Japan nuclear leak - health risks
It is not surprising that many people in Japan are deeply worried about the potential health threat from the radiation leak at the Fukushima nuclear plant. The earthquake and subsequent tsunami produced tangible, visible destruction whereas radiation is an invisible danger.
The images of families being screened for contamination by workers in protective suits add to the sense of alarm. So what are the risks at present? Scientists I have spoken to say we cannot give a clear answer yet because we don't know enough about the amount and type of radioactive material that has leaked. Nonetheless, most experts seem to suggest the danger to the public is low.
To start with, some background on radiation exposure which is measured in the unit known as sievert. This quantifies the amount of radiation absorbed by human tissues.
It is worth pointing out that everyone gets exposed to radiation, all the time. This is from the air, cosmic rays, food, water and so on. The levels are very low.
Figures from the Health Protection Agency say:
A chest x-ray gives a dose of about 20 microsieverts (that is 20 millionths of a sievert)
The average annual background radiation dose for individuals in the UK is 2,200 microsieverts.
So how does that compare with what is happening in Japan? Earlier today, a Japanese minister said at one point, anyone at the Fukushima plant itself would be exposed to 11,000 microsieverts per hour, but this had fallen back.
At another point radiation levels are said to have reached as high as 400 millisieverts (one millisievert is 1,000 microsieverts). That would be 20 times the annual permitted limit for nuclear workers. Clearly it is the small group of nuclear workers remaining at the plant who are most at risk.
For the public there is a 20 kilometre (12 mile) exclusion zone around the plant. People living up to 30 kilometres (18 miles) away have been told to stay indoors. "That would be effective in reducing the chances of inhaling radiation from an airborne plume" said Steve Jones, Professor of Environmental and Occupational Toxicology at the University of Central Lancashire. He said, "We don't know what is in that plume released after explosions at the plant, but the risk would decrease very quickly the further away you travel from the site."
All of the experts I spoke to said the health risks to the public, at present, were low. Professor Jones said if the situation did not get worse then it would probably be impossible to show any measurable health effects on the wider public in the decades to come. Cancer is a key long-term risk from radiation exposure and officials will undoubtedly be monitoring the health outcomes of the population around Fukushima..
So how does the danger compare to the worst nuclear accident in history, at Chernobyl, 25 years ago? The radiation leak in Japan is minute by comparison. At Chernobyl a huge explosion was followed by a fire which raged for 10 days and emitted a huge amount of radiation which spread over a vast area.
In a report on the 20th anniversary of the disaster, the World Health Organisation said up to 4000 people may eventually die from the health effects of radiation poisoning, but so far there had been around 60 deaths. Around 50 of those were emergency workers and nine children who died from thyroid cancer. Children are especially at risk from radiation poisoning because of their developing bodies.
Dr Jim Smith, Reader in Environmental Physics at Portsmouth University and author of "Chernobyl: Catastrophe and Consequences" spoke to me from Kiev. He is part of a team on its his way to visit Chernobyl.
He said: "The Chernobyl disaster resulted in a major release of radioactivity. It was a graphite reactor and huge amounts of radioactive caesium and iodine escaped. It was partly due to the design of the plant - very different from those in Japan."
He said several hundred thousand people worked on the subsequent clean up and decontamination of the plant. Many had received an average of around 100 millisieverts over the duration of their work at the site. Professor Smith estimated that this had increased their lifetime risk of cancer to the extent that for every 100 workers an extra one would get cancer. This is not a risk anyone would choose to take, but he pointed out it was far less than the danger of cancer from being a life-long smoker.
One of the main health effects of the Japanese radiation leak maybe the psychological impact. Professor Jones said the stress of being displaced from your home and the fear of radiation contamination could have serious consequences. And that fear factor extends as far as Tokyo, 155 miles from the nuclear plant. "Even though people in Tokyo maybe completely safe, it is understandable that they are nervous and that can lead to stress and ill-health", he said.
~RS~q~RS~~RS~z~RS~37~RS~){kind=spacer}
I'm 
Comments
Sign in or register to comment.
Part of the problem here is the sensationalist reporting by the media. And the BBC has been just as bad as all the others. Anyone reading much of the newspaper reports or watching rolling news channels will be under the entirely false impression that Japan is inches away from a Chernobyl-style disaster, or worse.
If you read more into the background, then it becomes clear that the risk to the public is very low - as this blog post points out. But this information is too important to be tucked away in a blog; it should be the headline news.
