Comments: Notes from Dr. Edwards
Background:
Nuclear proponents and regulators often refer to "natural
background radiation" as if it is a benign, possibly even
beneficial experience.
In fact natural background radiation kills many thousands
of people every year.
The article reproduced here deals with radon gas, one of
many natural radioactive byproducts of uranium that is
extremely harmful to health.
Radon harms the lungs in particular. The U.S. Environmental
Protection Agency estimates that between 20,000 and 30,000
Americans die every year from lung cancer caused by
breathing radon gas in their homes.
Like radium-226 and polonium-210 -- two extremely hazardous
radioactive materials that were identified by Marie Curie
over a hundred years ago -- radon gas gives off a non-
penetrating but exceptionally damaging form of atomic
radiation called "alpha rays" or "alpha particles".
Like radon gas (aka radon-222), radium-226 and polonium-210
are also natural -- but deadly -- radioactive byproducts of
uranium. Every atom of radon-222, or radium-226, or
polonium-210, starts out as a uranium atom.
Radium killed so many people in the 20th century -- by
pernicious anemia, bone cancer and cancers of the head --
that it went from being the most expensive material on earth
in 1920 ($100,000 per gram!) to being discarded as a waste
byproduct from uranium mills nowadays.
Polonium-210 is thought to be responsible for about 90
percent of the deaths attributed to cigarette smoking --
lung cancer, heart attacks and strokes. It was also the
material used to murder Alexander Litvinenko in London
England in 2006. Polonium-210 is estimated by the Los
Alamos Laboratory to be 250 billion times more toxic than
cyanide.
The nuclear industry does little or nothing to educate people
-- even their own workers -- about the dangers of alpha radiation.
They will say, for example, that alpha rays "cannot pass through
a sheet of paper". Although this is true, it is profoundly mis-
leading -- unless you add that it is the most dangerous kind
of atomic radiation when inside the body, in contact with
living cells.
In fact the word "radiation" is a misnomer when applied to
"alpha radiation", since alpha rays are in no sense waves, or
photons, but very dense electrically-charged particles that
smash into living cells and break chemical bonds randomly.
If a beta particle can be described as a kind of subatomic
bullet, then an alpha particle can be described as a
subatomic cannonball.
Alpha radiation is about 20 times more effective in causing
biological damage (leading to cancer, mutations and blood
diseases) than beta radiation or gamma radiation, per unit
of energy delivered to living tissue.
But since each alpha particle is about 10 times as energetic
as a beta particle or a gamma photon, alpha radiation is
about 200 times more damaging per radioactive disintegration.
Because a "becquerel" refers to one radioactive disintegration
occurring every second, it follows that each becquerel of
alpha radiation is about 200 times more damaging than a
becquerel of beta or gamma radiation.
An alpha-emitting material is exceedingly dangerous stuff.
The most commonly encountered alpha emitters are radium,
radon, polonium, plutonium, americium -- and uranium itself.
Gordon Edwards
------------------------------
Radon Gas 'Targets Everyone'
Jaclyn Tersigni , The Toronto Star, December 1, 2012
Health Canada estimates that 16 per cent of all lung cancer deaths in Canada are related to radon exposure.
“It’s one of the most significant environmental health risks that exists today,” says Kelley Bush, a radon spokesperson for Health Canada.
Radon is produced from decaying uranium in soil, rock or water. If a home is built on bedrock or soil containing uranium, radon can seep through foundation walls and floor cracks and any gaps around pipes and cables.
“[But] at the end of the day, from my perspective, it’s a good news story,” Bush says. “There’s solid science behind the understanding of what radon is and what the health risk is.
“And there is something that Canadians can do to find out if it’s an issue for them. If it is an issue for them, then there are actions they can take to reduce their risk.”
Health Canada is urging Canadians to measure radon levels in their home with a do-it-yourself kit (available at hardware stores) or by hiring a certified professional. It’s recommended that testing be done in the fall or winter, when levels may be at their highest, over a minimum of three months to ensure an accurate, long-term reading.
“The levels [of radon] vary quite significantly hour to hour, day to day. . . . You don’t get lung cancer overnight. You want to know what your long-term exposure is,” Bush says.
The current radon level guideline is 200 Bq/m3 (radon radioactivity is measured in becquerel units). Results from a two-year Health Canada study released in March found that 6.9 per cent of Canadians live in homes with radon levels above that guideline. The highest levels of radon have been found in homes in Manitoba, Saskatchewan, New Brunswick and the Yukon.
Those who find high levels of radon in their home can have a radon reduction system called active soil depressurization installed.
“Simply put, it’s a four-inch [10-centimetre] PVC pipe that’s put through your foundation floor. It’s piped outside with a fan on it,” says Bush. It draws the radon away from the home before it gets in, and pushes it back outside where it gets diluted. Bush says the system is between 90- and 95-per-cent effective.
Not everyone who is exposed to radon will develop lung cancer. Risk depends on how high the levels of radon are in the air a person breathes, and the length of time a person is exposed. Smokers, however, do face an increased risk of developing lung cancer when exposed to high levels of radon.
Health Canada says the time between exposure and the onset of cancer is usually many years and occasional exposure doesn’t cause symptoms such as headaches or coughing.
Bush often receives calls from Canadians who suspect their lung cancer might be related to radon exposure.
Their comments to me are always the same,” says Bush. “’‘I didn’t know about radon. I wish I had, I would have tested’ or ‘I heard about it but I didn’t think it was going to happen to me.’ ”
Making sure people know about radon and encouraging them to test for it in their homes is the focus of Bush and her colleagues’ work – and it’s a challenge.
“Radon is the most difficult health risk to get people to react to,” says Bush. “If you can’t blame someone for it or it’s not targeting a particular group of people . . . if it’s not an immediate health risk or it’s not tangible, then people tend to believe it’s not going to happen to them.
“[But] radon targets everyone.”
