[Nuance-adding disclaimer: Added Jan 8, 2014 – Until lab tests are performed on rain samples at the time of radiation spikes, no statement about the cause of the observed elevated radiation measurements can be made scientifically: neither that it’s natural, nor that it’s from Fukushima. It requires lab tests.]
Not exactly what one would expect from the “reassurance” by Japanese Prime Minister Shinzo Abe’s (to the International Olympic Committee) that the crippled Fukushima nuclear plant’s leaks are “under control”(*): Gamma Radiation in the Northern hemisphere is apparently more affected by ‘the weather’ than by solar activity these days…
Even far inland places like Salt Lake City, Utah (where I walked through the lovely rain today), all major rain events and all major radiation spike events correlate perfectly.
See how the data sets match up (precipitation data in dark green (inside the black box) inserted on top of EPA Radnet gamma radiation data:
I took the gamma radiation(s) graph from the EPA’s Radnet and combined it with a daily hours of rain graph (the latter I had to cut short and stretch a bit for the calendar days to match (more the less). The correlation is pretty obvious.
Data Sources used:
- US EPA Radnet Monitor Salt Lake City, Utah: http://epa.gov/radnet/radnet-data/radnet-saltlakecity-bg.html
- Historical Weather Data by Weatherspark.com: http://weatherspark.com/history/31629/2013/Salt-Lake-City-Utah-United-States
Radnet Gamma’s data for last three months in Salt Lake City, UT:
Last year of rain data in Salt Lake City: UT:
Similar results can be found all over, such as very clearly recently in Seattle. If you’ve explored my page with radiation monitors, you know that in Germany the precipitation and radiation data are combined in the graph (which makes sense), on which you can see the same signature of radioactive particles coming down with the rain.
So is is dangerous?
That’s people main concern, understandably. Since radiation coming down appears to be on par or possibly higher than in 2011, consider the different warnings, which I mentioned in a blogpost way back in April 2011: ‘Above or Below “levels of concern”: USA vs. France‘ [re. 2011 rain measurements in France], of which this is the gist:
- CRIIRAD (France): “These low level activities do not imply that there was any risk for people who might have been under the rain without protection. However, the use of rainwater as main source of water supply for the alimentation is not recommended, particularly if consumers are young children.“
- US EPA (USA), regarding radioactivity in rain, which measured higher than in France after Fukushima: “…The levels detected are far below levels of concern. […] …the levels detected are far below levels of public-health concern.“
Although the amount of radioactive particles in a day of rain is likely to be relatively extremely low, but the cumulative effect of exposure through absorption (through foods that bioaccumulate/concentrate such particles) over a prolonged period is likely to be harmful to some. To find out which specific isotopes (of Iodine, Tellurium, Cesium, Strontium, etc.), and how much activity (in Bq) is being deposited (of each) per square meter, and where precisely, would require additional and widespread testing, something that is still not being done at this moment, as far as I know.
[edited on Sept 17, 2013]