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DISTRIBUTION

U-5. ENVIRONMENTAL PROTECTION AGENCYCLP Sample Management OfficeP.O. Box SIS . Alexandria, Virginia 22313Phone? 703/557-2*90 - FTS/557-2%90 prrI *?«..

SPECIAL ANALYTICAL SERVICESClient Request S I r' ?. 7

fearir, V.':?':f I

Regional TransmittaU ( _ | Telephone Request c""l<)

A. EPA Region/Client: REGION III __________________ -

B. RSCC RepresenUtive: Colleen Walling

C. Telephone Number: (301) 266-9180

D. Date of Request: _____________

Site Name: DuPont Newport Site

Please provide below description of your request for Special Analytical Services underthe Contract Laboratory Program. In order to most efficiently obtain laboratorycapability for your request, please address the following considerations, if applicable.Incomplete or erroneous information may result in a delay in the processing of yourrequest. Please continue response on additional sheets, or attach supplementaryinformation as needed.

1. General description of analytical service requested: The Samples are to beanalyzed for Gross Alpha/Beta, Thorium 232, Radium 226 and Radium288.

2. Definition and number of work units involved (specify whether whole samples orfractions; whether organics or inorganics; whether aqueous or soil and sediments;and whether low, medium or high concentration):

Sample quantities for Radionuclide analysis only, 3-water and1-Sediment sample, low organic and radionuclide concentration,samples may be high in barium concentration. Available quantitiesare 2-liters per water sample and 1-8 oz jar for Sediment sample.(see attachment)

3. Purpose of analysis (specify whether Superfund (enforcement or remedial action),RCRA, NPDES, etc.): ______Superfund RI/FS________________

flR303089

*. Estimated date(s) of collection: August IT.

Estimated date(s) and method of shipment: At notification of laboratoryassignment. Federal Express or equal method of shipment.

6. Number of days analysis and data required after laboratory receipt of samples:Routine turnaround not to exceed 45 days.______________^_

7. Analytical protocol required (attach copy if other than a protocol currently used Inthis program): (see attachment)____________________*

Special technical instructions (if outside protocol requirements} specify compound*names, CA5 numbersf detection limits, etc.): ____________________

Initial calibration data must be included in the data report.__

9. Analytical results required (if known, specify format for data sheets, QA/QCreports, Chain-of-Custody documentation, etc.) If not completed, format of resultswill be left to program discretion. Include all raw data for instrument

calibration and sample analysis as indicated in the latest CLPprotocol. The SAS data package must be consistent with and_______equivalent to the CLP format, (see attachment)____________________

10. Other (use additional sheets or attach supplementary information, as needed):Previous sampling indicated presence of Thorium 232 particlesin.water samples. . ,_ . .11. Name of sampling/shipping contact: Steve Loftus (Jacobs Engineering Group)

Phone: (202) 628-1903/Nick Cianfrone DynaMac (215)440-7340______

AR303090

12. Data RequirementsPrecision Desired

Parameter____ ___Detection Limit (-% or Concentration)Gross Aloh/BetaRadium 226 0.1 pCi/1Radium 228 0.1 oCi/1Thorium 232 0.05 pCi/1

30%30%30%

-

OC RequirementsUmits

Audits Required Frequency of Audits (Percent or Concentration)1 1 30% .. .

One-Field duplicate is providedOne-Laboratory method blankOne-Matrix spike is required, (if sufficientavailable) target, compound concentration shalp<;timatpH practical qnanti tat i nri limit

sample quantity is1 bp 10 times the(see attachment)

14. Action Required if Limits are ExceededNotifv Colleen WallinaRSfT (301)766-9180 andRorp'nn TTT Fnfnrcpmpnt

, EPA Region IIIRandv Sturaeon,(715)597-0978

EPA

Please return this request to the Sample Management Office as soon as possible toexpedite processing of your request for special analytical services. Should you have anyquestions or need any assistance, please contact your Regional representative at theSample Management Office.

AR30309I

(Attachment)

cont'd 2. One of the water samples will have the second liter designated asfield duplicate.

cont'd 7. Analytical methods to be used are per Eastern Environmental RadiationFacility, Radiochemistry Procedures Manual. EPA 520/5-84-006, August1984.

Procedure 00-01 Radiochemical Determination of Gross Alpha andGross Beta Particle Activity in Water.

Procedure 00-05 Radiochemical Determination of Thorium and Ura-nium in a Ashed Samples including Soil.

Procedure 00-07 Radiochemical Determination of Thorium and Ura-nium in Water.

Procedure Ra-01 Radiochemical Determination of Radium-226 insolid samples requiring Fusion.

Procedure Ra-03 Radiochemical Determination of Radium-226 inWater Samples.

Procedure Ra-04 Radiochemical Determination of Radium-226.

Procedure Ra-05 Radiochemical Determination of Radium-228 inWater Samples.

Acceptible substitutes for Gross Alpha and Beta, Radium-226 andRadium-228 analysis are SW-846 Methods;

Method 9310 Gross Alpha and Gross Beta

Method 9315 Alpha Emitting Radium Isotopes

Method 9320 Radium-228

cont'd 9. Include all information for sample preparation/clean-up. Chain-of-custody documentaion must be included in data report.

cont'd 13. QC Requirements

No action required if MS results are out of control limits, butshould be noted.

Report results without correction for recovery data. Report dup-licate and spike sample analysis with the sample results.

SR303092

534 ?3ft509/25/1989 13:08 usEPfl EERF MONT. «_«. 534

RADIOCHEMICAL DETERMINATION OF RADIUM-228 IN HUTER

PrincipleThe sample nay be taken from the stored radium solution following

Ra-226 de-emanation or from a water sample. £jf using the stored ToTut1on>o J7>The radium 1s rtpreclpltated as a rad1u«-bar1u»

nn$ precipitate Is dissolved In a pentasodlun d1tthylenetr1a«1nepent-acetate solution. The rad1ura-228 Is a weak beta emitter and decays^ actlnlum-228, which 1$ allowed to Ingrow for three days. Theact1n1um-228 1s then extracted with 01 -2-ethylhexyl phosphoric acid andback-extracted with nitric acid. The act1n1u»-228 1s beta Counted 1n a

background proportional counter.

Apparatus' 1. Centrifuge.

2. PI a r>c hats, stainless steel, 5 cm diameter.3. Separator? funnels, 125 »1 , 2 liter capacity.4. Magnetic stlrrer and stirring bars.5. Glaiswart.6. Suction filter apparatus.

Reagents1. Acetic acid, glacial 17.Q. HC2H302 reagent.2. Acetic add «. Dilute 345 nl of the reagent grade

to one liter with distilled water.3. Actinium wash solution. Dissolve 100 g monochloroacetlc add and

2.4 ml of 41 percent Na$DTPA In 800 nl of distilled water anddilute to 1 liter. Adjust the pH to 3.0 with NaOK pellets(approximately 25.4 g NaOH).

4. Ammonium hydroxide !££. Reagent grade HK^OH.5. Barium carder, 10 mg Ba /•!. Dissolve 17.76 g BaClg ' 2^0 1n

800 ml distilled water and dilute to 1 liter. Allow to stand 24hours and filter.

August 1967Ra-OS-1

534 T3b509/25/1989 13 = 09 USEPfl EERF nONT. RLfl. 534 7365 P.03

6. Barium carrier, 5 «g la*2/»l. Dissolve 4.45 g BaC12 • 2H^1n 400 nl distilled wttr and dilute to 500 •!.

7. Blsaiuth carrier, 20 ng B1*3/m1. Dissolve 46.4 g B1(M03)3 • 5HgO1n 800 •! distilled water and dilute to 1 liter.

8. Chloroacetlc add, ». Add 189 g of reagent grade chloroacetlcacid to a beaker, dissolve 1n distilled water and dilute to 1 liter.

9. DlaRirmonlun dtratc. 2M. Dissolve 226.2 g dibasic ammoniumcitrate, (NH gHCgHjOj, 1n distilled water and dilute to 500 ml.

10. DI-2-ethylhexylphosphoric acid, HDEHP, 15 percent 1n n-heptane.Dilute 150 »1 HDEHP to 1 liter with n-heptane and transfer to a2-liter separatory funnel. Wash the HDEHP twice with 200 mlall quots of a 1:1 mixture of 2H_ dlammonium citrate and 15MNH4OH. The nlxture 1s prepared by adding 100 •! IBM NH4OH to100 ml 2M_ dlammonluB citrate 1n a beaker and mixing. Add to theseparatory funnel containing the HDEHP. Shake for one minute,releasing pressure frequently. Allow the layers to separate anddiscard lower layer. Wash the HDEHP twice with 200 ml allquotsof <M HMO,, discarding the lower layer each tine after shakingfor one minute. Store the cleaned HDEHP 1n a polyethylenebottle. Immediately before using the HDEHP solution, the amountto be used 1s washed first with an equal volume of distilledwater and then with one-half the volume of actinium wash. Thelower layers are discarded each time after shaking for one minute.

11. D1ethy1enetr1am1ne pentaacetlc add, pentasodlun salt, Na5DTPA, 41 percent reagent solution.

12. D1 ethylenetrlamine pentaacetlc add. pentasodlum salt, Na^DTPA,0.17M, pH 10. Add 209 ml of the 41 percent Ma5 DTPA solutionto 400 ml of distilled water and filter through glass wool withsuction. Dilute to 1 liter with distilled water and adjust to pH10 using either perchloric add or sodium hydroxide {usuallyrequires 10 to 12 ml perchloric add). Store In a polyethylenebottle.

August 1987

Ra-05-2

flR30309lt

534 ?36509/25/1989 13=10 USEPfi EERF MCKT. «_fl. 5347365 P.04

13. n-Heptane. Reagent grade.14. Hydrochloric acid, 1», 37 percent HC1 reagent.IS. Hydrochloric add, 1M. Dilute 83 ml of the 37 percent reagent

grtd« HC1 to 1 liter with distilled water.+216. Lead carrier, 100 mg Pb /ml. Dissolve 160 g reagent grade

Pb(N03)2 In 800 ml distilled water and dilute to 1 11t«r.17. Nitric acid, 16M, 70 percent HNOj reagent.18. Nitric add, 4M. Dilute 250 ml of the 70 percent reagent grade

HN03 to 1 liter with distilled water.19. Nitric acid. 1M. Dilute 63 ml of the 70 percent reagent

grade HM03 to 1 liter with distilled water.20. Perchloric acid, 12H, 70 percent HC104 reagent.21. Sodium hydroxide. Reagent grade pellets.22. Sodium sulfate. 20 percent. Dissolve 20 g anhydrous Na2S04

In 60 ml distilled water and dilute to 100 nl.23. Sulfurlc add, 1£M, 96 percent H2S04 reagent.24. Sulfurlc acid, 4M. Dilute 222 ml of the 96 percent reagent grade

H2S04 to 1 liter with distilled water.

1. Transfer 1,000 ml of the water to a 1,500 ml beaker. Adjust thepH to approximately 1.0 with 16M HM03 and add 200 mg of leadcarrier.

2. Add 100 ml 1W H2$04 and heat to 70*C with stirring for onehour. Allow the lead sulfate to settle overnight.

3. Carefully decant as much clear liquid as possible without losingany precipitate. Pour equal volumes of the remaining liquid Intotwo centrifuge tubes of equal volume (40-ml or 100-ml}.Centrifuge and decant supernate. If necessary, repeat until allprecipitate has been collected 1n the two centrifuge tubes.Slurry the precipitate in one tub* with 4£ HpSO^ and transferquantitatively to the other tube using *^ H2S04 as wash.

Ra-05-3

flR303095

534 736509x25/1989 13:12 USEPft EERF MONT. flLfl. 534 7365 p.35

Centrifuge and discard the supernaU.Place a stirring bar 1n the tub* containing the Pb$04, add 1 mlof glacial acetic add, 6 ml of 41 percent DTPA, and 1 mldistilled water. Heat with stirring until dissolution 1scomplete.Add with stirring, (ggblsmtj'tl^carrle^M^- 2 ml 1W H2S04.Digest 5 to 10 minutes in ft hot water bath, cool, centrifuge, anddiscard supernate. See Note 1. -&T *&AddX^ of Q.l7ft_ DTPA to the precipitate, place In a boilingwater bath and heat with stirring to dissolve the precipitate(dissolution may r*qu1re 20 minutes).

7. When the precipitate has dissolved In step1 ml Na2$04 (20 percent),and then a d d * 1 of & «cet1c add. Heat

In a hot water bath for five minutes while stirring with amagnetic stirring bar.

8. Transfer to an ice bath. Allow to cool for five minutes withstirring. Remove stirring bar and centrifuge. Decant anddiscard supernate.

*29. Repeat steps 6, 7, and 8 omitting the addition of Ba 1n step7. Record the time the acetic acid 1s added. See Note 2.

10. To the BaS04 precipitate, add^ml O.l^DTPA, heat and stiruntil all dissolves. ?°

11. Allow solution to cool, stopper centrifuge tube and store for atleast 36 hours to allow for Ac-228 Ingrowth.

12. After the Ingrowth period, place sample In a boiling water bath,Insert a magnetic stirring bar and stir until any precipitatethat may have formed during the ingrowth period has dissolved.Then add 1 ml 20 percent Na2S04, dilute -to 26-i4-*UhdlsttWexTsrater-aJxJ add /'ml of 6M^ acetic add. Record time.See Note 3.

