The latest media repeatedly broadcast about the “hot spot” where radiation becomes locally high. Additionally, some weekly magazines write that a city in Chiba is so contaminated that people cannot live there from now on. Although these media are inciting fear of “getting cancer if exposed to radioactivity”, we don’t have to be afraid of so many things because the Fukushima No.1 nuclear power plant is to some extent controlled now from releasing radioactive material.

At the Chernobyl nuclear accident in 1986, 4,000 childhood thyroid cancers occurred and 15 children died of the cancer because they drank the milk contaminated by radioactive iodine. The radioactive cesium media make a fuss about is also a radioactive material for which should watch out.

The risk of thyroid cancer in Fukushima?

Professor Jun Takada, a radiological protection study specialist at Sapporo Medical University, lately investigated the dosage of external and internal exposure of residents in Fukushima concerning radioactive iodine and cesium. He has so far visited two neighboring nations after the Chernobyl disaster, the Semipalatinsk nuclear test site in the Soviet Union, and the Marshall Islands, affected by the nuclear explosion at Bikini Atoll, where he has investigated the residents’ health problems (note 1). He aims to make the most of the techniques and experimental knowledge gained for Fukushima.

Professor Takada, who arrived at Fukushima Prefecture on the afternoon of June 18th, told us that he thought the risk of the thyroid cancer from iodine had disappeared and cesium was also decreasing. He said he would like to investigate it and answer the questions from people of the prefecture.

First of all, he measured the environmental radiation dosage near Fukushima Station. It had been halved from a 2.0-micro-sievert reading at the investigation conducted on April 6th to 10th to a 0.92-micro-sievert reading.

Then he also measured the radiation dosage in front of the Iitate village office where the amount of radiation was comparatively high and refuge is called for. The village is located outside the 20 km off-limits area (the evacuation zone) and within the scheduled evacuation zone. No iodine was detected. Cesium was ten or twenty percent lower than the previous investigation in April.

90 percent of the villagers have taken refuge from Iitate village. Professor Takada murmured, “The result shows the level of whether villagers might return. It would be clarified if I measured residents’ dosages.” This time residents’ internal exposure was investigated not in Iitate village, but in neighboring Minamisoma. Then the actual conditions of the health problem in this area came to light.

Radioactive iodine in Fukushima does not exist any more.

Professor Takada who measures radioactive iodine and cesium in Iitate. Mr. Takada's　original portable apparatus was very useful.

Minamisoma city has the evacuation zone, the scheduled evacuation zone and the emergency evacuation preparation zone. Some citizens continue to live there. When we arrived at the hotel in the city past 4:00 p.m., 20 children from babies less than twelve months old to high school students waited for us with their families, and the measurement of their internal exposure started soon after (note 2).

“Radioactive iodine was not found in the thyroid gland. Strong cesium could not be detected.”

Their mothers were pleased with Professor Takada’s comments as they heard the announcements of test results. 70 percent of the schoolchild in the area had already taken refuge and the mothers who decided to stay there were very uneasy about whether it was safe or not.

The numerical values were not displayed right away due to the faulty apparatus. Some mothers mistook the situation and believed that it meant a high dose of radiation. However, high levels of radiation were not detected in the 20 children after all.

Professor Takada told the families “The radioactive iodine has collapsed and does not exist any more in Fukushima. The remaining radiation problem is cesium. Although the half-life of cesium is said to be 30 years, it will be halved in a body in about 100 days. Therefore the cesium problem is also temporary.” All mothers expressed a great relief and said “Oh, it was good”.