AFP, ABC with Yahoo!7
March 16, 2011, 2:43 pm
How do we protect ourselves, how much radiation is dangerous and what are the dangers outside Japan?
How high is the danger near the Fukushima nuclear plant?
Experts are urging a rapid rotation of emergency crews at the plant to limit their exposure to DNA-destroying energy, after some reports warned of extremely high radiation levels of 400 millisieverts an hour.
At these levels, the 50 workers still on site ran the real risk of developing acute radiation sickness if not given proper protection, said Associate Professor Tilman Ruff, a public health physician at the University of Melbourne's Nossal Institute for Global Health.
Other experts yesterday sought to tone down the health concerns.
Peter Burns, former chief executive of the Australian Radiation Protection and Nuclear Safety Agency, said radiation releases so far in Japan were "I suspect... a million times, probably several million times, less" than in Chernobyl, where basic prevention measures would have greatly lessened the health impacts.
"The problem at Chernobyl (was that) people still drank the milk and ate the vegetables," he said.
Are Tokyo and other areas in Japan in danger?
Experts have advised the risk in Tokyo and areas outside the 20 km exclusion zone are extremely low at this stage. Fears were heightened yesterday as radiation levels were detected at approximately 30 times the normal reading and a plume of slightly contaminated air was blown away from the Fukushima plant by wind.
Currently, the level of radiation is still not even close to a level where it would cause health problems, unless there was exposure for an extremely extended period.
Important information:
*Donate to Save the Children's Japan Earthquake Appeal: Call 1800 76 00 11
*Online at www.savethechildren.org.au
*DFAT assistance helpline: +61 2 6261 3305
*DFAT hotline for Australians concerned about family and friends: 1300 555 135
*Online at http://www.dfat.gov.au/
Human spirit in face of disaster
How do we protect ourselves from radiation?
Authorities are advising people within 30km of the nuclear plant to stay indoors, close windows and turn off air-conditioning systems, which will help to stop the movement of air carrying radioactive particles into their homes. Refraining from eating food or drinking water which may have been exposed to outside air is also being suggested. If it is necessary to go outside, people are advised to wear facemasks and an extra outer layer of clothes which can be disposed of before re-entering their home, leaving radioactive particles outside.
There are three weapons against contamination - evacuation, confinement and iodine," Patrick Gourmelon, from the Institute for Radioprotection and Nuclear Safety, told AFP.
People should avoid nail-biting, smoking and sucking or licking one’s fingers after being in an affected area.
"You take a good shower to remove any contact between the fallout and the skin, but you shouldn't scrub, because this helps particles to penetrate," Mr Gourmelon said.
What is the risk outside Japan?
While the reactor cores in Fukushima power plants remain intact, there is no serious contamination risk outside Japan or immediate danger in other countries. Currently, the serious effects can be confined to the 20km radius around the plant.
This will only change if one of more of the reactions melt down, which may cause plumes of radioactive dust to move offshore. This could ultimately affect countries around the North Pacific, including Russia, China, Canada and the US.
The separation of climate systems in the northern and southern hemispheres meant it was unlikely to affect Australia, as it would make it difficult for airborne contamination to cross the equator.
Meanwhile, Australians outside the affected areas in Japan "are extremely unlikely to be contaminated and the health risks are negligible," the Department of Foreign Affairs and Trade updated travel advice says.
Australians in Japan are being warned by DFAT to not enter the 20km – 30km exclusion zone, and to stay away from the Fukushima Nuclear Power Plant and Miyagi Prefecture on the east coast of Japan.
Currently there is "a very low to negligible chance of contamination" to Australians in affected areas, the Australian Radiation Protection and Nuclear Safety Agency says.
Foreign Minister Rudd says at present the Government has no safety advice for Australians outside of the 30-kilometre radius around the Fukushima nuclear plant.
"This nuclear situation on the ground out of Fukushima we take seriously. If there are any further developments on this score, we will of course advise the Australian public immediately, and we're working with the Japanese as we are working with the International Atomic Energy Agency, and this work continues through the night," he said.
How much radiation is dangerous?
Chief Cabinet Secretary Yukio Edano said radiation levels near the stricken plant on the northeast coast reached as high as 400 millisieverts (mSv) an hour, thousands of times higher than readings before the blast, but later gave a lower figure. A level of 400 mSV would be 20 times the annual exposure for some nuclear-industry employees and uranium miners.
*Exposure to 350 mSv was the criterion for relocating people after the Chernobyl accident, according to the World Nuclear Association.
*People are exposed to natural radiation of about 2 mSv a year.
*A typical chest X-ray involves exposure of about 0.02 mSv, while a dental one can be 0.01 mSv
*Airline crew flying the New York-Tokyo polar route are exposed to 9 mSv a year.
*Exposure to 100 mSv a year is the lowest level at which any increase in cancer is clearly evident. A cumulative 1,000 mSv would probably cause a fatal cancer many years later in five out of every 100 persons exposed to it.
*A single 1,000 mSv dose causes radiation sickness such as nausea but not death. A single dose of 5,000 mSv would kill about half of those exposed to it within a month.
*"Very acute radiation, like that which happened in Chernobyl and to the Japanese workers at the nuclear power station, is unlikely for the population," said Lam Ching-wan, a chemical pathologist at the university of Hong Kong.
