Under normal conditions, RadNet air monitors operate continuously and samples of air, precipitation and drinking water are analyzed on a routine schedule. In a radiological emergency, EPA can send RadNet portable deployabledeployableIn the RadNet system, portable monitors that can be sent (deployed) quickly to a location where they are needed. monitors to any U.S. location and increase sampling and analyses frequency.
Routine Sampling
Medium
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Sampling Frequency
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Testing Frequency
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Air Filters
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Continuous (real time) |
Continuous (real time) |
Precipitation
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As rainfall, snow or sleet occurs |
Monthly analysis of a composite sample |
Drinking Water
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Quarterly |
Quarterly |
Routine Sample Analyses
Medium
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Analyses
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Air Filters
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Individual Samples
Annual Composite Samples
- Gamma analysis is performed on all annual composite samples.
- Isotopic plutonium (Pu) and uranium (U) analyses are performed on composite samples from one-fourth of the stations on a four-year rotating schedule.
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Precipitation
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Monthly Composite Samples
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Drinking Water
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Individual Samples
- Tritium (H-3) analysis is performed on each quarterly sample received.
- Iodine-131 (I-131) analyses are performed on one sample per station per year.
Composite Samples
- Gross alphaalpha Alpha particles come from heavy radioactive elements such as uranium, radium and polonium. They can be stopped by a thin layer of light material, such as a sheet of paper, and cannot penetrate the outer, dead layer of skin. Therefore, they do not damage living tissue when outside the body. However, they can damage living tissue and pose a serious health threat if swallowed or inhaled., betabetaBeta particles come from many different radioactive elements, both natural and man-made. Although they can be stopped by a thin sheet of aluminum, beta particles outside the body can cause burns to unprotected skin. They can pose a serious health threat if swallowed or inhaled. and gammagammaGamma rays come from many different radioactive elements, both natural and man-made. Gamma rays can penetrate several feet of concrete or a few inches of lead. Gamma rays can pose a serious health threat inside and outside the body and can be lethal depending on the amount received. Scientists use the properties of gamma rays to identify radioactive elements. are performed on all composite samples.
- Strontium-90 (Sr-90) is performed on composite samples from one-fourth of the stations on a four-year rotating schedule.
- Radium-226 if the gross alpha exceeds 2 pCi/L.
- Radium-228 if the Radium-226 results are between 3 and 5 pCi/L.
- Isotopic uranium and plutonium if gross alpha exceeds 2 pCi/L.
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RadNet sampling and analysis are particularly useful when an event such as an explosion or fire sends significant levels of radionuclides into the air. Results of real-time data acquisition and subsequent sample analysis can provide critical information on the identity and concentration of radionuclides in air, precipitation and drinking water. Data from RadNet are useful in dose assessments, as health physicists estimate the immediate and long-term environmental and public health effects.
Learn how RadNet was used during and after Chernobyl, Fukushima and other radiological incidents on the Historical Radiological Event Monitoring page and in the report, Historical Uses of RadNet Data (PDF) (36 pp, 564.16 K, About PDF).