Ra-05-4

5R303096

534 736509/25/1989 13=13 USEPft EERF MONT. PLfl. 534 7355 p.0g

13. Allow mixture to heat 1n the boiling water bath for five minuteswith stirring, then remove stirring bar and place centrifuge tubeIn an ice bath for five minutes. Centrifuge and decant suptroateInto a clean 40-«1 centrifuge tube. Rinse walls with 2 to 3 mlof water, exercising care not to disturb precipitate. Add washto the tube containing the supernate.

14. LA* 1 •! f>* >>*"< iM*~£*xrA&r ( g/Bl) -to--£h« -centdfug*-tub«containing the_sjjcftrnat». Heat with stirring 1n a boiling waterbath for five minutes. Cool In a Ice water bath for five minutesand centrifuge. See Nott 4.

15. Quantitatively transfer supernate to • 100-ml beaker containing 5ml of 24 monochloracetic acid. Measure the pH to confirm that 1tIs 3.0. See Not* S.

16. Transfer the solution to a 125-ml separatory funnel. Add 10 mlof cleaned and actinium washed 15 percent HDEHP using a portionto wash the 100-ml beaker. See Note 6.

17. Shake vigorously for two minutes (relieve pressure as needed).Allow layers to separate and discard lower (aqueous) phase.

18. Add 10 ml of the actinium wash solution. Shake for one minute,allow layers to separate and discard lower (aqueous) layer.

19. Repeat step 18.20. Add 10 ml of 1M HW>3> Shake for one minute, allow layers to

separate, and collect lower layer in an 80-ml beaker.21. Repeat step 20 using 5 ml of 1M HN03. Combine lower aqueous

layer In 80-ml beaker containing aqueous fraction from step 20.Discard organic phase.

22. Evaporate solution to dryness on a 5 cm planchet. Continueheating planchet until all nitric acid vapors have been removed.

23. Count sample and compute Ra-228 concentration. See Note _7.

August 1987

Ra-05-5

0R303Q97

534 736509X25X1989 13:14 USEPfl EERF MONT. flLfl. 534 7365 P.07

CalculationsCalculate the concentration, Z. of radiucn-228 in plcocuries per liter

as follows:

Cl " CB

(2.22HYMEKV) (l-t-°-113tl) (e-°'113t2)

where

C. • sample count rate,C.. • background count rate,Y . chemical yield based on counting rate of spike added and

recovered (see Note 7).E - beta counting efficiency,V • staple size (liters),tj • actinium-228 period of Ingrowth from rad1um-228 (hours) (see

steps 9 and 12),t2 « actlnlun-228 decay period (hours) measured from the actinium

separation (step 12} to the mid-time of the beta count, and2.22 . dpm/pCI.

Calculate the lower Harit of detection (LLD) 1n plcocuries per literas follows:

LLD(2.22)(Y)(E)(V)(T)

where

Y * chemical yield,E « beta counting efficiency,V - sample volume (liters), andT « counting time.

August 1987

Ra-05-6

SR303098

09x25/1999 13-15 USEPP EEPF MONT. 534

This LLD calculation 1s valid If the sample counting time Is equal tothe background counting tin*.

Motes1. If fta-226 is determined by de-eroanatlon of Rn-222 between steps 4 and

5, the supernate will contain the B1-210 that grew in during the30-day Rn-222 Ingrowth period and can be used to determine Pb-210 (Fora 30-day Ingrowth period, 81-210 will be 98.4 percent of Usequilibrium value).

2. Steps 6, 7. and 8 are performed to reoove all Ac-228 present. Thesecond BaS04 precipitation with acetic acid provides an actiniumfree precipitate and begins the measured Ingrowth of the Ac-228 fromthe fta-228 present.

3. The precipitation of BaS04 in step 10 isolates the actinium in thesupernate and ends the Ac-228 ingrowth period.

4. The second BaS04 precipitation Insures complete removal of theradium.

5. It 1$ Important that the pH of the solution containing the actinium is>->tJeu 3.0. If necessary, adjust pH with additional 2^ monochloracctic add.

6. It 1s important that the HDEHP be washed with an equal volum* ofdistilled water and half volume aliquot of actinium wash solutionimmediately prior to using.

7. There is no isotope of actinium available to monitor the chemicalyield of Ac-228. To determine the chemical yield, a second Mitersample of acidified water 1s spiked with a known quantity of Ra-228and analyzed In the exact manner and at the same time as the unknownsample. The chemical yield determined for the spiked sample isassumed equal to that for the unknown sample. The spiked sampleshould be analyzed with each batch of unknown samples.

Ra-05-7

0R303099

534 ?3b509x25x1989 13:16 U3EPQ EERF MONT. PLfi. 534 7355 p.09

References1. Johnson, J.O., Determination of Radium-228 in Natural Waters.

Radiocheaical Analysis of Water, Geological Survey Water-Supply Paper1696-6., U.S. Government Printing Office, Washington, D.C.. (1971).Percival, D.R. and Martin, D.B., "Sequential Determination ofRadiun-226, Radium-228, Actinium-227, and Thorium Isotopes inEnvironoental and Process Waste Samples," Analytical Chemistry, 4£1742-1749. (1974).Krieger, H.L., and Whittaker, E.L., prescribed Procedures forMeasurement of Radioactivity in Drinking Water. EPA-600/4-80-032,Environmental Monitoring and Support Laboratory, Office of Researchand Development, U.S. Environmental Protection Agency, Cincinnati,Ohio (August 1980).

Ra-05-8

TOTfiL P.B9

AR303IOO

RADIOCHEMICAL DETERMINATION OF GROSS ALPHA AND GROSS BETAPARTICLE ACTIVITY IN MATER

The water sample is evaporated onto a stainless steel planchet andcounted for gross activity. This procedure provides a rapid screeningmeasurement to indicate whether specific analyses are required.

Special Apparatus1. Conductivity meter.2. Hot plates.3. Drying lamps.4. Stainless steel planchets, 5 cm diameter.5. Pleated filter paper, 24 cm diameter.6. Muffle furnace.

ProcedureIf some samples require separating the dissolved solids from the

undissolved solids, acidify with HNO-j and--1. Filter the water sample with pleated filter paper. Dry and ash

filter paper at 500°C for 12 to 24 hours.2. Determine the dissolved solid content of the filtrate by measuring

the conductivity and determining the solids from Figure 1. Thisis to determine the volume to be evaporated. The maximum sample

2 2thickness should be less than 5mg/crn (on 20 cm area, i.e. 100 mg)3. Transfer the specific volume of water to a beaker and evaporate to

a small volume on a hot plate. Avoid dryness.4. Transfer residue from beaker to a tared stainless steel planchet

using a rubber policeman and as little distilled water as possible.5. Dry under a heat lamp, flame over a burner until dull red, cool,

weigh and store in a desiccator. See Note 1.6. Count for gross alpha and gross beta particle activity.7. Repeat steps 4, 5, and 6 for the ash, if necessary.

August 1987

00-01-1

CalculationsCalculate the concentration, Z, of gross alpha or beta in plcocuries

per liter as follows:

Z = Cl ' CB(2.22HAHYHF)

where

C, = sample counts per minute,CD = background counts per minute,D

A = counting efficiency for natural uranium,V = sample volume (liters),F = self absorption factor from Table 1 or Table 2 based on dry

sample weight, and2.22 = dpm per pCi.

Calculate the lower limits of detection (LLD) as follows:

4.66"LLD=(2.22){A)(V)(F)(T)

where

CD = background counts per minute,DT = counting time,A = counting efficiency for natural uranium,V = sample volume (liters),P _ self-absorption factor from Table 1 or 2 based on sample

weight, and2.22 = dpm per pCi.

This LLD calculation is valid if the sample counting time is equal tothe background counting time.

August 1987

00-01-2

flR303!02

TABLE 1

Alpha Particle Absorption Factor vs Sample Weight

————— . . ————— • —— ———— — ——————— _.

Sample Weight, mg

" ™ — -- — " • "" —— •• — __

0510152025303540455055606570758090100110120130140150160

———— ' ————————— - ————— - ————

————————— • ——————————— ———— ..Alpha Absorption Factor

- ——— ——— ————— _ ______ __———— - —— ———— _

1.0.95

. >90.84.79.74.69.64.59.55.50.45.42.40.38.36.35.34.33.32.30.29.28.27.27

- ———— . ——————

00-01-3 AR303I03

TABLE 2

Beta Particle Absorption Factor vs Sample Weight

*Sample Weight, mg

less than 40404550556065707580859095100

2For sample thickness, mg/cm ,weight by 20.

Beta Absorption Factor

1.000.989.982.975.968.961.954.947.940.933.926.919.912.905

on 5 cm dia. planchet, divide sample

Notes1. Flaming the planchet will result in the loss of polonium-210, if

present.

00-01-4

AR3G3 j

References1. Analysis of Radionuclides in Water. Training Course Manual, U.S.

Department of Health, Education, and Welfare, Public Health Service(1965). '

00-01-5

flR303if)5

JU90J9J

00-01-7flR303!06

L-

100,000'

•p 10,000CLQ.

+—*>oD

1.000- •

20010 100 500

Volume, mL

Rgur* 1. Conductivity v*. volum*.

00-01-6

fiR303{Q7

RADIOCHEHICAL DETERMINATION OF THORIUM AND URANIUM IN ASHEDSAMPLES INCLUDING SOIL. COAL, FLY ASH, ORES, VEGETATION AND BIOTA

Fusion Method

PrincipleThe sample is ashed at 550°C for 72 hours. Thorium-234 and

uranium-232 tracers are added to a weighed aliquot. Silica is volatilizedand the sample is fused with potassium fluoride and potassiumpyrosulfate. The uranium is extracted into triisooctylamine (TIOA). Thethorium is purified by adsorption on am'on exchange resin from nitricacid. Uranium is stripped from the resin with HCl and coprecipitated.Each actinide isotope is radioassayed by alpha spectroscopy.

Special Apparatus1. Nuclepore filter membranes, 25 mm dia., 0.2 micrometer pore

size or equivalent. See Note 1.2. Ion exchange column, 2 cm I.D. x 10 cm.3. Plastic graduated cylinder, 100 ml capacity.4. Planchets, stainless steel, 32 mm diameter.5. Separatory funnels, 1 liter capacity.6. Suction filter for 25 mm membrane.7. Teflon beakers. See Note 2.8. Glassware.9. Platinum Crucible.10. Alpha spectrometric system consisting of multichannel analyzer,

t

biasing electronics, printer, silicon surface barrier detector,vacuum pump and chamber.

11. Meker burner.

Reagents1. Anion exchange resin; BioRad AG1X8 (200-400 mesh, nitrate form)

00-05-1

or equivalent. Convert to nitrate form for thorium analysis bywashing the resin with 6M HN03 until the washing shows no traceof chloride, when tested with AgN03.

2. Ascorbic add, crystalline reagent.3. Hydrochloric acid, 12M_. 37 percent HC1 reagent.4. Hydrochloric acid, 9^. Dilute 750 ml of the 37 percent reagent

grade HC1 to 1 liter with distilled water.5. Hydrochloric add, 1M_. Dilute 83 ml of the 37 percent reagent

grade HC1 to 1 liter with distilled water.6. Hydrofluoric acid, 29M , 48 percent HF reagent.7. Hydrofluoric acid, 3 ,. Dilute 104 ml of the 48 percent reagent

grade HF to 1 liter with distilled water. Use a plastic graduateand storage bottle.

+38. Lanthanum carrier, 0.1 mg La /ml. Dissolve 0.0779 gLa(N03)3- 6H20 per 250 ml 1M HC1.

9. Nickel foil, 15 cm x 1 cm x 0.1 mm.10. Nitric acid, 16 , 70 percent HN03 reagent.11. Nitric acid, 6M_. Dilute 375 ml of the 70 percent reagent grade

HN03 to 1 liter with distilled water.12. Nitric acid, 0.1M. Dilute 6 ml of the 70 percent reagent grade

HN03 to 1 liter with distilled water.13. Perchloric acid, 12M_, 70 percent HC104 reagent.14. Potassium fluoride, crystalline reagent.15. Potassium pyrosulfate, crystalline reagent.16. Silver nitrate, crystalline reagent.17. Silver nitrate, 0.1M_. Dissolve 1.7 g AgN03 reagent in

distilled water. Add 1 ml 6M HN03 and dilute to 100 ml withdistilled water. Keep in brown bottle.

18. Sulfuric acid, 3M. Dilute 167 ml of the 96 percent H2S04reagent to 1 liter with distilled water.

19. Titanium trichloride, 20 percent reagent grade.

00-05-2

SR3Q3I09

20. Titanium trichloride, 0.4 percent. Dilute 1 ml of the 20 percentTiCl3 to 50 ml with 1 M HC1. Prepare fresh daily.

21. Triisooctylamine (TIOA), reagent grade.22. TIOA solution in p-xylene, 10 percent. Dissolve 100 ml of

triisooctylamine in p-xylene and dilute to 1 liter with p-xylene.23. p-Xylene, reagent grade.24. Thorium-234 tracer solution, approximately 800 pCi/ml, accurately

calibrated.25. Uranium-232 tracer solution, approximately 1 pCi/ml, accurately

icalibrated.

Sample Preparation1. Place 100 g sample in ceramic dish for ashing.2. Ash in muffle furnace, gradually raising temperature over several

hours to 550eC. Maintain at temperature for 72 hours.3. Carefully weigh 1 g aliquot of cooled ash and transfer to Teflon

?^A ?i?beaker. Add 1 ml each of * Th and "*U tracers.4. Wet ash with two additions of 20 ml each 29M HF and evaporate

each time to dryness.5. Transfer the residue to a platinum crucible with the aid of a

spatula. Use a 20 ml crucible for a 1 g sample.6. Add 2 grams of KF for a 1 gram sample or 4 grams KF for a 5 gram

sample and fuse covered over a Meker burner for 30 minutes.7. Add 7.5 grams KpSpO^ for a 5-grarn sample or 3 grams for a

1-gram sample and continue fusing for 30 minutes.8. Cool the crucible in an ice bath, add 15 ml 12M_ HC1 and evaporate.9. Add 15 ml of water and partially evaporate to 10 ml volume.10. Transfer to 1000-ml beaker and add 150 ml water.11. Heat and evaporate to dryness and add 200 ml 3M HgSO^.

