Radioactive contamination from the Fukushima power plant disaster has been detected in the Pacific Ocean almost 400 miles off the Japanese coast.
The findings were delivered to the Annual Ocean Sciences Meeting in Salt Lake City after samples taken three months after the power plant disaster should lveles nearly 1000 times higher than normal levels.
However, despite this lead scientist Ken Buesseler of the Woods Hole Oceanographic Institution in Massachusetts reported that the levels of cesium-137 are still far below the levels that are generally considered harmful. Samples taken from water, plants fish and plankton 20-400 miles off the coast east of the Fukushima plant were 10-1,000 times above normal levels but still only around 1/10th the levels considered to be harmful.
Although he was keen to stress: "We're not over the hump" yet in terms of radioactive contamination of the ocean because of continued leakage from the plant.
Nicholas Fisher, a marine science professor at New York's Stony Brook University reported that zooplankton, collected in those waters had levels of cesium-137 and the shorter-lived cesium-134 that were on average 40 times higher than the surrounding water and much higher levels of a radioactive form of silver produced by nuclear reactions.
However he too stressed that the readings amounted to a fraction of the amount of radioactivity sea life is exposed to from naturally occurring potassium in seawater.
"The total radiation in the marine organisms that we collected from Fukushima is still less than the natural radiation background that the animals already had, and quite a bit less," he said. "It's about 20%."
Hartmut Nies, of the International Atomic Energy Agency, said Buesseler's findings were not surprising, given the vastness of the ocean and its ability to absorb and dilute materials:
"This is what we predicted," Nies continued, adding that the water's cesium-137 concentration was so diluted that just 20 miles offshore, "if it was not seawater, you could drink it without any problems."
He added that this was good news and that scientists could expect to see levels continue to fall with time.
"We still don't have a full picture," Nies said, "but we can expect the situation will not become worse."
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