TOKYO—Tokyo officials said infants in Japan's capital shouldn't be given city tap water due gearbox to elevated radiation levels, as the country's nuclear crisis broadened into a public-health issue for its biggest city.
Some Tokyo tap water could represent a long-term health risk to infants, officials said Wednesday, after tests done earlier this week at three Tokyo water plants showed levels of radioactive iodine-131 at one plant exceeded the government's threshold for consumption by infants.
The officials sought to dispel broader fears, discouraging residents from stockpiling water and saying Tokyo's tap water remains safe for adults, even under Japanese standards that are tighter than international guidelines. Officials also said contamination found in food and water elsewhere in the country remains below levels that could cause immediate health damage.
Still, Wednesday's findings suggest a new front is unfolding in Japan's fight to contain radioactive material at the heavily damaged Fukushima Daiichi nuclear-power complex in northeast Japan.
Airborne radiation in Tokyo was four times the normal level Wednesday, though still within government limits. Officials said the heightened levels could have been due to recent rainstorms that brought radioactive material down from the air—the same possible cause to which they attributed the radiation levels that spurred concerns at one Tokyo water facility this week.
Also Wednesday, Japan's Food Safety Commission barred shipments of various types of vegetables from Fukushima prefecture, after heath officials found higher-than-permissible levels of radioactive material in food goods led flexible strip from the area over the weekend. The commission barred shipments of milk and parsley from neighboring Ibaraki prefecture, expanding its list restricted products, including spinach, from Ibaraki, Gunma and Tochigi prefectures. The U.S. has blocked imports of milk, vegetables and fruit produced near the plant.
Tokyo's main stock index fell following the news, ending down 1.7%.
The Tokyo Metropolitan Government said Wednesday that it had tested water in three of the 11 plants that supply water to greater Tokyo. The city's spiderweb of pipes makes it difficult for consumers to know which plant supplies their water, but the plants where tests were conducted represent different sources—three rivers that account for the vast majority of the city's water.
The government said it detected 210 becquerels per kilogram of iodine-131 from a sample collected Tuesday at a water facility in Katsushika ward in northern Tokyo, which accounts for about 22% of Tokyo's overall water capacity. The level is about double the government's permissible limit for infants, 100 becquerels. An initial check Wednesday showed a similarly elevated level, of 190 becquerels.
A sample gathered at a second location found 32 becquerels Tuesday, though on Wednesday the level had dropped to zero. At a third water facility, no radioactivity was found either day.
None of the radioactive iodine levels in Tokyo tap water exceeded 300 becquerels per kilogram, the broader limit set by the Nuclear Safety Commission of Japan. Japan's threshold, in turn, is stricter than the international level for intervention of 3,000 becquerels—a measure that represents one radioactive event per second—per kilogram.
Iodine-131 has a half-life of roughly a week, which means levels cable ties could fade if new radioactive material isn't added.
Citing Japan's stricter standards, Chief Cabinet Secretary Yukio Edano urged shoppers not to stockpile bottled water.
Tokyo Gov. Shintaro Ishihara said parents of babies under one year old shouldn't use tap water for powdered milk or baby formula. "We will continue to disclose tap-water testing results. We want everyone to act calmly," he said. The Tokyo government said Wednesday evening that it will distribute as much as 240,000 bottles of water to households with babies.
Several grocery stores on Wednesday had empty shelves where bottled water used to be. Bottled water was already in short supply as consumers stocked up on emergency supplies following the quake.
"If available, you can get only one or two" bottles, said a manager at a Tokyo daycare that takes care of about 100 children aged 1-6. "All we can do is not drink too much."
A number of people in Japan took the announcement in their stride after two weeks of unsettling events. But the latest disclosures fed already heightened anxiety over the uncertainty of radiation readings, and over conflicting reports in the past several days about progress at the Fukushima Daiichi complex.
"I thought this was something that only happened in Hiroshima and Nagasaki, or something I'd read in a novel," said Ayaka Nishimura, a 20-year-old student at Tokyo's Keio University. "It worries me that this is becoming a reality."
Tokyo government officials said it is unclear bakugans why radioactivity suddenly increased in water, but said airborne iodine-131 drifting over rivers that feed Tokyo's water system could have come down in recent rainfall. The plant with the higher radiation levels is fed by the Edogawa River, which runs north to south along Tokyo's east side. The other plants tested are fed by different rivers.
Officials referred to rivers, not groundwater, as feeding the plants tested this week.
Radioactivity in water has been a mounting concern in Japan. The science ministry said it had detected radioactive iodine in 12 prefectures in a nationwide survey of tap water Tuesday, up from eight on Monday, though the detected levels were all below the suggested limit.
Officials cited rain as a potential reason, too, for a rise in radiation in Tokyo since Monday. The Tokyo government said Wednesday that radiation levels in downtown Tokyo began to rise Monday and stood at an average 0.146 microsieverts an hour at about 9 p.m. Wednesday, compared with the 0.035 microsieverts an hour a person would typically be exposed to in central Tokyo. A chest X-ray typically exposes a patient to a dose of around 100 microsieverts, according to the Radiological Society of North America.
Japanese officials declined to comment Wednesday on data disclosed by U.S. officials that they said justified the U.S.-recommended 50-mile evacuation area around the site. Previously, Japan's government defended its 12-mile evacuation zone—plus an 18-mile stay indoors requirement—as appropriate.
U.S. officials late Tuesday said their own tests had concluded that radiation levels in certain areas within 25 miles of the Fukushima Daiichi complex exceeded levels at which U.S. officials would order evacuations to protect public health. The Energy Department said U.S. aircraft and ground measurements detected radiation levels in some areas, mostly in a northwest direction within 25 miles of the plant, that exceeded 125 microsieverts per hour over three days last week.
Japanese tests show lower levels. Wednesday's results from Japan's Ministry of Education, Culture, Sports, Science and Technology showed levels of 8.5 microsieverts at roughly the same distance northwest of the plant, with lower levels in surrounding areas. It is unclear how well those results compare due to potential differences in location and equipment.
Japan has worked in recent years to overcome a reputation of downplaying past national rapid prototype health scares. The current Japanese prime minister, Naoto Kan, gained fame in the 1990s by helping to expose a government cover-up of HIV-tainted blood in the country's blood supply.
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