Fukushima radioactive particle release was significant says new research

May 24, 2018, University of Manchester

In the immediate aftermath of the Fukushima Daiichi nuclear accident, it was thought that only volatile, gaseous radionuclides, such as caesium and iodine, were released from the damaged reactors. However, in recent years it has become apparent that small radioactive particles, termed caesium-rich micro-particles, were also released. Scientists have shown that these particles are mainly made of glass, and that they contain significant amounts of radioactive caesium, as well as smaller amounts of other radioisotopes, such as uranium and technetium.

The abundance of these micro- in Japanese soils and sediments, and their environmental impact is poorly understood. But the particles are very small and do not dissolve easily, meaning they could pose long-term health risks to humans if inhaled.

Therefore, scientists need to understand how many of the micro-particles are present in Fukushima soils and how much of the soil radioactivity can be attributed to the particles. Until recently, these measurements have proven challenging.

The new method makes use of a technique that is readily available in most Radiochemistry Laboratories called Autoradiography. In the method, an imaging plate is placed over contaminated soil samples covered with a plastic wrap, and the radioactive decay from the soil is recorded as an image on the plate. The image from plate is then read onto a computer.

The scientists say radioactive decay from the -rich micro particles can be differentiated from other forms of caesium contamination in the soil.

The scientists tested the new method on rice paddy soil samples retrieved from different locations within the Fukushima prefecture. The samples were taken close to (4 km) and far away (40 km) from the damaged nuclear reactors. The new method found caesium-rich micro-particles in all of the samples and showed that the amount of caesium associated with the micro-particles in the was much larger than expected.

Dr. Satoshi Utsunomiya, Associate Professor at Kyushu University, Japan, and the lead author of the study says "when we first started to find caesium-rich micro-particles in Fukushima , we thought they would turn out to be relatively rare. Now, using this method, we find there are lots of caesium-rich microparticles in exclusion zone soils and also in the soils collected from outside of the exclusion zone."

Dr. Gareth Law, Senior Lecturer in Analytical Radiochemistry at the University of Manchester and an author on the paper, adds: "Our research indicates that significant amounts of caesium were released from the Fukushima Daiichi reactors in particle form.

"This particle form of caesium behaves differently to the other, more soluble forms of caesium in the environment. We now need to push forward and better understand if caesium micro-particles are abundant throughout not only the exclusion zone, but also elsewhere in the Fukushima prefecture; then we can start to gauge their impact."

The new method can be easily used by other research teams investigating the environmental impact of the Fukushima Daiichi accident.

Dr. Utsunomiya adds: "we hope that our will allow scientists to quickly measure the abundance of caesium-rich micro-particles at other locations and estimate the amount of caesium radioactivity associated with the particles. This information can then inform cost effective, safe management and clean-up of soils contaminated by the nuclear accident."

Explore further: New evidence of nuclear fuel releases found at Fukushima

More information: Ryohei Ikehara et al. Novel Method of Quantifying Radioactive Cesium-Rich Microparticles (CsMPs) in the Environment from the Fukushima Daiichi Nuclear Power Plant, Environmental Science & Technology (2018). DOI: 10.1021/acs.est.7b06693

Related Stories

Fluorescent label sheds light on radioactive contamination

February 8, 2013

Researchers in Japan have developed a way to detect caesium contamination on a scale of millimetres enabling the detection of small areas of radioactive contamination. The research is published in Science and Technology of ...

Microbial soil cleanup at Fukushima

March 10, 2015

Proteins from salt-loving, halophilic, microbes could be the key to cleaning up leaked radioactive strontium and caesium ions from the Fukushima Dai-ichi Nuclear Power Plant incident in Japan. The publication of the X-ray ...

Fukushima nuke pollution in sea 'was world's worst'

October 27, 2011

France's nuclear monitor said on Thursday that the amount of caesium 137 that leaked into the Pacific from the Fukushima disaster was the greatest single nuclear contamination of the sea ever seen.

Some land in Japan too radioactive to farm: study

November 15, 2011

Farmland in parts of Japan is no longer safe because of high levels of radiation in the soil, scientists have warned, as the country struggles to recover from the Fukushima atomic disaster.

Recommended for you

Light-based production of drug-discovery molecules

February 18, 2019

Photoelectrochemical (PEC) cells are widely studied for the conversion of solar energy into chemical fuels. They use photocathodes and photoanodes to "split" water into hydrogen and oxygen respectively. PEC cells can work ...

Sound waves let quantum systems 'talk' to one another

February 18, 2019

Researchers at the University of Chicago and Argonne National Laboratory have invented an innovative way for different types of quantum technology to "talk" to each other using sound. The study, published Feb. 11 in Nature ...


Adjust slider to filter visible comments by rank

Display comments: newest first

3.7 / 5 (3) May 24, 2018
"...smaller amounts of other radioisotopes, such as uranium..."
Uranium is relatively abundant in nature, present in drinking water and food everywhere.
"Fun fact: the average person eats (and poops) about a microgram of Uranium each day!"
"alpha radiation from naturally occurring Polonium-210 is more damaging to biological tissues than gamma radiation from Cesium-137."

This kind of fearmongering research has only served to favor coal(backup for intermittent renewables) which emits radioactive particles and which air pollution respects no border and kills millions of people every year.
"Japanese government planning to build 45 new coal fired power stations to diversify supply" - Jan 2017
"Coal Ash Is More Radioactive Than Nuclear Waste"
2 / 5 (4) May 24, 2018
geez willie, there ya go again! Mixing up your apples & pineapples with pine cones.

Dear boy, the difference is in the intensity of radioactivity from diluted sources throughout the natural environment.

Against the sheer quantity of radiation emitted by refined nuclear fuels and weapons. Condensed to leave a swath of long-lasting contaminants throughout the environment.

How about an experiment "Oh High Priest of The Atomic DemiUrge"?

I toss a pebble at you. Oh good, you're paying attention. Just a natural event, a pebble bouncing off of you. Right?

So I take a brick and smack you across your head with it! Definitely NOT a natural event.

You noticed being hit with a brick? From the blood I'd say the greater mass and energy applied had a unfortunate result.

Yeah? Nay? Hello. is there anyone still in there?

But officer! We were doing a consensual scientific experiment. He insisted that excessive mass & energy are good for his health.
5 / 5 (1) May 25, 2018
the difference is in the intensity of radioactivity from diluted sources throughout the natural environment.
Fukushima: zero deaths from radiation exposure.
People receive more radiation(up to 65mSv) during a commercial flight, or visiting Kerala/Ramsar/Guarapari(up to 800mSv), than visiting Chernobyl(5mSv) or Fukushima(20mSv).
leave a swath of long-lasting contaminants throughout the environment.
What about arsenides and other chemical carcinogens found in solar panels that never lose their toxicity with time, worse than asbestos, and that are dumped directly into the environment?
"If Solar Panels Are So Clean, Why Do They Produce So Much Toxic Waste?" - May 2018

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.