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FACT SHEbl

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BUILDING A SCIENTIFIC FOUNDATION FOR SOUND ENVIRONMENTAL DECISIONS
EPA's rapid radiochemical methods expedite analytical
turnaround time for selected radionuclides while providing
quantitative results that meet measurement quality objectives.
Methods are applicable to samples where contamination is
from either known or unknown origins, This fact sheet is
intended for radioanalytical laboratory personnel, decision
makers within the incident command structure, additional
reoccupancy decision makers (e.g., state and local public
health), and other field environmental response personnel.
Method Summary: A known quantity of radium-225 (225Ra) is used as the yield determinant in this analysis. Since the
source of the suspected contamination may not be known, the sample is initially digested using concentrated nitric acid,
followed by volume reduction and conversion to the chloride salt using concentrated hydrochloric acid. The solution is
adjusted to a neutral pH and batch equilibrated with manganese oxide resin to separate radium from some radioactive and
non-radioactive matrix constituents. Further selectivity is achieved using a column which contains a gel-type cation resin.
The radium (including 226Ra) eluted from the column is prepared for counting by microprecipitation with barium sulfate. Low-
level measurements are performed by alpha spectrometry. The activity measured in the 226Ra region of interest is corrected
for chemical yield based on the observed activity of the alpha peak at 7.07 MeV (217At, the third progeny of 225Ra).
Rapid Radiochemical Method
Radium-226 (226Ra) in Water
Samples
Time to Process: 37 hr
Includes radiochemical processing and counting
Compare to traditional method (EPA 903.0): 18-22 hr
Without ingrowth: Needs 2-3 weeks ingrowth time
Method Application
The method is specific for the determination of soluble 226Ra in
drinking water and aqueous samples, Application of this
method should be validated by the laboratory using the
protocols provided in Method Validation Guide for Qualifvino
Methods Used bv Radioloaical Laboratories Particioatina in
Incident Response Activities, or the protocols published bv a
recognized standards organization for method validation.
Measurement Quality Objectives
Required method uncertainty: 0.65 pCi/L
Analytical action level (AAL): 5 pCi/L
Required relative uncertainty: 13% above AAL
Minimum detectable concentration: 1,0 pCi/L
Sample quantity: ~ 200 mL
Count time: 4 hr
Equipment and Supplies
Alpha spectrometer: calibrated for use over ~ 3.5-10 MeV ]
Centrifuge tubes: polypropylene, 50 mL, disposable, or
equivalent | Chromatography columns, polypropylene,
disposable: 1.5 cm I.D.x 15 cm with funnel reservoir, or
equivalent; 0.8 cm I.D. x 4 cm, or equivalent | Filter stand
and funnels | Filter 0.1 pm, ~ 25 mm diameter | Glass
beaker: 600 mL | Heat lamp: 250-300 watt, reflectors
mounted ~ 25 cm above base | Membrane filter: 0.45 pm,
~ 47 mm diameter j Petri dish or other suitable container for
storing sample test sources | pH paper | Stainless steel
planchets or suitable holders/backing for sample test
sources, to accommodate 25 mm diameter filter | Stirring hot
plate | Vacuum filtration apparatus
Optional: Centrifuae bottle: polypropylene, 250 mL,
disposable, or equivalent \ Magnetic stir bar
Sample Preservation
Samples should be collected in 1 L plastic containers
Analysis within 3 days of sampling: No preservation
required
Holding time >3 days: Adjust pH to <2 with concentrated
nitric acid
Waste Generated
Nitric acid | Hydrochloric acid | Radioactive tracer
Method Access:
https://www.epa.qov/sites/production/files/2015-
06/documents/ra-226 in water rev 0 1 epa 402-r-10-
Contacts
Proqram: Kathv Hall Technical: John Griaqs
001c.pdf
513-379-5260	334-270-3450
hall.kathy@epa.gov	griggs.john@epa.gov
U.S. Environmental Protection Agency	EPA/600/S-17/060
Office of Research and Development, Homeland Security Research Program	March 2017

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