ASTM D4107-2008 Standard Test Method for Tritium in Drinking Water《饮用水中氚含量的试验方法》.pdf

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1、Designation: D 4107 08Standard Test Method forTritium in Drinking Water1This standard is issued under the fixed designation D 4107; 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

2、indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of tritium indrinking water by liquid scintillation counting of the tritiumbeta particle activity.1.2 This test me

3、thod is used successfully with drinkingwater. It is the users responsibility to ensure the validity of thistest method for untested water matrices.1.3 The tritium concentrations, which can be measured bythis test method utilizing currently available liquid scintillationinstruments, range from less t

4、han 0.037 Bq/mL (1 pCi/mL) to555 Bq/mL (15 000 pCi/mL) for a 10-mL sample aliquot.Higher tritium concentrations can be measured by diluting orusing smaller sample aliquots, or both.1.4 The maximum contaminant level for tritium in drinkingwater as given by the United States Environmental ProtectionAg

5、ency (U.S. EPA) National Interim Primary Drinking WaterRegulations (NIPDWR) is 0.740 Bq/mL (20 pCi/mL). TheNIPDWR lists a required detection limit for tritium in drinkingwater of 0.037 Bq/mL(1 pCi/mL), meaning that drinking watersupplies, where required, should be monitored for tritium at asensitivi

6、ty of 0.037 Bq/mL (1 pCi/mL). In Appendix X1,EqX1.3 is given for determining the necessary counting time tomeet the required sensitivity for drinking water monitoring.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of

7、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:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2777 Practice for Determinati

8、on of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 3648 Practices for the Measurement of Radioactivity3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D 1129. For ter

9、ms not defined inthis test method or in Terminology D 1129, reference may bemade to other published glossaries.34. Summary of Test Method4.1 In this test method, a 100-mL drinking water samplealiquot is treated with a small amount of sodium hydroxide andpotassium permanganate, distilled, and a speci

10、fied fraction ofthe distillate is collected for tritium analysis. The alkalinetreatment is to prevent other radionuclides, such as radioiodineand radiocarbon from distilling over with the tritium. Somedrinking water supplies will contain trace quantities of organiccompounds, especially surface water

11、 sources that contain fishand other life. The permanganate treatment is to oxidize traceorganics in the sample aliquots which could distill over andcause quenching interferences. A middle fraction of the distil-late is collected for tritium analysis because the early and latefractions are more apt t

12、o contain interfering materials for theliquid scintillation counting process.4.2 As the sample distills, there is a gradient in the tritiumconcentration in the accumulating distillate due to isotopeeffects; therefore, it is important to collect the same fraction ofthe distillate for all samples and

13、standards for tritium analysis.4.3 The collected distillate fraction is thoroughly mixed anda portion (up to 10 mL) is mixed with liquid scintillatorsolution, and after dark adapting, is counted in the liquidscintillation counting system for tritium beta particle activity.5. Significance and Use5.1

14、This test method was developed for measuring tritium inwater to determine if the concentration exceeds the regulatorystatutes of drinking water. This test method also is applicablefor the determination of tritium concentration in water asrequired by technical specifications governing the operations

15、ofnuclear power facilities. With suitable counting technique,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. 15, 2008. Published February 2008. Origin

16、allyapproved in 1991. Last previous edition approved in 2002 as D 4107 98 (2002)e1.2For 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 pa

17、ge onthe ASTM website.3American National Glossary of Terms in Nuclear Science and Technology,available from American National Standards Institute (ANSI), 25 W. 43rd St., 4thFloor, New York, NY 10036, www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, P

18、A 19428-2959, United States.sample size, and counting time a detection limit of less than 37Bq/L (1000 pCi/L) is attainable by liquid scintillation.6. Interferences6.1 A reduced detection efficiency may result from quench-ing in the sample scintillator mixture. Quenching is caused byimpurities in th

19、e sample, which can inhibit the transfer ofenergy, or by colored materials, which may absorb some of theemitted light. Corrections for quenching can be made by theuse of internal standards3or by the ratio method.4Theapproach described in this test method, distillation after alka-line permanganate tr

