ncreased emissions bring on cancer
Doctors say ever-growing exposure could eventually harm human health
An official in a radiation protection suit scans dogs with a Geiger counter at a shelter in Koriyama in Fukushima prefecture, 60 kms west from the Fukushima nuclear power plant, on March 20, 2011.
Photograph by: KEN SHIMIZU, AFP/Getty Images
“There is no doubt in the minds of medical experts ... that increasing the global burden of radioactivity will increase the incidence of cancer,” Physicians for Global Survival said in a news release.
Dr. Perry Kendall, British Columbia’s provincial health officer, reiterated Wednesday that British Columbians have no immediate cause for concern after radiation from Japan was detected on the coast of B.C.
“I would like to be clear that the levels noted are very low. In fact, radiation levels so far have all been within the normal range of variability, and are below what a person on a long-distance flight may be exposed to,” Kendall said in a statement.
The health risks are not immediate at such low doses, but this accident will mean future generations live in a world with higher background radiation, said Dale Dewar, a practicing physician and the executive director of Physicians for Global Survival, an Ottawa organization formed to oppose nuclear weapons.
“Your hair won’t fall out because you’ve got a little bit of radioactivity, but ‘no immediate danger’ is an easy way for the nuclear industry to duck the long-term effects,” Dewar said in an interview.
Twelve days after the Fukushima Daiichi power plant was disabled by the March 11 earthquake and tsunami, the reactors are still not stabilized. High levels of Iodine-131 and Cesium-137 have been found in foods from the region, and in sea water, the International Atomic Energy Agency reported, saying Wednesday afternoon that “the overall situation remains of serious concern.”
Both Dewar and Kendall told The Sun that scientists assume there is no low limit of exposure to iodizing radiation that is safe and that higher exposure to radiation leads to an increased risk of cancer.
“With radiation, you have to assume that there is no safe level. It’s a linear relationship; the more you’re exposed to, the more the risk,” Kendall explained.
“The radiation we have on the coast is less than what you see in the Interior, which is a lot less than what you see in Denver, Colo., for background radiation,” Kendall said. “Statistically there’s an increased risk if you live in Denver, Colo., than if you live on the coast of B.C. because they have higher background radiation.”
Kendall said the small increases being seen in B.C. will not make a statistical difference in the number of cancers.
“The point at which you start seeing a statistical increase in cancers is around about 100 millisieverts a year, and we’re not seeing anything like that for the Japanese population, and for us it’s nowhere near that.”
Although the amounts may be very small, they do leave traces in the human body, Dewar said.
“Cesium-137 is used in forensics to find out how long a body has been lying in a grave. If a person died before the 1950s they will have no Cesium-137 in their body,” Dewar said. “Everyone now has Cesium-137 in their bodies, but it’s a totally man-made radioactive substance that we’ve been adding to our environment since they started exploding nuclear bombs.
“We also all have markers from Chernobyl. A little bit of Chernobyl is in everybody.”
(The Chernobyl nuclear plant in what is now Ukraine had a meltdown in 1986.)
Dewar could not say exactly how much background radiation has risen since before the first nuclear testing, but she said there is no doubt that it is going up.
“We can be very confident that background radiation is increasing, and it’s increasing at different levels in different places around the world,” Dewar said.
Iodine-131, one of the radioactive products emitted in Japan, releases gamma rays as it decays, Dewar said.
“Gamma radiation is little bursts of energy that knock electrons, and sometimes protons, out of the sphere that they are in our bodies, so that you may have an enzyme that loses a few molecules and can no longer function,” Dewar said. “At a low dose, you’ll only have a couple of enzymes affected. However, all of our cells have built-in longevity, a way in which the cell will stop growing. If that is knocked out, that’s when cancer occurs because the cell doesn’t know how to stop replicating itself.”
Ionizing radiation may also play a role in auto-immune diseases.
“Many physicians believe that radiation plays a role in the less obvious diseases like diabetes or gluten sensitivity or arthritis, which we’re now seeing younger,” Dewar said. “There’s so much that we just don’t know. We do know that as soon as we increase the background radiation very slightly — for example suntanning — we increase the potential cellular damage.”
Today, the average Canadian is exposed to between two and three millisieverts of radiation annually from background radiation.
Whether it is absorbed into the human body through food, water or the air, radiation is essentially silent. You can’t taste it, see it or smell it, Dewar said.
Kendall reminded people that there is no need to take potassium iodide tablets at this time and that they can cause health problems because of potential side effects.
tsherlock@vancouversun.com
