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Bored Chemist wrote ...
Patrick wrote ...
this is a scary pic.
Very scary picture, and misleading.
The bulk of that plume is roughly 100 bq/m^3 of whatever it is they are measuring (it would be better science if they specified that).
Normal sea water contains about 400ppm of potassium
That's 400 g/m3
Each gram gives a natural background of about 30Bq so that's a background of 12000 bq/ m3
In a real picture you simply wouldn't be able to see the (less than 1%) change from the background radioactivity .
If you were swimming in that sea you would be at roughly 1% increased risk from the radiation, compared to the background.
People, on the other hand, contain rather more potassium than sea water (about 1500 ppm vs about 400) so you are more radioactive than sea water by a factor of roughly 4 .
That "contaminated" water is more radioactive by a factor of about 1.01
Does that put this risk in context for you?
How about this? Normal human urine contains about 25 to 125mMol/liter of potassium.
call it 100mMol to keep the arithmetic simple. That's a tenth of a mole in each litre or 4000 mg / litre.
That 4 grams per litre in turn will give rise to 4*30 i.e 120 Bq.
And if you amassed a cubic metre of it, you would have 120000 Bq of radiation from potassium (there are other contributors too)
And that big scary splodge on the picture depicts 100 Bq/m3
It's a thousand fold less radioactive than piddle.
Why are people making a fuss about it?
It sounds like potassium pretty much passes straight through the human body, BC. How do other radioactive isotopes compare?
As I understand it, put simply, the various isotopes in the Pacific off Fukushima attach themselves to algae at the bottom of the food chain, and get more concentrated higher up the food chain, with blue fin tuna at the top. The impression I get is that they don't all pass through the body as easily as potassium does.
Fukushima
