Infinitesimal radioactive isotopes can be carried along on the breeze, landing unseen on the ground, clothes and skin. These tiny products of nuclear reactions are capable of causing large-scale bodily damage if they make it inside through inhalation, ingestion or even a cut. And many fear that such isotopes spewed from the damaged Fukushima Daiichi nuclear plant are traveling inter-continentally—and in higher quantities than Japanese officials are reporting.

This invisible threat has spurred people as far from Japan as the U.S. and Europe to snatch up and swallow potassium iodine pills in hopes of staving off any accumulation of radioactive iodine 131 particles in their thyroid glands (which can lead to cancer).

Although the most pressing immediate health concern is the powerful direct gamma radiation that threatens workers at the plant, "we need also to focus on the radioactive isotopes that are being dispersed at some distance from the plant," Ira Helfand, a former president of Physicians for Social Responsibility, said at a Wednesday news conference organized by that group, which is opposed to nuclear power.

The Japanese government has maintained that residents of Tokyo, some 220 kilometers south of the compromised Fukushima Daiichi nuclear plant, are not facing dangerous levels of radiation. Winds are expected to shift slightly more southerly at the end of the weekend, which could move more radioactive isotopes toward the capital city, but a rainstorm predicted for Sunday could help knock many of these harmful particles out of the air.

Some nuclear experts are concerned that "even if the total radiation dose is not real high downwind from a plant, the concentration of these isotopes can pose a very serious health problem," Helfand said. 

Elemental issues
The correlations among total body radiation exposure, ingested or inhaled isotopes and cancer are convoluted at best. The major studies in this field have used event-based samples, such as survivors of the atomic bombs dropped on Japan by the U.S. in World War II, to measure and map cancer rates years out.

The clean "linear relationship between your dose of total body radiation and the effect on your health is really lost when you're talking about low-dose radiation at some distance from the source," Helfand said. "You can have a very small total body radiation dose and end up getting thyroid cancer, or ingest some radioactive strontium and end up getting leukemia."

But the likelihood of this event causing large-scale cancer increases in the Tokyo population is slim, says Jeffrey Clanton, director of radiopharmacy services at Vanderbilt University Medical Center.

Iodine 131 is relatively short-lived (with a half-life of about eight days, compared with strontium 90, which decays to half its potency in 29 years). So the spent fuel stores would likely have already lost the majority of their iodine 131 before last Friday's earthquake and tsunami damaged the plant, Clanton explains. And any that is released "will most likely fall out of the atmosphere fairly quickly."

Strontium 90 isotopes, however, are a concern because the body treats them like calcium, integrating them into the bone, which can cause leukemia. But, Clanton says, they are not likely to travel more than a few kilometers—"five miles, probably, max."

Plutonium is of graver concern because of its exceptionally long half-life (about 24,000 years) and its propensity to cause lung cancer if inhaled. (There is plutonium in the fuel rods used at reactor No. 3 at the Fukushima complex.)

Clanton, however, maintains that a person would have to inhale or ingest "a reasonably large amount" of one or more radioactive isotopes to see negative effects. "It would take more than I've seen published from the area."

People in the U.S. purchasing prophylactic potassium iodine pills (which saturate the thyroid with regular iodine in hopes of preventing the uptake of radioactive iodine 131) "are wasting their money," Clanton says.

Winds of concern
No matter how much radioactive material is released, the worrisome isotopes from the Fukushima Daiichi facility are not particularly likely to follow a Chernobyl-scale distribution, Clanton notes. Even if the fuel temperatures fail to drop significantly, it is unlikely to produce the type of catastrophic explosion that launched so much radioactive material into the atmosphere over Chernobyl 25 years ago. The material at Fukushima also lacks the graphite-tipped control rods that were elemental in dispersing the isotopes from the Chernobyl event.

7 Comments

1. 1. William McDavid 05:08 PM 3/18/11

   The horrible tragedies in Japan should be responded to by every nation on Earth which has the expertise and resources to do so. The fact is, no place on Earth is immune to natural disasters of that magnitude or greater. Americans must band together to make sure that greedy dirty energy companies can't keep us vulnerable to added threats to our lives and health in order to maximize their windfall profits.
   The nuclear emergencies and natural gas and oil fires in Japan should be an object lesson, and dire warning, to every nation. This is why it is of utmost urgency to convert the world's energy systems to TRULY clean, safe, abundant, inexhaustible and FREE energy sources, such as Wind, Sunshine, Geothermal Heat, Tidal/River Flows and Hydrogen/Oxygen extracted from Water using electricity from those sources.
   If you think massive conversion to clean energy would be "too expensive", I have 2 questions for you:
   1) In your cost/benefit analysis, how do you value the lives of nuclear plant radiation victims, coal miners, drilling rig workers, billions of sea creatures and the millions of people who die from pollution-caused illnesses?
   2) If we fail to restore and protect the ONLY known natural life-support system in the Universe, how will you justify that failure to your gasping, wheezing Great-Grandchildren, and what do you think the money saved will be worth to THEM?
   If Japan's energy came from self-renewing energy sources, there would be no oil and gas fires or nuclear emergencies adding to the other crises they are facing.

