Validity of this map on past cesium deposition from global tests

According to estimates from the NCI and DOE, Washington County, Utah was one of the areas which received some of the highest levels of radioactive contamination from Nuclear Fallout. Cesium 137, a byproduct of Nuclear Fission was one of the nuclides deposited during this fallout period. Cesium 137 has a half life of 30 years and relatively high photon energy so it is easily detected and theoretically would still be present in the soil if it was originally deposited there. A study was conducted using soil samples from the Washington County area to determine if Cesium 137 still exists in the area in detectable amounts. 102 soil samples were collected and analyzed. Only one of the 102 soil samples did not have detectable amounts of Cesium contained within it. Several of the samples contained levels substantially higher than earlier estimates would have predicted. This leads us to conclude that doses to the public from the testing could also have been higher than earlier thought.

http://ir.library.oregonstate.edu/xmlui/handle/1957/9293