On March 11, 2011, Japan experienced the unprecedented Tohuku earthquake. It was the largest in Japan’s history, and created a massive tsunami that impacted Japan’s northeastern coast. A result of the earthquake and tsunami was the meltdown of the Fukushima Daiichi Nuclear Power Plant. This meltdown had immediate and long-term impacts on the area. This blog will cover the impacts on the area. Our next Soils Matter blog will discuss current research by Japanese and American scientists to help solve some of the problems caused by the contamination in Fukushima soils.
The northern area of Japan contains a village called Iitate (Ee-tah-tay) Village. Before the Fukushima disaster, this was a highly productive agricultural area. The farmers made a living selling rice and other crops grown from their nutrient-rich soil.
When the nuclear waste at the power plant melted down, radioactive Cesium was released. Citizens had to evacuate, as the meltdown resulted in high levels of radioactivity near the power plant. This was on top of the disaster caused by the tsunami.
Less well known, however, is that the explosion at the power plant ejected radioactive particulates into the atmosphere. These spread throughout much of northern and central Japan. The total area affected may have been as large as 15,000 square miles.
The highest levels of radioactive contamination affected a much smaller area of approximately 100 square miles, which is where Iitate Village is located. Radioactive particulates mostly settled out of the atmosphere in the regions immediately downwind of the power plant. They deposited their radioactive pollution into the soil. Much of this contamination remains there to this day.
Of the contaminants that affected the soils in this area, radiocesium is one of the most serious. Radiocesium decays very slowly and will likely continue to emit radiation for at least 300 years. This might not be a problem in other locations, as cesium is very water soluble. That means it can quickly move downwards through the soil until it disperses into the groundwater. This dilutes the radioactivity and moves it out of the area.
The soils in the northeastern region of Japan, including Iitate Village, are rich in a particular kind of clay mineral. Soil is made up of particles of sand, silt and clay in varying amounts. It’s this reason that soil is referred to as the world’s largest bioreactor– physically, chemically and biologically.
In this case, however, high clay count is a problem. The clay particles are holding onto the radiocesium. That means the radiocesium that remains is trapped very close to the surface of the soil. Its radiation can more easily impact people and wildlife in the region than if the soil had less clay.
The Japanese government’s solution to this problem was to scrape off the contaminated topsoil and place it in bags, which are then stockpiled. Unfortunately, almost eight years after the disaster, this temporary solution is still in place. That’s because no one has yet come up with a viable long-term solution for what to do with those stockpiles.
Another serious problem for the farmers who live in this area is the impact that the loss of their topsoil has had on the fertility of their farms. The topsoil is where most of the soil’s organic matter is. That organic matter has huge impacts on the soil’s ability to supply water and nutrients to plants.
When the government removed the topsoil, they replaced it with fresh fill created by digging up rocks and grinding them into smaller particles. This is basically like replacing the topsoil with beach sand. It is very difficult now for farm fields to grow crops as effectively as they used to and farmers are still struggling with how to farm in this region where the soil fertility has deteriorated so much.
The farmers in Iitate Village are impacted by the deposition of radiocesium in their region after the meltdown of the Fukushima Daiichi Nuclear Power Plant in many ways. They have to deal with the health hazards created by the presence of this dangerous radioactive pollutant in their soil. They had to comply with a 5-year mandatory evacuation that ensued. When they returned, it was to farm fields which have had their nutrient rich topsoil removed and replaced with a barren and sterile mineral rich fill material. Clearly this seriously hampers their ability to farm the land.
Farmers who have somehow managed to make their soil productive again are faced with resistance from customers. People are scared to buy food grown in Iitate Village, despite the fact that all food is rigorously tested and proven to be safe. Many farmers have now taken to growing non-food products such as tobacco or flowers which are easier to sell. They do not, however, bring as high a price as the rice or vegetables that are typically produced in this region.
It may be natural to wonder why the residents of Iitate Village don’t just move to some other region that was not contaminated. One has to keep in mind, however, that Japan is an ancient culture and that many of the families living in this region have been farming this land for as long as 300 years. For these farmers, the deep connection between their families and the land is not so easily abandoned. They will continue to work the soil that their family has farmed for generations and hope that scientists will be able to help them solve the problems that the Tohoku earthquake and the Fukushima Daiichi Nuclear Power Plant meltdown have created in their small corner of Japan.
By Dan Ferreira, Kennesaw State University
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