Evaporate past white fumes to dryness.12. Dissolve the residue in 200 ml 9M HC1.

00-05-310

Uranium Determination1. Place 100 ml of 10 percent TIOA solution in a 1 liter separatory

funnel. Add 50 ml 9M HC1 and shake funnel for 1 minute. Drainand discard lower aqueous acid phase after clean separation ofthe two phases.

2. Add the aqueous sample from step 12 above, to the TIOA in theseparatory funnel and shake the funnel vigorously for twominutes. Vent the funnel stopcock to prevent pressure buildup inthe funnel.

3. Allow the phases to separate cleanly and draw off the loweraqueous acid phase. Save for thorium analysis.

4. Add 50 ml 9M_ HC1 to the TIOA solution in the separatory funneland shake for 1 minute.

5. Allow the phases to separate; withdraw and discard lower aqueousacid phase.

6. Repeat steps 4 and 5.7. Strip the uranium from the TIOA solution by adding 100 ml 0.1 M_

HNO., to the separatory funnel and shaking the funnel for 2minutes.

8. Allow phases to separate; withdraw and save lower acid phase,discard organic phase.

9. Repeat steps 7 and 8 and combine strip solutions.10. Place combined strip solutions in the clean separatory funnel.11. Add 100 ml p-xylene to combined strip solution and shake funnel

for 1 minute. See Note 3.12. Allow phases to separate cleanly; withdraw lower aqueous acid

layer into beaker.13. Evaporate combined solution from step 12 to dryness. Discard

organic phase. Do not overheat.14. Add 100 ml 16M_ HN03 to residue and evaporate to dryness. Do

not overheat.

00-05-4

A R 3 0 3 I I I

15. Add 5 ml 9M_ HC1 and 5 ml 12M HC10. to residue and evaporate todryness.

16. Repeat step 15.17. Add 10 ml 12M_ HC1 and evaporate to dryness.18. Repeat step 17.19. Add 50 ml 1M HC1 to sample residue and warm gently to dissolve

residue.20. Heat sample solution to 80"C with stirring. Do not overheat.21. Suspend clean nickel metal strip into solution for two hours to

remove polonium.22. Remove nickel and evaporate solution to dryness.23. Add 15 ml 1M_ HC1 to sample residue and warm to approximately 50"C.24. Add enough ascorbic acid to reduce iron in the sample, indicated

by the disappearance of yellow color.25. Add 1 ml of 0.4 percent TiCl3 to reduce uranium.26. Add 1 ml of lanthanum carrier and 5 ml of 3M HF. Mix well and

set aside for 30 minutes.27. Using suction, filter coprecipitated sample through a filter

membrane.28. Rinse sample beaker with 10 ml water and add to filter funnel.

Rinse beaker with 10 ml ethanol and add to funnel.29. Remove clamp and top of funnel with suction on. Allow membrane

to dry.30. Mount membrane carefully on 32 mm planchet using double stick

tape.31. Count sample for 1000 minutes on alpha spectrometer.

Thorium Determination1. Evaporate aqueous acid fraction containing thorium from step 3 of

Uranium Determination.2. Add 10 ml 16M^ HNO., and evaporate to dryness.

December 1985

00-05-5

SR303!12

3. Add 5 ml 9M_ HC1 and 5 ml 12M^ HC10. and evaporate to dryness.4; Add 10 ml of 16M_ HN03 and evaporate to dryness.5. Repeat step 4.6. Dissolve sample in 10 ml of 6M HN03 with heat.7. Prepare ion exchange column with 25 ml BioRad AG1X8 resin. Wash

resin with 250 ml of 6M HN03.8. Decant sample into column at gravity flow (approx. 3ml/min) and

rinse the sample on the column with an additional 50 ml of 6?^HNO,. Discard wash.

9. Elute the thorium from the column with 200 ml of 6M HC1 at flowrate of 3 ml /minute.

10. Evaporate thorium eluate to dryness.11. Add 10 ml 12M HC1 to residue and evaporate to dryness.12. Add 15 ml 1M_ HC1 to sample residue and warm to approximately 50°C.13. Add 1 ml lanthanum carrier and 5 ml of 3M_ HF. Mix well and set

aside for 30 minutes.14. Using suction, filter copreci pita ted sample through a filter


Rinse beaker with 10 ml ethanol and add to funnel.16. Remove clamp and top of funnel with suction on. Allow membrane to

dry.17. Mount membrane carefully on 32 mm planchet using double stick tape.18. Beta count the sample to measure thorium-234 recovery.19. Count sample for 1000 minutes on alpha spectrometer.

CalculationsCalculate the concentration, Z, of uranium in picocuries per gram as

follows:

z _ (A-Aj) x F

(2.22)(B-B_)(E)(W)(T)

December 1985

00-05-6

AR303!13

where

A = gross sample counts which appear in the uranium-234,-235,or-238 alpha energy region,

A = background counts in the same alpha energy region as J\ above,B r gross tracer counts which appear in the alpha energy region

of the tracer isotope,B. = background counts in the same alpha energy region as JJ above,E = alpha detector efficiency,F = total calibrated tracer counts for same counting time as

sample counts,W = sample weight (grams),T = counting time (minutes), and2.22 = dpm per pCi.

Calculate the concentration, Z, of thorium in plcocuries per gram asfollows:

z = (A - Aj) x F

(2.22HB - BjHEHWHT)

where

A = gross sample counts which appear in the thorium -227, -228,-230 or -232 alpha energy region,

A, = background counts in the same alpha energy region as £ above,B = gross tracer beta counts,B. = beta counter background,E = alpha detector efficiency,F = total calibrated tracer beta counts,W = sample weight (grams),T = counting time (minutes), and2.22 = dpm .per pCi.

00-05-7

AR3Q3I Ik

Calculate the lower limit of detection (LLD) for uranium or thoriin plcocuries per gram as follows:

4.66

um

LLD(2.22)(E)(R)(W)(T)

where

Cn = background count rate,T = counting time; same for sample and background,E = alpha detector efficiency,R = fractional yi Id based on B-B./F in calculation,W = sample weight (grams), and2.22 = dpm per pCi.

This LLD calculation is valid if the sample counting time is the sameas the background counting time.

Notes1. Nuclepore is a registered trademark of Nuclepore Corp., Pleasanton, CA.2. Teflon is a registered trademark of Dupont, Co., Wilmington, DE.3. The p-xylene removes most of the TIOA carried into the aqueous acid

phase. Residual TIOA makes the coprecipitation step more difficult.

References1. Moore, F.L., "Liquid-Liquid Extraction of Uranium and Plutonium from

Hydrochloric acid Solution with Tri (iso-octyl) amine," AnalyticalChemistry 30, 908 (1958).

2. Volchok, H. L. and dePlanque, G., editors, EML Procedures Manual, 25thEd., Environmental Measurement Laboratory, U.S. Department of Energy,New York.

3. Johns, F.B., et a!., Radiochemical Analytical Procedures for Analysisof Environmental Samples, EMSL-LV-0539-17, U.S. E.P.A., Las Vegas, NV,(1979).

00-05-8

A R 3 Q 3 I 1 5

RADIOCHEMICAL DETERMINATION OF THORIUM AND URANIUM IN WATER

PrincipleThe water sample is filtered. Thorium-234 and uranium-232 tracers are

added to 1 to 4 liter aliquots. After evaporation, the uranium isextracted into triisooctylamine (TIOA). The thorium is purified byadsorption on anion exchange resin from nitric acid. Uranium is strippedfrom the TIOA with nitric acid and copreci pita ted. Thorium is strippedfrom the resin with HC1 and copreci pita ted. Each actinide is radioassayedby alpha spectroscopy.

Special Apparatus1. Nuclepore filter membranes, 25 mm dia., 0.2 micrometer pore

size or equivalent. See Note 1.2. Ion exchange column, 2 cm internal diameter x 10 cm.3. Plastic graduated cylinder, 100 ml volume.4. Planchets, stainless steel, 32 mm diameter.5. Separatory funnels, 1 liter capacity.6. Suction filter for 25 mm membrane.7. Teflon beakers. See Note 2.8. Glassware.9. Pleated filter paper.10. Alpha spectrometric system consisting of multichannel analyzer,

biasing electronics, printer, silicon surface barrierdetectors, vacuum pump and chamber.

Reagents1. Anion exchange resin; BioRad AG1X8 (200-400 mesh, nitrate form)

or equivalent. Convert to nitrate form for thorium analysis bywashing the resin with 6M_ HN03 until the washing shows notrace of chloride, when tested with AgN03>

2. Ascorbic acid, crystalline reagent.

00-07-1

3. Hydrochloric acid, 12M . 37 percent HC1 reagent.4. Hydrochloric acid, 9NL Dilute 750 ml of the 37 percent reagent

grade HC1 to 1 liter with distilled water.5. Hydrochloric acid, 1NL Dilute 83 ml of the 37 percent reagent

grade HC1 to 1 liter with distilled water.6. Hydrofluoric acid, 29J , 48 percent HF reagent.7. Hydrofluoric acid, 3M^ Dilute 104 ml of the 48 percent reagent

grade HF to 1 liter with distilled water. Use a plasticgraduated cylinder and storage bottle.

+38. Lanthanum carrier, 0.1 mg La /ml. Dissolve 0.0779 g

La(NO.).- 6H00 per 250 ml 1M HC1.O O i. ~

9. Nickel foil, 15 cm x 1 cm x 0.1 mm.10. Nitric acid, 16M, 70 percent HN03 reagent.11. Nitric acid, 6M_. Dilute 375 ml of the 70 percent reagent grade

HN03 to 1 liter with distilled water.12. Nitric acid, O.IJ . Dilute 6 ml of the 70 percent reagent grade

HN03 to 1 liter with distilled water.13. Perchloric acid, 12 , 70 percent HC104 reagent.14. Silver nitrate, crystalline reagent.15. Silver nitrate, 0.1M_. Dissolve 1.7 g AgN03 reagent in

distilled water. Add 1 ml 6M HN03 and dilute to 100 ml withdistilled water.

16. Titanium trichloride, 20 percent reagent grade.17. Titanium trichloride, 0.4 percent. Dilute 1 ml of the 20

percent TICK to 50 ml with 1 M_ HC1. Prepare fresh daily.18. Triisooctylamine (TIOA), reagent grade.19. TIOA solution in p-xylene, 10 percent. Dissolve 100 ml of

triisooctylamine in p-xylene and dilute to 1 liter with p-xylene.20. p-Xylene, reagent grade.21. Thorium-234 tracer solution, approximately 800 pCi/ml, accurately

calibrated.22. Uranium-232 tracer solution, approximately 1 pCi/ml, accurately

calibrated.

00-07-2

AR303I17

Sample Preparation1. Filter water sample of one to four liters through a pleated

filter.2. Add 50 ml 12M HC1 and measured aliquots of 234Th and 232U

tracers.3. Evaporate sample to 200 ml volume.4. Add 600 ml of 12M HC1 to make sample concentration 9M in HC1.

Uranium Determination1. Place 100 ml of 10 percent TIOA solution in a 1 liter separatory

funnel. Add 50 ml 9M_ HC1 and shake funnel for one minute. Drainand discard lower aqueous acid phase after clean separation ofthe two phases.

2. Add the aqueous acid sample to the TIOA in the separatory funneland shake the funnel vigorously for two minutes. Vent the funnelstopcock to prevent pressure buildup in the funnel.

3. Allow the phases to separate cleanly and draw off the loweraqueous acid phase. Save for thorium analysis.

4. Add 50 ml 9M HC1 to the TIOA solution in the separatory funneland shake for one minute.

5. Allow the phases to separate; withdraw and discard lower aqueousacid phase.

6. Repeat steps 4 and 5.7. Strip the uranium from the TIOA solution by adding 100 ml

0.1M HN03 to the separatory funnel and shaking the funnel fortwo minutes.

8. Allow phases to separate; withdraw and save lower acid phase.9. Repeat steps 7 and 8 and combine strip solutions. Discard TIOA

solution.10. Place combined strip solutions in the clean separatory funnel.11. Add 100 ml p-xylene to combined strip solution and shake funnel

for one minute. See Note 3.

December 1985

00-07-3

flR303l(8

12. Allow phases to separate cleanly; withdraw lower aqueous acidlayer into beaker. Discard p-xylene.

13. Evaporate combined solution from step 12 to dryness. Do notoverheat.

14. Add 100 ml 16M_ HN03 to residue and evaporate to dryness. Donot overheat.

15. Add 5 ml 9M^ HC1 and 5ml 12M HC104 to residue and evaporate todryness.

16. Repeat step 15.17. Add 10 ml 12M_ HC1 and evaporate to dryness.18. Repeat step 17.19. Add 50 ml 1M HC1 to sample residue and warm gently to dissolve

residue.20. Heat sample solution to 80°C with stirring. Do not overheat.21. Suspend clean nickel metal strip into solution for two hours to

remove polonium.22. Remove nickel and evaporate solution to dryness.23. Add 15 ml 1M_ HC1 to sample residue and warm to approximately 50°C.24. Add enough ascorbic acid to reduce iron in the sample, indicated

by the disappearance of yellow color.25. Add 1 ml of 0.4 percent TiCl3 to reduce uranium.26. Add 1 ml of lanthanum carrier and 5 ml of 3M_ HF to precipitate

LaF, carrying uranium. Mix well and set aside for 30minutes.