Thousands, possibly tens of thousands, of people have already died as a direct result of the earthquake and tsunami. The media's obsession with the nuclear power plants is obscuring the real human tragedy in Japan.
Complain about this comment
Hi Fergus,
Probably an opportune time to reprise Wade Allison's thought provoking 2010 New Scientist article that stating that historic, very low radiation limits do more harm than good. See [Unsuitable/Broken URL removed by Moderator]- unfortunately subscrition required which you no doubt have.
This current crisis looks like proving the article correct to a greater or lesser degree.
I think the blogsphere here would appreciate a discussion of the issues that Wade has raised and your take on them.
Many thanks.
Complain about this comment
"At another point radiation levels are said to have reached as high as 400 millisieverts..."
You mean, of course, millisieverts per hour here.
The reason that the radiation levels are so high is that radioisotopes with very short half lives are being released in the steam which is cooling the reactors. As they have very short half lives they emit a lot of radiation. The good thing about these isotopes is that they cease to be radioactive seconds after they have left the reactor, meaning that, while you might acquire a dose of 400 mSv/hour if you are standing in one part of the nuclear site, the dose around the corner might be much lower.
This is the other difference with Chernobyl: many of the radioisotopes released in that disaster had long half lives, so that the site is still radioactive 25 years later.
I tend to agree with Mark that the media have blown this element of the Japanese tragedy out of proportion. There is no appreciable risk to public health – something which I dare say cannot be said for sanitary conditions following the tsunami – yet the public health angle is the one which makes the story 'sexy'. If the plant blows up and kills people with radioactive fallout – which, at this stage, is extraordinarily unlikely – that will make good television. Who would be interested in the story of a nuclear power plant which did not emit much radiation even after it had been hit by both a powerful earthquake and tsunami?
Complain about this comment
I take it that the BBC will soon be returning its journalists to the area, then?
Complain about this comment
I also agree that there hass sensationalist reporting. I have seen no end of nuclear physicists say that public risk is low ( eg Prof. Paddy Regan) yet I have yet to hear the BBC down play the present dangers.
Regards the future of nuclear power, if there is no further escalation of danger from the reactors, then I think it is a testament to nuclear engineering that even an earthquake of this magnitude could not cause a catastrophe or even serious radiation danger.
Complain about this comment
Mr. Walsh,
1. You said "A chest x-ray gives a dose of about 20 microsieverts (that is 20 millionths of a sievert). The average annual background radiation dose for individuals in the UK is 2,200 microsieverts". Could you elaborate the difference between " getting a chest x-ray check once Vs exposing in the open air for a longer period of time, say a few hours ?
2. No crises are identical and it may be difficult for the specialists to compare "Chernobyl Vs Fukushima" based on past experience. So, neither optimistic nor pessimistic comments is appropriate as we're dealing with human health & life. The best way is to pressurize the Japan Authority to uncover the right data for a fair individual & professional evaluation and action planning. How do you think ?
Rgds,
Complain about this comment
These reactors seem to be very short of water, no power and now authorities are looking at water delivery methods that seem to have no chance of providing the cooling needed. The largest self contained pumping systems I know of are Dredges. Some more than 1m dia at 10+ meters /sec. That is a volume of water that should be able to pressurize the whole delivery system of the of the plant with some volume to spare. The Trailer type ship is usually able to travel at 18 kts. or so and can carry all the piping needed to send the water ashore. Just speculating but that seems a more likely way to provide the needed cooling than a Helicopter with a bucket of ocean water at a time.
Complain about this comment
Interesting how several people commenting here and the author seek to minimize the risks. True, so far the releases are not large, particularly of cesium 137, but that can change. As for the statement above that the radioisotopes released in the steam are so short-lived that the on site levels will rapidly dissipate, so what? The problem now is the increased on-site radiation levels; they spiked to about 1,000 millisieverts per hour and remained elevated at 600 to 800 millisieverts per hour. As a result the plant personnel have now all been evacuated. The levels are so high that even if workers were to try to remain on duty they would receive lethal doses in just a few hours and soon thereafter would be incapacitated, too quickly to allow them to perform the hard labor required.
