The old method took four hours for each type of radium you needed to testtotaling eight hours for radium-226 and radium-228, said Rosson. Our method does the two tests simultaneously and it takes about half an hour of actual technician time.
Previously approved EPA methods for measuring radium required several isolation and purification steps involving sequential precipitations from large sample volumes and sometimes liquid-liquid extractions. They all ended with a complicated final preparation step before measurement with an alpha scintillation detection system. The scintillation detector detects and counts the flashes of light that are produced when a radioactive substance interacts with a special coating on the inside of the detection container.
The EPAs December 2007 deadline requiring every water supply be tested for radium-228 and gross alpha radioactivity greatly increased the number of radium-228 measurements required, as well as the likelihood both radium-226 and radium-228 must be measured in the same sample, also increasing the number of measurements required.
If the total radium concentration measured is above five picocuries per liter, then the water supply is out of compliance and radium-226 and radium-228 must be measured quarterly. This may require the water source to be replaced or treated to reduce the radium concentration. If the amount of radioactivity measured is less than five picocuries per liter, samples may be collected at three-, six- or nine-year intervals.
Since the EPA approved this new testing procedure in July 2006, GTRIs ERC has been able to use the testing method they developed to analyze water samples from Georgias Department of Natural Resources.
We analyze about 1,200 samples per year for them. With 3,000 to 6,000 water supply entry po
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Georgia Institute of Technology Research News