27. Using suction, filter coprecipitated sample through a filtermembrane.

28. Rinse sample beaker with 10 ml water and add to filter funnel.Rinse beaker with 10 ml ethanol and add to funnel.

29. Remove clamp and top of funnel with suction on. Allow membraneto dry.

December 1985

00-07-4

AR3Q31 19

30. Mount membrane carefully on 32 mm planchet using double sticktape.

31. Count sample for 1000 minutes on alpha spectrometer.

Thorium Determination1. Evaporate aqueous acid fraction containing thorium from step 3 of

Uranium Determination.2. Add 10 ml 16M_ HNOo and evaporate to dryness.3. Add 5 ml SM HC1 and 5 ml 12M HC104 and evaporate to dryness.4. Add 10 ml of 16M HN03 and evaporate to dryness.5. Repeat step 4.6. Dissolve sample in 10 ml of 6M HNO, with heat.— ,3

7. Prepare ion exchange column with 25 ml BioRad AG1X8 resin. Washresin with 250 ml of 6M HN03>

8. Decant sample into column at gravity flow (approx. 3m1/nrin) andrinse the sample on the column with an additional 50 ml of 6MHN03. Discard wash.

9. Elute the thorium from the column with 200 ml of 6M HC1 at flowrate of 3 ml/minute.

10. Evaporate thorium eluate to dryness.11. Add 10 ml 12M_ HC1 to residue and evaporate to dryness.12. Add 15 ml 1M_ HC1 to sample residue and warm to approximately 50"C.13. Add 1 ml lanthanum carrier and 5 ml of 3M HF. Mix well and set

aside for 30 minutes.14. Using suction, filter coprecipitated sample through a filter .


Rinse beaker with 10 ml ethanol and add to funnel.16. Remove clamp and top of funnel with suction on. Allow membrane

to dry.17. Mount membrane carefully on 32 mm planchet using double stick

tape.

00-07-5

18. Beta count the sample to measure thorium-234 recovery.19. Count sample for 1000 minutes on alpha spectrometer.

Calculation^Calculate the concentration, Z, of uranium in picocuries per liter as

follows:

Z = (A-A x F

(2.22)(B-B1)(E)(Y)(T)

where

A = gross sample counts which appear in the uranium-234,-235,or-238 alpha energy region,

A, = background counts in the same alpha energy region as A_ above,B = gross tracer counts which appear in the alpha energy region

of the tracer isotope,B, = background counts in the same alpha energy region as B above,lE = alpha detector efficiency,F = total calibrated tracer counts for same counting time as

sample counts,Y = sample volume (liters),T = counting time (minutes), and2.22 = dpm per pCi.

Calculate the concentration, Z, of thorium in picocuries per liter asfollows:

z _ (A - Aj) x F

(2.22MB - B_)(E)(V)(T)

00-07-6

AR3Q3I2I

where

A = gross sample counts which appear in the thorium -227, -228,-230 or -232 alpha energy region,

A = background counts in the same alpha energy region as A^ above,B = gross tracer beta counts,B = beta counter background,E = alpha detector efficiency,F = total calibrated tracer beta counts,V = sample volume (liters),T = counting time (minutes), and2.22 = dpm per pCi.

Calculate the lower limit of detection (LLD) for thorium inpicocuries per liter as follows:

LLD - ' CBT(2.22)(E)(R)(W)(T)

where

CD = background count rate,DT = counting time (same for sample and background),E = alpha detector efficiency,R = fractional yield based on B-B,/F in calculation,V = sample volume (liters), and2.22 = dpm per pCi.

This LLD calculation is valid if the sample counting time is the sameas the background counting time.

00-07-7

^303/22

Notes1. Nuclepore is a registered trademark of Nuclepore Corp., Pleasanton, CA.2. Teflon is a registered trademark of Dupont, Co., Wilmington, DE.3. The p-xylene removes most of the TIOA carried into the aqueous acid

phase. Residual TIOA makes the copredpitation step more difficult.

References1. Moore, F.L., "Liquid-Liquid Extraction of Uranium and Plutonium from

Hydrochloric acid Solution with Tri (iso-octyl) amine," AnalyticalChemistry 30. 908 (1958).

00-07-8

AR303I23

RADIOCHEMICAL DETERMINATION OF RADIUM-226 IN SOLID SAMPLES

REQUIRING FUSION

PrincipleSolid samples are solubilized by fusion with a special flux. The

radium-226 in solution is determined by coprecipitation from the samplewith barium sulfate. The precipitate is solubilized and sealed in adeemanation tube. After an Ingrowth period, the radon-222 is removed intoan alpha scintillation counting cell for measurement.

Special Apparatus1. Metricel DM800 filter membranes or equivalent, 25 mm dia., 0.8

micrometer pore size. See Note 1.2. Magnetic stirrer and stirring bar.3. Platinum crucibles, 20 ml with lids.4. Suction filter apparatus.5. Tongs for platinum crucibles.

Reagents1. Acetone-ethanol mixture, 50 percent each reagent by volume.2. Ammonium sulfate, 10 percent. Dissolve 10 g reagent grade

(NH4)2S04 in distilled water and dilute to 100 ml.3. Barium chloride, 10 mg Ba*2/ml. Dissolve 17.79 g BaCl2' 2H20

in 1 liter distilled water.+24. Barium chloride, 2 mg Ba /ml. Dilute 200 ml of the 10 mg/ml

barium chloride solution to 1 liter. Filter after 24 hours.5. Fusion flux. Mix thoroughly 15 mg barium sulfate (BaS04),

32.9 g potassium carbonate (K2C03), 25.3 g sodium carbonate (Na2C03),16.8 g sodium tetraborate decahydrate (Na2B407 • 10H20).Heat to expel water, then fuse in a platinum crucible and mixthoroughly by swirling. Cool and grind in a porcelain mortar topass a 10 to 12 mesh screen. Store in an airtight bottle.

Ra-01-1

6. Hydrochloric acid, 3M. Dilute 250 ml of the 37 percent HC1reagent to 1 liter with distilled water.

7. Hydrogen peroxide, 3 percent reagent.8. Hydrofluoric acid, 29W, 48 percent HF reagent.9. Phosphoric acid, 15M, 85 percent H.,P04 reagent.10. Radium-226 standard solution, 5 to 10 pCi/ml traceable to NBS.11. Sulfuric acid, 18M, 96 percent H2S04 reagent.12. Sulfuric acid, 0.1 M. Dilute 6 ml of the 96 percent reagent

HS0 to 1 liter with distilled water.

Procedure1. Weigh sample using minimum of 0.5 g of soil sample and place in

platinum crucible.2. Add flux and mix, using 8 g of flux for each gram of sample. Do

not use less than 4 g of flux (for minimum of 0.5 g soil).3. Put lid on crucible and place it on tripod over burner. Fuse for

30 minutes.4. Swirl mixture at least once during fusion.5. Remove crucible from heat with tongs and swirl mixture until it

begins to solidify.6. Prepare the following solution in a beaker, made up as needed:

120 ml distilled water, 10 ml 18M H2S04, and 5 ml 3 percentH202.

7. Place platinum crucible and lid in beaker. Fused sample willdissolve away from crucible in about 30 minutes.

8. Remove crucible from solution. Rinse crucible with distilledwater and pour back into beaker.

9. Place magnetic stirring bar in beaker and begin stirring.10. Add 50 ml dilute BaCU solution to beaker.11. Stir contents of beaker for 90 minutes.12. Remove magnetic stirring bar and wait overnight for the BaS04

to precipitate.

Ra-01-2

"303125

13. Pour clear liquid off top of beaker so that entire quantity doesnot have to be filtered.

14. Pour remaining liquid and precipitate into funnel attached tosuction filter. Use 0.1 f4 H2S04 as wash solution and washfilter funnel twice with wash solution.

15. Remove clamp and lift filter funnel carefully to avoid removingfiltered precipitate. Use 1/2 filter membrane to wipeprecipitate clinging to bottom of filter funnel and placemembrane in a platinum crucible.

16. Carefully remove filter membrane from filter frit and place inplatinum crucible.

17. Add 25 drops 29M HF and 0.3 ml 10 percent (NH4)2$04solution to the crucible.

18. Place crucible on hotplate at low temperature and evaporatecontents to dryness.

19. Add 2 ml of acetone-alcohol mixture and burn off solvents with amatch.

20. Put top on crucible, place on tripod over burner, and heat untilashed (about 10-15 minutes).

21. Remove from heat and add 1 ml 15M H.,P04.22. Place crucible on hot place at low setting for 15 minutes. Turn

up to higher temperature for additional 30 minutes.23. Hold crucible with platinum-tip tongs in the hottest part of

flame of a burner.24. When white material dissolves and the bubbling and fumes

decrease, swirl crucible in upper part of flame for one minute.The result is a clear material which solidifies when removed fromthe heat.

25. Place crucible in hot water bath.26. Fill crucible with 3M HC1.27. Leaving lid off, allow liquid in crucible to evaporate slowly (2

1/2 - 3 hours) until almost completely evaporated with whitecrystals remaining.

Ra-01-3

AR303I26

28. Fill crucible approximately 1/2 full with deionized water andallow the crystals to dissolve.

29. Carefully pour solution from crucible into deemanation storagetube described in Deemanation Procedure. Rinse crucible withdeionized water.

30. Flame seal tube for storage as described in Deemanation Procedure.

Notes1. Metricel is a trademark of Gelman Sciences Inc., Ann Arbor, MI.

References1. Standard Methods for the Examination of Water and Waste Water, 15th

Ed., American Public Health Association, Washington, D.C. (1980).

Ra-01-4

AR303I27

RADIOCHEMICAL DETERMINATION OF RADIUM-226 IN WATER SAMPLES

PrincipleRadium-226 in solution Is determined by coprecipitation from the

sample with barium sulfate. The sample is then analyzed using thede-emanation procedure.

Special Apparatus1. Metricel DM-800 filter membrane, 25-mm dia., 0.8-micrometer pore

size or equivalent. See Note 1.2. Pleated filter paper.3. Platinum crucibles, 20 to 30 ml and lids.4. Crucible tongs for platinum.5. Glassware.

Special Reagents1. Acetone-ethanol, 50 percent each by volume.2. Ammonium sulfate, 10 percent. Dissolve 10 g (NH4)2S04 in

distilled water and dilute to 100 ml with distilled water.+23. Barium chloride stock solution, 10 mg Ba /ml. Dissolve 17.79 g

BaCl0» 2H00 in 1 liter of distilled water.f. £. +2

4. Barium chloride dilute solution, 2 mg Ba /ml. Dilute 200 mlof the barium chloride stock solution to 1 liter in a volumetricflask with distilled water.

5. Hydrochloric acid, 12M: 37 percent HC1 reagent.6. Hydrochloric acid, 3M. Dilute 250 ml of the reagent grade HC1 to

1 liter with distilled water.7. Hydrofluoric acid, 29M: 48 percent HF reagent.8. Phosphoric acid, 15M: 85 percent H.,P04 reagent.9. Radium-226 standard solution, approximately 5 to 10 pCi/ml,

traceable to the National Bureau of Standards.10. Sulfuric acid, ISM: 96 percent H2S04 reagent.

Ra-03-1

AR303I28

11. Sulfuric acid, 0.05M_. Dilute 1.6 ml of the H2$04 reagent to1 liter with distilled water.

Procedure1. If water sample is not clear, filter a one liter aliquot through

a pleated filter paper. Save any precipitate if the radiumcontent of the precipitate is needed. It is then analyzed usingthe procedure for solid samples.

2. Place the water sample in a 1.5 liter beaker, add a magneticstirring bar and place on a stirrer.

3. Add the following to the water sample with stirring: 20 ml 12M_HC1, 50 ml dilute BaCl2 reagent, and 20 ml 18M H2S04>

4. Cover sample and allow to stir for a minimum of 30 minutes toprecipitate BaS04.

5. Remove magnetic stirring bar and allow mixture to stand overnight.6. Decant clear liquid off the top so that entire quantity does not

have to be filtered.7. Decant remaining liquid and precipitate into funnel attached to

suction filter. Use 0.05M_ H2S04 as wash solution and washfilter funnel twice with wash solution.

8. Remove clamp and lift filter funnel carefully to avoid removingfiltered precipitate. Use half of a filter membrane to wipeprecipitate clinging to bottom of filter funnel and placemembrane in a platinum crucible.

9. Carefully remove filter membrane from the filter apparatus andplace in platinum crucible.

10. Add 25 drops 29M HF and 0.3 ml 10 percent (NH4)2S04solution to volatilize silica as SiF4.

11. Place crucible on hotplate at low temperature and take to dryness,12. Add 2 ml of acetone-alcohol mixture and burn off solvents with a

match.

Ra-03-2

13. Put top on crucible, place on tripod over burner, and heat untilashed (about 10-15 minutes).

14. Remove from heat and add 1 ml 15M^ H.,P04.15. Place crucible on hot plate at low setting for 15 minutes. Turn

up to higher temperature for additional 30 minutes.16. Hold crucible with platinum-tip tongs in the hottest part of

flame of a burner.17. When white material dissolves and the bubbling and fumes

decrease, swirl crucible in upper part of flame for one minute.The result is a clear material which solidifies when removed fromthe heat.

18. Place crucible in hot water bath.19. Fill the crucible almost full with 3M HC1 .20. Leaving lid off, allow liquid in crucible to evaporate slowly (1

1/2 - 3 hours) until almost completely evaporated with whitecrystals remaining.

