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BBC MUNDO RADIO
- A Japanese minister says people from within 20 km of plant can't return for some time
- Tests are being conducted on meat, chicken and pork after cesium was found in beef
- Explaining and testing radiation levels in groundwater has become a growing priority
- Iodine-131 levels in sea are 4,385 times above normal, cesium-137 is 527 times above
Tokyo (CNN) -- Tens of thousands evacuated from around the stricken Fukushima Daiichi power plant may not be allowed home for months, a Japanese minister said Friday, with no end in sight for the nuclear crisis as fresh concerns mount about alarming radiation levels in beef, seawater and groundwater.
While he didn't set a firm timetable, Chief Cabinet Secretary Yukio Edano said people who'd lived within 20 kilometers (12 miles) of the nuclear facility would not return home permanently in "a matter of days or weeks. It will be longer than that."
"The evacuation period is going to be longer than we wanted it to be," Edano said. "We first need to regain control of the nuclear power plant."
The plight of the evacuees and those within a 20-to-30 kilometer radius of the facility, who have been told to stay indoors and encouraged to leave, is one of many storylines still playing out in relation to the crisis. Many are rooted at the northeast Japan power plant where dozens of workers, soldiers and others are rushing to prevent the disaster from worsening, while further afoot farmers, citizens and officials are dealing with the effects of already released radiation.
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Contamination risks in Japan That includes news Friday, from Edano, that more tests would be conducted on radiation levels in beef, as well as chicken and pork that came from the most affected areas.
Japan's health ministry reported the previous day thatradiation higher than the regulatory limit has been found in beef from Fukushima prefecture, the same province as the embattled nuclear plant. Radiation likely would enter a cow -- or, similarly, a pig or chicken -- indirectly, after it eats grass and other feed that itself has been contaminated.
The radiation levels, detected in a single cow, were slightly above the guidelines set by Japan's Nuclear Safety Commission -- 510 becquerels (a measurement of radioactivity by weight), compared to the official limit of 500 becquerels.
The meat will not be sold and will be retested, the ministry said.
This radiation finding is the first one involving beef, although authorities have banned the sale and transport of numerous vegetables grown in the area after tests detected radiation.
Cesium 134 loses half its radiation every 2.1 years, notes the Argonne National Laboratory in Argonne, Illinois. Cesium 137, experts have said, has a half life of 30 years.
Cesium 137 levels have also spiked in ocean waters off the nuclear plant, according to the nation's nuclear and industrial safety agency. A Wednesday afternoon sample showed levels of 527 times the standard.
Because of its long half life, experts have said its presence is worrisome.
"That's the one I am worried about," said Michael Friedlander, a U.S.-based nuclear engineer, explaining cesium might linger much longer in the ecosystem. "Plankton absorbs the cesium, the fish eat the plankton, the bigger fish eat smaller fish -- so every step you go up the food chain, the concentration of cesium gets higher."
Questions remain about how the cesium reached the sea, as did radioactive iodine-131 isotope samples taken Wednesday 330 meters (361 yards) into the Pacific Ocean that showed levels 4,385 times above the regulatory limit. This exceeded the previous day's reading of 3,355 times over the standard -- and was an exponential spike over the 104-times increase seen just last Friday.
Officials have downplayed the potential perils posed by this isotope, since it loses half of its radiation every eight days. All fishing is banned within 20 kilometers (12 miles) of the plant, and Hidehiko Nishiyama of Japan's nuclear safety agency adds that such waterborne radiation should dilute over time.
As efforts continued Friday to cool nuclear fuel in reactors and spent fuel pools -- using concrete pumping trucks and a new supply of fresh water from a U.S. Navy barge that docked in waters outside the plant Thursday -- concerns remained about other water sources that have shown high levels of radiation.
This includes water in exposed maintenance tunnels leading in and out of the Nos. 1, 2, 3 and 4 reactor buildings, one of which earlier had radiation levels 100,000 above the norm.
Authorities have been working in recent days to drain these tunnels, to prevent them from spilling over and sending tainted water into the ground. By Friday, an official with the Tokyo Electric Power Company -- which operates the plant and heads the recovery effort -- said water levels had dropped one or more meters, and that the issue was no longer urgent.
What has become more of a priority is testing, and finding the source of, an apparent spike in radiation in groundwater near the plant.
Just after midnight Friday, a Tokyo Electric official said that iodine-131 levels in ground water from a pipe near the No. 1 reactor had 10,000 times the standard limit. But the utility later backtracked, promising to get more clarity later.
Edano addressed this confusion in a press conference later Friday, noting that a "constant amount of radiation" appeared to be getting into the groundwater while noting that further tests are forthcoming.
"The numbers released ... looked strange, and that led to the recalculation," he said. "In either case, underground water seems to contain some level of radioactive substances, and this leads to an understanding that the ... soil in the vicinity needs to be monitored closely."
All this contamination -- both into the ground and, eventually, the sea -- is the result of a leak or some other sort of ground seepage from one of the nuclear plant's four most embattled reactors, a Tokyo Electric official said Thursday. The official noted that the high levels suggest the release of radiation into the atmosphere alone couldn't be the lone source.
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