20、eatment, eliminates quenching substances,as well as radionuclides which might be present in a volatilechemical form such as radioiodine and radiocarbon. A boilingchip must be used with each distillation to avoid bumping,which can amount to a carry over excursion.6.2 Scintillator stock solution or sa

21、mples exposed to day-light must be dark-adapted. Also, toluene or xylene basescintillators exposed to fluorescent lighting should be dark-adapted for a minimum of 6 h and dioxane base scintillatorsexposed to fluorescent lighting for 24 h. All fluors should bechecked for excitation under lighting con

22、ditions being used,and if possible, they should be exposed only to red light.7. Apparatus7.1 Liquid Scintillation Spectrometer, coincidence-type.7.2 Liquid Scintillation Vials, of low-potassium glass arerecommended. Polyethylene vials may be used when otherthan dioxane scintillator solution is used.

23、7.3 Distillation ApparatusFor aqueous distillation,250-mL and 1000-mL round bottom borosilicate flasks, con-necting side arm adapter,5condenser, graduated cylinder,boiling chips, and heating mantle.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unle

24、ss 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.6Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently

25、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 reagent water conformingto Specification D 1193, Type III.8.3 Reagents of Distillation Treatment:8.3.1 Sodium Hydroxide Pelle

26、ts.8.3.2 Potassium Permanganate.8.4 Background Water, with tritium activity below theminimum detectable activity (most deep well waters are low intritium content).8.5 Scintillator Solutions:8.5.1 Dioxane Liquid Scintillator SolutionDissolve4gofscintillation-grade PPO (2,5-diphenyloxazole), 0.05 g of

27、scintillation-grade POPOP 1,4-bis (5-phenyloxazolyl-2-yl)-benzene, and 120 g of naphthalene in 1 L of spectroquality,1,4-dioxane. Store the solution in a dark (amber) bottle. Thissolution can be used with glass or polyethylene vials.8.5.2 Solution G Scintillator SolutionDissolve 18 g ofscintillation

28、-grade PPO (2,5-diphenyloxazole) and 3.6 g ofscintillation-grade BIS-MSB p-bis (o-methylstyryl) benzenein 2 L of spectroquality p-xylene. Add 1 L of Triton N-1017detergent to the p-xylene scintillator solution. Dissolve 50 g ofSXS (sodium xylene sulfonate) in 100 mL of water and addthis solution to

29、the p-xylene scintillator-Triton solution. Mixthoroughly. Store the solution in a dark (amber) bottle. Thissolution should be used with glass vials since the p-xylenesolvent evaporates slowly through the wall of the polyethylenevials.8.5.3 Other commercially available scintillators can beused, such

30、as the environmentally safe di-isopropyl napthalenebased scintillators. It is the responsibility of the user to verifythe acceptability of a substitute scintillator.8.6 Tritium standard solution as tritiated water traceable toa National Standards Laboratory such as NIST or NPL,approximately 17 kBq/m

31、L.9. Sampling9.1 Collect the sample in accordance with Practices D 3370.9.2 Since tritium in drinking water is likely to be in the formof T2O or HTO, there is no need for special handling orpreservation.10. Calibration10.1 Determination of Recovery and Detection EffciencyFactors:10.1.1 Prepare in a

32、1-L volumetric flask, a tritium standardsolution containing approximately 17 Bq/mL using low leveltritium background raw water, RWS (undistilled), and standardtritium activity. Label this solution as raw water tritiumstandard solution, RWTS.10.1.1.1 Distill approximately 600 mL of water obtainedfrom

33、 the same raw water source (RWS) as above (withouttritium activity added). Use this distillate for backgroundtritium determinations. Using the distillate and standard tritiumactivity, prepare a tritium standard solution in a 500-mLvolumetric flask to contain the same specific activity as the rawwate

34、r tritium standard solution. Label this solution as distilledwater tritium standard solution, DWTS.4Bush, E.T., “GeneralApplicability of the Channels Radio Method of MeasuringLiquid Scintillation Counting Efficiencies,” Analytical Chemistry, 35:1024, 1963.5Corning part no. 9060 has been found satisf

35、actory for this purpose.6Reagent 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

36、United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.7The sole source of supply of the apparatus known to the committee at this timeis Rohm and Haas Company, Independence Mall West, Philadelphia, PA 19105. Ifyou are aware of alternative suppliers

