 1, 2017. Published June 2017. Originallyapproved in 2006. Last previous edition approved in 2013 as D7283 13. DOI:10.1520/D7283-17.2Wong, C. T., Soliman, V. M., and Perera, S. K., Journal of Radioanalytical andNuclear Chemistry, Vol
13、 264, No. 2, 2005, pp. 357363.3Ruberu, S.R., Liu, Y.G., and Perera, S.K., Health Physics, Vol 95, No. 4,October 2008, pp. 397406.4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D19-1195. ContactASTM CustomerService at serviceast
14、m.org.5For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO
15、 Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued b
16、y the World Trade Organization Technical Barriers to Trade (TBT) Committee.1E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Other Standards and Publications:EPA 900.0 Gross Alpha and Gross Beta Radioactivity inDrinkingWater, from Prescribed Procedu
17、res for Measure-ment of Radioactivity in Drinking Water(EPA-600/4-80-032)6Standard Methods 7110C Coprecipitation Method for GrossAlpha Radioactivity in Drinking Water7Standard Methods 8010E Table 8010: Recommended Com-position for Reconstituted Fresh Water7ISO 9696 Water QualityMeasurement of Gross
18、AlphaActivity in Non-saline WaterThick Source Method8ISO 11704:2010 Water QualityMeasurement of Gross Al-pha and BetaActivity Concentration in non-saline water Liquid Scintillation Counting Method83. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminologies D
19、1129 or D7902. For terms notdefined in this test method or in Terminology D1129, referencemay be made to other published glossaries.3.2 Definitions of Terms Specific to This Standard:3.2.1 alpha-to-beta spillover, nin the measurement ofradioactivity, for a given emitting source, that fraction of alp
20、haparticles that are misclassified as beta particles by the counter.3.2.2 alpha particle detection effciency, nin the measure-ment of radioactivity, for a given emitting source, that fractionof alpha particles that are identified as alpha particles by thecounter.3.2.3 beta-to-alpha spillover, nin th
21、e measurement ofradioactivity, for a given emitting source, that fraction of betaparticles that are misclassified as alpha particles by the counter.3.2.4 beta energy, maximum, nthe maximum energy of thebeta particle energy spectrum produced during beta decay of agiven radionuclide.3.2.4.1 Discussion
22、Since a given beta emitter may decayto several different nuclear energy levels of the progeny, morethan one maximum energy may be listed for a given radionu-clide.3.2.5 beta particle detection effciency, nin the measure-ment of radioactivity, for a given emitting source, that fractionof beta particl
23、es that are identified as beta particles by thecounter.3.2.6 detector background, nin the measurement ofradioactivity, the counting rate resulting from factors otherthan the radioactivity of the sample and reagents used.3.2.6.1 DiscussionDetector background varies with thelocation, shielding of the
24、detector, and the electronics; suchbackground includes cosmic rays, contaminating radioactivity,and electronic noise.3.2.7 figure of merit, na numerical quantity based on oneor more characteristics of a system or device, representing ameasure of efficiency or effectiveness; figure of merit isgeneral
25、ly calculated as the square of the efficiency divided bythe background.3.2.8 gross alpha, nin the measurement of radioactivity, asemi-quantitative estimate of the combined activity of alpha-emitting radionuclides in a test sample.3.2.9 gross beta, nin the measurement of radioactivity, asemi-quantita
26、tive estimate of the combined activity of beta-emitting radionuclides in a test sample.3.2.10 homogeneous water sample, nwater in which thealpha and beta activity is uniformly dispersed throughout thevolume of water sample and remains so until the measurementis completed or until the sample is evapo
27、rated or precipitatingreagents are added to the sample.3.2.11 reagent background, nin the measurement of ra-dioactivity of water samples, the counting rate observed whena sample is replaced by mock sample salts or by reagentchemicals used for chemical separations that contain noanalyte.3.2.11.1 Disc
28、ussionReagent background varies with thereagent chemicals and analytical methods used and may varywith reagents from different manufacturers and from differentprocessing lots.4. Summary of Test Method4.1 The test sample is reduced by evaporation, transferred toa scintillation vial and mixed with a s
29、uitable liquid scintillationcocktail. Gross alpha- and beta- activity concentrations aremeasured simultaneously by liquid scintillation using alpha/beta discrimination. By optimizing the alpha/betadiscriminator, a high efficiency of alpha- and beta- particledetection can be achieved with acceptable
30、misclassification ofbeta particles into the alpha multi-channel analyzer (MCA) andalpha particles into the beta MCA.The alpha- and beta- particleefficiency and spillover calibrations of the liquid scintillationsystem are determined by using known activities of establishedreference nuclides in test s
31、ources having cocktail-solvent ratioscomparable to that of the test samples. Some commonlyemployed reference standards include241Am,239Pu,230Th,natural isotopic abundance uranium (234U,235U, and238U), forgross alpha, and90Sr/90Y, and137Cs/137mBa for gross beta.Results are reported in activity units
