This page is adapted from the original Japanese transcript of NHK’s Today’s Close-Up broadcast on November 8, 2011
People in Fukushima Prefecture recently celebrated their annual rice harvest, after clearing the government standard for levels of radioactivity.
But some farmers in Fukushima are dissatisfied with the fact that their crops simply met the government standard, and have started working to produce crops with zero radiation.
They say that simply waiting for national or local government measures would not help them regain the trust of consumers who are worried about product safety.
One farmer says there’s no use in simply waiting for official reconstruction projects to start. He says he has to act first and move to the next step while analyzing what he’s done.
The farmers are working to protect their crops from radioactive contamination through methods such as adding materials to their soil or plowing differently.
They’ve also found that rice paddies are unexpectedly vulnerable to radioactive material.
We’ll look at farmers’ efforts to minimize radioactive material in their crops.
Farmers are determined to fight for a near-zero radiation level to restore their contaminated farmland
Sukagawa is one of Fukushima’s rice production centers. The city is 60 kilometers from the crippled Fukushima Daiichi nuclear power plant.
Radiation tests in September 2011 showed that levels of radioactive material in rice from the area were far below the government limit. The result was a temporary relief to most local farmers.
But one group of farmers was not satisfied, and resolved to make their crops free of radiation.
Toshihiko Ito is the group’s leader.
The farmers collect radioactive material from soil, unpolished rice and straw and analyze data to work out ways to prevent such material from contaminating their crops.
The farmers started the efforts after determining that they needed to seek levels of safety beyond the government standard, to regain the trust of consumers who’d stopped buying Fukushima rice after the accident.
Ito founded an agricultural corporation with other farmers 18 years ago, with the goal of growing safe and tasty rice.
They grew organic rice that became popular across Japan, expanding their customer base to 4,000 people.
However, this year 60 percent of the customers did not order the group’s rice.
“The group has no choice but to bring radiation levels to near zero to reassure customers. We should do something on our own. If I were a customer, I wouldn’t want to hear farmers say that they’re simply waiting for someone to save them.”
(Toshihiko Ito: Group leader)
A member of the group says it takes a long time to improve soil.
The government’s research panel says scraping off farmland topsoil to reduce radioactivity is very effective.
But such work can be costly, and the farmers also worry that if they remove fertile topsoil that they’ve worked so long to produce, they won’t be able to grow high-quality rice anymore.
Another farmer says he heard that radioactive cesium has a half-life of 30 years, so the soil would not return to normal even after that long. He says it took him about 30 years to improve the soil. He says it’s very unfortunate.
In his search for another method, Ito focused on the mineral zeolite.
He learned about zeolite after hearing that it was used to prevent leakage of contaminated water from the Fukushima plant.
Zeolite has numerous small holes on its surface that can absorb radioactive cesium.
But as zeolite is not the only material with small holes on its surface, Ito and his group decided to conduct an experiment using such materials to find out what would be most effective.
The group prepared several paddies with the same soil quality for the experiment.
Ito says the powdered scallop shell gets so muddy like this when soaked in water.
One paddy was left untended. In another, zeolite was used. In another, powdered scallop shell.
The group also tested seabed soil and powdered seaweed, which it expected to absorb radioactive cesium. In one paddy, the group also sprayed liquid potassium, which is said to prevent plants from taking in cesium.
No comparative experiment on farmlands on such a large scale has ever been done by Japan’s national or local governments.
Ito says his group decided to use the largest areas possible to collect data, to increase the chance of finding a solution. He says farmers like them have no choice but to continue practical tests.
Another farmer is using a different approach to protect his crops from radioactive material.
His farm lies amid mountains in Nihonmatsu City, 50 kilometers from the Fukushima Daiichi plant.
Seiji Sugeno’s land has been cultivated by his family for generations. It was deemed safe for farming after checks found radiation levels there to be below government safety standards.
But like farmer Ito of Sukagawa City, Sugeno is trying his own method for keeping his crops from becoming contaminated.
Just after the nuclear accident in March, Sugeno cut his grass and plowed his fields just like every year, thinking it was better than doing nothing. This brought down radiation levels on the soil surface by half.
Removing contaminated grass and tilling the ground reduced the amount of radioactive cesium on the surface.
Sugeno sought advice from an expert and found out that once cesium gets underground, it binds with clay and other substances in the soil and stays there. This may prevent cesium from being absorbed by plants.
Sugeno decided to do the same thing on a larger scale in hopes of further reducing cesium’s effect on his crops.
He tilled and turned over soil and weeds to a depth of around 30 centimeters. This method is used to make soil fertile.
Sugeno thought that using the method at that depth would increase the chances that cesium would be stuck there and not harm his plants.
After stirring the soil, Sugeno planted rape blossom seeds, which are said to have been effective in decontaminating soil in Ukraine and Belarus after the Chernobyl accident.
Sugeno says he’s using his farming skills, rather than decontamination, to trap cesium and lessen its effect on his crops. He says he can’t wait for scientists to come up with research results, and that he has to use available technology to be ready for next year.
Now back to Ito and his group, who’ve launched an experiment to compare the effects of various materials they mixed in soil to prevent crop contamination.
In mid-October, the group carried out its first test to measure the radioactivity levels of rice harvested in their experimental paddies.
A farmer shows the results to Ito, calling them wonderful.
Did the zeolite and other substances work?
Ito says these are their very first results.
Radioactivity levels detected in the unpolished rice were below the detection limit of the group’s measuring equipment. Further analysis is planned to obtain accurate data, but Ito is encouraged by the results suggesting that his use of scallop shells and seaweed was effective.
