ASTM_D_2907_-_97.pdf

Designation:D 2907 97Standard Test Methods forMicroquantities of Uranium in Water by Fluorometry1This standard is issued under the fixed designation D 2907;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 year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover the determination of micro-quantities of uranium in water in the concentration range from0.005 to 50 mg/L.1.2 The uranium fluorescence is quenched by many cationsand some anions in the sample;it is enhanced by a few cations.If interfering ions are present,a direct fluorometric measure-ment is not suitable,and an extraction method shall be used toprovide accurate results.The test methods and their concen-tration ranges are as follows:ConcentrationRange,mg/LSectionsTest Method ADirect Fluorometric0.005 to 27 to 15Test Method BExtraction0.04 to 5016 to 241.3 The values stated in SI units are to be regarded as thestandard.1.4 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specifichazards,see Note 1.2.Referenced Documents2.1 ASTM Standards:D 1066 Practice for Sampling Steam2D 1129 Terminology Relating to Water2D 1192 Specification for Equipment for Sampling Waterand Steam2D 1193 Specification for Reagent Water2D 3370 Practices for Sampling Water2E 217 Test Method for Uranium by Controlled-PotentialCoulometry3E 318 Test Method for Uranium in Aqueous Solutions byColorimetry43.Terminology3.1 DefinitionsFor definitions of terms used in these testmethods refer to Terminology D 1129.4.Significance and Use4.1 These test methods have been referenced in the NationalInterim Primary Drinking Water Regulations(Title 40,Part141;Federal Register Vol 41,No.133,July 1976)as theapproved test methods of analysis for uranium in water.However,the following limitation of these test methods shouldbe duly noted when considering their use for determining theuranium alpha contribution to a gross alpha measurement of adrinking water sample.4.2 Uranium occurs naturally in three isotopic forms,namely as U-238,U-235,and U-234(U-234 being a decayproduct of U-238).These isotopics occur in the approximaterespective mass percentages of 99.3,0.7,and 0.0057.However,because of the different decay rates of the three isotopics,theirrespective alpha particle activities are 12.21,0.55 and 13.02Becquerels,per milligram(Bq/mg)(330,15,and 352 picocu-ries per milligram)(pCi/mg)of natural uranium.4.3 It is now known,from uranium isotopic analysis byalpha spectrometry,that the U-238/U-234 abundance ratios inground water systems can be well out of equilibrium.Insteadof the 1 to 1.07(12.21 to 13.02)alpha activity ratio that occursin natural uranium deposits,the isotopic alpha activity ratios inground water systems have been found to be as much as 1 to20.There is no single valid factor for converting measuredmass units of uranium in ground water samples to uraniumalpha particle activity.Therefore,a uranium mass measurementmethod such as this fluorometric(or colorimetric)methodshould not be used to determine the uranium alpha activity ofwater.5.Reagents5.1 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.5Other grades may beused,provided it is first ascertained that the reagent is of1These test methods are under the jurisdiction of ASTM Committee D-19 onWater and are under the direct responsibility of Subcommittee D19.04 on Methodsof Radiochemical Analysis.Current edition approved Aug.10,1997.Published October 1997.Originallypublished as D 290770T.Last previous edition D 290791.2Annual Book of ASTM Standards,Vol 11.01.3Discontinued;see 1991 Annual Book of ASTM Standards,Vol 12.01.4Annual Book of ASTM Standards,Vol 12.01.5Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmaceutical Convention,Inc.(USPC),Rockville,MD.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water con