Thanks very much, BC, very interesting! A lot of variability. 2:1 ratio of C134:Cs 137 doesn't seem to hold throughout--wonder why....
Also wonder if Canadian scientists will be coming out with something like this anytime soon...(I'm not holding my breath).
1) Gundersen and co. talked a lot early on about the PNW getting the worst of it. This report seems to indicate somewhat otherwise...it looks like the worst observed Cs fallout was in SoCal. Granted, the PNW saw more I-131, but that's gone now.
I am thinking that this is because the I-131 and Xe-133 (and probably a few others) have a higher volatility and were thus released at different times. So one place might get the gases while another gets the cesium, depending on time of releases and weather patterns.
One thing I am left wondering is about actinides - how much was there, and where did it go and when? Did any places just get pounded?
Gov-Co, if you're out there, how about you do us all a solid and test for this stuff?
2) On pg 26 they make it clear that there is a substantial margin of error on the Cs-134 measurement for all but one sample, and that is Co90, which had a ~1:1 Cs-134/Cs-137 ratio. This ~1:1 ratio is the benchmark, so when I look at the report I just look at the Cs-137 number and figure that a like amount of Cs-134 was there too.
Interestingly, they had a sample from near Berkeley that showed at total Cs-137 deposition of 30 bq/m2. This is very close to the amount I had figured using BRAWM's radioactivity measurements and precip info from weather underground. http://www.nuc.berkeley.edu/node/5449
3) Sampling ended 4/5. BRAWM had two detections after that, albeit with lower levels of nuclides and also smaller amounts of precip. So these numbers from USGS should not be taken as all inclusive even for the areas the samples were taken from. That having been said, I would say they are 80-90% accurate for most locations keeping in mind #2 above.
4) To give some perspective to these levels of fallout...Many areas in the USA saw cumulative levels of 50,000 to 100,000 bq/m2 of I-131 deposition during the atomic testing era. Some areas (Utah, New Mexico, Arizona, Colorado, Nevada) saw levels of I-131 deposition during that time of 500,000 bq/m2 and up. If you figure that the time of atomic testing at NTS was approx 15 years, it's fair to say that in any given year during the atmospheric testing era anyone downwind from NTS could have seen levels of I-131 similar to what the worst spot recorded in the USA saw from Fukushima (around 5000 bq/m2).
As for cesium, if we look at the worst cesium deposition of about 500 bq/m2 at that isolated SoCal point, it is helpful to see that most of USA saw depositions of 2000-4000 bq/m2 from atmospheric testing (most of the cesium was from "global", not NTS testing). So again, I think in any given year (or 2) combined during the testing era anyone in the USA might have seen a similar level of nukey-poo dumped on them as was seen at this worst recorded spot.
This is not to minimize. ANY fallout is bad fallout. Just some perspective based on past events.
"Measured were the radioactive isotopes Iodine 131, Cesium 134 and Cesium 137. Measurements over one or two weeks at 35 sites from Alaska to Vermont ranged from 0.47 to 5,100 Becquerels per square meter during the sampling period of March 15–April 5, 2011. A Becquerel is a measurement of a particle's radioactive decay rate." http://www.nola.com/science/index.ssf/2012/02/small_amounts_of_radiation...
"Had this been a national incident, (the National Atmospheric Deposition Program monitoring) would have revealed the spatial and temporal patterns of radioactive contamination in order to help protect people and the environment," said USGS director Marcia McNutt.
The southeastern sites were not used because it would have disrupted a special study tracking airborne food-crop pathogen spores, said Mark Nilles, a USGS researcher and co-author of the radiation study. http://www.nola.com/science/index.ssf/2012/02/small_amounts_of_radiation...
Sorry southeast pathogen study trumped radiation study...
it's fair to say that in any given year during the atmospheric testing era anyone downwind from NTS could have seen levels of I-131 similar to what the worst spot recorded in the USA saw from Fukushima
=====================================
Even with all the fallout due to nuclear testing; Mother Nature still TRUMPS with regard to the average person's radiation exposure.
Courtesy of the Health Physics Society at the University of Michigan:
we see that the amount due to "Fallout" from nuclear tests amounts to <0.03% of the average person's radiation exposure.
The main source of radiation exposure for the average person is NOT Fukushima, is NOT nuclear testing, is NOT nuclear medicine. The main source of radiation exposure to the average person is now, and has always been good old Mother Nature.
Ok , people who read this forum at this point are aware of natural radiation .If you haven't noticed what we are discussing here is the monitoring of radiation from FUKUSHIMA DAIICHi...tdm
It's good to see some good scientists or people who know science comment on all the fear mongering by the anti-nuclear community. The anti-nuclear community has been trying to milk Fukushima for all it is worth by telling gargantuan lies. Thanks to BRAWM and the posters here, it's been shown to be the work of first-class propagandists.
