1、Designation: D3454 11Standard 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 indicate
2、s 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 soluble,suspended, and total radium-226 in water in concentrationsabove 3.7 3 103Bq/L. This test method is not applicable
3、tothe measurement of other radium isotopes.1.2 This test method may be used for quantitative measure-ments by calibrating with a radium-226 standard, or for relativemeasurements by comparing the measurements made witheach other.1.3 This test method does not meet the current requirementsof Practice D
4、2777.1.4 The values stated in SI units are to be regarded as thestandard. The inch-pound units given in parentheses are forinformation only.1.5 Hydrofluoric acid (HF) is very hazardous and should beused in a well-ventilated hood. Wear rubber gloves, safetyglasses or goggles, and a laboratory coat. A
5、void breathing anyHF fumes. Clean up all spills promptly and wash thoroughlyafter using HF.1.6 This standard does not purport to address all of theother safety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health
6、practices and determine the applica-bility of regulatory limitations prior to use.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 Wa
7、terD3370 Practices for Sampling Water from Closed ConduitsD3648 Practices for the Measurement of RadioactivityD3649 Practice for High-Resolution Gamma-Ray Spec-trometry of WaterD3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of WaterD4448 Guide for Samplin
8、g Ground-Water MonitoringWellsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD6001 Guide for Direct-Push Ground Water Sampling forEnvironmental Site CharacterizationD7282 Practice for Set-up, Calibration, and Quality Controlof Instruments Used fo
9、r Radioactivity Measurements3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D1129. For terms not defined in this test methodor in Terminology D1129, reference may be made to otherpublished glossaries.4. Summary of Test Method4.1 This test method3is based on t
10、he emanation andscintillation counting of222Rn, a gaseous daughter productof226Ra, 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
11、 dissolved by evaporation with dilutehydrochloric acid to form soluble barium-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
12、scintillation counting chamber. About 4 hafter222Rn collection, the scintillation chamber is counted foralpha activity. The226Ra concentration is calculated from thealpha count rate of222Rn and its immediate daughters. Theradioactive decay characteristics of226Ra and its immediatedecay progeny are l
13、isted 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, are226Ra1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.04 on Methods of
14、Radiochemi-cal Analysis.Current edition approved June 15, 2011. Published July 2011. Originallyapproved in 1975. Last previous edition approved in 2005 as D3454 05. DOI:10.1520/D3454-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceas
15、tm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3This test method is based on a previously published method by Rushing, D.E.,Garcia, W.J., and Clark, D.A. “The Analysis of Effluents and EnvironmentalSamples from Uranium Mil
16、ls and of Biological Samples for Radium, Polonium andUranium,” Radiological Health and Safety in Mining and Milling of NuclearMaterials, Vol. II, IAEA, Vienna, Austria, 1964), p. 187.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.an
17、d228Ra. These two isotopes also present the greatest healthrisk compared 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
18、 media once the medium has been completelydecomposed and put into an aqueous solution.5.3 The general methodology and basis of this technique aresimilar to the methodology “226Ra in Drinking Water (RadonEmanation Technique)” as described in the document EPA-600/4-80-032.46. Interferences6.1 Only the
19、 gaseous alpha-emitting radionuclides interfere,namely,219Rn and220Rn. Their half lives are 3.9 s and 54.5 srespectively; their presence indicates the presence of theirparents,223Ra and224Ra. These short-lived radon isotopes de-cay before the222Rn is counted; it is their alpha-emitting decayproducts
20、 that would interfere. These interferences are very rarein water samples but are frequently observed in certainuranium mill effluents.7. Apparatus7.1 Radon Bubbler5(Fig. 1).7.2 Radon Scintillation Chamber (also known as LucasCell) (Fig. 2).7.3 Manometer, open-end capillary tube or vacuum gagehaving