Ito calls the findings interesting.
Ito intends to test the crops more precisely to determine the effect of each cesium-blocking material for use in next year’s rice planting.
Ito says he’s getting excited.
Niigata University Professor Masanori Nonaka, who studies soil environment and is familiar with farming in Fukushima Prefecture, says that the nuclear accident has contaminated Japan’s farmland on an unprecedented scale. People involved in farming must have been struggling for the past 8 months trying to deal with the situation.
Data from the Chernobyl accident and nuclear tests are available. But soil in Japan is different from that in Europe where rice is not grown. So everything was a new challenge.
The farmers have been trying various methods to find out how to reduce radioactivity in soil.
Spring vegetables were contaminated by radioactive fallout from the March explosions at the nuclear plant. But hardly any radioactive substances that accumulated in the soil have been detected in summer and autumn vegetables. As for rice, data I obtained in Nihonmatsu show that even crops grown in areas with high radiation levels are almost radiation-free.
Even in places where soil was contaminated, hardly any radioactive substances were detected in crops, especially at organic farms. Also, the uptake of cesium from soil by rice plants was much lower than we expected.
The amount of cesium absorbed by unpolished rice was only about a tenth of what we predicted. Tests of unpolished rice in most areas detected no cesium. Small amounts have been found in rice straw, but not enough to worry about.
Crops, especially at organic farms, were free of contamination because organic farmers have taken good care of their land over many years to make it fertile. I believe careful plowing helped create mineral-rich soil that immobilizes cesium.
Further study is needed to find why good soil is better at trapping cesium. But I can say that good soil consists of clay and contains lots of organic material bacteria. I think well-balanced soil helps immobilize cesium and make crops more nutritious.
I’ve been involved in reconstruction projects for farmers since the March disaster. I know that for farmers, scraping away the soil they’ve plowed for many years is like having their own body parts torn off. So I believe it’s important to think of ways to make existing soil even more fertile and prevent crops’ uptake of cesium.
But recently, farmers in Nihonmatsu City were taken by surprise in late September.
Unpolished rice harvested in a mountain region turned out to be contaminated by radioactivity at levels as high as the government’s safety limit.
The level of the soil in which the rice was grown was below the safety limit, so the result didn’t seem to make sense.
But farmer Seiju Sugeno thought he knew the reason.
Sugeno says the water here comes from the mountains.
Farmers in the area use mountain spring water to fill their paddies. Radiation levels were unexpectedly high at a local water intake.
Sugeno says radiation at the spot ranges from 1.1-1.2 microsieverts.
What was happening to the mountain water?
In mid-October, farmers and researchers teamed up to investigate.
The group included 20 experts on soil, plants and microorganisms.
Sugeno says contaminants on fallen leaves or cedar trees could’ve been washed down by rain, and that he wants to know how to protect his paddies.
A field survey was set up immediately.
The group visited a slope thought to be the most contaminated, as it faces the disabled nuclear plant.
A layer of decaying leaves in the soil drew immediate attention.
The layer lies about 10 centimeters below the surface.
Experts thought water may have been contaminated by leaves exposed to radioactive materials.
This expert points to the layer, saying the plants remain partially in shape.
Rain in the mountains most likely washed over the decaying leaves, leaching radioactive material into underground water that flowed down the slope.
More radioactive substances could flow down the mountain when snow begins to melt next spring.
The overall scale of contamination was worse than expected.
Radioactivity of 10-thousand becquerels or higher was detected at most of the 10 places where measurements were made.
Radioactive runoff from the mountains to the paddies was also becoming a problem in Sukagawa City.
Farmers point to areas near the mountains.
Unpolished rice from such areas was found to contain radioactive materials far below the government standard, but higher than in other locations.
Farmer Toshihiko Ito believes he may have to extensively line the water intake with decontaminants that proved effective in his experiment.
Ito says that despite his efforts, the contaminated water may accumulate in the paddies after every rainfall in the mountains. He says a long battle lies ahead, and that he honestly can’t say if it’s going to continue for years or decades.
Contamination in the mountains was worse than feared: What measures are to be taken in the future?
My research team has also found high levels of radioactivity at the intake of a pre-harvest paddy that draws water from a forest and was mostly likely contaminated after rice was planted.
A 200-square-meter paddy can contain up to three tons of water. Given that volume, even per-unit radioactivity of one becqurel could cause serious problems. Japan has to follow the example of southern Germany, which measured radioactivity at a level as low as one hundredth of a becquerel.
Surveys must be conducted at the water source in the woods, and with the water there. It’s especially important to check wooded areas upstream by collecting soil samples, and to take proper countermeasures.
The water must be prevented from reaching the paddies.
One way is filtering out radioactive substances at intakes by using the mineral zeolite. I think several options are available.
Farmers would have to win back consumer confidence; how should they -- along with the central and local governments -- face this enormous challenge?
The farmers know best what happened to their fields after the explosions at the nuclear plant. So I think they should combine their resourcefulness with researchers’ expertise, with support from authorities. Decisions must be made bottom-up, not top-down. Reconstruction plans should fully reflect farmers’ views.
The views of people on the ground must be respected since the paddies where natural forms of farming were practiced also proved naturally resilient against cesium.
Those who’ve engaged in recyclable organic farming have plenty of knowledge, and their consistent efforts to improve soil helped lessen the impact of contamination. It’s important to encourage further development of such efforts while keeping consumers well aware that Fukushima farmers are producing safe food.