I appreciate you taking the time to review and recap this for us. And I agree with your presentation of comparisons with the still-astonishing amount of fallout that was dumped on us from the testing.
I agree with your assessment BC, it certainly seems like the fallout in the Northern Hemisphere and all over Western Europe from Chernobyl was orders of magnitude higher. here are two questions still in my mind, however:
1. the USGS data, as well as every published study on Fukushima emissions outside of Japan, only examines the at most the two month period following the disaster. If anyone puts any stock in the continued evidence of releases following that period then there is no data at all on what the cumulative deposition has been.
2. the USGAS study and others typically look only at radionuclides that can be detected by gamma spectrometry, i.e. Cs 137/134 and I 131. This has been bothering me because the deposition of bone-seeking radionuclides of Sr, U, Pu and Am, all of which have been detected in by somebody following fukushima, is completely unknown.
I think that we can assume that: the above mentioned unaccounted-for isotopes must be in lower amounts than Cs 137/134, though I've not been able to find a reference specifically detailing this.
Sr is a beta emitter so it is very difficult to separate it from all the other natural beta emitters. I would expect that anywhere you detect Cs there will also be Sr.
Strontium and Radium are both in the same line of the periodic table as Calcium so their chemical behavior is similar. The body will concentrate them in the bones.
I haven't heard of U, Pu and Am being "bone-seekers".
I realize it's more difficult to find, but there's a wealth of information regarding levels of Sr 90 in the food supply from the 50's and 60's. I think it's strange there has been so little testing for it now.
all those listed are known to deposit in bones, the kidneys and the liver.
Thanks very much, BC, very
Thanks very much, BC, very interesting! A lot of variability. 2:1 ratio of C134:Cs 137 doesn't seem to hold throughout--wonder why....
Also wonder if Canadian scientists will be coming out with something like this anytime soon...(I'm not holding my breath).
Yeah, it is interesting.
Thoughts-
1) Gundersen and co. talked a lot early on about the PNW getting the worst of it. This report seems to indicate somewhat otherwise...it looks like the worst observed Cs fallout was in SoCal. Granted, the PNW saw more I-131, but that's gone now.
I am thinking that this is because the I-131 and Xe-133 (and probably a few others) have a higher volatility and were thus released at different times. So one place might get the gases while another gets the cesium, depending on time of releases and weather patterns.
One thing I am left wondering is about actinides - how much was there, and where did it go and when? Did any places just get pounded?
Gov-Co, if you're out there, how about you do us all a solid and test for this stuff?
2) On pg 26 they make it clear that there is a substantial margin of error on the Cs-134 measurement for all but one sample, and that is Co90, which had a ~1:1 Cs-134/Cs-137 ratio. This ~1:1 ratio is the benchmark, so when I look at the report I just look at the Cs-137 number and figure that a like amount of Cs-134 was there too.
Interestingly, they had a sample from near Berkeley that showed at total Cs-137 deposition of 30 bq/m2. This is very close to the amount I had figured using BRAWM's radioactivity measurements and precip info from weather underground. http://www.nuc.berkeley.edu/node/5449
3) Sampling ended 4/5. BRAWM had two detections after that, albeit with lower levels of nuclides and also smaller amounts of precip. So these numbers from USGS should not be taken as all inclusive even for the areas the samples were taken from. That having been said, I would say they are 80-90% accurate for most locations keeping in mind #2 above.
4) To give some perspective to these levels of fallout...Many areas in the USA saw cumulative levels of 50,000 to 100,000 bq/m2 of I-131 deposition during the atomic testing era. Some areas (Utah, New Mexico, Arizona, Colorado, Nevada) saw levels of I-131 deposition during that time of 500,000 bq/m2 and up. If you figure that the time of atomic testing at NTS was approx 15 years, it's fair to say that in any given year during the atmospheric testing era anyone downwind from NTS could have seen levels of I-131 similar to what the worst spot recorded in the USA saw from Fukushima (around 5000 bq/m2).
As for cesium, if we look at the worst cesium deposition of about 500 bq/m2 at that isolated SoCal point, it is helpful to see that most of USA saw depositions of 2000-4000 bq/m2 from atmospheric testing (most of the cesium was from "global", not NTS testing). So again, I think in any given year (or 2) combined during the testing era anyone in the USA might have seen a similar level of nukey-poo dumped on them as was seen at this worst recorded spot.
This is not to minimize. ANY fallout is bad fallout. Just some perspective based on past events.