Nuclear crisis in Japan
Experts say three factors determine whether a blast of radiation will be harmless, debilitating or lethal: the intensity of exposure, its duration and access to treatment.
Radioactive fallout includes caesium 137, a long-term element, and iodine, which is a short-term element.
Exposure
Intensity of exposure is measured in a unit called millisieverts (mSv), while the absorbed dose in the body is measured in milligrays.
Small, controlled doses of exposure for medical applications cause no ill effects, doctors say.
A brain scan, for example, generates 25 mSv while a whole body scan puts out 150 mSv. A single dose of 1,000 mSv, though, can cause temporary radiation sickness, including nausea and vomiting.
About half of people exposed to a 5,000 mSv dose across the entire body would probably die, while 6,000 mSv would be fatal without immediate treatment.
Exposure to 10,000 mSv in a single dose would lead to death "within a few weeks", according to the World Nuclear Association (WNA), an industry group.
During a severe nuclear accident, exposure can reach several thousand mSv near the reactor core.
Radiation illness
The main health danger is cancer, especially leukaemia, along with lung, thyroid and colon cancer.
"The risk is proportional to the dose received," said Patrick Gourmelon, a top researcher at the French Institute for Radioprotection and Nuclear Safety (IRSN).
"Even for relatively small doses, the risk of developing cancers rises."
In cases of extreme irradiation, the body's bone marrow stops making red and white blood vessels, resulting in death. Cells inside the digestive tract are also especially vulnerable.
Over the long term radiation can also damage DNA, leading to potential birth defects.
Massive quake and tsunami hits Japan
Treatment options
Potassium iodine pills taken beforehand can help prevent radioactive iodine in the air from settling in the thyroid and causing cancer, especially in infants and children.
The tablets are preferably taken an hour before a known fallout incident.
Japanese guidelines say the pills should be distributed when the likely absorbed dose of radioactivity is 100 milligray, a unit named after a British physicist.
Once exposed, the best first step is to throw away contaminated clothes and wash one's hair and body.
Some drugs help boost white-blood cell production inside bone marrow and build up the body's compromised immunity.
Health experts warning over iodine rush
Japan'S nuclear crisis has sparked panic buying of iodine pills, with online bids exceeding $500 for a single packet, but health experts hosed down the hysteria and warned the pills are of limited use.
As fresh blasts rocked a stricken atomic plant on Japan's east coast, and crews worked frantically to cool reactors that emitted dangerous levels of radiation near the facility, jitters spread to Tokyo and beyond.
US-based firms selling potassium iodide, a radiation sickness preventative, completely ran out of stock and pharmacies across the country's Pacific-facing West Coast had a rush on the over-the-counter pills.
"We are quite slammed with orders, but we are working as fast as we can to get orders out," said NukePills.com, which had sold out of iodine tablets and was fast exhausting oral liquid supplies.
"We are experiencing delays in shipping due to the Japan nuclear crisis. A delay in shipping may be a week or more."
Potassium iodide is a salt used to saturate the thyroid gland to block the uptake of radioactive iodine, a highly carcinogenic substance that can leak from nuclear reactors in an accident.
Another major supplier, Anbex, said it was also out of stock and didn't expect new orders until April 18.
One packet of 14 pills had attracted bids of up to $US540 ($A535.87) at online auction house eBay and talk about radiation poisoning was so feverish on Twitter and other forums that the World Health Organisation issued a statement urging calm.
"Consult your #doctor before taking #iodine pills. Do not self-medicate!" the WHO said on its Twitter page.
Iodine pills are "not radiation antidotes" and offer no protection against radioactive elements such as caesium, the UN's health agency said, stressing they also carried health risks for some people, including pregnant women.
The WHO also cautioned against drinking or applying iodine liquid, commonly used as an antiseptic, after a rush on the wound cleaner in Asian countries, where iodine is typically only available in hospitals or by prescription.
"It is crazy, people have been reading about the situation in Japan and they are demanding iodine tablets but most pharmacies don't stock the tablets," said Kuala Lumpur pharmacist Paul Ho.
"There have also been text messages and emails going round that you can use the iodine antiseptic solution, which you place around your neck, to help cut down on radiation absorption," he added.
"I don't know if its true but we have run out of all our iodine antiseptic solution at the moment."
Japan disaster from above
The text message, also circulating in China, Hong Kong and the Philippines, is billed as a "newsflash" from a major news organisation and urges Asian residents to "take precautions" including sheltering indoors and swabbing the thyroid region of the neck with iodine.
Malaysia's Health Minister Liow Tiong Lai dismissed the purported warning as "nonsense", saying there was "no need to apply such solutions to the neck and private parts."
"People must not panic. The health ministry is keeping very close tabs on the situation," he told AFP.
The assurances were echoed in Taiwan, where officials were preparing to hand out 100,000 boxes of iodine tablets to residents near two nuclear plants in New Taipei city, and also in Manila.
"Let me be very clear, we don't see the necessity for that," said Philippines Health Secretary Enrique Ona.
"We know where we can get it if necessary. But we are not going to order it yet."
Stephen Tsui, a biomedical expert from the Chinese University of Hong Kong, described the risk of contamination outside of Japan as "low" but said "all countries could be affected" in the region if the Fukushima plant had a total meltdown.
Tens of thousands have already been evacuated from a zone within a radius of 20 kilometres of the 40-year-old plant, where authorities said radiation levels reached dangerous levels.
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