37、, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.D 4107 08210.1.2 Aqueous Alkaline Permanganate DistillationPlacea 100-mL aliquot of the RWTS solution in a 25

38、0-mL distilla-tion flask. Add 0.5 g of sodium hydroxide, 0.1 g of potassiumpermanganate, and a boiling chip. Proceed with the distillateaccording to the procedure described in 11.1, discard 10 mL,and collect 50 mL of distillate for analysis. Mix the 50-mLdistillate fraction. Repeat the distillation

39、with two more100-mLaliquots for triplicate analyses. This is the distilled rawwater tritium standard (DRWTS).10.1.3 Prepare for counting three aliquots of the DRWTSdistillate tritium standard solution (from 10.1.2), three aliquotsof the DWTS, and three aliquots of the distilled raw water (forbackgro

40、und). Mix 4 mL of water with 16 mL of the dioxanescintillator solution, or 10 mL of water with 12 mL of SolutionG scintillator solution in a liquid scintillator vial (glass vialsshould be used for detergent-type scintillator solutions). Shakewell, dark-adapt the vials overnight, and count in a liqui

41、dscintillation counter. Count each vial long enough to meet therequired detection (0.037 Bq/mL) or longer (see Appendix X1for calculating required counting time).11. Procedure11.1 Add 0.5 g of sodium hydroxide and 0.1 g of potassiumpermanganate to a 100-mL aliquot of the sample in a 250-mLdistillati

42、on flask. Add a boiling chip to the flask. Connect aside-arm adapter and a condenser to the outlet of the flask.Place a graduated cylinder at the outlet of the condenser. Heatthe sample to boiling to distill, collect the first 10 mL ofdistillate as a separate fraction and discard it.11.2 Collect the

43、 next 50 mL of distillate for tritium analysis.Thoroughly mix the 50-mL distillate fraction.NOTE 1It is important that only the first 10-mL fraction be discardedor the same fraction for samples and standards alike since there is agradient in the tritium concentration of the distillate.11.3 Thoroughl

44、y mix 4 mL of the distillate with 16 mL ofthe dioxane scintillator or 10 mL of distillate with 12 mL ofSolution G scintillator in a liquid scintillation vial. Threealiquots of each sample distillate should be analyzed fortritium.11.4 Prepare background standard tritium-water solutionsfor counting, u

45、sing the same amount of water and the samescintillator as used in the preparation of samples. Use lowtritium background distilled water for these preparations (dis-tillate of most deep well water sources is acceptable, but eachsource should be checked for tritium activity before using).11.5 Dark-ada

46、pt all samples, backgrounds, and standards.Count the samples, backgrounds, and standards at least longenough to meet the required detection limit (0.037 Bq/mL) forthe sample (see Appendix X1 for calculating counting time forrequired detection limit). The DRWS distillate should becounted for sufficie

47、nt time to accumulate at least 50 000 netcounts.12. Calculation12.1 Detection Effciency, e:e5RDWTS RbADWTS(1)ue! 5RDWTStDWTS1RbtbADWTS21e2SuADWTS!ADWTSD2where:ADWTS= activity of distilled water tritium standard, inbecquerels (Bq),Rb= background aliquot count rate, in counts persecond (s1),RDWTS= dis

48、tilled water tritium standard count rate(s1),u(ADWTS) = standard uncertainty of the activity ADWTS(Bq),tDWTS= count time for the distilled water tritiumstandard (seconds),tb= count time for the background sample (sec-onds).12.2 Recovery Correction Factor, F:F 5RDWTS Rbe3ARWTS(2)where:RDRWTS= count r

49、ate of distilled raw water standard (s1),ARWTS= activity of (undistilled) raw water tritium stan-dard Bq.12.3 Sample Tritium Activity, AC, for each aliquot:AC 5Ra Rbe3F 3 V 3 elt(3)where:Ra= sample aliquot gross count rate (s1),Rb= background aliquot count rate (s1),e = detection efficiency, as determined in Eq 1,V = volume of the sample aliquot (mL),F = recovery factor, as determined in Eq 2,l = decay constant for tritium, (ln 2) / t1/2,t1/2= half-life of tritium, 4500 d,t = elapsed time between sampling and counting, indays.12.4 The result of the measurem