BC 2/25/11
Any idea where the 5,100 bq per square meter was located
"Measured were the radioactive isotopes Iodine 131, Cesium 134 and Cesium 137. Measurements over one or two weeks at 35 sites from Alaska to Vermont ranged from 0.47 to 5,100 Becquerels per square meter during the sampling period of March 15–April 5, 2011. A Becquerel is a measurement of a particle's radioactive decay rate."
http://www.nola.com/science/index.ssf/2012/02/small_amounts_of_radiation...
"Had this been a national incident, (the National Atmospheric Deposition Program monitoring) would have revealed the spatial and temporal patterns of radioactive contamination in order to help protect people and the environment," said USGS director Marcia McNutt.
The southeastern sites were not used because it would have disrupted a special study tracking airborne food-crop pathogen spores, said Mark Nilles, a USGS researcher and co-author of the radiation study.
http://www.nola.com/science/index.ssf/2012/02/small_amounts_of_radiation...
Sorry southeast pathogen study trumped radiation study...
Mother Nature still trumps...
it's fair to say that in any given year during the atmospheric testing era anyone downwind from NTS could have seen levels of I-131 similar to what the worst spot recorded in the USA saw from Fukushima
=====================================
Even with all the fallout due to nuclear testing; Mother Nature still TRUMPS with regard to the average person's radiation exposure.
Courtesy of the Health Physics Society at the University of Michigan:
http://www.umich.edu/~radinfo/introduction/radrus.htm
we see that the amount due to "Fallout" from nuclear tests amounts to <0.03% of the average person's radiation exposure.
The main source of radiation exposure for the average person is NOT Fukushima, is NOT nuclear testing, is NOT nuclear medicine. The main source of radiation exposure to the average person is now, and has always been good old Mother Nature.
Ok , people who read this
Ok , people who read this forum at this point are aware of natural radiation .If you haven't noticed what we are discussing here is the monitoring of radiation from FUKUSHIMA DAIICHi...tdm
Perspective
YES - I know we are discussing Fukushima.
Part of that discussion is to keep Fukushima in PERSPECTIVE!!!
With all the hype from the media and the pea-brained anti-nukes; many may not realize that they get more radiation from Mother Nature than Fukushima.
Keep it up champ, you're
Keep it up champ, you're terrific!
I second that
It's good to see some good scientists or people who know science comment on all the fear mongering by the anti-nuclear community. The anti-nuclear community has been trying to milk Fukushima for all it is worth by telling gargantuan lies. Thanks to BRAWM and the posters here, it's been shown to be the work of first-class propagandists.
Thanks BC
Thanks BC,
I appreciate you taking the time to review and recap this for us. And I agree with your presentation of comparisons with the still-astonishing amount of fallout that was dumped on us from the testing.
A Lurker from the Very Beginning...
two points
I agree with your assessment BC, it certainly seems like the fallout in the Northern Hemisphere and all over Western Europe from Chernobyl was orders of magnitude higher. here are two questions still in my mind, however:
1. the USGS data, as well as every published study on Fukushima emissions outside of Japan, only examines the at most the two month period following the disaster. If anyone puts any stock in the continued evidence of releases following that period then there is no data at all on what the cumulative deposition has been.
2. the USGAS study and others typically look only at radionuclides that can be detected by gamma spectrometry, i.e. Cs 137/134 and I 131. This has been bothering me because the deposition of bone-seeking radionuclides of Sr, U, Pu and Am, all of which have been detected in by somebody following fukushima, is completely unknown.
I think that we can assume that: the above mentioned unaccounted-for isotopes must be in lower amounts than Cs 137/134, though I've not been able to find a reference specifically detailing this.
AR
measurement limitations
Sr is a beta emitter so it is very difficult to separate it from all the other natural beta emitters. I would expect that anywhere you detect Cs there will also be Sr.
Strontium and Radium are both in the same line of the periodic table as Calcium so their chemical behavior is similar. The body will concentrate them in the bones.
I haven't heard of U, Pu and Am being "bone-seekers".
Actually...
For people who do radiation spectroscopy like BRAWM; they can separate the signals from the differing isotopes.
That's how BRAWM can tell us how much exposure was from I-131, Cs-137, or St-90. They can tell the difference in the spectrum.
I realize it's more difficult
I realize it's more difficult to find, but there's a wealth of information regarding levels of Sr 90 in the food supply from the 50's and 60's. I think it's strange there has been so little testing for it now.
all those listed are known to deposit in bones, the kidneys and the liver.
AR
Bone seekers are particularly
Bone seekers are particularly dangerous, acutely radiating the body for many years on end. Yes, years.