The utility that runs the Fukushima Dai-ichi plant has repeatedly been forced to retract such figures, fueling fears over health risks and a lack of confidence in the company's ability to respond effectively to the crisis. The Tokyo Electric Power Co. has not been able to stabilize the plant's dangerously overheating reactors since cooling systems were knocked out in the March 11 tsunami.
Among the measurements called into question was one from Thursday that TEPCO said showed groundwater under one of the reactors contained iodine concentrations that were 10,000 times the government's standard for the plant, the safety agency's spokesman Hidehiko Nishiyama said. Seawater and air concentrations from this week also are under review.
"We have suspected their isotope analysis, and we will wait for the new results," Nishiyama said, adding that the agency thinks the numbers may be too high.
TEPCO has conceded that there appears to be an error in the computer program used to analyze the data and that recent figures may be inaccurate. They have indicated they are probably too high but have also said that the figures may be correct, despite the glitch.
The Nuclear and Industrial Safety Agency has held out the possibility that a complete review of all radiation data collected since the tsunami might eventually be ordered.
Though the size of more recent leaks is now unclear, it appears radiation is still streaming out of the plant, underscoring TEPCO's inability to get it under control. The company has increasingly asked for international help in its uphill battle, most recently ordering giant pumps from the U.S. that were to arrive later this month to spray water on the reactors.
Seiki Kawagoe, an environmental science professor at Tohoku University, said it was unlikely that radiation seeping into the ground under the plant would affect drinking water. He noted that radiation tends to dissipate quickly in the ground, as it does in the ocean.
But there are two ways the iodine could eventually affect drinking water if concentrations were high enough. One is if it were to seep into wells in the area. For now, a 12-mile (20-kilometer) radius around the plant has been cleared, though residents of the area are growing increasingly frustrated with evacuation orders and have been sneaking back to check on their homes.
Tsunami Relief: Network for Good
The other concern is that contaminated water from the plant could seep into underground waterways and eventually into rivers used for drinking water. Tomohiro Mogamiya, an official with the Ministry of Health, Labor and Welfare's water supply division, said that was "extremely unlikely" since groundwater would flow toward the ocean, and the plant is right on the coast.
The two closest filtration plants for drinking water have both been shut down because they are just inside the exclusion zone.
"When people return to the area we will test the water to make sure it is safe," said Masato Ishikawa, an official with the Fukushima prefecture's food and sanitation division.
Radiation concerns have rattled the Japanese public, already struggling to return to normal life after the earthquake-borne tsunami pulverized hundreds of miles (kilometers) of the northeastern coast. Three weeks after the disaster in one of the most connected countries in the world, 260,000 households still do no have running water and 170,000 do not have electricity. Officials fear up to 25,000 people may have been killed.
In the latest report of food becoming tainted, the government said Friday that a cow slaughtered for beef had slightly elevated levels of cesium, another radioactive particle. Officials stressed that the meat was never put on the market.
Radioactive cesium can build up in the body and high levels are thought to be a risk for various cancers. It is still found in wild boar in Germany 25 years after the Chernobyl nuclear disaster, making the pigs off-limits for eating in many cases.
Contamination has also affected work at the plant itself, where radioactive water has been pooling, often thwarting the vital work of powering up the complex's cooling systems.
Despite the leaks, TEPCO hasn't had enough dosimeters to provide one for each employee since many were destroyed in the earthquake. Under normal circumstances, the gauges, which measure radiation, would be worn at all times.
Officials said Friday that more meters had arrived and there are now enough for everyone.
"We must ensure safety and health of the workers, but we also face a pressing need to get the work done as quickly as possible," said nuclear safety agency spokesman Hidehiko Nishiyama. Until now, sharing meters "has been an unavoidable choice."
TEPCO has repeatedly relaxed safety standards during the crisis in order to prevent frequent violations. That is not uncommon during emergencies.
Though the company has acknowledged that it was initially slow to ask for help in dealing with the nuclear crisis, experts from around the world are now flooding in. French nuclear giant Areva, which supplied fuel to the plant, is helping figure out how to dispose of contaminated water, and American nuclear experts are joining Japanese on a panel to address the disaster.
Japan has also ordered two giant pumps, typically used for spraying concrete, from the U.S. They are being retrofitted to spray water first, according to Kelly Blickle, a spokeswoman at Putzmeister America Inc. in Wisconsin. At least one similar pump is already in operation at the plant.
U.S. troops also are involved in the search for the dead. Japan's defense ministry said that, starting Friday, the two militaries will create joint teams to look for bodies from the air. So far 11,500 people have been confirmed dead. Of those, more than 9,000 have been identifed. Another 16,400 are missing, and many may never be found.
Some residents are growing angry and frustrated with the government and are increasingly violating the bans to return to their homes to gather whatever they can find.
Fukushima officials have put up posters in all evacuation centers urging residents not to violate the cordon, but also are pressing Tokyo to arrange trips in for the residents as soon as possible.
"There is no doubt in my mind that it is dangerous in there," said Kazuko Hirohara, a 52-year-old nurse from Minami Soma. "I just wish they would have thought about safety before they ruined our lives."