It becomes more and more likely that workers will not able to return as the release rate keeps increasing. Unless workers are able to return, which seems increasingly unlikely, the situation will inevitably progress to full failure of all the reactor cores. Without ongoing management it is inevitable that the situation will progress to complete failure of reactors 1, 2 and 3, as well as uncovering of the large amounts of spent fuel stored on-site. The spent fuel pools are reported to be overheating and the pool at reactor 4 is reported to be boiling due to loss of cooling. Worse the spent fuel will soon catch fire and ongoing release of large amounts of very dangerous isotopes especially cesium 137 is about to begin. We are now on the verge of a nuclear catastrophe orders of magnitude worse than Chernobyl
Complain about this comment
EORANGE says:
"- I think it is a testament to nuclear engineering that even an earthquake of this magnitude could not cause a catastrophe or even serious radiation danger. "
Well... the things are still largely there but they have blown up, I'm not sure that matches my understanding of a good testament to quality engineering. Basic design says if the reactor loses electric power for whatever reason - it blows up! Yep, good design.
Also on the radiation levels - some ramifications of the numbers above: "radiation levels are said to have reached as high as 400 millisieverts" (per hour) - that means a worker can work for 1/20 of an hour here to get his yearly dose. Moreover, at the apparently acceptable lower stated amount of 11,000 microseiverts per hour - hmm... that's the same as taking 550 chest xrays per hour - doesn't sound all that healthy to me.
Complain about this comment
For those knowing commentators who say it's over-reacting to call Fukushima Chernobyl-like. Well, yes... Chernobyl didn't have tons and tons of spent fuel stored above its reactors in open tanks, chernobyl was only 1 reactor melting down, not 4 melting down, Chernobyl was in a deserted area, not next to 26 million people and the core of a good percentage of the world's economy. So it's clear it's not a Chernobyl level incident - we can all rest easy.
Complain about this comment
I agree completely with infrederick and dlweld. This blog post might have made limited sense if it had been written 3 days ago but given what we know today it is completely off the mark.
The situation in Fukushima is currently out of anyone's control, and it hasn't been under control since the tsunami hit Friday. It's high time to get out of the way. The sooner people become aware of this the better.
Complain about this comment
At this point, why are people still talking about the superiority of our designs vs Chernobyl? It doesn't make any difference that your design includes a containment structure if the containment structure fails completely. By the way, industry simulations had predicted a 90% probability of containment failure in this type reactor if it lost both grid power and generator backup power, which is exactly what is happening.
Complain about this comment
Its not rocket science ,when a core is exposed and as a last desperate attempt to cool it they get a helicopter to dump seawater into it ,what do you think will happen ? 1/ the water is converted into steam and goes up into the surounding area, 2/ the water runs out of the reactor and seeps into the water couses and the drainage system poluting everything in sight and beyond .
as for the british [expert]interviewed on BBC tv news about background ,he compared the radiation around the plant with the background radiation in london with the radiation in cornwall .
perhaps he would like to stand outside at the scene and tell us from there !
I must sat that the BBC coverage coment on was very condesending [was it steam or smoke ? why could not they just get a reporter to get the actual level of radiation from an acurate sorce ,does the BBC realy expect the public to belive that in such a catistrofic explosion only one man injurd !
when the whole building blown apart with such force it might as well have been a nuclear bomb .
mean while back in england in somerset our old reactor has a crack in the reator but the government say its ok as we shut it down in 2016 anyway !
One of the best indicators was that the american aircraft carrier was moved back away their so called safe ,another marker was that the government told people in the safe zone to turn their airconditioners off.
Complain about this comment
Ok you build a nuclear reactor on the coast because you need the water to cool it down ,then you have a problem with eathquakes and you are on the back end of the pacific rim ,well if were me i would build a massiv artificial reef to minimise any sunarmies ,but then thats only me :
Complain about this comment
Fergus,
You can go on all you like about a tiny risk (equivalent to a dental xray), but dental xrays are safe as they are done by a nice dentist in a white coat (We conveniently don't worry about why he/she leaves the room when he/she uses his/her machine!) But deep in our subconscious is Hiroshima, Nagasaki, Three Mile Island and Chernobyl.
One issue you have not touched on is the different types of radiation risk. People need to understand, not just the level of radiation risk, but the different types of radiation source. For example the risks of inhaling alpha emitters and getting them embedded in the lungs where they can do terrible long term damage. Whereas gamma radiation exposure is generally transitory.
You are also making assumptions about your readers ability with number which are unfounded and this is where our terrible pride in being innumerate creates policy errors and spurious feelings of risk and safety.