21、a volume which is small compared to the volume of thescintillation chamber, 0 760 mm Hg (Fig. 3).7.4 Gas Purification Tube, 7 to 8 mm outside diameterstandard wall glass tubing, 100 mm long, constricted at lowerend to hold a glass wool plug (Fig. 3). The upper half of thetube is filled with magnesiu
22、m perchlorate and the lower halfwith a sodium hydrate-asbestos absorbent.7.5 Scintillation Counter Assembly, consisting of a 50 mm(2 in.) or more in diameter photomultiplier tube mounted in alight-tight housing and coupled to the appropriate preamplifier,high-voltage supply, and scaler. A high-volta
23、ge safety switchshould open automatically when the light cover is removed toavoid damage to the photomultiplier tube. The preamplifiershould incorporate a variable gain adjustment. The countershould be equipped with a flexible ground wire which isattached to the chassis photomultiplier tube by means
24、 of analligator clip or similar device. The operating voltage isascertained by determining a plateau using222Rn in thescintillation chamber as the alpha source. The slope of theplateau should not exceed 2 %/100 V. The counter and thescintillation chamber should be calibrated and used as a unitwhen m
25、ore than one counter is available. The backgroundcounting rate for the counter assembly without the scintillationchamber should range from 0.00 to 0.0005 s1.7.6 Membrane Filters, 0.45 m pore size.7.7 Silicone Grease, high-vacuum, for bubbler stopcocks.7.8 Platinum Ware, crucibles, 20 to 30 mL, and o
26、ne 500 mLcapacity dish. Platinum ware is cleaned by immersing androtating in a molten bath of potassium pyrosulfate, removing,cooling, and rinsing in hot tap water, digesting in hot 6M HCl,rinsing in water, and finally flaming over a burner.7.9 Laboratory GlasswareGlassware may be decontami-nated be
27、fore and between uses by heating for1hinEDTA-Na2CO3decontaminating solution at 90 to 100C, then rinsingin water, in 1M HCl and again in water.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended that4“Radium-226
28、in Drinking Water (Radon Emanation Technique),” PrescribedProcedures for Measurement of Radioactivity in Drinking Water, August 1980.5The sole source of supply of the radon bubbler known to the committee at thistime is Corning Glass Works, Special Sales Section, Corning, N.Y. 11830. If you areaware
29、of alternative suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee.TABLE 1 Radioactive Decay Characteristics of Radium-226 andIts DaughtersRadionuclide Half-life Mode of De
30、cay226Ra 1600 years a222Rn 3.82 days a218Po 3.10 min a214Pb 26.8 min b, g214Bi 19.9 min b, g214Po 164/3 s a210Pb 22.2 years b, gFIG. 1 Radon BubblerD3454 112all reagents shall conform to the specifications of the Commit-tee onAnalytical Reagents of theAmerican Chemical Society.6Other grades may be u
31、sed, provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean conforming to Specifi-cation D1193, Type III.8.3 Radi
32、oactive Purity of ReagentsRadioactive purityshall be such that the measured results of blank samples do notexceed the calculated probable error of the measurement or arewithin the desired precision.8.4 Ammonium Sulfate Solution (100 g/L)Dissolve 10 gof ammonium sulfate (NH4)2SO4) in water and dilute
33、 to 100mL.8.5 Barium Chloride Carrier Solution Stock, (17.8 g/L)Dissolve 17.8 g of barium chloride (BaCl22H2O) in water anddilute to 1 L. This solution will contain 10 mg/mL Ba+.8.6 Barium-133 Tracer Solution(approximately 3 kBq/mL).8.7 Barium Chloride Carrier Solution, WorkingAdd 100mL of barium ch
34、loride carrier stock solution and 10 mL ofbarium-133 tracer solution to 890 mL of water and mixthoroughly. This solution will contain approximately 1 g/L ofBa+. Allow to stand for 24 h and filter through a membranefilter.8.8 EDTA-Sodium Carbonate Decontaminating SolutionDissolve 10 g of disodium eth
35、ylenediaminetetraacetate and 10g of sodium carbonate (Na2CO3) in water and dilute to 1 L.8.9 FluxTo a large platinum dish (about 500-mLcapacity)add 30 mg of BaSO4,65.8gofK2CO3,50.5gofNa2CO3, and33.7gofNa2B4O710 H2O. Mix well and heat cautiously untilthe water is expelled; fuse and mix thoroughly by
