On 12 November the Japanese government published a contamination map compiled by helicopter, showing areas where the soil was contaminated by radioactivity of cesium-134 and cesium-137. Japan’s Ministry of Health, Labor and Welfare has focused on establishing centers to test and monitor contamination of vegetables, fruit, marine products, edible wild plants, honey, fresh milk, grains, eggs grass, forage crops and others.
The center members began their test with the soil, for radioactivity accumulates in the layers of soil up to a depth of five centimeters. The area is largely covered by forests. They could not do much for the forests, but Mr. Kusano said, “We removed the surface soil, up to a depth of five centimeters and replaced it with clean soil. We removed the entire surface soil and began cultivation again.”
About half of the total paddy field area, which is the dominant agricultural land in Fukushima Prefecture, was contaminated by radiocesium released by the Fukushima Daiichi Nuclear Power Plant accident.In order to prevent losses to farmers who live on the earnings from their products, “We thought agriculture is under human control and we must do something. We defined our policies. We decided to decontaminate radiocesium, which could reduce contamination or, in fact, decontaminate the　products. We did and tested, and it worked”.
“After decontamination efforts, we realized that the contamination level declined. We also warned the people not to use wild mushrooms and vegetables, for we were not sure about their safety.” After the release of radiocesium, cesium first enters the tree trunks, then the fruit. “However, after we began to research and found out that if we washed the trees, water itself could wash away the contamination.
We did it for one year, and the next year our tests showed that we could collect clean fruits,” said Mr. Kusano. In fact, cesium was controlled because of our measures.
The Fukushima Prefecture Government has set up 500 centers for people who cultivate for personal use to test their produce.
But the Prefecture’s produce that are to be exported, including meat, fish, vegetables, mushrooms and milk, are tested and analyzed at this center. If they are clean, their export permit is issued; otherwise, they are dumped.
There are two containers for testing the materials in the center. It takes 33 minutes to test meat and fish, and ten minutes to test other materials.
Since the products are brought to the center for testing in containers or plastic bags, to prevent any possible contamination, the containers or plastic bags are tested before the products are sent to the laboratory.
Before entering the center, we had to remove our shoes and put on a pair of slippers. And again before entering the laboratory, we had to change our slippers. Mr. Kusano said that in January 2016, a reporter had gone to Fukushima reactor one week before coming to the center. “His gloves reacted to our testers. They were contaminated.
We asked him to remove his gloves.” In order to be precise, we chop vegetables to get into their inner layers before testing them.
“We have had 11,410 tests this year, of which three cases were contaminated above the permitted level.” Mr. Kusano said. “In such cases, the products are dumped and are not exported. Overall, from 2011 to date, 170,000 tests have been conducted.”
The test machines are made of lead, each weighing 1.1 tons. The result of the tests is announced on the same day, or at most, on the next day. The results are also uploaded on the Internet website of Fukushima Prefecture, which is accessible to all. The test machines were imported from the United States.
“They are now five years old, but they are checked and controlled regularly to prevent human error. Every product is checked several times,” he said.
In order to meet international standards, the IAEA annually sends some liquid or solid samples to be tested in the center. The test results of the center are then sent to the IAEA, where they are precisely measured in order to be sure about the accuracy of Fukushima Center’s tests.
The maximum permitted levels of radioactive contamination of foodstuffs is 100 Bq/kg. However, after the Fukushima disaster, the level reached tens of thousands of Bq　/　kg in some areas.
There are 100 full-time and 200 part-time employees working in this center.　The monitoring section has 11 staff members and 11 Germanium Semiconductor Detectors.
Mr. Kusano is a plant pathologist, or phytopathologist. His colleagues are rice experts, some of whom work on the development of new varieties of rice, special to Fukushima. Some of his colleagues are forest experts, botanists, and aquatic products experts. After joining the center, they studied radioactive contamination and have a high knowledge in the field.