The Determination of 226Ra in Water Samples

1
The Determination of 226Ra in Water Samples
eichrom
TECHNOLOGIES INC

• Anil H. Thakkar Michael Fern
• Eichrom Technologies, Inc.
• David McCurdy
• Duke Engineering Services

2
Objectives
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TECHNOLOGIES INC

• To design a procedure for radium in water which
  would
• be a simple, short and quick procedure
• allow to measure Ra-226 and Ra-224 via alpha
  spectroscopy and Ra-228 via Ac-228 measurements
• eliminate the tedious steps of precipitation and
  metathesis

3
Current Procedure Used
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TECHNOLOGIES INC

• Barium sulfate precipitation
• Conversion to BaCO3- tedious and time consuming

4
Current Procedure Used
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TECHNOLOGIES INC

• Sample Ba carrier Ba-133 Conc.H2SO4_ Heat
  BaSO4
• Precipitate allowed to settle for several hours
  or overnight
• Precipitate collected and converted to BaCO3

5
New Approach
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TECHNOLOGIES INC

• Water samples
• Cation exchange resin column
• Eichrom Ln Resin column

6
Preparation of Water Samples
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TECHNOLOGIES INC

• 0.5 L / 1.0 L water samples, acidified to
• pH 2
• Add 133Ba as a tracer

7
Eichrom Cation Exchange Column
eichrom
TECHNOLOGIES INC

• Load solution 0.5 L/ 1.0 L of sample
• Rinse with 50 mL of 0.1M HNO3
• Strip Ra and Ba with 50 mL of 8M HNO3

8
eichrom
TECHNOLOGIES INC
Preparation of Load Solution for Ln Resin Column

• Evaporate eluent from cation exchange column to
  dryness
• Dissolve residue in 10 ml of 0.095M HNO3 acid
• Load on Eichrom Ln Resin column

9
eichrom
TECHNOLOGIES INC
Ln Resin Column Separation

(1) Load 10 mL of mL 0.095M HNO3,
Collect (1) and (2) for Ba 226Ra
(2) Rinse 15 mL of 0.095M HNO3
(3) Strip 10 mL of 0.35M HNO3
collect (3) for 228Ac
10
226Ra Via Alpha Spectrometry
eichrom
TECHNOLOGIES INC

• Evaporate 226Ra/133Ba fraction to 10 mL volume
• Add 0.1 ml of 75 mg/ml barium carrier
• Add 3 mL of 40 sodium sulfate, 4 drops of 11
  acetic acid. Swirl
• Add 0.2 mL of seeding suspension. Mix
• Place tubes in cold water bath for 30 minutes
• Filter on 0.1 micron filters, count via alpha
  spectrometry

11
133Ba Via Gamma Counter
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TECHNOLOGIES INC

• Count 133Ba tracer yield via gamma spectrometry

12
228Ac Via Gas-Flow Proportional Counter
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TECHNOLOGIES INC

• Add 50 micrograms of cerium carrier
• Add 1.0 mL of HF
• Filter on 0.1 micron filters
• Measure for beta radiation

13
226Ra Recoveries-0.5L DI Water
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TECHNOLOGIES INC

14
226Ra Alpha Spectrum
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TECHNOLOGIES INC
15
133Ba Gamma Spectrum
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TECHNOLOGIES INC
16
226Ra, 224Ra, and Daughters
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TECHNOLOGIES INC
224Ra
226 Ra
220Rn
218Po
222Rn
17
226Ra Recoveries in Tap water
eichrom
TECHNOLOGIES INC

18
226Ra in EPA SampleSept.18, 1998
eichrom
TECHNOLOGIES INC

19
226Ra in NJ Sample
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TECHNOLOGIES INC

20
226Ra in Georgia Inst. Of Tech. Sample S8933
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TECHNOLOGIES INC

21
226Ra in Georgia Inst. Of Tech. Sample WS 14776
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TECHNOLOGIES INC

22
Summary
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TECHNOLOGIES INC

• Cation exchange resin option
• provides a good replacement for the time
  consuming BaSO4 precipitation steps
• it eliminates inconsistent metathesis steps
• reduces usage of chemicals/reagents
• provides consistency and saves time
• Acceptable 226Ra recoveries

23
Future Work

• To evaluate the effect of Ba/Ra uptake in high
  TDS samples especially with high Ca and Mg
  content
• To measure Ra-228 concentrations in samples

24
Acknowledgements

• Special thanks to
• Dr. B. Parsa, New Jersey department of health, NJ
• Dr. B. Kahn, Georgia Institute of Technology, GA