32、equivalent along with thereference radionuclide (for example, Bq/L gross alpha equiv.241Am).4.2 If the measurement quality objectives (MQOs) do notrequire a low detection limit, an aliquant of the sample may bemixed directly with a suitable liquid scintillation cocktail foranalysis.5. Significance a
33、nd Use5.1 This test method is intended for the measurement ofgross alpha- and beta-activity concentrations in the analyses of6Available from United States Environmental ProtectionAgency (EPA), WilliamJefferson Clinton Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460,http:/www.epa.gov.7Availab
34、le from American Water Works Association (AWWA), 6666 W. QuincyAve., Denver, CO 80235, http:/www.awwa.org.8Available from International Organization for Standardization (ISO), ISOCentral Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.D7283 1
35、72environmental and drinking waters. For samples submitted tosatisfy regulatory or permit requirements, the submitter shouldassure that this or any other method used is acceptable to theregulator or permit issuer.5.2 This test method is also applicable to the direct analysisof gross alpha- and beta-
36、activity concentrations in water whenlow detection limits are not required. Direct analysis providesa rapid method for determination of gross alpha- and beta-activity concentrations when low detection limits are notrequired.5.3 This test method is not capable of discriminating amongalpha emitting ra
37、dionuclides or among beta emitting radionu-clides. Those intending to identify and quantify specific radio-nuclides should use test methods specific to the radionuclidesof interest.5.4 This test method may not be cited as a method for thedetermination of gross alpha- or beta-activity concentrations
38、ina solid/soil matrix or the acid digestate of the same. The use ofthis test method for such applications brings the potential forserious bias and incomparability of results dependent on thematrix constituents, manner of sample preparation ortreatment, or both.6. Interferences6.1 The counting effici
39、encies and spillover for both thealpha and beta components are dependent on the energy of thealpha- or beta-emitter chosen to determine the calibrationcoefficient. Biases may occur if the energies of the alpha- orbeta-particle emitting nuclides in the test sample differs sig-nificantly from those us
40、ed to determine the respective countingefficiencies. Best results are obtained when the radionuclidecomposition of the sample is known and the calibrationradionuclide is selected to match as closely as possible theenergy of the sample radionuclide.6.2 The use of137Cs/137mBa as a calibration standard
41、 forsamples containing radionuclides other than137Cs may intro-duce a low bias in the analytical results unless there is acorrection for conversion electron emissions. The conversionelectrons from the137mBa progeny are detected by liquidscintillation yielding greater than 100 % detection efficiencyf
42、or the137Cs/137mBa calibration standard.6.3 When using uranium as a calibration standard theisotopic abundance of each of the isotopes (234U,235U,and238U) must be known to accurately determine the standardactivity concentration. Many uranium standards used for massmeasurements are depleted uranium.
43、Natural isotopic abun-dance uranium and depleted uranium standards contain short-lived decay progeny (234Th,234mPa) which interfere with thespillover calibration unless they are removed immediately priorto calibration.6.4 Radon is a noble gas, and therefore easily emanatesfrom most matrices. If the
44、radon progeny of the uranium(222Rn), thorium (220Rn), and actinium (219Rn) series emanatefrom the sample test source prior to counting, radioactiveequilibrium is disrupted. EPA 900.0 recognizes this disruptionby suggesting a delay of 72 h before the prepared sample iscounted for gross alpha. Other p
45、ublished methods such asStandard Methods 7110C provide for a shorter delay of 3 h.Thus the activity of samples containing226Ra will increasesignificantly with time during the first several weeks afterpreparation. This delay will result in overestimation of theactivity of samples relative to their tr
46、ue226Ra concentration.This test method advises that any such delay period used by thelaboratory be based on the MQOs inherent in the intended datause (see 11.7).6.5 Radionuclides may be present in the sample in disequi-librium with their parent radionuclides. Many factors, includ-ing differential so
47、lubility of radionuclides from the matrix inwhich the parent radionuclide occurs can cause this disequi-librium.Where these radionuclides have a half-life on the orderof a few days or shorter, the time elapsed between samplingand the beginning of sample counting will tend to bias the finalresult low
48、. In those cases, the MQOs inherent in the intendeddata may dictate the maximum time between sample collectionand the beginning of sample counting. The laboratory shouldbe aware of such requirements and be prepared to comply withthem.6.6 Radionuclides incorporated in volatile compounds arelost durin
49、g the conduct of this test method. These includetritium in HTO or14C in the carbon dioxide formed during theaddition of acid. The pertechnetate ion (99TcO42)isanexample of a radionuclide which may be lost through semi-volatility. The MQOs should address the potential loss of suchradionuclides and provide direction for their quantification byspecific methods.6.7 When counting gross alpha- and beta-activity by a liquidscintillation counter using alpha/beta discrimination, somepulses resulting from alpha particles are misclassified as betaparticles