21. Fill crucible approximately half full with deionized water andallow the crystals to dissolve.

22. Carefully pour solution from crucible into de-emanation storagetube described in De-emanation Procedure. Rinse crucible withdistilled water.

23. Flame seal tube for storage as described in the Radium-226De-emanation Procedure and proceed.

Notes1. Metricel is a trademark of Gelman Sciences, Inc., Ann Arbor, MI.

References1. Standard Methods for the Examination of Water and Waste Water, 15th

Ed., American Public Health Association, Washington, D.C. (1980).

Ra-03-3

AR303I30

RADIOCHEMICAL DETERMINATION OF RADIUM-226

De-emanation Procedure

PrincipleAfter sample preparation is completed, individual samples are sealed

in disposable storage tubes. Radon-222 ingrowth proceeds through threeweeks storage of the tubes. The tubes are then connected to a gasmanifold and the accumulated radon-222 is swept into evacuated Lucas alphascintillation counting cells. The alpha activity in the cells is measuredafter five hours ingrowth of radon-222 progeny.

Special Apparatus1. De-emanation manifold assembly.2. Lucas alpha scintillation cells.3. Photomultiplier tube assembly and associated electronics.4. Tank of nitrogen.5. Glass-sealing torch.6. Vacuum pump assembly.7. Pyrex brand glass tubing, 15-mm inside diameter, 60-cm lengths.8. Acid dichromate cleaning solution.9. Vinyl tubing, 1.3 cm inside diameter, 1.6 cm outside diameter.

Procedure1. Clean 60-cm lengths of glass tubing in dichromate cleaning

solution and dry.2. Flame seal one end of the individual sections of the glass tubing.3. Starting approximately 10 cm from the open end of a section of

the tubing, soften the tubing in a flame and form a constrictionapproximately 6.5 cm long and 0.6 cm diameter.

4. Transfer prepared sample to de-emanation tube using distilledwater as wash. Fill to within 1.3 cm of constriction.

Ra-04-1

5. Flame seal tube at constriction without overheating.6. Store sample-containing sealed tubes for at least 21 days.7. Soak one end of each of two 9 cm long by 1.25 cm in diameter

pieces of vinyl tubing in acetone until slight swelling occurs.8. Place a serum stopper in the solvent treated end of each piece of

tubing so that the tubing surrounds the sleeve of the stopper.9. Insert 26-gauge hypodermic needles in the rubber serum stoppers.10. Soak the other ends of the vinyl tubing in acetone until swelling

is evident.11. Slip the solvent-treated tubing over the sealed end of the sample

tube. Leave the needle inserted in the stopper to relievepressure as tubing dries.

12. Remove needles from stoppers after 24 hours.13. Evacuate Lucas scintillation cells by inserting needle connected

to vacuum line through stopper attached to neck of cell.14. Disconnect cell from vacuum line with vacuum pump operating.15. Set up radon transfer manifold as shown in the cell evacuation

illustration (Figure 1).16. Insert needle from vacuum line into lower stopper of the vacuum

tube. Insert needle attached to vacuum gauge into the samestopper.

17. Remove vacuum line needle and check gauge for possible leak.18. Reapply vacuum to tube and close upper valve.19. Insert needle from vacuum line into upper stopper of the sample

tube being careful not to break tip of tube with needle.20. Repeat step 19 for other end of sample tube.21. Allow 10 minutes to elapse in order to check for air leaks at

both ends of sample tube. A leak is indicated by partialrefilling of the collapsed vinyl tubing.

22. Attach sample cell to manifold as shown in purging illustration(Figure 2).

23. Break both top and bottom tips of sample tube using long nosepliers.

Ra-04-2

"R303/32

24. Record time.25. Put rubber sealant on the vinyl tubing in the area of the broken

glass tips as a precaution against puncture of the tubing.26. Cautiously open top valve to permit pressure equalization between

sample tube and Lucas cell, being careful not to draw up sampleliquid into drying tube.

27. Close upper valve.28. Start nitrogen purge with flow rate barely detectable through

hole in tubing.29. Flush valve, and, with valve closed, insert needle from flow tube

into lower stopper of sample tube.30. Cautiously open lower valve to control flow of nitrogen into

sample tube. The bubble rate should be between 15 and 45 perminute.

31. For a period of 30 minutes open upper valve briefly in order toequalize pressure between Lucas cell and sample tube.

32. After 30 minutes, open upper valve completely and open lowervalve to increase bubble rate.

33. When nitrogen flow has stopped and vinyl tubing has expanded toshape, simultaneously remove needles from stoppers of Lucas celland lower stopper of sample tube.

34. The Lucas cell is stored for 5 hours prior to counting foringrowth of radon-222 progeny.

35. Count the sample for 1000 minutes.36. Dispose of needles and drying tube.37. Clean upper valve by the following steps: (a) disassemble valve,

(b) submerge in acetone and rinse with water, (c) submerge inmineral spirits, (d) wash in hot soapy water and rinse, and(e) dry in oven at 75° C.

CalculationsCalculate the concentration^, of radium-226 in picocuries per liter

Ra-04-3

4R303133

as follows:

C 1 - C B(2.22MEHY) 1-e "xtl e "Xt2 1-e ~xt3

where

x = decay constant for radon-222 (t 1/2 = 3.825 days),t. = time interval allowed for ingrowth or radon from radium,t2 = time interval between de-emanation and counting,t- = counting time,C, = observed count rate of sample,CD = background count rate,DE - calibration constant of the scintillation cell in counts per

unit time per picocurie of radon plus decay products (All ofthe corrections can be obtained directly or indirectly fromTable 1),

V = sample volume (liters), and2.22 = dpm/pCi.

Sample Calculation

Assume the following data:

t. = 13d., 14 h., 6 m,t2 = 4 h., 15 m,t3 = 16 h., 30 m,C. = 199.2 counts/hour,CB = 9.3 counts/hour, andE = 151.1 counts/hour/dpm. See Note 1.

Ra-04-4

From Table 1,

1-e ~XtU 1. - 0.09484 x 0.89969 x 0.99925 = 0.91474,

e "Xt2 = 0.97025 x 0.99811 = 096842, and

Xt3/ (l-e"xt3) = 1.06358 (by linear interpolation).

From these data,

pCi Ra = (199.2 - 9.3) x 1 x 1 x 1.06358 = 0.680.

(151.1) (2.22) 0.91474 0.96842

Calculate the lower limit of detection (LLD) in plcocuries per literas follows:

LLD= 4.66(2.22){E)(V)(T)

where

CD = background count rate,bT = counting time,E = calibration constant of the scintillation cell in counts per

unit time per picocurie of radon plus decay products incounts per hour per dpm, and

V = sample volume, liters.

This LLD is valid if the background counting time is approximatelyequal to the sample counting time.

Notes1. The calibration constant is determined by sealing a known quantity of

radium-226 in a de-emanation tube. After 21 days storage, the radon

Ra-04-5

. fl-R303!35

is transferred to a Lucas cell and counted. The Lucas cells areindividually calibrated. The radium-226 used is traceable to theNational Bureau of Standards. Approximately 5-10 of radium-226,accurately known, is used for each calibration.

References1. Blanchard, R.L., An Emanation System for Determining Small Quantities

of Radium-226, U.S. Department of Health, Education, and Welfare,Public Health Service Publication No. 999-RH-9 (1964).

2. Ferri, E., Magno, P.J., and Setter, L.R., Radionuclide Analysis ofLarge Numbers of Food and Water Samples, U.S. Department of Health,Education, and Welfare, Public Health Service Publication Number999-RH-17 (1965).

3. Standard Methods for the Examination of Water and Waste Water, 15thEd., American Public Health Association, Washington, D.C. (1980).

4. Rushing, D.E., The Analysis of Effluents and Environmental Samplesfrom Uranium Mills and of Biological Samples for Uranium, Radium andPolonium. SM/41-44. Symposium of Radiological Health and Safety,Vienna, Austria (August 1963).

December 1985

Ra-04-6

AR3Q3J36

TABLE 1

A. Decay of Radon (in minutes, hours, and days)B. Growth of Radon from Radium (in days).C. Multiplicative Factor for Correction of Radon

Activity for Decay during Counting (in hours)

(Based on 3.825 days as half-life of radon)

Time

0

12345678910

1112131415

16171819202122232425

Minutes

1.000,00

0.999,870.999,750.999,620.999,590.999,370.999,250.999,120.998,990.998,870.998,74

0.998,620.998,490.998,370.998,240.998,11

0.997,990.997,860.997,740.997,610.997,490.997,360.997,240.997,110.996,990.996,86

A. e~xt

Hours

1.000,00

0.992,480.985,010.977,600.970,250.962,950.955,710. 943,520.941,390.934,310.927,27

0.920,310.913,380.906,510.899,690.892,93

0.886,210.879,550.872,930.866,360.859,850.853,380.846,960.840,590.834,270.827,99

Days

1.000,00

0.834,270.696,000.580,650.484,420.404,140.337,160.281,280.234,660.195,770.163,33

0.136,260.113,680.094,840.079,120.066,01

0.055,070.045,940.038,330.031,980.026,680.022,250.018,570.015,490.012,920.010,78

B. l-e-*t

Days

0.000,00

0.165,730.304,000.419,350.515,580.595,860.662,840.718,720.765,340.804,230.836,67

0.863,740.886,320.905,160.920,880.933,99

0.944,930.954,060.961,670.968,020.973,320.977,750.981,430.984,510.987,080.989,22

At

C. 1-e**

Hours

1.000,00

1.003,721.007,541.011,391.015,161.018,981.022,831.026,651.030,511.034,361.038,23

1.042,101.045,971.049,881.053,791.057,69

1.061,611.065,541.069,491.073,441.077,401.081,371.085,351.089,341.093,331.097,34

Ra-04-7 fl _ nSR3G3I37

TABLE 1 (Continued)

Time

2627282930

3132333435

3637383940

4142434445

4647484950

5152535455

5657585960

Minutes

0.996,730.996,610.996,480.996,360.996,23

0.996,110.995,980.995,860.995,730.995,61

0.995,480.995,360.995,230.995,110.994,98

0.994,850.994,730.994,600.994,480.994,35

0.994,230.994,100.993,980.993,850.993,73

0.993,600.993,480.993,350.993,230.993,10

0.992,980.992,850.992,730.992,600.992,48

A. e~x*

Hours

0.821,770.815,580.809,450.803,360.797,32

0.791,320.785,370.779,460.773,600.767,78

0.762,010.756,280.750,590.744,940.739,34

0.733,780.728,260.722,780.717,340.711,95

0.706,590.701,230.696,000.690,770.685,57

0.680,420.675,300.670,220.665,180.660,18

0.655,210.650,280.645,390.640,540.635,72

Days0.008,990.007,500.006,260.005,220.004,36

0.003,630.003,030.002,530.002,110.001,76

0.001,470.001,230.001,020.000,850.000,71

0.000,590.000,500.000,410.000,340.000,29

0.000,240.000,200.000,170.000,140.000,12

0.000,100.000,080.000,070.000,060.000,05

0.000,040.000,030.000,030.000,020.000,02

B. l-e-xt

Days

0.991,010.992,500.993,740.994,780.995,64

0.996,370.996,970.997,470.997,890.998,24

0.998,530.998,770.998,980.999,150.999,29

0.999,410.999,500.999,590.999,660.999,71

0.999,760.999,800.999,830.999,860.999,88

0.999,900.999,920.999,930.999,940.999,95

0.999,960.999,970.999,970.999,980.999,98

xt

C. l-e*t

Hours

1.101,361.105,391.109,451.113,471.117,52

1.121,581.125,661.129,741.133,831.137,94

1.142,051.146,171.150,301.154,441.158,59

1.162,751.166,921.171,091.175,281.179,47

1.183,681.187,891.192,12,1.196,351.200,60

1.204,851.209,111.213,381.217,661.221,95

1.226,251.230,561.234,881.239,211.243.54

Ra-04-8

flR303J38

18 ga. needles(glued)

H/468Ladapter

To VacuumoI

LucasScintillationCell

MagnesiumPerchlorate

18 ga. needles __ ,. , ,- w ML/ML sliplockadapter

Figure 1. C«fl evacuationAR3U3I39

18 ga. needles(glued)

MagnesiumPerchlorate

ML/ML sliplock18 ga. needles ^ UcT adapter

LucasScintillationCell

Tygon tubing L' "— SamPle

ML/MLsliplockadapter

__ 26 ga. needle

H/468Ladapter

From Nitrogen

Figure 2. C«l purging a*MmMy.

AR303UO

-r i • • i Serum Stopper20mm T i iiT

90mm i i iKovar Metal

PhosphorCoated

Clear SilicaWindow

50mm

Brass Collar

Flgurt 3. Lucas type scintillation eel.

Ra-04-11

AR303UI

METHOD 9310

GROSS ALPHA AND GROSS BETA

1.0 SCOPE AND APPLICATION

1.1 This method covers the measurement of gross alpha and gross betaparticle activities in surface and ground waters.

1.2 The method is applicable to the measurement of alpha emitters havingenergies above 3.9 mega electron volts (MeV) and beta emitters having maximumenergies above 0.1 MeV.

1.3 The minimum limit of concentration to which this method isapplicable depends on sample size, counting-system characteristics,background, and counting time.

1.4 Because, in this method for gross alpha and gross beta measurement,the radioactivity of the sample is not separated from the solids of thesample, the solids concentration is very much a limiting factor in thesensitivity of the method for any given water sample. Also, for samples withvery low concentrations of radioactivity, it is essential to analyze as largea sample aliquot as is needed to give reasonable times.