36、swirling.Cool flux, grind it in a porcelain mortar to pass a U. S. StandardNo. 10 (2.00-mm) (or finer) sieve. Store in an airtight bottle.(Flux can be prepared in smaller batches.)8.10 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).8.11 Hydrochloric Acid Solution 6M (1 + 1)Mix 1
37、 vol-ume of concentrated HCl (sp gr 1.19) with 1 volume of water.6“Reagent Chemicals,American Chemical Society Specifications,”Am. Chemi-cal Soc., Washington, DC. For suggestions on testing of reagents not listed by theAmerican Chemical Society, see “Analar Standards for Laboratory Chemicals,”BDH Lt
38、d., Poole, Dorset, U.K., and the “United States Pharmacopeia,” and NationalFormulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.FIG. 2 Radon Scintillation ChamberFIG. 3 De-emanation AssemblyD3454 1138.12 Hydrochloric Acid Solution 1M (1 + 11)Mix 1 vol-ume of concentrated HCl (sp gr
39、1.19) with 11 volumes ofwater.8.13 Hydrochloric Acid Solution 0.24M (1 + 49)Mix 1volume of concentrated HCl (sp gr 1.19) with 49 volumes ofwater.8.14 Hydrochloric Acid Solution 0.1M (1 + 119)Mix 1volume of concentrated HCl (sp gr 1.19) with 119 volumes ofwater.8.15 Hydrofluoric Acid (sp gr 1.15)Conc
40、entrated hydro-fluoric acid (HF). Use extreme caution.8.16 Hydrogen Peroxide3%(1+9)Mix 1 volume ofH2O2(30 %) with 9 volumes of water.8.17 Magnesium PerchlorateAnhydrous magnesium per-chlorate Mg(ClO4)2.8.18 Phosphoric Acid (sp gr 1.69)Concentrated phos-phoric acid (H3PO4).8.19 Radium Standard Soluti
41、on (0.37 Bq/mL).5,78.20 Sodium Hydroxide-Coated Silicate Absorbent, Propri-etary,5,88 to 20 mesh.8.21 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).8.22 Sulfuric Acid Solution 0.05M (1 + 359)Mix 1 vol-ume of concentrated H2SO4(sp gr 1.84) with 359 volumes ofwater. This solution is 0.1
42、N. Slowly add acid to water.8.23 Helium, in a high-pressure cylinder with a two-stagepressure regulator and needle valve.9. Sampling9.1 Collect the sample in accordance with the applicablestandards as described in Practices D3370.10. Calibration and Standardization10.1 Close the inlet stopcock of a
43、bubbler, (Note 1) add 5mL of BaCl22H2O carrier solution, 1 mL of concentrated HCl(sp gr 1.19), 3 mL (1.11 Bq) of standard radium solution andfill the bubbler23 to34 full with water.NOTE 1Before using, test bubblers by placing about 10 mL of waterin them and passing air through them at the rate of 3
44、to 5 mL/min. Thisshould form many fine bubbles rather than a few large ones. Do not usebubblers requiring excessive pressure to initiate bubbling. Reject unsatis-factory bubblers. Cornings “medium-porosity” fritted glass disks areusually satisfactory.10.2 Insert the outlet stopcock into the bubbler
45、with thestopcock open. Adjust the helium regulator (diaphragm) valveso that a very slow stream of gas will flow with the needlevalve open.Attach the helium supply to the inlet of bubbler andadjust the inlet pressure to produce a froth a few millimetresthick. Establish a zero ingrowth time by purging
46、 the liquid withhelium for 15 to 20 min.10.3 In rapid succession, close the inlet stopcock, removethe gas connection, and the close outlet stopcock. Record thedate and time and store the bubbler preferably for 2 to 3 weeksbefore collecting and counting the222Rn.10.4 Attach a scintillation chamber as
47、 shown in Fig. 3;substitute a glass tube with a stopcock for the bubbler so thatthe helium gas can be turned on and off conveniently. Open thestopcock on the scintillation chamber; close the stopcock to thegas and gradually open the stopcock to vacuum source toevacuate the cell. Close the stopcock t
48、o the vacuum source andcheck the manometer reading for 2 min to test the system,especially the scintillation chamber for leaks. If leaks aredetected they should be identified and sealed.10.5 Open the stopcock to the helium gas and allow the gasto enter the chamber slowly until atmospheric pressure i
49、sreached. Close all the stopcocks.10.6 Place the scintillation chamber on the photomultipliertube (in a light-tight housing), wait 10 min, and obtain abackground count rate (preferably over a period of at least 100min). Phototube must not be exposed to external light with thehigh voltage applied.10.7 With the scintillation chamber and bubbler in positionsindicated in Fig. 3 and all stopcocks closed, open the stopcockto vacuum and then to the scintillation chamber. Evacuate thescintillation cell and the gas purification system. Close thestopc
