Taking KCl (salt substitute) for protection from Cs
Posted by BC 7/4/11
I thought about it. Turns out, it is a BAD IDEA.
Mark from BRAWM has made some very good points about K40 and how much internal radiation we experience from it. One thing that stuck in my mind - Milk has something like 50bq/l from K40.
Well check it out. If you look at recommended daily intake for potassium it's around 3.5 grams/day. Each gram of naturally occurring potassium has about 31 bq/PER GRAM of activity. So if one takes in 3.5 grams of K per day, and it's activity is 31 bq/g, then we intake about 109 bq/day from naturally occurring K-40.
I had thought to myself, well maybe I will take some KCl to block cesium activity. And that could make sense at a high level of exposure, and I may have my K level checked, and if it is low I will bulk it up for general health. But let me make it clear - I swallowed ~ 1 gram (which is .527 grams of potassium, and the rest is chlorine) of KCl salt substitute yesterday. If you use the latest UCBNE milk sample, the cesium activity was .24 bg/l, and figure that .527 grams of K (.527G X 31 bq/g) has 16 bq of activity, you can also see that in order to ingest as much "activity" as that gram of KCl I ingested (1 gr KCl@ 16 bq divided by .24/bq/l in milk (that's Cs only, not K), that one would need to drink 66 liters of milks to get the same amount of "cesium sourced radiation" as I got from the "potassium sourced" radiation in one gram of salt substitute. FWIW, K40 and Cs-134/137 have similar types of radioactive decay.
At current levels, you would need to drink 66 liters of milk to get the same amount of radiation from added cesium as you would get from 1 gram of KCl "salt substitute".
Also, bear in mind that an average liter of milk has 49 bq of activity from potassium. Divide that number (49bq/l) by the amount of cesium activity in the latest homogenized sample (.24bq/l) and you can see that there are 204 bq of activity from K40 for every bq of Cs 134/137 (combined).
The take away is that the levels of radiation from cesium in milk the USA, as being measured my UCBNE, are quite low. If you are trying to get a feel, buy some potassium chloride and take a gram. 16 BECQUERELS!!! The same as 16+ gallons of milk.
Disclaimer - Japan is likely super hosed. And the hot particles issue is not resolved to my satisfaction. Also, I know little about cesium's chemical toxicity, which is a whole different thing. It decays into barium, which is pretty crappy. You wouldn't want to have much barium in your cheerios. Also, it would be very good to know more about the physical properties of the cesium fallout - what is their size? If they are molecular or near so, great. Big chunks? Different story for inhalation, probably "OK" for ingestion. To bring another unknown in, potassium levels, and their ratios to sodium, and a bunch of other things, influence blood pressure and goodgodamighty knows what else. Cesium in biologically significant quantities may enter this equation, in a chemical way.
But it looks like "the radiation" a glass of milk is pretty low level :). Just stay away from wild boar until we get that tested.