1、Designation:D345421Standard Test Method forRadium-226 in Water1This standard is issued under the fixed designation D3454;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the
2、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 soluble,suspended,and total226Ra in water in concentrations above3.7 103Bq/L.This test method is not applicable to themeasurement of
3、 other radium isotopes.1.2 This test method may be used for quantitative measure-ments by calibrating with a226Ra standard,or for relativemeasurements by comparing the measurements made witheach other.1.3 This test method does not meet the current requirementsof Practice D2777.1.4 The values stated
4、in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.5 Hydrofluoric acid(HF)is very hazardous and should beused in a well-ventilated hood.Wear rubber gloves,
5、safetyglasses or goggles,and a laboratory coat.Avoid breathing anyHF fumes.Clean up all spills promptly and wash thoroughlyafter using HF.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to est
6、ablish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles
7、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:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination
8、 of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Flowing ProcessStreamsD3649 Practice for High-Resolution Gamma-Ray Spectrom-etry of WaterD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Anal
9、ysisD7902 Terminology for Radiochemical Analyses3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminologies D1129 and D7902.4.Summary of Test Method4.1 This test method is based on the emanation and scintil-lation counting of222Rn,a gaseous decay product o
10、f226Ra,from a solution.4.2226Ra is collected from water by coprecipitation on arelatively large amount of barium sulfate.The barium-radiumsulfate is decomposed by fuming with phosphoric acid,and theresulting glassy melt is dissolved by evaporation with dilutehydrochloric acid to form soluble barium-
11、radium phosphatesand chlorides.These salts are dissolved,and the solution isstored for ingrowth of222Rn.After a suitable ingrowth period,the radon gas is removed from the solution by purging with gasand transferred to a scintillation counting chamber.About 4 hafter222Rn collection,the scintillation
12、chamber is counted foralpha activity.The226Ra concentration is calculated from the1This 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.Current edition approved May 1,2021.Published Dece
13、mber 2021.Originallyapproved in 1975.Last previous edition approved in 2018 as D3454 18.DOI:10.1520/D3454-21.2For 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 standard
14、s Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO 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
15、Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1alpha count rate of222Rn and its immediate progeny.Theradioactive decay characteristics of226Ra and its immediatedecay progeny are lis
16、ted in Table 1.5.Significance and Use5.1 The most prevalent of the five radium isotopes in groundwater,having a half life greater than one day,are226Ra and228Ra.These two isotopes also present the greatest health riskcompared to the other naturally occurring nuclides of equalconcentrations if ingested via the water pathway.5.2 Although primarily utilized on a water medium,thistechnique may be applicable for the measurement of the226Racontent of any medium once the medium has been completelydecom
