Flikr Creative Commons image by Xiaming
This guest post was written by Geert Biermans, a Belgian radioecologist I connected with on Twitter (@encephalartos). My thanks to Geert for providing his scientist’s perspective on the nuclear disaster in Japan and what it will mean for the earth’s environment far into the future.
By Geert Biermans
It’s hard to believe in the wake of Fukushima, but people once believed that radioactivity had curative powers.
People stood in line to drink “radium water” and bathed in it at natural baths. Radium, a decay product of uranium and also highly radioactive, was added to toothpaste, hair creams, and even food.
And then came Chernobyl, the little town in the Ukraine where nuclear energy production went so wrong.
I was born in 1986, the year the disaster occurred, so I can only imagine the scary period when everyone in Western Europe looked at the sky every time a cloud passed, hoping it wouldn’t bring rain. Even now, any child older than 12 knows what happened in Chernobyl.
Now We Know: Radioactivity To Be Feared
Now we face the same danger again, this time from Fukushima. And by now, all of us know that radioactivity is something to be feared.
One result has been increasing importance of radioecology, the branch of science that studies the effect of radioactivity not just on humans but on the environment as a whole.
Before Chernobyl, we thought that if humans were sufficiently protected by legal exposure limits, the environment would be protected as well. Now we know we must do far more.
Effects on the Body
Scientists have long known that all isotopes of radium are highly radioactive, emitting ionizing particles though decay of atomic nuclei. We know that radium is over a million times more radioactive than the same mass of uranium.
We know that it decays slowly over years and that the human body treats it as calcium, depositing it in the bones where it degrades bone marrow and can cause cancer.
But after Chernobyl we began to understand the effects of radioactivity on the biosphere as well as the body.
Today, radioecologists collect data on how radioactive elements behave in complex chemical and biological environments such as surface water and in marine ecosystems.
Effects on Our Biological Environment
Once we understand how radionuclides (also called radioisotopes) like cesium-137 or iodine-131 (those that were released at Fukushima) interact with our physical and biological environment, we can predict what will happen to the biosphere if they are released into the open, whether on purpose or by accident.
The data we collect helps determine, first, how animals and plants take up these isotopes under different physical conditions as shaped by pH level, soil type and climate. Then it helps determine how the isotopes start to cycle inside the ecosystem.
That helps tell us whether or not it is safe for people in contaminated areas to eat the salad in their gardens, or drink the milk of their cows.
‘Dry Lab’ Modeling
The processes involved when radioactivity is released are complex.
Some elements stay in the soil. Some are transported to plant leaves or accumulated in animal tissues.
Modeling these interactions and pathways for the entire ecosystem is even more complex, and a great deal of radioecology is now done within computer models, which could be seen as ‘dry labs.’
Dry lab modeling helps us predict the effect of worst-case scenarios and advise governments about whether contaminated regions should be evacuated.
By now, considerable quantities of radioactive material have been deposited within a large area around the Fukushima Daiichi nuclear power plant, and we are only beginning to see what the consequences will be.
What will be Result of Japanese disaster?
Will the people in the contaminated Japanese villages ever be able to return to their homes? If so, how long will it take before they can safely live there? Will they be able to farm again?
Those are questions radioecology can help to resolve. The answers can help save lives – and our global environment.
We do not hear an awful lot about which isotopes are emitted from Fukushima, but I doubt it’s only cesium-137 or iodine-131. Can you maybe enlighten us which isotopes are released and which may arrive in Europe?
Tia, Jean.
Hello Jean, and thanks for responding. Geert, the guest writer of the post, is traveling right ow and not in range of a good Internet connection. When he is, we’ll respond to your question.
Hi,
As to which isotopes are released from Fukushima, it’s important to note that for the atmospheric releases it’s mainly Iodine 131 and Cs 137.
There are others, of course, but these two are the ones that matter most in calculating effects, as they decay with a high energy (the radioactive particle has higher energy, and can interact deeper inside matter when it impacts biological tissues, for example).
More important, though, is that, should they be ingested, the body will accumulate them because of their resemblance to essential elements (Cs looks like potassium. Radioactive iodine looks like…well…stable iodine.) something that won’t happen that easily with other heavy elements.
If you really want to see which elements are formed and in which relative rates, i advise you to check the Wikipedia article on fission products here:
http://en.wikipedia.org/wiki/Nuclear_fission_product#Fission_products_in_power_reactors
Cesium will be retained for years in the soil because of the accumulation and recycling in plants and fungi, whereas other elements that aren’t taken up move and dilute in the soil and ground water
Iodine 131 has a half-life of a little bit more than one week, meaning half of the activity will be left after 8 days, 25% after 16 days, etc…
Cesium 137 has a halflife of 30 years, so you can see that that particular element can be a problem in long term.
That is a crucial difference with Chernobyl, where the reactor core was exposed, and long-living non-volatile compounds in spent fuel, such as Strontium, were spread out into the environment and over long distances.
What the effects of Fukushima in Europe are concerned,
i can be rather brief. There have been a lot of scary reports in the media about a “radioactive cloud” over Europe. That’s rubbish.
Yes. Measuring stations all over the northern hemisphere have indeed detected ‘increased’ isotope levels. And yes, they’ve measured I-131 and Cs-137, But almost everywhere this so-called “increase” was well within the natural variation of the natural background radiation. It’s like releasing a bottle of ink on one side of an olympic swimming pool and measuring “ink molecules” at the other side after all the water went round the pumping systems.
So, unless something very dramatic happens with the situation at the reactors in Fukushima, the only direct environmental concern will be in Japan. And please, please, please. Let’s focus on that.