[ RadSafe ] You can't "milk" large quantities of Po-210; irradiation of Bi-209 is the likely route
parthasarathy k s
ksparth at yahoo.co.uk
Tue Nov 28 18:56:35 CST 2006
If you want substantial quantities of polonium-210, you may not be able to "milk" it from the Radium-226 series.You may have to irradiate Bi-209 and process the stuff to recover polonium-210.
K.S.Parthasarathy
----- Original Message ----
From: John R Johnson <idias at interchange.ubc.ca>
To: Cindy Bloom <radbloom at comcast.net>; radsafe at radlab.nl
Sent: Tuesday, 28 November, 2006 9:26:57 PM
Subject: RE: [ RadSafe ] Fwd: Polonium-210
Cindy
I have never seen any chemical toxicity data either, probable because it
doesn't have a stable isotope.
FYI, the easiest way to get Po-210 is from Pb-210. I've copied and pasted
information frm my earlier message to Radsafe
"The progeny of Ra-226 is Rn-222, Po-218, Pb-214, Bi-214, Po-214, Pb-210,
Bi-210, Po-210 and Pb-206 (stable). The longest lived one is Pb-210 (~21
years) and it could be a/the source for Po-210 (half life ~ 138 days)"
Collecting Po-210 from Pb-210 in NORM would be easier than from Rn-222.
John
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John R Johnson, Ph.D.
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-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl]On
Behalf Of Cindy Bloom
Sent: November 28, 2006 7:31 AM
To: radsafe at radlab.nl
Subject: [ RadSafe ] Fwd: Polonium-210
>I should first say that I am a health physicist and an internal
>dosimetrist, but my knowledge of biology and toxicology is related
>primarily to internal dosimetry (and family and friend's medical
>crises). I do have a fair amount of experience in operational health
>physics and estimating internal doses and find that the alleged polonium
>poisoning case engages my curiousity.
>
>The following are some thoughts and questions about polonium. I don't
>seem to be able to find any specific information regarding the ingestion
>toxicity of polonium, but it seems like a number of "poisons" require
>acute ingestion doses on the order of milligram quantities to produce
>their short-term toxic chemical (versus radiological) effects. That would
>be a whole lot of radioactive polonium: a milligram of Po-210 would be
>almost 4.5 curies.
>
>Polonium-210 (138.38-day half-life) is available in a variety of forms,
>and as some have pointed out is readily available in static eliminator
>brushes (I've typically seen quantities of 150 microcuries to 10
>millicuries, but I'm sure they are available in larger activities), and I
>suppose it might be easy enough for an experienced chemist to recover this
>metal and create a chemical form that was readily transportable and easy
>enough to add to food. (It would also be possible to collect polonium
>from the radon in the air, although perhaps not very practical if the
>radon levels were not elevated. If you had a facility that had an average
>Rn concentration of 4 picocuries/liter, and an equilibrium factor of 0.4,
>about 1.25 billion liters of air would be needed to collect a millicurie
>of Po-210 (assuming 100% collection efficiency). A concentrated source of
>radium might allow for more practical collection, and some have noted
>there are other means of creating/collecting/obtaining Po-210, but these
>methods might require special access to equipment/materials.
>
>Using ICRP 60+ models, the dose from a 1 millicurie Po-210 ingestion
>intake on November 1 (this would be an intake of about 0.22 micrograms of
>Po, if I've done my math correctly) would result in the organ doses
>equivalent and doses as of November 8, 16 (day of hospitalization?) and 23
>(day of death) shown at the end of this note. As Jim Barnes pointed out,
>it probably doesn't make sense to look at dose equivalent, rather the dose
>in rad should be considered to determine deterministic effects, so the
>organ doses were calculated by dividing the doses equivalent by the alpha
>weighting factor of 20.
>
>Based on the above, it seems like the ingested dose would have had to be
>at least in the range of 3 to 10 millicuries to result in the effects
>reported. This is still in the range of micrograms of Po-210 intake.
