ASTM_D_7535_-_09_2015.pdf

Designation:D753509(Reapproved 2015)Standard Test Method forLead-210 in Water1This standard is issued under the fixed designation D7535;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()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of radioac-tive210Pb in environmental water samples(for example,drinking,non-process and effluent waters)in the range of 37mBq/L(1.0 pCi/L)or greater.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are provided forinformation purposes only.1.3 This method has been used successfully with tap water.It is the users responsibility to ensure the validity of this testmethod for samples larger than 500 mL and for waters ofuntested matrices.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 specific hazardsstatements,see Section 9.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD4448 Guide for Sampling Ground-Water Monitoring WellsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD6001 Guide for Direct-Push Groundwater Sampling forEnvironmental Site CharacterizationD7282 Practice for Set-up,Calibration,and Quality Controlof Instruments Used for Radioactivity MeasurementsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.4.Summary of Test Method4.1 This test method is based on the utilization of solidphase extraction of lead from water samples with detection ofthe radioactive lead by beta gas flow proportional counting.Analiquot of the sample is measured into a beaker;iron carrier andlead carrier are added.Lead is scavenged by an iron hydroxideprecipitation.Lead is then selectively sorbed on a solid phaseextraction column and eluted with water.Lead is precipitatedas lead sulfate and is collected on a filter paper.The lead sulfateprecipitate is covered with aluminum foil and held for 5 daysor longer for210Bi ingrowth.It is then counted for betaradiation on a gas flow proportional counter.5.Significance and Use5.1 This test method was developed to measure the concen-tration of210Pb in nonprocess water samples.This test methodmay be used to determine the concentration of210Pb inenvironmental samples.6.Interferences6.1 Significant amounts of stable lead(0.3 mg/L)presentin the sample will interfere with the chemical yielddetermination,leading to positive bias in the yield.If it isknown or suspected that natural lead is present in the sample,blank sample aliquots to which no lead carrier content is addedshould be analyzed.The amount of natural lead contained inthe sample shall be used to correct the yield.6.2 In most cases measurable amounts of210Pb will bepresent in the Pb carrier used in 12.1.This additional contri-bution to the measured sample activity must be determined andtreated as additional background activity.For each new carriersolution,the inherent210Pb in the carrier must be measured.Abrief description of this additional background calibration isgiven in 11.2.Accurate determination of the combined stan-dard uncertainty and the minimum detectable concentrationshould include this additional activity in the method back-ground count rate.1This 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 Jan.1,2015.Published January 2015.Originallyapproved in 2009.Last previous edition approved in 2009 as D7535 091.DOI:10.1520/D7535-09E01.2For 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 standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.3 Previous experimental data suggests that barium con-centrations of approximately 30 ppm can be a source ofinterference,leading to chemical yield determinations that maybe non-representative and outside normal acceptance criteria.7.Apparatus7.1 Analytical Balance,0.0001 g.NOTE1A thickness of aluminum of approximately 0.003 in.(arealdensity of appro