Re: Occupational exposure to radon update

[Les Fraley <les@lamar.ColoState.EDU>]

I don't see this as much of a problem for Iowa (or other states) farmers.
When tilling the soil, most farmers, now-a-days, ride in an enclosed cab,
often air conditioned. The cab is 4 to 6 ft above the soil, the tractor is
moving so half the time there will be a headwind component, and only a
very small fraction of a field is tilled at any one short time interval.
For those (unfortunate?) farmers that still ride on an open tractor, dust
inhalation is by far the most serious long term threat. This doesn't take
into account factors like tilling on the side of a hill such that the
tractor rolls over or other machinery accidents. These result in farming
being one of the most hazardous occupations in the USofA.
While such a study might be interesting to carry out, I don't see that any
results would have any practical application.
Les Fraley
les@lamar.colostate.edu

On Thu, 19 Nov 1998 Christoph_Hofmeyr/CNS1@cns.co.za wrote:

> RADSAFERS and Bill Field,  Allow me to belatedly add a rock to the tailings
> pile and propose an expansion of the 12th category.  Uranium and Radium are
> well distributed in the ground and not confined to particular geological
> formations.    Agricultural workers who till the land, particularly when
> ploughing, obviously change (enhance) the emanation conditions for Radon
> from the top layer of soil by changing the general porosity as well as the
> concentration gradient by bringing higher concentrations  to the surface -
> until a new equilibrium has developed.   The quantification of this effect
> in terms of air Radon concentration could be a very interesting field of
> study in the fields of Iowa (no pun intended) - millions of acres.   A few
> inches below ground the Radon concentration is at least 3 orders of
> magnitude higher than in the air above, explaining why small changes in the
> transport conditions for Radon gas in the top layers or disturbance of the
> concentration profiles could result in significant changes in emanation.
> Care would have to be exercised to separate the surface disturbance effect
> from other sources of fluctuation, e.g. barometric pressure.  The exposure
> impact of temporarily enhanced Radon escape would depend on the dynamics of
> the process, which would have to be investigated.  It seems logical that
> persons in the proximity would be mainly affected, but that there should
> also be a more general elevation of open air Radon concentrations in the
> case of extensive operations.   The average life of Rn-222 is 5.5 days; the
> daughter equilibrium factor (~ 0.8)  is established in about 2 hours.   I
> think the effect should be considered seriously and investigated, although
> in lighter vein, it remains doubtful whether the weekend gardener, pulling
> weeds and turning the soil,  needs to be classified as a radworker....
> Personal musings.
> Chris Hofmeyr. chofmeyr@cns.co.za.   CNS, PO Box 7106, Centurion 0046,
> South Africa. Fax +27 12 6635513.
> 
> 
> Bill Field wrote:
> 
> 
> Re: Occupational exposure to radon update
> 
> 
> 
> 
> RADSAFERS
> 
> The following is a list of occupations that have the potential to result in
> radon exposures exceeding those concentrations commonly encountered in
> homes
> near the work site.  This list has been compiled to date with the help of
> radsafers.  Thanks to all that have emailed me.  I enjoyed some of the
> discussions that accompanied the suggestions and the personal insight some
> of
> the radsafers shared.  If you can think of an occupation I have not
> included,
> please email me at mailto:bill-field@uiowa.edu.
> 
> 1.  Mining -- including hard rock, uranium, vanadium, phosphate and coal.
> 
> 2. Workers remediating radioactive sites including uranium mill sites and
> mill
> tailings.
> 
> 3.  Radon mitigation contractors and testers
> 
> 4.  Guides and care keepers of natural caves
> 
> 5.  Employees of radon spas or health mines
> 
> 6.  Phosphate fertilizer plant workers
> 
> 7.  Oil refinery workers
> 
> 8.  Utility tunnel workers
> 
> 9.  Power plant workers including geothermal and coal
> 
> 10.  Water plant operators (waterborne source)
> 
> 11. Fish hatchery attendants (waterborne source)
> 
> 12.  Incidental exposure in almost any occupation from local geological
> sources
> 
> I would be interested in hearing whether or not other radsafers agree that
> these are indeed occupations that expose workers to higher radon
> concentrations than they may find in their home near their place of
> employment.  Also, please email me directly if you can think of an
> occupation
> not on the list.
> 
> Thanks again,
> 
> Bill Field
> bill-field@uiowa.edu
> 
> 
> 
> 
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