>
>I also wonder what Po tastes like. Would polonium chloride taste like a
>salt? Would Po be easy to add to food or drink. It seems like the dose
>added to the food might need to be much larger to ensure that the intake
>was sufficiently large.
>
>Po-210 is primarily an alpha emitter, but 1e-5 of the time it emits a 0.8
>MeV photon. Using the old 6CEn equation indicates that for a millicurie,
>the photon exposure rate at a foot would be 0.048 microentgen per
>hour. This doesn't seem like much but the 0.8 MeV photon emission rate
>would be 22,200 per minute, and that seems like a detectable quantity (if
>someone were really looking). (A curie (223 milligrams) of Po-210 would
>produce an exposure rate of about 48 microroentgen per hour, which is
>about 4 times a typical background level.)
>
>ICRP 23 notes that we all have Po-210 in us, primarily from foods, but
>cigarettes are a significant source for some. Blood levels reportedly
>range from 1 to 54 pCi/kg (reference man has a blood volume of 5200 ml,
>and assuming a density of 1 g/ml, reference man's blood would contain 5.2
>to 280 pCi of Po-210). At 149 days, dogs exposed to Po-210 aerosols had
>about half the retained Po-210 in their hair follicles (I can't tell if
>this was 149 days after exposure or after 149 days of chronic exposure -
>I'm guessing the former). Also ICRP 23 notes that trace amounts of Po-210
>are normally found in hair and sweat.
>
>(Just an aside pico = 1E-12, micro = 1E-6, milli = 1E-3)
>
>Below are calculated doses per millicurie ingested (assumed to occur on
>November 1). Sorry for not using SI units, but so many values were
>readily available in curie-based units. Also, I seem to be unable to
>align the columns in my table. They look alligned here, but they shift
>when I send.
>
>Ingestion equivalent dose per millicurie
>equivalent dose (rem) 11/8/2006 11/16/2006 11/23/2006
50-y
>Kidneys 1.08E+03 2.25E+03 3.14E+03 9.43E+03
>Spleen 9.33E+02 1.94E+03 2.70E+03 8.12E+03
>Liver 5.61E+02 1.17E+03 1.62E+03
>4.87E+03
>Red Bone Marrow 2.26E+02 4.68E+02 6.51E+02 1.95E+03
>Lower Large
>Intestine 2.06E+02 2.32E+02 2.53E+02 3.95E+02
>Bone
>Surface 1.38E+02 2.83E+02 3.94E+02 1.18E+03
>Upper Large
>Intestine 8.78E+01 1.14E+02 1.33E+02 2.71E+02
>Small Intestine 3.63E+01 6.16E+01 8.08E+01 2.16E+02
>Stomach 3.07E+01 5.59E+01 7.51E+01 2.11E+02
>All other
>organs 2.62E+01 5.14E+01 7.06E+01 2.06E+02
>
>Ingestion dose per millicurie for the period defined by an acute intake on
>11/1/2006 and a period ending on the dates listed below.
>dose (rad) 11/8/2006 11/16/2006 11/23/2006
50-y
>Kidneys 5.42E+01 1.13E+02 1.57E+02 4.72E+02
>Spleen 4.66E+01 9.70E+01 1.35E+02 4.06E+02
>Liver 2.80E+01 5.83E+01 8.12E+01
>2.44E+02
>Red Bone Marrow 1.13E+01 2.34E+01 3.26E+01 9.75E+01
>Lower Large
>Intestine 1.03E+01 1.16E+01 1.26E+01 1.98E+01
>Bone
>Surface 6.88E+00 1.42E+01 1.97E+01 5.90E+01
>Upper Large
>Intestine 4.39E+00 5.68E+00 6.65E+00 1.36E+01
>Small Intestine 1.82E+00 3.08E+00 4.04E+00 1.08E+01
>Stomach 1.54E+00 2.80E+00 3.76E+00 1.06E+01
>All other
>organs 1.31E+00 2.57E+00 3.53E+00 1.03E+01
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