Oct. 31 — Monday morning in Washington D.C., Marco Kaltofen, PE, of the Department of Civil & Environmental Engineering at Worcester Polytechnic Institute in Massachusetts, discussed current issues concerning radiation exposure in Japan.
Kaltofen is a Massachusetts Registered Professional Engineer engaged in the investigation of nuclear material release. He investigated the transport of radioactive particles in his dissertation research at WPI.
Here are excerpts from the description for his presentation, ‘Radiation Exposure to the Population in Japan After the Earthquake’:
- “The Fukushima nuclear accident dispersed airborne dusts that are contaminated with radioactive particles. When inhaled or ingested, these particles can have negative effects on human health that are different from those caused by exposure to external or uniform radiation fields.”
- “A field sampling effort was undertaken to characterize the form and concentration of radionuclides in the air and in environmental media which can accumulate fallout. Samples included settled dusts, surface wipes, used filter masks, used air filters, dusty footwear, and surface soils.”
- “Isolated US soil samples [outskirts of Portland, OR] contained up to 8 nanoCuries per Kg of radiocesium, while control samples showed no detectable radiocesium.”
According to UC Berkeley, the highest cesium content in topsoil for each location sampled was fairly consistent throughout California:
- Sacramento, CA Topsoil on Aug. 16, 2011: Total Cesium @ 2.737 Bq/kg
- Oakland, CA Topsoil on Sept. 8, 2011: Total Cesium @ 2.55 Bq/kg
- Alameda, CA Topsoil on Apr. 6, 2011: Total Cesium @ 2.52 Bq/kg
- San Diego, CA Topsoil on June 29, 2011: Total Cesium @ 2.51 Bq/kg
- Sonoma, CA Topsoil on Apr. 27, 2011: Total Cesium @ 2.252 Bq/kg
The highest cesium levels of any topsoil measurements by UC Berkeley since the crisis began was 2.737 becquerels/kg in Sacramento. This is is equal to 73.9 picocuries/kg. (Conversion: 27 picocuries = 1 becquerel)
According to Kaltofen, the highest cesium levels detected in U.S. “surface soil” were up to 8 nanoCuries per Kg of radiocesium in the outskirts of Portland, OR. This is equal to 8,000 picocuries/kg. (Conversion: 1 nanocurie = 1,000 picocuries)
Kaltofen’s highest findings were up to 108 times greater than the highest findings by UC Berkeley.
Before Kaltofen’s finding, the highest cesium content in US topsoil post-Fukushima was 700 picocuries/kg near Reno at the base of the Sierra Nevada Mountains by a person affiliated with the University of Nevada. However, this was only preliminary and appears to not have been confirmed. See: 700 pCi/kg of Cesium-137 found in soil from base of Sierra Nevada mountains according to preliminary data
Though we do not know what location in the U.S. Kaltofen’s samples were from (hopefully that information will soon be made available UPDATE: SEE BELOW), we do know that UC Berkeley’s samples were taken in areas that had some of the highest radiation readings in the nation post-Fukushima.
Finally, Kaltofen’s control surface soil samples (known to be unaffected by Fukushima fallout) “showed no detectable radiocesium”, meaning the 8,000 pCi/kg finding of cesium was caused by the triple meltdowns in Japan rather than leftover from atomic weapons tests decades ago.
UPDATE: The slideshow from Kaltofen’s presentation is now available online via the Fairewinds website. However, it does not provide any specific information on the cesium detection in the US. The only additional mention on this topic is that “US samples had only two isolated Cs-134 and Cs-137 detections in soil.” It shouldn’t take to long before we find out how many US samples were tested, where they were from, and what the results and minimum detectable amounts were.
UPDATE II: In Arnie Gundersen’s latest video he says, “There is also data that indicates contamination on the ground in the Cascades, which are a mountain range right up against the Pacific Ocean.” The only other time he mentions a specific location for ground contamination is, “The Rocky Mountains stopped most of the radiation and deposited it on the ground.” Gundersen says there is ‘data’ about the Cascade’s ground contamination, where his statement about the Rockies was more general — So it looks like it was somewhere around the Cascade range in the Pacific Northwest.
Published: November 1st, 2011 at 12:00 am ET
- Highest Yet: Cesium-137 levels in Northern California soil hits post-Fukushima peak — UC Berkeley blames nuclear weapons tests 50+ years ago September 7, 2011
- Head Researcher: Boulder, Colorado a “hot spot” for Fukushima fallout — None of their other US or Canadian samples came close to Boulder’s contamination, except Portland which was even higher April 6, 2012
- On the Rise: Highest level of Cesium-137 in Bay Area topsoil since April June 11, 2011
- Cesium-137 in soil 40 km NW of Fukushima Daiichi more than highest levels found at Chernobyl March 26, 2011
- Cesium-137 levels continue to rise in San Francisco Bay Area topsoil May 3, 2011