1.5 The largest sample aliquot that' should be counted for gross alphaactivity is that size aliquot which gives a solids density thickness of5 mg/cm2 in the counting planchet. For a 2-1n. diameter counting planchet(20 cm2), an aliquot containing 100 mg of nitrated dissolved solids would bethe maximum aliquot size for that sample which should be evaporated andcounted for gross alpha activity.

1.6 When the concentration of total solids (TS) is known for a givenwater sample and the alpha background and the counting efficiency of a givencounting system are known, the counting time that is needed to meet therequired sensitivity (3 pC1/L) can be determined by equations given inAppendix C.

1.7 For the counting of gross beta activity in a water sample, the TS isnot as limiting as for gross alpha activity because beta particles are notstopped in solids as easily as are alpha particles. Very often a singlesample aliquot is evaporated and counted for both gross alpha and gross betaactivity. In that case, the sample aliquot size would be dictated by thesolids limitations for alpha particles. For water samples that are to becounted for gross beta activity, equations 1n Appendix C can also be used todetermine the necessary counting time to meet a sensitivity for gross betaactivity (4 pC1/L).

1.8 Radionuclides that are volatile under the sample preparationconditions of this method will not be measured. In some areas of the countrythe nitrated water solids (sample evaporated with nitric acid present) will

9310 - 1RevisionDate September 1986

AR3G3II.2

not remain at a constant weight after being dried at 105*C for 2 hr and thenexposed to the atmosphere before and during counting. Other radioactivities(such as some chemical forms of radioiodine) may also be lost during thesample evaporation and drying at 105*C. Those types of water samples need tobe heated to a dull red heat for a few minutes to convert the salts to oxides.Sample weights are then usually sufficiently stable to give consistentcounting rates, and a correct counting efficiency can then be assigned. Someradioactivities, such as the cesium radloisotopes, may be lost when samplesare heated to a dull red color. Such losses are limitations of the testmethod.

1.9 This method provides a rapid screening measurement to indicatewhether specific analyses are required. When the gross alpha particleactivity exceeds 5 pC1/L, the same or an equivalent sample shall be analyzedfor alpha-emitting radium isotopes (Method 9315) or an alternative measurementof radium-226 alpha emission (Standard Methods for the Examination of Waterand Wastewater, 15th edition, Method 705 or 706, respectively). Gross betaparticle emissions exceeding 15 pC1/L in a sample shall be analyzed forstrontlum-89 and ceslum-134 (Standard Methods for the Examination of Water andWastewater, 15th edition, Methods 704 and 709, respectively). If gross betaactivity exceeds 50 pC1/L, the identity of the major radioactive constituentsmust be evaluated and the appropriate organ and total body doses determined.

2.0 SUMMARY OF METHOD

2.1 An aliquot of a preserved water sample 1s evaporated to a smallvolume and transferred quantitatively to a tared 2-1n. stainlesscounting planchet. The sample residue 1s dried to constant weight,to determine dry residue weight, and then counted for alpha and/orradioactivity.

2.2 Counting efficiencies for both alpha and beta particle activitiesare selected according to the amount of sample solids from counting efficiencyvs. sample solids standard curves.

3.0 INTERFERENCES

3.1 Moisture absorbed by the sample residue Is an Interference becauseit obstructs counting and self-absorption characteristics. If a sample Iscounted 1n an Internal proportional counter, static charge on the sampleresidue can cause erratic counting, thereby preventing an accurate count.

3.2 Nonun1form1ty of the sample residue in counting planchet interfereswith the accuracy and precision of the method.

3.3 Sample density on the planchet area should be not more than 10rag/cm2 for gross alpha and not more than 20 mg/cm2 for gross beta.


AR3Q3U3

3.4 When counting alpha and beta particle activity by a gas-flowproportional counting system, counting at the alpha plateau discriminatesagainst beta particle activity, whereas counting at the beta plateau Issensitive to alpha particle activity present in the sample. This lattereffect should be determined and compensated for during the calibration of thespecific instrument being used.

4.0 APPARATUS AND MATERIALS

4.1 Gas-flow proportional counting system, or4.2 Scintillation detection system, or

4.3 Stainless steel counting planchets.

4.4 Electric hot plate.

4.5 Drying oven.

4.6 Drying lamp.

4.7 Glass desiccator.

4.8 Glassware.

4.9 Analytical balance.

5.0 REAGENTS

5.1 All chemicals should be of "reagent-grade" or equivalent wheneverthey are commercially available.

5.2 Distilled or deionized water (Type II) having a resistance valuebetween 0.5 and 2.0 megaohms (2.0 to 0.5 mhos)/cm at 25*C.

5.3 Nitric acid. 1 N: Mix 6.2 ml 16 N HN03 (cone.) with deionized ordistilled water and dilute to 100 mL.

6.0 SAMPLE COLLECTION, PRESERVATION, AND HANDLING ""'

6.1 All samples must have been collected in a manner which addresses theconsiderations discussed 1n Chapter Nine of this manual.

6.2 It is recommended that samples be preserved at the time of collec-tion by adding enough 1 N HNC<3 to the sample to bring it to pH 2 (15 ml 1 NHN03 per liter of sample Is usually sufficient). If samples are to becollected without preservation, they should be brought to the laboratorywithin 5 days and then preserved and held in the original "container for aminimum of 16 hr before analysis or transfer of the sample.

9310 - 3Revision 0Date September 1986

/IR303UI*

6.3 The container choice should be plastic rather than glass to preventloss due to breakage during transportation and handling.

7.0 PROCEDURE

7.1 Calibration;

7.1.1 For absolute gross alpha and gross beta measurement, thedetectors must be calibrated to obtain the ratio of count rate todisintegration rate. Americ1ura-24l (used for alpha activity 1n thecollaborative test of this method) has higher alpha particle energy andradium-226 radlonuclides but is close to the energy of the alphaparticles emitted by naturally occurring thorium-228 and radium-224.Standards should be prepared In the geometry and weight ranges to beencountered in these gross analyses. It is, therefore, the prescribedradionuclide for gross alpha calibration. NBS or NBS-traceable,americium-241 is available from Standard Reference Materials Catalog, NBSSpecial Publications 260, U.S. Department of Commerce (1976) and fromQuality Assurance Branch, EMSL-LV, P.O. Box 15027, Las Vegas, Nevada89114.

7.1.2 Strontium-90 and cesium-137 have both been used quiteextensively as standards for gross beta activity. Standard solutions ofeach of these radionuclides are readily available. Cesium 1s volatile atelevated temperatures (above 450*C). Some water supplies have dissolvedsolids (salts) that, when converted to nitrate salts, are quitehygroscopic and need to be converted to oxides by heating to red heat toobtain sample aliquots that are weight-stable. Sample weight stability1s essential to gross alpha and gross beta measurements to ensure theaccuracy of the self-absorption counting efficiency factor to be used forthe samples. Strontium-90 in equilibrium with Its daughter yttrium-90 1sthe prescribed radionuclide for gross beta calibrations.

7.1.3 For each counting instrument to be used, the analyst shouldprepare separate alpha and beta particle self-absorption graphs showingwater sample residue weight (mg) vs. the efficiency factor (cpm/dpra),using standard alpha and beta emitter solutions and tap water. For thealpha graph standard, alpha activity is added to varying sizes ofaliquots of tap water such that the aliquot residue weight is variedbetween 0 and 100 mg (for a 2-1n. counting planchet). A similar graph 1sprepared with standard beta activity and tap-water aliquots, varying theresidue weight between 0 and 300 mg (for a 2-in. planchet). If It 1splanned to use water-sample aliquot volumes that always contain 100 mg ofdried water solids, then only the efficiency factor for that residueweight needs to be established.

": 7.1.4 Tap water aliquots, with added americium-241 or strontlura-90standard, should be acidified with a few ml 16 N HN03, evaporated to asmall volume in a beaker on a hot plate, transferred quantitatively in 5-mL portions or less to a tared counting planchet, evaporated to dryness,and finally dried at 105*C for 1 hr (or flamed to a red heat if dried


AR303U5

solids appear to be noticeably hygroscopic). Weight-stable aliquotresidues should then be alpha and/or beta counted until at least 10,000total counts have been accumulated. A single set of reference standardsprepared In this way can be used for each counting Instrument forseparate graph preparations and can be stored for reverificatlon wheneverneeded.

7.2 Transfer to a beaker an aliquot of water sample of a volume thatcontains no more than 100 mg (for alpha only or alpha and beta determination)or 200 mg (for beta only determination) of total water solids. Evaporate thealiquot to near dryness on a hot plate. If water samples are known orsuspected to contain chloride salts, those chloride salts should be convertedto nftrate salts before the sample residue is transferred to a stainless steelplanchet (chlorides will attack stainless steel and increase the samplesolids, and no correction can be made for those added solids). Chloride saltscan be converted to nitrate salts by adding 5-mL portions of 16 N HN03 to thesample residue and evaporating to near dryness. (Two treatments are usuallysufficient.) Add 10 ml 1 N HNOs to the beaker and swirl to dissolve theresidue. Quantitatively transfer the aliquot concentrate In small portions(not more than 5 mL at a time) to a tared planchet, evaporating each portionto dryness.

7.3 Dry the sample residue in a drying oven at 105'C for at least 1 hr,cool in a desiccator, weigh, and count. Store the sample residue in adesiccator until ready for counting.

7.4 Some types of water-dissolved solids, when converted to nitratesalts, are quite hygroscopic even after being dried at 105*C for 1 hr. Whensuch hygroscopic salts are present with samples that are put into an automaticcounting system, those samples gain weight while they are waiting to becounted, and inaccurate counting data result. When there is evidence ofhygroscopic salts In sample-counting planchets, it is recommended that they beflamed to a dull red heat with a Meeker burner for a few minutes to convertthe nitrate salts to oxides before weighing and counting. (It is possible tohave a loss of cesium during the flaming of the samples.)

7.5 Count for alpha and beta activity at their respective voltageplateaus. If the sample is to be recounted for reverification, store it in adesiccator.

NOTE: As long as counting chambers are capable of handling the same sizeplanchet, alpha and beta activities can be determined at theirrespective voltage plateaus in the designated countingInstruments. Keep the planchet in the desiccator until ready tocount because vapors from moist residue can damage detector andwindow and can cause erratic measurements. If the gas-flowInternal proportional counter does not discriminate for the higherenergy alpha pulses at the beta plateau, the alpha activity mustbe subtracted from the beta plus alpha activity. This 1sparticularly Important for samples with high alpha activity.


3R303U6

7.6 Calculations:

7.6.1 Calculate the alpha radioactivity by the following equation:

Alpha (pCi/liter) - g^z

where:

A » net alpha count rate (gross alpha count rate minus thebackground count rate) at the alpha voltage plateau;

C » alpha efficiency factor, read from the graph (Paragraph7.1.3) of efficiency vs. mg of water solids per da2 ofplanchet area, cpm/dpm);

V » volume of sample aliquot (ml); and2.22 » conversion factor from dpm/pC1.

7.6.2 Calculate the beta radioactivity by the following equations:

7.6.2.1 If there are no significant alpha counts when thesample is counted at the alpha voltage plateau, the beta activitycan be determined from the following equation:

Beta (pci/liter) * z.LV

where: ~\B * net beta count rate (gross alpha count rate minus the

background count rate at the beta voltage plateau),

..-,. . D » beta efficiency factor, read from the graph (Paragraph'.'''. ,.. 7.1.3) of efficiency vs. mg of water solids per on2 of • .

planchet area, (cpm/dpm). -"'••

.'". . V » volume of sample aliquot (mL).

2.22 » conversion factor from dpm/pd.

7.6.3 When counting beta radioactivity in the presence of alpharadioactivity by gas-flow proportional counting systems (at the betaplateau), alpha particles are also counted. Because alpha particles aremore readily absorbed by Increasing sample thickness than beta particles,the alpha/beta count ratios vary with increasing sample thickness.Therefore, 1t 1s necessary to prepare a calibration curve by countingstandards containing amer1cium-24l with increasing thickness of solids on


AR303U7

the alpha plateau and then on the beta plateau, plotting the ratios ofthe two counts vs. density thickness. The alpha amplification factor (E)from that curve 1s used to correct the amplified alpha count on the betaplateau. When significant alpha activity Is Indicated by the samplecount at the alpha voltage plateau, the beta activity of the sample canbe determined by counting the sample at the beta voltage plateau andcalculating the activity from the following equation:

Beu (pci/mer) . fBwhere:

B * as defined above.

D » as defined above.

A - as defined above.

E * alpha amplification factor, read from the graph of theratio of alpha counted at the beta voltage/alpha countedat the alpha voltage vs. sample density thickness.

V a volume of sample aliquot (mL).

2.22 » conversion factor from dpm/pCi.

7.7 Errors associated with the results of the analysis should also bereported .

8.0 QUALITY CONTROL

8.1 All quality control data should be maintained and available for easyreference or inspection.

8.2 Employ a minimum of one blank per sample batch to determine Ifcontamination is occurring.

8.3 Run one duplicate sample for every 10 samples. A duplicate sampleis a sample brought through the whole sample-preparation and analyticalprocess.

8.4 Spiked samples or standard reference materials shall be periodicallyemployed to ensure that correct procedures are being followed and that allequipment 1s operating properly.


AR303U8

9.0 METHOD PERFORMANCE

9.1 In a collaborative study of two sets of paired watercontaining known additions of radlonuclldes, 15 laboratories determinedgross alpha activity and 16 analyzed gross beta activity. The samplescontained simulated water minerals of approximately 350 ng fixed sollds/L.The alpha results of one laboratory were rejected as outliers.

