I post this in the main section because questions about radiation and radiation dosage are pretty common. Radiation can be an issue, or non-issue in both large and small situations. And in more places than people might think.

Handy factoid: Sleeping next to someone exposes you to an approximate dose of 0.05 micro-Sieverts. Is that a problem? Follow the links to the handy Radiation Dose Chart (suitable for printing out/framing). Just the thing for a fallout shelter wall.

Closer to home. In the 80s a truck carrying a half dozen small industrial radiation sources, used to check material thickness for process control, crashed. The police rolled up and saw a small radiation hazard sticker on the overturned truck and a box marked with a radiation warnings on it and they blocked traffic, both ways, and started evacuation people. They told people there was a possible radiation hazard.

The NRC was alerted, a local military base sent a team, and many a bunny suit was seen. Some people who were evacuated, or who had been near the accident, said they felt symptoms of radiation poisoning and were directed to a local ER, which set up a receiving and decontamination area. Scores went to the ER where they were stripped and decontaminated because someone thought they detected radiation. Just to be sure.

In the end the company that owned the truck was contacted. They sent out a guy ... who, wearing jeans and tee shirt, simple stooped under the perimeter tape, strode up to the overturned truck, with bare hands stuffed the sources back into the box. He strode back and stuck the box with the sources on the front seat of his waiting truck.

Later investigation showed that there was little or no risk. The detector used at the accident site was faulty. The guy at the ER didn't know much and even though his detector worked correctly he had his instrument set at the most sensitive possible setting and the radiation they did detect was from the limerock driveway they were using as a staging area.

Local emergency services considered it a useful training exercise, and strong warning that they needed to get their act together. After more training and practice they have got a lot better.

Radiation is a scary word but knowing the difference between a micro-Sievert, a milli-Sievert and a Sievert can be the difference between protecting yourself when it is smart to do so, possibly saving yourself serious injury, and freaking out and wasting resources over nothing.


http://blog.xkcd.com/2011/03/19/radiation-chart/


This post suggested by, and respectfully stolen from:
http://scienceblogs.com/deltoid/2011/03/andrew_bolt_says_that_radiatio.php

What is curious about the media response indicating the different levels of radiation dosages is their lack of any explanation as to the difference between alpha, beta and gamma radiation sources. After watching CNN with Anderson Cooper and Sanjay Gupta explaining to everyone why rad bunny suits used by nuclear power station workers were being used to stop gamma radiation, I thought even medical doctors (brain surgeons) don't understand the basics of schoolboy nuclear physics. Gupta should have known better.

An alpha radiation source (such as Plutonium) sitting on a desk 1 metre away will not register on a Geiger Muller tube counter. Does it means that is safe to spread on a peanut butter sandwich as apposed to the fore mentioned banana.

Nowhere in the linked article is Relative Biological Effectiveness taken into consideration. No where on any news media either let alone the mention of MOX fuel used at the Fukushima plant.

http://en.wikipedia.org/wiki/Relative_biological_effectiveness

Again the RBE factor is hugely important and will radically skew the simplistic rad dosage scale shown on your link especially when it comes to human health hazard.

It would appear that everyone and his grandmother who earns their living from the nuclear industry is attempting to downplay the seriousness of the exposure to the release of long term toxic radionuclide isotopes into the environment.

Maybe the article should have calculated the radiation dose of the 10 day round trip to the moon as well.

Your post is just one example of why I get less and less information from TV "news" sources. It is a waste of time and mostly concerns car chases and the legal woes of some bimbo starlet.

https://orise.orau.gov/reacts/capabiliti...eparedness.aspx

This was a great course and these people go over the real risk you have, and also differentiate between being "irradiated" and being "contaminated".

Am_Fear_Liath_Mor - It also made me wonder when I didn't hear the 3 types. Though, Dr. Gupta on CNN did mention "Time, Distance and Shielding".

If you don't know, are guessing, and, I suspect, are basing your objections primarily on a ten minute class at Google-U, you would do better to couch your objections less aggressively. It always helps to know a little bit of something about what your talking about so you don't make clueless statements like:



RBE is incorporated into the calculation of the Sievert as the Q value so the Sv is entirely independent of the type of radiation. Alpha, Beta, and Gamma radiation all have different effects on tissue but one Sv of gamma, one Sv of Beta, or one Sv of Alpha radiation all have equivalent biological effects on humans because they use different Q values in calculation. That is why the Sievert is used. One number with all the adjustment factors to translate it into effects on humans already rolled in.

