RE: Radon

["Christoph Hofmeyr" <chofmeyr@nnr.co.za>]

Radsafers,

Radon concentrations a metre or so below the ground surface are

typically a thousand times higher than in the air above ground, so there

are concentration profiles due to diffusion out of the ground, which

ensure continuity.  Where there is an effective barrier to diffusion,

like below a concrete basement, the concentration there builds up to a

high equilibrium value, so that even small openings or cracks can cause

an elevated concentration inside, compared with outdoors, particularly

if the ventilation is poor.

Ploughing would disturb the concentration profiles in the top soil

layers and temporarily cause a faster release of radon gas until a new

equilibrium has been established.  According to e.g. IAEA definitions,

should farming therefore be classed as a practice, and the farmer a

potential radworker?

Chris Hofmeyr

chofmeyr@nnr.co.za





Herbert Kouts [hjckouts@rcn.com] wrote:

>Studies at Oak Ridge a number of years ago revealed that the principal

>source of atmospheric radon  is plowing of agricultural land, which

>releases radon that has percolated into the soil.  Very likely this is

>the largest cause of radon exposure of the population at large.



>I recall that some years ago the atmospheric sensors in Sweden were set

>off by radon released from the soil as snow cover melted in the north.

>For a time it was thought that atmospheric testing of nuclear weapons

>had been resumed, or that a large accident to a nuclear power plant had

>taken place.  I believe that this phenomenon is now anticipated and

>taken into account.



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