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Posted Saturday, July 7, 2007
The Silent Killer Lurking Beneath the Floorboards:
Recently we have all been bombarded by media representations of wars and terrorist threats - and the fear factor in the collective brain of Britain is no doubt burdened by the imminent dangers from the prospective use of chemical and biological weapons.
This fear factor heightened following the discovery of Ricin by anti-terrorist squads and of course, the use of the deadly and virtually undetectable Sarin gas which killed people en masse in Japan several years ago also serves to underline the threat that we all face from the unscrupulous manufacturers and users of such deadly chemicals.
It may all seem a distant threat to most of us who are tucked away in the centre of England, safe in the land-locked county of Derbyshire and far away from the fermenting trouble-spots of the world.
But there is a threat far closer to home from a silent killer gas that could lurk beneath our floorboards!
This gas is both invisible and odourless and according to scientific and medical studies is one of the main causes of lung cancer - second only to cigarettes as the main cause of death from lung cancer throughout the world..……
The threat from exposure to this killer gas comes from no terrorist organisation - for the deadly gas radon occurs naturally - and Derbyshire has one of the highest concentrations of it in the entire country!
But there's no need for panic or for any of us to start trawling frantically through the Yellow Pages for Gas Mask Manufacturers and Suppliers, for according to the National Radiological Protection Board, who admit that `People who are exposed to high levels of radon are more likely to get lung cancer, also assure us that, `households at risk from radon can easily take simple and effective steps to make their home safe.
To avoid accusations of scaremongering here's what the NRPB has to say about radon:
It is a natural gas found in soil and rocks. It has no colour, taste or smell. Levels vary from country to country, region to region, and even from house to house in the same street. In open spaces, when radon mixes with air it is quickly diluted into the atmosphere. But when air containing radon rises from the soil and rocks beneath your home it may find its way in, mainly through cracks in floors, walls, and gaps around service pipes.
Both the Ministry of Health and the National Radiological Protection Board warn of the health risks from radon, the NRPB says:
Health studies around the world have linked radon with lung cancer, and in fact, radon is the second largest cause of lung cancer, the first is smoking, - whilst MoH figures suggest that incidences of lung cancer are proportionately higher in areas where there are the highest concentrations of radon. This is double bad news for smokers, for the NRPB warns that in areas of high radon concentration, like parts of Derbyshire, `the risk to smokers will be much higher than the risks to non-smokers!'
So are we in danger? What are the risks from radon?
What actually is radon gas and how is it formed?
I asked scientific boffin Terry Dutson, former ICI Senior Consultant Industrial Chemist and Radiation Protection Supervisor, who explained:
`Radon is a colourless, inert gas. It is the heaviest known gas and one of the so-called `noble ' inert gases such as xenon and krypton, (nothing to do with Superman!).
Its atomic number is 86, its mass number is 222, and it's formed from the radioactive decay of radium-226, which is a naturally occurring radioactive isotope in uranium ores which are abundant worldwide. Radon itself is relatively short-lived, having a `half-life ' of only 3.82 days, but it is constantly being formed via radium-226, which has a half-life of 1600 years; this in turn comes from uranium-238 with a half-life of 4.46 billion years!
Radon is an element, consisting of a nucleus of 86 protons and 136 neutrons, with a shell of 86 electrons.
All this proved too technical for me, so I requested the same information in lay terms, and Mr. Dutson told me:
`It is naturally radioactive and emits alpha particles (two protons and two neutrons) as a mode of decay. Radon itself also decays to other non-gaseous elements or 'daughters', some of which also emit alpha particles, so if radon is inhaled these `daughters' are formed in the lungs as microscopic solid particles and can cause lung cancer. The problem with radon is that it seeps up through the ground and can accumulate in buildings and confined spaces with no ventilation. The concentrations can be assessed, but require a long-term measurement, so its not quite as simple as fitting a smoke detector'.
I learned that the national average radon activity in houses within the UK is two hundred becquerels per cubic metre, and Mr. Dutson explained that a becquerel equalled `one radioactive particle disintigration per second', ominously adding, `and this is associated with a life-time risk of lung cancer of 1 in 300'.
In response to my query about the increased risks to smokers, Mr. Dutson said, 'At the action level for radon (i.e. 200 becquerels per cubic metre) the life-time risk of lung cancer would be increased ten fold, to around 1 in 30'. 'We can avoid cigarettes, he said 'but unfortunately, we can't avoid radon, it is the biggest single source of our exposure to radiation'.
So to summarise, the level of radon in our homes is dependent on the amount of radioactive decay beneath our floorboards, and that in turn is dependent on the concentrated amount of the radioactive isotope radium-226 derived from the uranium ore in the underlying geological strata.
Martyn Green of the NRPB showed me an official county-by-county chart containing the facts and figures from radon studies in homes around the UK. It shows the heaviest concentrations of radon to be in Cornwall and Derbyshire.
The figures are for Local Authority Councils and of the eight in Derbyshire by far the highest is the Derbyshire Dales with 2,200 dwellings well above the action safety level of 200 Becquerels per cubic metre, in fact the highest reading in this area is recorded at 6,900 Bq per cubic metre, which Terry Dutson described as `frightening'.
(Amazingly at this level of radon the risks of lung cancer are odds-on!)
This can be compared to Bedfordshire where there were no dwellngs at all above the action level, or Cheshire, where out of over 700 dwellings tested only one was above the action level.
It is no coincidence that Cornwall and the Derbyshire Dales and High Peak areas of Derbyshire have a high concentration of radon gas; Cornwall is known for its rich mineral deposits of tin and lead, whilst these areas of Derbyshire are renowned mineral rich lead-mining areas, abundant with uranium ore in both the limestone and gritstone, and therefore rich in radium-226.
The NRPB has devised a safe, simple and confidential test to measure levels of radon in the home.
Two test detectors are sent by post, one for the living room and one for an occupied bedroom. After three months they are returned in the reply paid envelope and sent for analysis.
Martyn Green explained: 'The tests cost £36.19 inclusive of VAT, post, packing and analysis for two detectors, unless there is a current government backed programme in the area when the measurements are free to targetted householders'. He added, 'The detector is nothing more than a piece of spectacle lens plastic in a protective shell, about the size and shape of a small doorknob. The plastic records radon which will be measured by experts in accredited laboratories'.
The NRPB offers the following advice if your home proves to have particularly high radon levels:
`There are simple, inexpensive and effective measures you or a builder can take to reduce radon to acceptable levels. They usually involve minor construction work and possibly the installation of a fan system to keep radon from entering the premises'.
The NRPB maintains a radon information service and individual householders can obtain a free information pack about radon in homes simply by ringing the freephone number 0800 614529. Leave your name, address and postcode and an information pack will be posted the next working day.
So finally, the risks? I leave the last words to the expert: Terry Dutson says, 'To put it all into perspective as a scientist, although radon is the biggest single source of our exposure to radiation, there are far greater risks to life - like smoking for instance¼...'
Compared to the odds of death from smoking - i.e. One death in 300 by age 65, other risks include:
airplane crash 1 in 4.6 million
Shark attack 1 in 300 million
Snakebite 1 in 36 million
Motorcycling 1 death in 50 riders
Hang gliding 1 in 1,250
Driving, without seatbelt 1 in 2,500
Driving, with seatbelt 1 in 5,000
Contact Tom: firstname.lastname@example.org