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AW: Emergency Preparedness



 
-----Ursprüngliche Nachricht-----
Von: owner-radsafe@list.vanderbilt.edu [mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von Engelbretson, David A.
Gesendet: Montag, 06. Jänner 2003 20:44
An: radsafe@list.vanderbilt.edu
Betreff: Emergency Preparedness

Dear Colleagues,
 
In regard to chemical agents used for treating certain types of RAM exposures, are there any substitutes available for the following two chemicals ?
 
Ferric ferrocyanide (Prussian Blue), a blocking agent for Cs-137, is not recognized by the U.S. Pharmacopeia and is not approved by the FDA.
 
DTPA, a chelating agent, is not commercially available either. I believe it is only available under Investigational New Drug (IND) permits for treatment of persons contaminated internally with plutonium. However, calcium EDTA is available and has effectiveness for the transuranium metals, but DTPA is generally more effective.
 
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Dave,
 
I cannot recommend you any substitutes, but I offer you the possibility to think a little about the use of such chemicals.
 
Regarding Prussian Blue: It is not really a "blocking agent", but complexes caesium (also Cs-137 and Cs-134) strongly - this is known since decades and has been used to remove Cs-137 from drinking water and milk and has actually been used to enrich Cs-137 from drinking water in order to measure its concentration. It has been used after the Chernobyl accident to reduce Cs-137 levels in meat (for instance in Norway, where sheep were treated with ferrocyanides) and the levels in milk. For the latter purpose, which actually did use a slightly different ferrocyanide ("Gieses salt") I recently found a paper which I had not had track of for years, so if somebody is interested I could forward the site, where it can be retrieved.
However, the efficiency of reducing Cs-137 levels in meat and milk is rather limited. A reduction by a factor of two or at most three in meat and milk is something, which is in my opinion not worth the effort. In case of a very severy case of internal contamination by Cs-137, which might result in extremely high doses I personally would not hesitate to swallow ferrocyanides, whether they are approved or not.
 
Regarding DTPA: It is of course commercially available as well as all kind of ferrocyanides. Contamination with plutonium or americium should not occurr frequently unless in places with a potential for it and there health physicists should be prepared to it, so I personally would swallow that stuff, if such internal contamination - in a range of causing very high doses - occurred to me.
 
I would be very surprised, if it would not be possible to use in a real emergency situation - not ingestion of femto-Becquerels - such agents. I remember an Austrian Standard for Internal Decontamination I have worked with many years ago. I would have to look it up, but as far as I remember we recommended the use of complexing agents and we did not bother about their official approval. Moreover I think to remember that Health Physics has published during the last 20 years several papers on the decorporation of radionuclides.
 
Best regards,
 
Franz