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Japanese Nuclear Emergency: Radiation Monitoring

RadNet Laboratory Data

EPA no longer updates the information at this link, but it may be useful as a reference or resource. This site contains information and data from March 11, 2011 to June 30, 2011. EPA has returned to routine RadNet operations. This site will continue to be available for historical and informative purposes.

For real-time air monitoring data, please visit the EPA RadNet website and Central Data Exchange. To view both current and historical laboratory data, please visit our Envirofacts database.

In the tables below we provide sampling results for:

The links above provide all data. You can also view the original sampling data reports published through April 6, 2011.

Air Filter and Air Cartridge

During detailed filter analyses from several RadNet air monitor locations across the nation, the U.S. Environmental Protection Agency (EPA) identified trace amounts of radioactive isotopes consistent with the Japanese nuclear incident. These types of findings are to be expected in the coming days and are far below levels of public health concern.

About air filter and air cartridge laboratory data


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Elevated levels of radioactive material in rainwater have been expected as a result of the Japanese nuclear incident. Since radiation is known to travel in the atmosphere - precipitation data collected in several states have shown elevated levels of radiation in recent precipitation events. In all cases, these are levels above the normal background levels historically reported in these areas. While short-term elevations such as these do not raise public health concerns and the levels seen in rainwater were expected to be relatively short in duration-U.S. EPA took steps to increase the level of monitoring of precipitation, drinking water, and other potential exposure routes to continue to verify that. After a thorough data review showing declining radiation levels in these samples, EPA has returned to the routine RadNet sampling and analysis process for precipitation, drinking water and milk.

About precipitation laboratory data

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The milk sampling results are far below the Food and Drug Administration's Derived Intervention Level for iodine-131 in milk. These types of findings are to be expected in the coming days and are far below levels of public health concern, including for infants and children. Iodine-131 has a very short half-life of approximately eight days, and the level detected in milk and milk products is therefore expected to drop relatively quickly.

About milk laboratory data

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Drinking Water

Drinking water samples collected by EPA since the Japanese nuclear incident have shown radioactive material at levels well below public-health concern. Similar findings are to be expected in the coming weeks.

About drinking water laboratory data

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Original Sampling Data Reports

As of April 5, 2011, EPA will present its laboratory data in an interactive format and move away from posting sampling results in pdf's. This is part of our continued effort to make the data more useful to the public. The pdf's published in the past are still available below, but are also incorporated into the current interactive format.

Air Filter and Cartridge Results

Precipitation Results

Milk Results

Drinking Water

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