I don't claim to entirely understand this, but FAO seems to consider 1000 Bq/kg from all isotopes other than plutonium a reasonable limit for radioactivty in food. So the food looks OK, the water which he largely ignored looks like a big problem. http://www.fao.org/docrep/u5900t/u5900t08.htm
----- Forwarded Message ---- From: John M. Steele <[email protected]> To: [email protected]; U.S. Metric Association <[email protected]> Sent: Mon, April 8, 2013 6:46:11 AM Subject: Re: [USMA:52625] Unclear use of radiation units What is more amazing is that a few becquerels per kilogram in food makes the top of the article, but a few thousand becquerels per kilogram in water falls near the end of the article. Don't most people drink an amount of water daily approximately equal to their food intake? It seems to me the dose from water is about 3 orders of magnitude higher. I have no idea how to calculate body dose, but Cs-137 decays with a 512 keV beta particle, and a 662 kEV gamma ray. If internally ingested, the beta particle would almost certainly be absorbed, the gamma ray probably only if it hit bone. ________________________________ From: Pierre Abbat <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Mon, April 8, 2013 1:51:11 AM Subject: [USMA:52625] Unclear use of radiation units http://www.naturalnews.com/039828_Fukushima_radiation_media_blackout.html He gives a distance in only miles and messes up the capitalization, but that's not the point. The amount of radiation in food is given in becquerels per kilogram. Two paragraphs later, the maximum exposure is given in millisieverts per year. A becquerel is one random event per second; I can imagine putting a kilogram of tangerines in a Geiger counter and hearing about four clicks a second. A sievert is a joule per kilogram, adjusted for how much damage it does to a body. The amount of damage done by a particle emitted by a radioactive atom depends on the kind of particle and the energy with which it's thrown out. Not being a nuclear scientist, I have no idea how much this is for any nuclide, and the author doesn't state it. Also submitted on the web form. Pierre -- li fi'u vu'u fi'u fi'u du li pa