Yes I know that RBE weighting is incorporated into the Seivert calculation. I also know that the RBE weighting used which is greater than 1 is very very rarely used in that Sv calculation (measurement is Gy) as heavy nucleus alpha radiation is quite rare in normal everyday circumstances . I am complaining about some of the assumptions that are being put forward in the linked chart.

Take for example in the chart the Radiation dose chart which mentions the Fukushima entry of 3.7mSv/day (at 2 sites 50km to the NW), yet the chart which refers to system of measurements that people can refer to are mostly yearly dosages. i.e. 3.8mSv/day = 1.387 Sv/year or 1,380 times greater than the EPA limit for radiation exposure for man made external sources for a member of the public every year or around 5 times that for the Chernobyl relocation criteria of 350mSv/lifetime. The Q values for the Fukushima entry and the basis for the measurement Sv calculation are not described (waving the Geiger counter in the air will mostly pick up Gamma sources with a Q value of 1 rather than heavy nucleus alpha source Q value of 20-1000). The chart mainly describes external gamma and X-ray (photon) sources exposure except for bodily internal potassium (beta emitter, again the Q weighting factor of 1) rather than internal alpha sources (Q = 20-1000). This is why the Plutonium is such a danger in the MOX fuel used at Fukushima.

Again the news media are given values such as 400mSv/hr measurements at the Fukushima site but the RBE Q or Weighting factor for these measurements has not been specified (most likely set as a Q=1 to minimise the Sv calculation figure given out to the public) then go on to make a direct comparison with a CAT scan, airline flight or a Banana Equivalent Dose (BED). The linked chart is doing exactly the same (esp when mixing up single event, hourly, daily and yearly dosages) and again is very misleading in its attempt to basically dupe the public as to the issue surrounding the Fukushima release. The news media doesn't even know the appropriate questions to ask.

There appears to be lies, damned lies, statistics then radiation comparisons from nuclear industry experts.

This issue with external versus internal alpha particle Q weighting or time scale confusion would seem to be a huge issue in terms of the recent topic of contaminated milk, spinach, and other food products not yet tested by the Japanese.

I had not thought about it before, I have heard a number of times that after Chernobyl, the consumption of contaminated food was by far the largest source of radiation risk for the civillian population, not direct exposure to any airborne fallout. I had not realized that the internal versus external Q weighting, and not necessarily the number of particles involved, is the main driver of this greater risk for ingested particles. In other words, 150 alpha particles settling on my skin and clothes is not as dangerous as, say, 20 particles that I ingest in milk, is that correct?

Am_Fear_Liath_Mor - You clearly have no idea of how radiation readings are made, the actual instruments used (ie: "waving the Geiger counter in the air will mostly pick up Gamma sources with a Q value of 1 rather than heavy nucleus alpha source Q value of 20-1000"),and how they relate to dose calculation and dose.

The one-time and time based values are pretty clearly marked, or immediately obvious to anyone paying attention. You are confused because you do not understand and you don't understand because you haven't taken the time to learn before claiming people are lying. The reports from the Japanese authorities don't look like an attempt to deceive.

Your deeply flawed interpretation looks like it is a result of a toxic mix of intellectual laziness, and paranoia.

"It would appear that everyone and his grandmother who earns their living from the nuclear industry is attempting to downplay the seriousness of the exposure to the release of long term toxic radionuclide isotopes into the environment."

My guess is that the Japanese Gov't is going to have to do everything possible to clean up the neighborhoods with high radiation levels i.e. those in the immediate vicinity of the nuclear plant. If this means gathering up all the contaminated crops, and shoveling up gardens and contaminated farmland, so be it. I don't see how they can leave radioactive debris in peoples' backyards. This is going to be an expensive operation.

cheers,
Pete #2

And I even hadn't moved on to the subject of the dangers of the Hot Particle.



I think they have recovered around 35 hot particles (about the size of a single grain of sand) from the beach at Dounreay (Scotland) in the last 30 years but still represents a major human health hazard to anyone using the beach.

http://www.bbc.co.uk/news/uk-scotland-highlands-islands-11442701



Unless the folks whose back yards and property is contaminated have access to Geiger Counters and mass spectrometers etc for radionuclide species determination then they will be none the wiser.