Massive seawalls were built along Japan’s eastern coast. Fukushima was dotted with incinerators that burned up the debris left behind by the wave that washed up to 20 miles inland. Decontaminating the area included a pharaonic project to remove and bag all the topsoil contaminated with cesium 137. About 100,000 workers in protective suits and masks swarmed over Fukushima’s farms and fields, scraping up five centimeters of soil and piling it into great pyramids of black plastic garbage bags.
Radiation levels in town centers and school yards were lowered, but a short walk into neighboring patches of grass will spike the needle on a dosimeter. So, too, do the winter storms that wash radioactive material down from the mountains. In the forested hills that ring the coast, there is no way to lessen Fukushima’s radioactivity other than to wait out the half-life of cesium 137, which is 30 years. So how long does one have to wait? In about 300 years, or 10 times the half-life, the quantity of this radioactive isotope will have dropped to a thousandth of what it was.
Other strategies for decontaminating the area have had mixed results. Big gashes on the hillsides show where sand has been quarried and dumped into Fukushima’s rice paddies. With their intricate drainage systems destroyed by heavy equipment, deprived of topsoil, and covered in sand and gravel, many of Fukushima’s rice paddies have been abandoned, and the crop is barely more than half of what it was before 2011.
Many of Fukushima’s fields are covered with solar arrays. Others hold state-sponsored projects for building hydrogen fuel cells or drones. This is part of the government’s effort to turn Fukushima into what it calls the “innovation coast,” beginning with demonstration projects that the government hopes will develop into businesses. Another stretch of abandoned farmland is filled with the multimillion-dollar Great East Japan Earthquake and Nuclear Disaster Memorial Museum. Opened in 2020, the museum is currently being expanded to include a hotel, a convention center, and even possibly a golf course.
A town in Fukushima, such as Iitate, might be considered decontaminated when as little as 15 percent of the radioactive soil is removed. This creates a kind of lily pad effect; people can safely hop from one clean spot to another or walk along narrow paths between radioactive hot spots. A law passed in November 2011 mandates that all of Fukushima’s radioactive soil, roughly 15 million cubic meters, will be removed from the prefecture by 2045. With no place having volunteered to take any of the soil, the government has decided to spread it across Japan.
Most of Fukushima’s bagged soil has been re-deposited into a dump built on the cliff behind the destroyed reactors. This facility separates the most radioactive elements from the soil and sequesters them in concrete bunkers. Soil containing less than 8,000 becquerels per kilo of radioactivity, which the Ministry of the Environment calls “Happy Soil,” is readied for shipment across the country, to be used in landfills and construction. (A becquerel is a unit of radioactivity, corresponding to one nuclear disintegration per second.) A load of Happy Soil, described as “revitalized and strong,” was recently dumped into the flower beds in front of the Prime Minister’s office in Tokyo.
“This is a dangerous level of radioactivity,” says Yukio Shirahige, who worked for 36 years as a cleaner mopping up spills at Fukushima Daiichi. “At these levels, you have to wear gloves and protective gear. If you had any cuts or open wounds, you were taken off the job.” At up to 8,000 becquerels per kilogram, one would not want to use this soil for growing food. (The maximum radioactivity concentration allowed for food in Japan is 100 becquerels per kilogram.)