Japan Sets Radiation Standards for Fish
By ANDREW POLLACK, KEN BELSON and KEVIN DREW
Published: April 5, 2011
TOKYO — Japan’s government announced on Tuesday its first radiation safety standards for fish, hours after the operator of a crippled nuclear power plant said that seawater collected near the facility contained radiation several million times the legal limit.
Shiho Fukada for The New York Times
On Monday, people in Otsuchi, Japan, in Iwate Prefecture, searched for belongings in homes damaged by the March 11 tsunami.
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The small fish had 4,080 becquerels of iodine 131 per kilogram (2.2 pounds). The new standard allows up to 2,000 becquerels of iodine 131 per kilogram, the same standard used for vegetables in Japan.
The fish also contained cesium 137 — which decays much more slowly than iodine 131 — at a level of 526 becquerels per kilogram.
“Clearly the fish are consuming highly radioactive food,” Paul Falkowski, professor of marine, earth and planetary Sciences at Rutgers University, said. But he emphasized that even those levels were not likely to present health hazards in Japan or farther away, since fishing is restricted in Japan and these levels of radiation are not likely to travel far.
Nicholas Fisher, a professor of marine sciences at the State University of New York at Stony Brook, said that according to some radiation safety guidelines people could eat 35 pounds of fish per year containing the level of cesium 137 detected in the Japanese fish.
“So you’re not going to die from eating it right away, but we’re getting to levels where I would think twice about eating it,” he said, noting that Japanese consume far more seafood than Americans.
Still, experts on radiation in seafood said it was nearly impossible to get a full sense of the scope of the environmental and health risks until the Japanese released information on radiation levels in more species of fish and seaweed and in a greater number of locations.
Measurements in the seawater are often not a good indication of how much radiation may be entering the food chain, scientists say.
Fish and seaweed both have the capacity to concentrate radioactive elements as they grow, leading to levels that are higher — sometimes far higher — than in the surrounding water. Seaweed can concentrate iodine 131 10,000-fold over the surrounding water; fish concentrate cesium 137 modestly.
The announced standards for fish came hours after the Tokyo Electric Power Company, which runs the plant, said it had found iodine 131 in seawater samples at 200,000 becquerels per cubic centimeter, or five million times the legal limit. The samples were collected Monday near the water intake of the No. 2 reactor of the Fukushima Daiichi Nuclear Power Station.
The samples also showed levels of cesium 137 to be 1.1 million times the legal limit, according to the public broadcaster NHK. Cesium remains in the environment for centuries, losing half its strength every 30 years.
The Monday sampling of seawater was collected before Tokyo Electric began dumping more than 11,000 tons of low-level radioactive water into the Pacific Ocean. It showed a drop of radioactive iodine levels since Saturday, when the company said the level of iodine 131 was 300,000 becquerels per cubic centimeter.
Meanwhile, the death toll from the March 11 9.0-magnitude earthquake and tsunami rose to 12,341 on Tuesday, the country’s National Police Agency said. More than 15,000 people remain missing, and more than 160,000 are staying in temporary shelters across the country, the agency said.
The crisis at the power station, now in its fourth week, has shaken public confidence in Tokyo Electric Power. Its share prices plunged to an all-time low on Tuesday over concern by investors about the financial burden of the work being carried out at Daiichi.
A government panel on Tuesday suspended work revising the country’s policy platform on nuclear power, according to local news media reports, saying the crisis needed to be resolved before Japan could publicly assess its nuclear power policies.
“We have to admit that there has been an error in the criteria of judgment in promoting the country’s nuclear power policy,” Shunsuke Kondo, chairman of the Japan Atomic Energy Commission, said in a report by the Kyodo news agency.
Most of the low-level radioactive water being dumped from the Daiichi plant is to be released by Tuesday evening, mainly to make room in storage containers for increasing amounts of far more contaminated runoff, including highly radioactive water that has flooded the turbine building of Reactor No. 2. The water being released contains about 100 times the legal limit of radiation, Tokyo Electric said. The more contaminated water has about 10,000 times the legal limit.
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The pumping effort is not expected to halt a leak from a large crack in a six-foot-deep concrete pit next to the seawater intake pipes near the No. 2 reactor. The leak has been spewing an estimated seven tons of highly radioactive water an hour directly into the ocean.
Government officials said Tuesday that they were able to slow, but not stop, the leak by using sodium silicate, sometimes called water glass, which acts like a cement. The country’s trade and industry minister, Banri Kaieda, said on Tuesday that 60,000 tons of radioactive water was thought to be flooding the basements of the plant’s reactor buildings and underground tunnels, according to a report by the Kyodo news agency.
Tokyo Electric is rushing tanks to the plant, though they may not arrive until mid-April, a company spokesman said. The company also plans to moor a giant barge off the coast to store contaminated water, though getting the barge in place will take at least a week, he said.
Japan has asked Russia’s nuclear agency, Rosatom, to send a radioactive waste-disposal facility to help get rid of the contaminated water. A Rosatom spokesman, Sergei Novikov, said talks were being held to send the floating facility to Japan, according to RIA Novosti news service.
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