nuclear-news

Radioactive contamination of ocean continues from Fukushima

the Fukushima disaster appeared to be by far the largest accidental release of radioactive material into the sea…..

The working hypothesis is that contaminated sediments and groundwater near the coast are continuing to contaminate the seas, …

 fuller understanding of the effect on fish that are commercially harvested will probably take several years of data following several feeding cycles,

Fukushima’s Contamination Produces Some Surprises at Sea, NYT, By DAVID JOLLY, September 28, 2011, Six months after the accident at Fukushima Daiichi, the news flow from the stricken nuclear power plant has slowed, but scientific studies of radioactive material in the ocean are just beginning to bear fruit.

The word from the land is bad enough. ….

Off the coast, the early results indicate that very large amounts of radioactive materials were released, and may still be leaking, and that rather than being spread through the whole ocean, currents are keeping a lot of the material concentrated.

Most of that contamination came from attempts to cool the reactors and spent fuel pools, which flushed material from the plant into the ocean, and from direct leaks from the damaged facilities.

Japanese government and utility industry scientists estimated this month that 3,500 terabecquerels of cesium 137 was released directly into the sea from March 11, the date of the earthquake and tsunami, to late May. Another 10,000 terabecquerels of cesium 137 made it into the ocean after escaping from the plant as steam.

The leakage very likely isn’t over, either. The Tokyo Electric Power Company, the operator of the plant, said Sept. 20 that it believed that something on the order of 200 to 500 tons a day of groundwater might still be pouring into the damaged reactor and turbine buildings.

Ken Buesseler, a scientist at the Woods Hole Oceanographic Institution, who in 1986 studied the effects of the Chernobyl disaster on the Black Sea, said the Fukushima disaster appeared to be by far the largest accidental release of radioactive material into the sea…..

While Mr. Buesseler declined to provide details of the findings before analysis is complete and published, he said the broad results were sobering.

“When we saw the numbers — hundreds of millions of becquerels — we knew this was the largest delivery of radiation into the ocean ever seen,’’ he said. ‘‘We still don’t know how much was released.’’…

an unpleasant surprise. “Rather than leveling off toward zero, it remained elevated in late July,’’ he said, up to about 10,000 becquerel per cubic meter. ‘‘That suggests the release problem has not been solved yet.”

The working hypothesis is that contaminated sediments and groundwater near the coast are continuing to contaminate the seas, he said.

The international team also collected plankton samples and small fish for study. Mr. Buesseler said there were grounds for concern about bioaccumulation of radioactive isotopes in the food chain, particularly in seaweed and some shellfish close to the plants. A fuller understanding of the effect on fish that are commercially harvested will probably take several years of data following several feeding cycles, he said….

http://green.blogs.nytimes.com/2011/09/28/fukushimas-contamination-produces-some-surprises-at-sea/

October 1, 2011 - Posted by Christina Macpherson | Japan, oceans