EPA-NERL: 900.0: Gross Alpha and Beta Activity in Water
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Official Method Name
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Gross Alpha and Gross Beta Radioactivity in Drinking Water |
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Current Revision
| Aug-80 |
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Media
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WATER |
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Instrumentation
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Alpha Gas Particle Counter |
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Method Subcategory
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Radiochemical |
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Method Source
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Citation
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Brief Method Summary
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An aliquot of a preserved drinking water sample is evaporated to a small volume and transferred quantitatively to a tared 2-inch stainless steel counting planchet. The sample residue is dried to constant weight, reweighed to determine dry residue weight, then counted for alpha and/or beta radioactivity. Counting efficiencies for both alpha and beta particle activities are selected according to the amount of sample solids from counting efficiency vs sample solids standard curves. |
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Scope and Application
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This method is a screening technique that covers the measurement of gross alpha and gross beta particle activities in drinking water.
This method covers the measurement of gross alpha and gross beta particle activities in drinking water. The method is a screening technique for monitoring drinking water supplies for alpha and beta particle activities according to the limits set forth under the Safe Drinking Water Act, PL 93-523, 40 FR 34324, and thereby determining the necessity for further analysis. The method is applicable to the measurement of alpha emitters having energies above 3.9 megaelectronvolts (MeV) and beta emitters having maximum energies above 0.1 MeV. For drinking waters with an extremely high solids content (>500 ppm), method 900.1 is recommended. |
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Applicable Concentration Range
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Alpha: 1 pCi/L - * Beta: 4 pCi/L - * (* Method does not specify an upper detection limit.) |
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Interferences
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(1) Moisture absorbed by the sample residue. (2) Non-uniformity of sample residue in counting planchet. (3) Sample density on planchet area should not be more than 5 mg/cm2 for gross alpha and 10 mg/cm2 for gross beta. (4) Discrimination against beta/alpha activity by gas flow proportional counting. |
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Quality Control Requirements
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Not Included |
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Sample Handling
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Samples must be collected from a free flowing source and should be preserved at the time of collection with 1N HNO3 to pH 2. When a preservative is not added, samples should be brought to the laboratory within 5 days of sample collection and then preserved with 1N HNO3 to pH 2 in the original container at least 16 hours before analysis or transfer of the sample. The container should be plastic rather than glass to prevent breakage loss. |
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Maximum Holding Time
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Relative Cost
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$51 to $200 |
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Sample Preparation Methods
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