AndyF said:
Les W said:
One of the reasons why radon is dangerous....
I think the whole point is that there is no evidence that it
IS dangerous.... It's something that has now gone into folklore without proper evidence.
. . .
The papers I've looked at have been based on poor science and bad maths, and I haven't seen any
demonstratable link established between workplace/home radon exposure and health. I stress the word "demonstratable" because obviously high radon exposure would be bad.
. . .
Another factor which needs to be taken into account is how accurate and reliable are the 'measurements' of radon levels in caves with which we're being presented?
In the case of the recent Llangattock caves results a startling factor stands out: the results previously obtained in Eglwys Faen, on more than one occasion, are appreciably lower than those reported for the current survey. This begs the question: where is the 'control'?
All instrumentation is subject to variation in performance depending on the prevailing circumstances at the time of use. When, for example, cavers carry out a cave survey using a magnetic compass for measuring bearings, the equipment needs to be calibrated at the start of the caving trip. A bearing is taken from a known point to a distant landscape feature and the resulting reading used to compute a 'correction factor'. This 'correction factor' relates to variations in the magnetic pole and the manner in which the compass is read by different individual surveyors.
In the case of measuring radon levels: how good are the detectors at responding accurately to levels of radon present and how critical is the duration of exposure of each detector to the environment under test? Have the detectors been contaminated between the point of manufacture and being set up in the cave? Do the detectors each have a unique serial number providing their 'batch no.', date and time of manufacture? Have the people who are carrying out the placements and readings been screened for radon? Have the detectors been contaminated between the cave and laboratory where the analysis of radon levels is performed?
A control in the case of the Llangattock caves, where 25 readings have been taken in separate locations underground, would perhaps be a minimum of 3 and preferably 5 surface locations in buildings subject to the same rainfall catchment as the caves? In each building one detector should be placed in as low and unventilated position as possible to produce a 'maximum' and another in a well-ventilated upstairs room to produce a 'minimum'. These detectors should be placed by the same person who is placing the detectors for the same period in the caves.
Such a control would help provide better evidence as to whether the readings taken underground are reliable or anomalous.
It appears that it is not too late for consideration to be given to incorporating a satisfactory control and also to place additional detectors in eg. Erse Passage and Midnight Passage, as previously suggested, for the present radon measurements being carried out in the caves. If presented with the argument that it is too late to be coming up with such suggestions, then I'll hasten to add that the first I heard of the experimentation being carried out in the Llangattock caves was that some very high readings had been obtained and then the report provided by the latest issue of
Descent landed on the floor in my hall.