Complain about this comment
Right mate where do want the emergency generators put to cool down them nuclear reactors, oh" just put them over there on the ground thats where they are going ,oy what if we get a sunarmi ? look mate it will never happen :
Complain about this comment
I see they now have snow ,i was just wondering how long it will be before they get black rain ?
Complain about this comment
I very much agree with the comments about sensationalist reporting. Anyone reading or hearing the BBC reports might imagine that residents of California will be at risk of airborne radiation within a few days.
It would certainly help if the Japanese authorities could produce a line-up of scientific experts who could put the risk in proper perspective. Meanwhile, it is no wonder that residents of the Tokyo area are experiencing a psychological impact. They are reading the sensationalist reports of potential risks in all the media, at the same time as investment bankers are fleeing the country.
Complain about this comment
So 60 deaths attributed to Chernobyl, with up to 4000 estimated? Still less than the 10,000+ who've died as a result of the tsunami, which experts now say is a once in a 1000-year event, so is hardly a reason for halting construction of nuclear power stations.
Of course, any risks of nucelar power pale into insignificance when you consider the effects worldwide of smoking (see Fergus's previous post). If we want to stop unnecessary deaths, shouldn't we start with something pointless that kills 100,000s a year, rather than something useful that kills very few people?
Complain about this comment
I'm generally pretty conservative but here side with the hippies & tree huggers.
I'd much rather see us putting serious efforts into conserving energy than messing about with something so potentially dangerous.
Beyond the natural disasters, there's always human error to contend with.
Complain about this comment
I am an exchange student currently living in Seoul, South Korea. Is there any current or potential risk for me here? A few of my classmates have already returned to their home countries. I usually don't over react, but I am worried. It would be nice to see an easy to read wind map, or something that would show where any plum would be heading. Someone mentioned that the isotope being released has a very short half life. Is anything else coming out that could make it as far as Seoul? I have heard nothing on the matter from the US (my home country) or South Korea.
Thank you for your article.
Complain about this comment
Dear Fergus,
Thank you for your article. I am a resident in Japan living in suburb of Tokyo only 200km away from Fukushima nuclear plant. So far, I don't see much panic among residents in Tokyo area trying to evacuate to farther away from Fukushima but the only people who are rushing to leave the country are non-Japanese residents who seem to have been exposed to those reportings by sensationalists. I have only been following Japanese media reports which is right now all about keeping people calm by explaining that the danger to the public is very low. The japanese authorities and TEPCO are not disclosing enough information to the public and I was almost convinced not to believe anaything I hear on Japanese media even if analysis was given by well-respected professors, scientists or nuclear specialists because they all say that the health risk is very low.
I have friends from overseas begging me to evacuate to western part of Japan because it's too dangerous to stay in Tokyo, telling me to go alone if my family don't agree to come with me. My family thinks I'm over-reacting by even mentioning the possible evaculation plan. The huge gap between Japanese media reports and those by sensatioinalists is causing so much stress when we have enough stress already for trying to stay calm and resume our ordinary lives through power-cuts arranged by TEPCO to conserve electricity.
I even feel ashamed of talking about such stress knowing that tens of thousands of people were affected by tsunami and the incident at Fukushima nuclear plant. What I'm dealing with is nothing compared to what those people are going through right now but I feel relieved to have read your article knowing that BBC takes very similar view of the situation in Fukushima as what have been reported here in Japan.
Complain about this comment
I agree about the sensationalist reporting. I have been in constant contact with my expat friends in Tokyo and Osaka since the earthquake. The most frustrating thing for us is to work out how much we should really worry and what, if anything, we should do because it is difficult and time consuming to filter out hard facts among all the rumours. Moreover, the fear mongering has actually made the situation worse for people in Japan. The media and foreign governments wanting to curry favour with voters have whipped up fears that the Japanese officials are playing down an impending "Armageddon", even though the International Atomic Energy Agency, the World Health Organisation, the UK Government's Chief Scientific Officer and other international organisations and experts confirmed that their statements appear to be truthful and the steps taken sensible and appropriate. As a result, people in Tokyo are finding it more and more difficult to buy food due to panic buying and even in Osaka food is now becoming scarce. Meanwhile, speculation about the impact of the quake on Japan's economy are pushing the yen even higher than it already was, making Japanese products uncompetitively expensive and therefore making it harder for Japan to recover from this tragedy. The World Health Organisation today urged governments and individuals to stop spreading rumours about radiation. Can they therefore please be more responsible and care less about headlines and votes and more about the victims?