The average recoveries of added gross alpha activity were 86, 87, 84, and82X. The precision (random error) at the 951 confidence level was 20 and 24Xfor the two sets of paired samples. The method was biased low, but notseriously.

The average recoveries of added gross beta activity were 99, 100, 100,and 100X. The precision (random error) at the 95X confidence level was 12 and18S for the two sets of paired samples. The method showed no bias.

10.0 REFERENCES^- . rr-r• '• : ~ ' v -1 •> .- ~ " / r •.10.1 None required. v

.2? fans:: Z~. -\j

"•:••.: .<: ..• ~i." .-i •;•••.- r "T ' ." -.-'I i i •": 1" "?•': • ;. • • -~ ' -


AR303U9

MCTHOO «30*055 M.*MA AMO MOSS »CTA

C "- )7. I

tc u(lngA»-*l 'o*- o«-o»«

•ion* • ctlvjty; Sr-90• r C»-J37 for gro««

»•«• activity

7. 1.3•*P>r*t«

«ndo»rtlcl»

••}f—•O«orotJon

C«Jeul»t« •ton,r«dlo»ct J»Ity

7.2

• wjrl; tr»n«f«r••en •liauet tot«rd ol»ncr»«t:

Acidify' t«D •»»t«f*

•liouots witni. •v»oor»tc:trmntftr top1«ncn«t

7. J .4ind dry:

count »Jpn«.

for r«f«r«nc«•t»nd*ra

7.2Tr»n«f«r

•llauat ofoctcr •••ol*to o«»k«r;•v»cor«t«

C«Icul«ter»oJo»ct1»Itr

( Stop )

9310 - 9Revision o

A R 3 0 3 i 5 0 ^te September 1986

METHOD 9315

ALPHA-EMITTING RADIUM ISOTOPES


1.1 This method covers the measurement of the total soluble alpha-emitting radioisotopes of radium, namely radium-223, radium-224, and radium-226, 1n surface and ground waters.

1.2 Although the method does not always give an accurate measurement ofthe rad1um-226 content of the sample (when other radium alpha emitters arepresent), 1t can be used to screen samples. When the total radium alphaactivity of a drinking water sample 1s greater than 5 pC1/L, then the radium-226 analysis Is required. If the level of radium-226 exceeds 3 pC1/L, thesample must also be measured for radlum-228 (Method 9320).

1.3 Because this method provides for the separation of radium from otherwater-dissolved solids 1n the sample, the sensitivity of the method 1s afunction of sample size, reagent and Instrument background, countingefficiency, and counting time.

1.4 Absolute measurement can be made by calibrating the alpha detectorwith standard rad1um-226 in the geometry obtained with the final precipitate.


2.1 The radium in the surface water or ground water sample is collectedby coprecipitation with barium and lead sulfate and purified by reprecipi-tation from EDTA solution. Citric acid 1s added to the water sample to assurethat complete Interchange occurs before the first precipitation step. Thefinal BaS04 precipitate, which includes rad1um-226, radium-224, and radium-223, Is alpha counted to determine the total disintegration rate of the radiumIsotopes.

2.2 The radium activities are counted in an alpha counter whereefficiency for determining radium-226 has been calibrated with a standard ofknown radium-226 activity. By making a correction for the ingrowth of alphaactivity 1n rad1um-226 for the elapsed time after separation, one candetermine radium activity 1n the sample. Because some daughter Ingrowth canoccur before the separated radium Is counted, 1t Is necessary to make activitycorrections for the count rate. A table of ingrowth factors for various timesafter radium separation is provided 1n Paragraph 7.14.

3.0 INTERFERENCES

3.1 Inasmuch as the radiochemical yield of the radium activity 1s basedon the chemical yield of the BaS04 precipitate, the presence of significantnatural barium in the sample will result 1n a falsely high chemical yield.


AR3-03I5I

3.2 Radium Isotopes are separated from other alpha-emlttiniradlonuclldes by this method.

3.3 The alpha count of the separated radlua must be corrected for Itspartially Ingrown alpha-emitting daughters.

4.0 APPARATUS AND MATERIALS

4.1 Alpha scintillation or a gas-flow proportional alpha particlecounting system with low background «1 cproj.



4.4 Drying oven and/or drying lamp.

4.5 Glass desiccator.


4.7 Centrifuge.

4.8 Glassware.

5.0 REAGENTS

5.1 Distilled or deionized water (Type II).

5.2 Acetic acid, 17.4 N: glacial CHsCOOH (cone.), sp. gr. 1.05, 99.85.-

- 5.3 Ammonium sulfate, 200 mg/mL: Dissolve 20 g (NH4)2S04 In a minimumof water and dilute to 100 ml.

... . 5.4 Barium carrier, 16 mg/mL, standardized:

',.." - 5.4.1 Dissolve 2.846 g BaCl2-2H20 in water, add 0.5 ml 16 N HN03,Z'T and dilute to 100 ml with water.

5.4.2 To perform standardization (in triplicate): Pipette 2.0 «Lcarrier solution Into a centrifuge tube containing 15 ml water. Add 1 mL18 N H2S04 with stirring and digest precipitate 1n a water bath for 10min. Cool, centrifuge, and decant the supernatant. Wash precipitatewith 15 ml water. Transfer the precipitate to a tared stainless steelplanchet with a minimum of water. Dry under Infrared lamp, store indesiccator, and weigh as BaS04.

5.5 Citric acid, 1 H: Dissolve 19.2 g C6H807-H20 In water and dilute to100 ml.


AR303I52

5.6 EDTA reagent, basic (0.25 M): Dissolve 20 g NaOH In 750 ml water,heat and slowly add 93 g d1sodium ethylened1n1tr1loacetate d1hydrate(Na2CioHi40sN2'2H20). Heat and stir until dissolved; filter through coarsefilter paper and dilute to 1 liter.

5.7 Lead carrier. 15 mg/mL: Dissolve 2.397 g Pb(N03)2 1n water, add 0.5ml 16 N HN03, and dilute to 100 ml with water.

5.8 Sodium hydroxide. 6 N: Dissolve 24 g NaOH In 80 mL water and diluteto 100 mL.

5.9 Sulfurlc add, 18 N: Cautiously mix 1 volume 36 N H2S04 (concen-trated) with 1 volume of water.

5.10 Sulfurlc add, 0.1 N: Mix 1 volume 18 N H2S04 with 179 volumesof water.

6.0 SAMPLE COLLECTION, PRESERVATION, AND HANDLING

6.1 All samples must have been collected 1n a manner which addresses theconsiderations discussed 1n Chapter Nine of this manual.

6.2 It 1s recommended that samples be preserved at the time ofcollection by adding enough 1 N HNOs to the sample to bring 1t to pH 2 (15 mL1 N HN03 per liter of sample 1s usually sufficient). If samples are to becollected without preservation, they should be brought to the laboratorywithin 5 days and then preserved and held 1n the original container for aminimum of 16 hr before analysis or transfer of the sample.

6.3 The container choice should be plastic rather than glass to preventloss due to breakage during transportation and handling.

7.0 PROCEDURE

7.1 Calibration: ._.$>

7.1.1 The counting efficiency for radium alpha particles withbarium sulfate carrier present must be determined using a standard(known) radium alpha activity and 32 mg of barium carrier as BaS04 (samecarrier amount used 1n samples). This 1s done with spiked distilledwater samples, and the procedure for regular samples 1s followed. Notethe time of the Ra-BaS04 precipitation.

7.1.2 The radium alpha counting efficiency, E, 1s calculated asfollows:

E (cpm/dpm) - -


R D O r\ o i r- -M i\ o u j j r^

where:

C - sample net cpra (gross counts minus background dividedby the counting time 1n minutes).

A * dpm of rad1um-226 added to sample.

I « Ingrowth factor for the elapsed time from Ra-BaS04,precipitation to midpoint of counting time.

7.2 To a 1,000-mL surface water or ground water sample, add 5 mL 1 MC6H8°7*H2°' ! mL lead carrier, and 2.0 mL barium carrier, and heat to boiling.

7.3 Cautiously, with vigorous stirring, add 20 mL 18 N H2S04. Digest 5to 10 min and let the mixed BaS04-PbS04 precipitate settle overnight. Decantand discard supernate.

7.4 Transfer the precipitate to a centrifuge tube with a minimum amountof 0.1 N H2S04. Centrifuge and discard supernate.

7.5 Wash the precipitate twice with 0.1 N H2S04. Centrifuge and discardwashes.

7.6 Dissolve the precipitate by adding 15 mL basic EDTA reagent; heat Ina hot-water bath and add a few drops 6 N NaOH until solution 1s complete.

- 7.7 Add 1 mL (NH4)2S04 (200 mg/mL) and stir thoroughly. Add 17.4 NCH3COOH dropwise until precipitation begins and then add 2 raL extra. Digest 5to 10 min.

7.8 Centrifuge, discard the supernate, and record time.NOTE: At this point, the separation of the BaS04 is complete, and the

Ingrowth of radon (and daughters) commences.

7.9 Wash the BaS04 precipitate with 15 mL water, centrifuge, and discardwash.

7.10 Transfer the precipitate to a tared stainless steel planchet with aminimum of water and dry under Infrared lamps.

NOTE: Drying should be rapid, but not too vigorous, to minimize any lossof radon-222 that has already grown Into the precipitate.

7.11 Cool, weigh, and store 1n desiccator.

7.12 Count in a gas-flow Internal proportional counter or an alphascintillation counter to determine the alpha activity.


flR30315lf

7.13 Calculation;

7.13.1 Calculate the rad1um-226 concentration, D (which wouldInclude any radium-224 and rad1um-223 that Is present), 1n plcocuries perliter as follows:

2.22 x E x V x R x I

where:C « net count rate, cpm.

E » counter efficiency, for rad1um-226 1n BaS04 predeterminedfor this procedure (see Paragraph 7.1.2).

V « liters of sample used.

R * fractional chemical yield.

I » Ingrowth correction factor (see Paragraph 7.14).

2.22 = conversion factor from dpm/pC1.

7.14 It 1s not always possible to count the BaS04 precipitateImmediately after separation; therefore, corrections must be made for theIngrowth of the radium-226 daughters between the time of separation andcounting, according to the following table:

Hours from separation Ingrowth correctionto counting factor

0 1.001 1.022 1.043 1.06

4 1.085 1.106 1.12

24 1.4948 1.9172 2.25

96 2.54120 2.78144 2.99

192 3.29240 3.51


flR303!55

8.0 QUALITY CONTROL

8.1 All quality control data should be maintained and available for easyreference or Inspection.

8.2 Employ a minimum of one blank per sample batch to determine 1fcontamination or any memory effects are occurring.

r

8.3 Run one duplicate sample for every 10 samples. A duplicate sampleIs a sample brought through the whole sample-preparation process.

8.4 Spiked samples or standard reference materials shall be periodicallyemployed to ensure that correct procedures are being followed and that allequipment 1s operating properly.


9.1 No data provided.

10.0 REFERENCES . . .

10.1 None required.


flR303i56

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7.6

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pr«clpit«t«to pl»ncr>«c;

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Correctfor Ingrowth

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St«rt )

9315 - 7Revision

AR303I57

METHOD 9320

RADIUM-228


1.1 This method covers the measurement of radium-228 1n ground waterand, 1f desired, the determination of radium-226 on the same sample. If thelevel of rad1um-226 1s above 3 pC1/L, the sample must also be measured forrad1um-228.

1.2 This technique 1s devised so that the beta activity from actlnlum-228, which 1s produced by decay of rad1um~228, can be determined and relatedto the rad1um-228 that 1s present 1n the sample.

1.3 To quantify act1nium-228 and thus determine rad1um-228, theefficiency of the beta counter for measuring the very short half-livedact1nium-228 (avg. beta energy of 0.404 keV) 1s to be calibrated with a betasource of comparable average beta energy.


2.1 The radium 1n the water sample Is collected by copredpitatlon withbarium and lead sulfate and purified by reprec1p1tat1on from EDTA solution.Both rad1um-226 and rad1um-228 are collected 1n this manner. After a 36-hrIngrowth of actin1ura-228 from radiura-228, the act1n1um-228 1s carried onyttrium oxalate, purified and beta counted. If rad1um-226 1s also desired,the activity 1n the supernatant can be reserved for copredpitatlon on bariumsulfate, dissolving In EDTA and storing for Ingrowth in a sealed radonbubbler.

3.0 INTERFERENCES

3.1 As evidenced by the results of the performance studies, the presenceof strontlum-90 1n the water sample gives a positive bias to the rad1um-228activity measured. However, strontlum-90 1s not likely to be found 1n groundwater, except possibly 1n monitoring wells around a radioactive burial site.

3.2 Excess barium 1n the water sample might result 1n a falsely highchemical yield.

4.0 APPARATUS

4.1 Gas-flow proportional counting system (low-background beta <3 cpro).



AR303I58

4.3 Centrifuge.

4.4 Membrane filters; Matrlcel 47-mra.

4.5 Drying lamp.

4.6 Glassware.



5.0 REAGENTS

5.1 ASTM Type II water (ASTM D1193): Water must be monitored forImpurities.

5.2 Acetic acid. 17.4 N: Glacial CthCOOH (concentrated) sp. gr. 1.0599.81.

5.3 Ammonium hydroxide. 15 N: NH40H (concentrated) sp gr. 0.90, 56.6X.

5.4 Ammonium oxalate, 5X: Dissolve 5g (Hti yCyQ HyO 1n Type II waterand dilute to 100 mL.

5.5 Ammonium sulfate. 200 rog/mL: Dissolve 20 g (NH4)2S04 1n Type IIwater and dilute to 100 mL.

5.6 Ammonium sulfide, 25: Dilute 10 mL (NH4)2S (20-241), to 100 mL withType II water.

5.7 Barium carrier, 16 mg/mL, standardized: Dissolve 2.846 g BaCl2-2H20in Type II water, add 0.5 mL 16 N HN03, and dilute to 100 mL with Type IIwater.

