[ RadSafe ] Iodine measurements in Europe

[Peter Bossew]

For more than 2 weeks stations across Europe have been measuring 131I in
air filter samples. The concentrations of particle-bound 131I are between
10^0 and 10^1 uBq/m³, i.e. a factor about 10² - 10³ below what has been
recorded in Europe after Fukushima. 


Conc. in the gaseous phase appears to be higher for a factor almost 10,
than of particulate conc., but only very few data on gaseous iodine are
available.


No other radionuclides have been reported. Therefore a reactor can be
excluded as a source with high probability, to current knowledge. Likely
sources are medical facilities but none could be identified so far.


Meteorologists think that the source is located in SE direction, as seen
from Central Europe. However to my knowledge CTBTO stations into that
direction (the nearest in Kuwait) have not responded. Therefore apparently
the source is not located far away, but rather in Europe.


The concentrations are far too low to have the European emergency warning
network respond (about 4000 automatic doserate monitoring stations across
Europe). The immersion dose from the event can be estimated in the order
of magnitude 10^-2 pSv/h while the LLD of monitors is typically 10 nSv/h.
(This was also so after Fukushima when the highest immersion doses in
Europe were calculated ~ pSv/h)


Since monitoring such low concentrations affords long sampling times, such
as typically one week (i.e. the period over which air is sucked through
filters with high volume samplers), the temporal resolution with which the
dynamic can be followed is very low.


Peter Bossew






"The International Radiation Protection \(Health Physics\) MailingList"
<radsafe at health.phys.iit.edu> schreibt:
>http://www.reuters.com/article/2011/11/11us-nuclear-iodine-iaea-idUSTRE7AA4u020111111
>
>
>I received several questions about the incident referenced in the article
>that came out today.  I was wondering if any of our European colleagues
>on the list could give any details to what the incident may be that has
>occurred?
>
>I have read the update posted on the IAEA website today where they are
>trying to locate the source.
>
>It does not  appear to be plausible to be attributed to Fukushima at this
>stage.
>
>Any additional information would be helpful as the questions came from
>the first responder community that I work with.
>
>Many thanks,
>
>Kathy McLellan
>
>
>
>Katharine McLellan, MS
>Health Physicist
>
>Division of Radiation Safety
>National Institutes of Health
>Building 21
>Bethesda, MD 20892-6780
>
>Telephone direct:  301-594-0906
>FAX:     301-496-3544
>Email: 
>mclellak at mail.nih.gov<mailto:mclellak at mail.nih.gov><mailto:mclellak at mail.nih.gov>
>
>_