Japan sets radiation safety standards for fish

Japan sets radiation safety standards for fish

April 6th, 2011 in Local - Breaking News


c.2011 New York Times News Service

TOKYO - Japan's government announced 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.

The standards were announced after a sample of kounago fish, or sand lance, that was caught last Friday off the coast halfway between the plant and Tokyo was found to have high levels of radioactive iodine 131.

The small fish had 4,080 becquerels of iodine 131 per kilogram. The standards allow 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 G. Falkowski, professor of marine, earth and planetary sciences at Rutgers University, said. But Falkowski 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," Fisher said, noting that the 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 can 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 Co., which runs the damaged plant, said it had found iodine 131 in seawater samples at 200,000 becquerels per cubic centimeter, or 5 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 Japanese 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 are 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, known as TEPCO. Its share prices plunged to an all-time low Tuesday over concern by investors about the financial burden of the work being carried out at Daiichi.

A government panel suspended work Tuesday on 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.

The low-level radioactive water was being dumped from the Daiichi plant 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.

Another problem at the plant is a leak from a large crack in a 6-foot-deep concrete pit next to the seawater intake pipes near the No. 2 reactor. The leak has been spewing an estimated 7 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, which acts like a cement. The country's trade and industry minister, Banri Kaieda, said 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.

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.