   Reply | Report Abuse | Link to this

2. 2. Jorge Ianis in reply to William McDavid 08:19 PM 3/18/11

   It would be interesting to read real proposals and not only dreams that will never be a reality or help in the discussion, no matter how much we can desire it.
   
   As to produce electricity, the wind fails to blow in a more permanent and reliable base, besides the problem of bird killing by wind turbines blades, Sun rays not always make it to the ground with its whole energy, clouds and nights interfere. Sea water and high currents can destroy big electricity producing facilities that use tides, remember hurricanes. Even waste burning is useful but not enough. And there renewable energies list ends.
   
   So we need something else to produce the electrical flow in a more regular basis, and atomic energy is by far the most clean and regular of the electricity providers can offer.
   Now of course, as in every industry, there are risks and dangers. Hundred of coal miners are killed in mining accidents around the globe every year, and thousands get sick or injured extracting coal for electricity facilities that doesn’t have even a 10% of the regulations atomic ones have.
   
   Don’t forget the steady flow of millions of Gigawatts of clean energy the 450 atomic powered plants generate minute by minute around the globe, year by year, for the use of human civilization. Only in 2009 the 6 Fukushima plants generated 22,760,000 Gigawats h, preventing 22 billion tons of CO2 entering our atmosphere.
   
   Fretting about atomic energy doesn´t do any good to the combat against global warming, where atomic energy has a predominant place, to replace and prevent CO2 producing facilities.
   
   After all humans are the end users of energy, and we have to assume the risks that comes with any way electricity is produced. Now we have to choose between more global warming and severe climate change or an atomic accident like the one in Fukushima every 20 or more years.
   
   Lets then work in a more positive way for even safer atomic plants with renewable complements to cope for the energy we need now and tomorrow.
   
   

   Reply | Report Abuse | Link to this

3. 3. Pugsley 02:40 AM 3/19/11

   This article is based on an assumption that the problem will be purely from a core meltdown. Unfortunately, the latest news is the possibility of re-criticality occurring at spent fuel pool #4. That's a much larger amount of radioactive material than Chernobyl getting hotter very quickly.
   
   It's already time to re-assess the possible fallout patterns .... what's all-important is not the US, but Tokyo. Let's hope Tokyo doesn't have to be evacuated at this critical time in history.

   Reply | Report Abuse | Link to this

4. 4. Pugsley 03:10 AM 3/19/11

   By the way, Kyodo News has already censored out the reference to a renewed chain reaction. Earlier today it read
   
   -- Reactor No. 4 - Under maintenance when quake struck, no fuel rods in reactor core, temperature in spent-fuel storage pool reached 84 C on Monday, fire Tuesday possibly caused by hydrogen explosion at pool holding spent fuel rods, fire observed Wednesday at building housing reactor, pool water level feared receding, [b]renewed nuclear chain reaction feared,[/b] only frame remains of reactor building roof. http://english.kyodonews.jp/news/2011/03/79482.html
   
   Now it reads:
   
   -- Reactor No. 4 (Under maintenance when quake struck)
   
   Renewed nuclear chain reaction feared at spent-fuel storage pool, fire at building housing containment of reactor Tuesday and Wednesday, only frame remains of reactor building roof, temperature in the pool reached 84 C on Monday.
   
   http://english.kyodonews.jp/news/2011/03/79535.html

   Reply | Report Abuse | Link to this

5. 5. Jehovah Akbar 06:04 PM 3/25/11

   the following extract is poppycock and balderdash e.g. north-east scotland was only cleared of chernobyl safety concerns in 2010.
   
   "After all, 30 kilometers was the extent of the spread of dangerous radioactive material even at Chernobyl, ...."

   Reply | Report Abuse | Link to this

6. 6. Elderlybloke 09:31 PM 3/25/11

   The death toll from coal is a lot greater than any possible happening at the Japanese power plants.
   Sc.Am. article reports that over 2400 people died in China's mine accidents last year.
   
   Did anyone notice that?

   Reply | Report Abuse | Link to this

7. 7. Shivajirao 12:51 PM 11/5/12

   Nuclear plants are just silent killers of mankind and natural life systems.scientific academies proved that any dose of radiation above the natural background level will cause a corresponding increase in cancer increases and loss of immunity powers particularly in the young and the aged population.The smallest amount of radioactivity can release the alpha and beta particles and gamma ays that that enter the body of living organisms through the air and water and food taken by people and they strike at the body cells and they impact tghe water and cells and ultimately the DNA suffers single or double strand breaks which cause tumours or cancer in life forms.hence promotion of nuclear plants by any head of state amounts to his becoming an environmental criminal and whose actions make the Criminal acts of Hitler in killing millions of Jews by slowly poisoning them in the Gas chambers fade into insignificance , Hence Nuclear plants must be banned in all countries of the world like in Germany and japan whose intelligent heads of states became statesmen and rightly decided to phase out the existing reactors by 2022 or 2030.All the people of the world must unite in this effort of making the life livable by making the worlds nuclear-free.For more scientific details in the scientific articles see web site"DiaNuke.org"
   Prof.T.Shivaji Rao .M.S[Rice,Texas,1962]
   Director,Gitam University,visakhapatnam

   Reply | Report Abuse | Link to this