5.8 Citric acid. 1 M: Dissolve 19.2 g CsHeOT-H^ 1n Type II water anddilute to 100 mL. o o / _ JK _•i

5.9 EDTA reagent, basic (0.25 M) : Dissolve 20 g NaOH 1n 750 mL Type IIwater, heat, and slowly add 93 g d1 sodium ethyl ened1n1tr1loacetate d1 hydrate(Na2C10H1408N2-2H20) while stirring. After the salt 1s In solution, filterthrough coarse filter paper, and dilute to 1 liter.

5.10 Lead carrier, 15 mg/mL: Dissolve 2.397 g Pb(N03)2 1n Type IIwater, add 0.5 mL 16 N HN03, and dilute to 100 mL.wlth Type II water.

5.11 Lead carrier. 1.5 mg/mL: Dilute 10 mL lead carrier (15 mg/mL) to100 mL with Type II water.


AR3Q3J59

6.0 SAMPLE COLLECTION, PRESERVATION, AND HANDLING

6.1 All samples must have been collected In a manner which addresses theconsiderations discussed 1n Chapter Nine of this manual.

6.2 It 1s recommended that samples be preserved at the time ofcollection by adding enough 1 N HN03 to the sample to bring 1t to pH 2(15 mL 1 N HNO^ per liter of sample Is usually sufficient). If samples are tobe collected without preservation, they should be brought to the laboratorywithin 5 days, then preserved, and held In the original container for aminimum of 16 hr before analysis or transfer of the sample. See also Note toParagraph 7.2 below.

6.3 The container choice should be plastic (rather than glass) toprevent loss due to breakage during transportation and handling.

7.0 PROCEDURE

7.1 Calibrations:

7.1.1 Counter efficiency: The beta counter may be calibrated withactinium-228 or strontlura-89 (tj/2 » 51 d). Strontium-89 has an averagebeta energy of 0.589 KeV, while the average beta energy for act1nium-228Is 0.404 KeV. A standard strontlum-89 tracer solution can be used todetermine beta efficiencies over a range of precipitate weights on thestainless steel planchet.

7.2 For each liter of water, add 5 mL 1 M C Oj- 0' and a ew drops ofmethyl orange Indicator. The solution should be red.

NOTE: At the time of sample collection add 2 mL 16 N HNOs for each literof water.

7.3 Add 10 mL lead carrier (15 mg/mL), 2 mL strontium carrier(10 mg/mL), 2.0 mL barium carrier (16 mg/mL), and 1 mL yttrium carrier(18 mg/mL); stir well. Add 15 N NH4OH until a definite yellow color Isobtained; then add a few drops excess. Heat to incipient boiling and maintainat this temperature for 30 min.

7.4 Precipitate lead and barium sul fates by adding 18 N H2SOd until thered color reappears; then add 0.25 mL excess. Add 5 mL (NH4)2S04 (200 mg/mL)for each liter of sample. Stir frequently and keep at a temperature of about90*C for 30 min.

7.5 Cool slightly; then filter with suction through a 47-mra matricelmembrane filter (GA6,0.45-m1cron pore size). Make a quantitative transfer of

• precipitate to the filter by rinsing last particles out of beaker with astrong jet of water.

7.6 Carefully place filter with precipitate in the bottom of a 250-mLbeaker. Add about 10 mL 16 N HN03 and heat gently until the filter completely


AR303160

dissolves. Transfer the precipitate Into a polypropylene centrifuge tube withadditional 16 N HNOs. Centrifuge and discard supernatant.

7.7 Wash the precipitate with 15 «L 16 N HN03, centrifuge, and dlscasupernatant. Repeat this washing a second time.

7.8 Add 25 mL basic EDTA reagent, heat 1n a hot-water bath, and stirwell. Add a few drops 10 N NaOH 1f the precipitate does not readily dissolve.

7.9 Add 1 mL strontium-yttrium mixed carrier and stir thoroughly. Add afew drops 10 N NaOH 1f any precipitate forms.

7.10 Add 1 mL (NH4)2SOd (200 mg/mL) and stir thoroughly. Add 17.4 Nacetic add until barium sulfate precipitates; then add 2 mL excess. Digestin a hot water bath until precipitate settles. Centrifuge and discardsupernatant.

7.11 Add 20 mL basic EDTA reagent, heat in a hot-water bath, and stiruntil precipitate dissolves. Repeat steps 7.9 and 7.10. (Note time of lastbarium sulfate precipitation; this 1s the beginning of the act1nium-228ingrowth time.)

7.12 Dissolve the precipitate In 20 mL basic EDTA reagent as before;then add 1.0 mL yttrium carrier (9 mg/mL) and 1 mL lead carrier (1.5 mg/mL).If any precipitate forms, dissolve by adding a few drops 10 N NaOH. Cap thepolypropylene tube and age at least 36 hr.

7.13 Add 0.3 mL (NH4)2S and stir well. Add 10 N NaOH dropwlse wit.,vigorous stirring until lead sulflde precipitates; then add 10 drops excess.Stir intermittently for about 10 min. Centrifuge and decant supernatant Intoa clean tube.

7.14 Add 1 mL lead carrier (1.5 mg/mL), 0.1 mL (NH4)2S, and a few drops10 N NaOH. Repeat precipitation of lead sulfide as before. Centrifuge andfilter supernate through Whatman 142 filter paper Into a clean tube. Washfilter with a few mL water. Discard residue. 0

7.15 Add 5 mL 18 N NaCH, stir well, and digest 1n a hot-water bath untilyttrium hydroxide coagulates. Centrifuge and decant supernate Into a beaker.Save for barium yield determination (step 7.20). (Note time of yttriumhydroxide precipitation; this 1s the end of the act1n1um-228 ingrowth time andbeginning of actinium-228 decay time.) :•

7.16 Dissolve the precipitate 1n 2 mL 6 N HN03. Heat and stir 1n a hotwater bath about 5 m1n. Add 5 mL water and repredpltate yttrium hydroxidewith 3 mL 10 N NaOH. Heat and stir 1n a hot water bath until precipitatecoagulates. Centrifuge and add this supernate to the supernate produced 1nstep 7.15 1n order to determine barium yield.

7.17 Dissolve precipitate with 1 mL 1 N HN03 and heat In hot-water batha few minutes. Dilute to 5 mL and add 2 mL 5X (NH4)2C204'H20. Heat tocoagulate, centrifuge* and discard supernatant.


AR303I6I

7.18 Add 10 nL water, 6 drops 1 N HN03 and 6 drops 5X (NH4)2C204'H20.Heat and stir 1n a hot-water bath a few minutes. Centrifuge and discardsupernatant.

7.19 To determine yttrium yield, transfer quantitatively to a taredstainless steel planchet with a minimum amount of water. Dry under anInfrared lamp to a constant weight and count In a low-background beta counter.

7.20 To the supernatant from step 7.15, add 4 mL 16 N HN03 and 2 mL(NH4)2S04 (200 mg/mL), stirring well after each addition. Add 17.4 N aceticadd until barium sulfate precipitates; then add 2 mL excess. Digest on a hotplate until precipitate settles. Centrifuge and discard supernatant.

7.21 Add 20 mL basic EDTA reagent, rest 1n a hot-water bath, and stiruntil precipitate dissolves. Add a few drops 10 N NaOH 1f precipitate doesnot readily dissolve.

7.22 Add 1 mL (NH4)2S04 (200 mg/mL) and stir thoroughly. Add 17.4 Nacetic add until barium sulfate precipitates; then add 2 mL excess. Digest1n a hot-water bath until precipitate settles. Centrifuge and discardsupernatant.

7.23 Wash precipitate with 10 mL water. Centrifuge and discardsupernatant.

7.24 Transfer precipitate to a tared stainless steel planchet with aminimum amount of water. Dry under an Infrared lamp and weigh for bariumyield determination.

7.25 Calculation:

7.25.1 Calculate the rad1um-228 concentration, D, 1n plcocuries perliter as follows:

C 2 l l——L2.22 XEVR

2 1s a factor to correct the average count rate to the count-Xt- rate at the beginning of counting time.


AR3Q3I62

where:

C » Average net count rate, cpm;E « Counter efficiency, for actinlum-228, or comparable beta

energy nucllde;

V » Liters of sample used;

R » Fractional chemical yield of yttrium carrier (Step 7.19)multiplied by fractional chemical yield of barriercarrier (Step 7.24);

2.22 » Conversion factor from disintegrations/minute toplcocuries;

X - The decay constant for actlniura-228 (0.001884 min~l);

ti * The time Interval (in m1n) between the first yttriumhydroxide precipitation in Step 7.15 and the start ofthe counting time;

t2 3 The time interval of counting in min; and

t3 » The Ingrowth time of actinlum-228 1n min measured fromthe last barium sulfate precipitation in Step 7.11 tothe first yttrium hydroxide precipitation 1n Step 7.15.

8.0 QUALITY CONTROL

8.1 All quality control data should be maintained and available for easyreference or Inspection.

8.2 Employ a minimum of one blank per sample batch to determine ifcontamination or any memory effects are occurring.

8.3 Run one spike duplicate sample for every 10 samples. A duplicatesample 1s a sample brought through the whole sample preparation and analyticalp_rpcess._._ ... .. - -—

- . * •


9.1 No data provided.


4R3Q3I63

10.0 REFERENCES

1. Greenberg, A.E., J.J. Connors, and D.J. Jenkens, eds., Standard Methodsfor the Examination of Water and Wastewater, 15th ed., American Public HealthAssoc., Washington, D.C., Method 707, p. 600, 1980.

2. Johnson, J.O., Determination of Radium 228 1n Natural Waters.Radiochemical Analysis of Water. U.S. Geol. Surv., Water Supply Paper 1696-G.U.S. Govt. Printing Office, Washington, D.C., 1971.

3. Krieger, H.L., Prescribed Procedures for Measurement of Radioactivity 1nDrinking Water, Environmental Monitoring and Support Laboratory, U.S. EPA,Cincinnati, OH, EPA-600/4-75-008, 1976.


METHOD

c7.1.1

CallbrBt*beta counter>»ltr» AC-22B•r 5r-es

7.5

Cool cllgritly:filter

7.1Add

C,M,Ot-MtO ana•telhyl orangeindicator to

vater

7.6

Pvt filter endprecipitate in

t>«»K»r; add HNOj:Meet: centrjfoo*:dl«c»r-o aupernate

7.3Add

lead, atrontluw.oariu*. ana

earrlar»; atir

7.7

preciol tate:e«nt«r-f oge:d iscire

•uacrnatc

7.3

Add NH4OH until

aotalnea; naat

7.7

Repeat once

7.4 I Add H,*q.__——I topr-*cloltatclead and uur-lumaulfatee: add

atir

7.8

Add baelc COTAreagent: neat:

atir

O

S 7.1 \<-" Doe. ^

pr«c Ipl t»teX. readily s^^dleeolve? .X

Y7.9

——— • — t AOO•trontluo

yttrlun Bluedcarrier: add

NaOW

7.10(NH )t SCCM COOM.

centr)dlscara

7.11

leaU: adooigeet:if ug«:•up*rn .

Add oaeic EOT*reegent; neat:

•tlr

7.1l[

M«o*»t section*7.9 and 7. 10

*•« 7.tz|\, ————— '' Add NaOH to

dlaaolve

., -_ . _.


AR303I65

MCTMOO »32O"ADIUM-229(Continued)

7. 12Olaeo Ive

precipitatein COT*; »oOyttrium andlead carrier*

7.

Centrifuge anafilter

7.IS

rteet: centrifuge»nd aiacare•upernate

AddNaOH:

atir: digest:centrlfugeand decant•uo*rnatc

7. IB

Add -ete-r. MNOt.- .

Meat: centr l fuge anddiscard auoernate

Cao tuoe andage at laaat36 noura

7.16

Olaaolvc precipitate:neat and itir; aoo

•ater andrepreeipltate

yttriu* nydroxide

7. 19 Transferto

plancnet:deter»jna

yttriu* yieldusing counter

7. »3 Add) z S;

• dd NaO-i; ctlr:centr 1 f uga•no decant•uoernate

7. t£Heat:

cantr i f ug«:•dd aucernatr

to trtat ofatcp 7.15

7.20

Add MNOj. {NM4)aSOtfto Supernat* from7. IS: add CH.COOrC

oigeft: centrifuee;discard auoernete

7 . Add leadcarrier.

Ma(X repeatprecipitation

of lead aulfate

7.17

OliaolvePrecipitatewltn MWO,; heat

7.21

Add baa 1C EDTAreagent: peatin hot Datn

9320 - 9Revision

flR303!66n -.

METHOD -320MAOXUM-220(Continued)

Add (NH4)zSO<: atlr;add CHjCOOH; a loot:centrifuge: discard

•uoernate

7.23pr«c]eentren•uo«

7.Z*

preclplplancrx

weltOar lu«

7.215Ci

r»cconcarusing

ir

rasriPitate;•1 f uge:cardrn«t«

'rmnmf ertat* toe: ory.n fori yield

IculatrIuei-a2e• tr-atlonformula

i Cent

f StOO J


** t . 4o M ^ 2

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Transcript of ** t . 4o M ^ 2