2011 Tōhoku earthquake and tsunami
It was reported that radioactive iodine was detected in the tap water in Fukushima, Tochigi, Gunma, Tokyo, Chiba, Saitama, and Niigata, and radioactive caesium in the tap water in Fukushima, Tochigi and Gunma. Radioactive caesium, iodine, and strontium were also detected in the soil in some places in Fukushima. There may be a need to replace the contaminated soil. Many radioactive hotspots were found outside the evacuation zone, including Tokyo. Food products were also found contaminated by radioactive matter in several places in Japan. On 5 April 2011, the government of the Ibaraki Prefecture banned the fishing of sand lance after discovering that this species was contaminated by radioactive caesium above legal limits. As late as July 2013 slightly elevated levels of radioactivity were found in beef on sale at Tokyo markets.
Radiation effects from the Fukushima Daiichi nuclear disaster
In a survey by the local and central governments conducted on 1,080 children aged 0 to 15 in Iwaki, Kawamata and Iitate on 26–30 March, almost 45 percent of these children had experienced thyroid exposure to radiation with radioactive iodine, although in all cases the amounts of radiation did not warrant further examination, according to the Nuclear Safety Commission on Tuesday 5 July. In October 2011, hormonal irregularies in 10 evacuated children were reported. However, the organization responsible for the study said that no link had been established between the children's condition and exposure to radiation.