“Japanese officials say radioactive iodine above government recommended limit found in drinking water in Fukushima prefecture” – AP
Additionally, trace amounts of iodine and cesium have been found in water supplies in Tokyo and other prefectures and cesium has been detected in milk.
The highest reading was less than a third of the allowable limit. A ministry official, who could not be quoted by name as is customary, said the government deems the small amounts safe and was awaiting further expert analysis.
“The figure is still below the national limit and safe,” said Masayuki Kubo, an environmental protection official at Tochigi prefecture, where the highest tap water reading was found. “You can drink it safely without limiting the amount of water you take.”
Nuclear reactors at the Fukushima plant began leaking radiation in the days after the March 11 earthquake and tsunami knocked out its cooling systems. The crisis has raised public alarm about the threat to public heath, and earlier Saturday, the government acknowledged that tests found iodine in spinach and iodine and the radioactive element cesium in milk from some farms 20 to 75 miles (30 to 120 kilometers) from Fukushima.
The areas where iodine turned up in the tap water are well to the west and south of the nuclear plant.
Cesium-137 has a half life of 30 years
Iodine -131 has a half life of 8 days
Much smaller incidental doses of iodine-131 than are used in medical treatment, are thought to be the major cause of increased thyroid cancers after accidental nuclear contamination. These cancers happen from residual tissue radiation damage caused by the I-131, and usually appear years after exposure, long after the I-131 has decayed.