Complain about this comment
I read BBC news frequently from Japan and I am Japanese.
Many Japanese read BBC,CNN,etc because can trust more than Japanese media.
BBC report very detail and exactly, however sometime real fact make new problem.
Last few days, the nuclear reactor got worse.
It is exactly right that BBC tell many Japanese concern the problem.
I would like to tell Media because Media makes PANIC.
Following problem happen in Japan NOW.
I live near Tokyo, resident got little PANIC.
Food and GAS can not deliver well,resident rush to the shop for stock those.
Japanese Media and Government repeatedly tell food supply capability enough, no rush please.
However, many bad rumor on Japanese famous internet Bulletin board what say BBC,CNN,Japanese media report more detail fact.
Therefore, people's concern make short supply food,GAS,etc.
Those short supply and nuclear concern make huge damage.
For instance
1.Some elderly home where about 30km away from the reactor is about to collapse.
Due to luck of nurse and hard to find driver to rescue the elderly by bus or car.
Some driver refuse go there who concern radio pollution.
2.Northern region Japanese concern that froze body and starve, due to luck GAS.
Few car for shop and Few heat for body.
I think that if I know real worst fact now, I do not have many option in more huge PANIC.
Imagine that if 20 million people try to evacuate NOW
what happen next.
Therefore, Media people report the news carefully please.
To prevent make more big PANIC.
PANIC could make more damage northern region Japanese.
Sensationalist reporting of nuclear do not useful now.
Complain about this comment
I agree Mark.
I am Japanese and live neaby Tokyo.
Resident who live Tokyo and region nearby the nuclear reactor
got small PANIC due to maybe sensationalist reporting by the media.
The PANIC make short supply food,GAS,etc
Resident who live northern Japan can not take enough food and GAS due to the short supply.
In addition, some private driver refuse drive car for rescue people who stay 30km radios of the reactor.
Concern radiation pollution.
If I know worst fact, I do not have many options.
I think that if got huge PANIC, get more worse.
Complain about this comment
I have no clue why people are panicking all over the world and buying iodine as far away as California but if the Nuclear Regulatory Commission in the U.S. is recommending an 80 km evacuation zone (50 miles), I'd follow their advice now and start taking iodine as well if I lived anywhere in this area. This is a large increase from the current 20km, with an evacuation area 16 times as large.
The NRC are not known for being freaked out about nuclear energy so my guess is that the 80km radius is correct.
I would also like to point out that the World Health Organization estimated 16,000 deaths from 41,000 cancers caused by Chernobyl in a report subsequent to the estimate mentioned by Fergus Walsh. You can find it at http://www.iarc.fr/en/media-centre/pr/2006/pr168.html
Finally, studies in the U.S. have estimated that the worst-case scenarios for reactor meltdowns lead to long term deaths in the tens of thousands depending on the proximity of populations, wind, etc.
The same is true for worst-case scenarios from fuel storage pools, with tens of thousands of additional deaths.
In this case, we potentially have 6 reactors and 6 storage pools.
Complain about this comment
I don't know whether the reporting is sensationalist or not. We probably won't know until this is over.
But I wish people would take more care when repeating the old lie about 60 deaths from Chernobyl. Just think about it, Fergus, for goodness sake. It's ludicrous.
Also take note of this from the New York Academy of Sciences in 2009:
"Chernobyl: Consequences of the Catastrophe for People and the Environment"
Written by three scientists, one of them, Alexey Yablokov, states - "Since 1990, mortality among the clean-up teams has exceeded the mortality rate in corresponding population groups. From 112,000 to 125,000 liquidators died before 2005 - that is, some 15 per cent of the 830,000 members of the Chernobyl clean-up teams.
"The calculations suggest that the Chernobyl catastrophe has already killed several hundred thousand human beings in a population of several hundred million that was unfortunate enough to live in territories affected by the fallout."
This too sounds ludicrous in its own way, but perhaps the truth lies somewhere in between.
Complain about this comment
The health risks from this disaster are real, and potentially very significant. The risks of exposure should certainly not be dismissed on the basis of our currently limited understanding of radiation effects, especially for internal exposures.
See
http://www.cerrie.org/pdfs/cerrie_press_release_final.doc
Complain about this comment
View these comments in RSS