http://nadp.sws.uiuc.edu/fukushima/

This project was implemented to add information about radioactive fallout from the March 12-14, 2011 incident and to test the capabilities of the NADP to respond to an unexpected atmospheric release.

The study found concentrations (activity) and fallout (deposition) of radioactive iodine and radioactive cesium in significant number of samples. Detectable quantities of Iodine-131, Cesium-137, and Cesium-134 were observed at 21% of the 167 tested locations. Concentrations of I-131 detected in 5 samples ranged from 29.6 to 1090 picocuries per liter (pCi/L). Concentrations of Cs-134 detected in 23 samples ranged from 0.4 to 55 pCi/L. Concentrations of Cs-137 in 33 samples ranged from 0.70 pCi/L to 39 pCi/L.

Detections and measurable fallout from wet deposition was observed primarily at NADP sites located along the West Coast of the US, the central Rocky Mountain region and northern Great Plains, the central and upper Mississippi River Valley and eastern mountainous regions ranging from Virginia northward through Vermont. Deposition was also observed at NADP sites in Alaska (see figure).

Health Effects of Cesium-137

How can cesium-137 affect people's health?

Like all radionuclides, exposure to radiation from cesium-137 results in increased risk of cancer. Everyone is exposed to very small amounts of cesium-137 in soil and water as a result of atmospheric fallout. Exposure to waste materials, from contaminated sites, or from nuclear accidents can result in cancer risks much higher than typical environmental exposures.

If exposures are very high, serious burns, and even death, can result. Instances of such exposure are very rare. One example of a high-exposure situation would be the mishandling a strong industrial cesium-137 source. The magnitude of the health risk depends on exposure conditions.

http://www.epa.gov/rpdweb00/radionuclides/cesium.html

Researchers at NILU estimate that the amount of cesium 137 released into the atmosphere to be just under half of the amount released at Chernobyl. Cesium 137, whether in the marine environment or in the atmosphere, presents a very real threat to raise the risk of cancer in those exposed to high amounts, especially since its half-life is measured at about 30 years.

http://www.cancertreatment.net/news/all-cancers/atmospheric-cesium-...

Through wind and rain Americans have been receiving radiation for the last 352 days. There is no ETA for containment.