Radioactive iodine detected in the capital’s water supply spurred a warning for infants and the government issued a new estimate about the costs of rebuilding from the earthquake and tsunami that slammed into the northeast of Japan this month. Ei Yoshida, head of water purification for the Tokyo water department, said that infants in Tokyo and surrounding areas should not drink tap water. He said that iodine-131 had been detected in water samples at a level of 210 Becquerel’s per liter. The recommended limit for infants is only 100 Becquerel’s per liter.
High levels of iodine that can be absorbed through the milk can accumulate in the thyroid gland and cause thyroid cancer. High levels of cesium can damage cells and put many people at higher risk of developing other kinds of cancer. Japan has already placed restrictions on foods, including spinach and milk that were produced in two plants near the Fukushima Daiichi plant. Food inspectors detected iodine and cesium in the food, two of which are more dangerous radioactive byproducts that are feared to have been released from the reactors in Fukushima.
The announcement added to the growing anxiety about public safety posed by the Fukushima Daiichi Nuclear Power Station. The Health Ministry said in a statement that it was unlikely that there would be negative consequences to infants who did drink the water, but that it should be avoided if possible and not be used to make infant formula. It was not clearly why the levels of iodine were so high and the prevailing breezes seem to be pushing radiation out to sea, said a senior western nuclear executive.