New pools of radioactive water have been detected around Japan's earthquake-damaged Fukushima nuclear complex, officials said Monday, as workers continued racing to contain leaks from the facility. Scientists are still trying to devise a plan to safely store the radioactive water seeping from the coastal Fukushima Daiichi power plant, 220 kilometres northeast of Tokyo. On Monday, officials said soil samples and seawater taken from around the station showed traces of plutonium a key ingredient in nuclear weapons. 'We cannot say at this time how many months or years it will take.'Sakae Muto, TEPCO vice-presidentAlthough operators insisted the presence of plutonium posed no threat to public health, they believe the contaminated water has sent radiation levels in the area soaring. They added that only some of the plutonium samples were from the leaking reactors, while the rest came from earlier nuclear tests. Years of weapons testing in the atmosphere left trace amounts of plutonium in many places around the world. The Fukushima Daiichi power plant has been leaking radiation since a magnitude-9.0 quake on March 11 triggered a tsunami that engulfed the complex. The wave knocked out power to the system that cools the dangerously hot nuclear fuel rods. Mounting problems, including badly miscalculated radiation figures and no place to store dangerously contaminated water, have stymied emergency workers struggling to cool down the overheating plant and avert a disaster with global implications. On Monday, workers resumed the laborious yet urgent task of pumping out the hundreds of tons of radioactive water inside several buildings at the six-unit plant. The water must be removed and safely stored before work can continue to power up the plant's cooling system, nuclear safety officials said. That process alone could take weeks, experts say. A delicate balance Radioactive water has been discovered in numerous places around the Fukushima complex. It must be pumped out and safely stored before electricity can be restored to the cooling system. At the same time, however, water must also be pumped in to keep the reactor fuel rods cool. Hiehike Nishiyama, a spokesman for Japan's Nuclear and Industrial Safety Agency, has called the sometimes-contradictory efforts "very delicate work." Source: Associated Press Meanwhile, highly radioactive iodine leaching from the complex may be making its way into seawater farther north of the plant than previously thought. New readings showed ocean contamination had spread about 1.6 kilometres farther north of the nuclear site than before. Still, it remains within the 20-kilometre radius of the evacuation zone. Airborne radiation 4 times higher than safe levels The contaminated water has been emitting radiation that measured more than 1,000 millisieverts per hour in a recent reading at Unit 2 some 100,000 times the normal amounts, plant operator Tokyo Electric Power Co. said. Highly radioactive seawater has also been detected at a turbine building and inside a deep trench outside the reactor buildings. As officials scrambled to determine the source of the radioactive water, chief Cabinet Secretary Yukio Edano repeated Monday that the contaminated water in Unit 2 appeared to be due to a temporary partial meltdown of the reactor core. Tokyo Electric Power Co. executives bow to apologize during a news conference in Tokyo on Sunday. Workers were pulled back from a reactor building at Japan's earthquake-damaged nuclear plant, where potentially lethal levels of radiation were detected in water. Kyodo/Reuters He called it "very unfortunate," but said the spike in radiation appeared limited to the unit. Nishiyama had said earlier there was no link between the radioactive water leaking inside the plant and the radiation in the sea. On Monday, though, he reversed that position, saying he does suspect that radioactive water from the plant may indeed be leaking into the ocean. Closer to the plant, radioactivity in seawater tested about 1,250 times higher than normal last week and climbed to 1,850 times normal over the weekend. Airborne levels outside the unit are more than four times the level that the government deems as safe for humans. Brief tsunami alert Early on Monday, a 6.5-magnitude earthquake off the battered Miyagi prefecture coast in the northeast shook the region again, and prompted a brief tsunami alert. No damage or injuries were reported and TEPCO said the quake would not affect work to stabilize the plant. Hatsuo Osugi, who was evacuated from Minamisoma in Fukushima, undergoes a test for signs of nuclear radiation at a health centre in Yonezawa, northern Japan, about 98 kilometres from the Fukushima nuclear plant. No signs of harmful levels of radiation were found on him. Yuriko Nakao/Reuters Confusion at the plant has intensified fears that the nuclear crisis will last weeks, months or years amid alarms over radiation making its way into produce, raw milk and even tap water as far as Tokyo. On Sunday, TEPCO officials said radiation in leaking water in the Unit 2 reactor was 10 million times above normal an apparent spike that sent employees fleeing the unit. The day ended with officials saying the huge figure had been miscalculated and offering apologies. "The number is not credible," TEPCO spokesman Takashi Kurita said. "We are very sorry." (Mhhhh!) A few hours later, TEPCO vice-president Sakae Muto said a new test had found radiation levels 100,000 times above normal still very high. Despite the errors, he ruled out having an independent monitor oversee the various checks. (Mhhhh!) Scores of strong earthquakes have rattled Japan over the past two weeks. The death toll for the March 11 disasters officially surpassed 11,000 on Monday. Another 17,000 people are still unaccounted for.