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„We Did It.“ The First Manufactured Nuclear Chain Reaction

14.07.2012

Susanne Gerber

On December 2, 1942, 49 scientists, led by Enrico Fermi, made history when Chicago Pile 1 (CP-1) went “critical” and produced the world’s first self-sustaining, controlled nuclear chain reaction. Seventy years later, two of the last surviving CP-1 pioneers, Harold Agnew and Warren Nyer, recall and explain the events of that historic day.

See the video here

http://ansnuclearcafe.org/2012/07/13/14696/?utm_source=ANS+Nuclear+Cafe&utm_campaign=70b559f5a2-RSS_EMAIL_CAMPAIGN&utm_medium=email

Einsortiert unter:Danger, Research

Information about Reactor 3?

11.07.2012

Susanne Gerber

TEPCO is sending 11 TEPCO employees and one robot (Survey Runner, which looks like a smaller version of Quince and has already gone inside Reactor 2’s Torus Room in April this year – photo, video) down to the basement of Reactor 3 to survey the inside of the Torus Room. Planned radiation exposure for the human workers is 8 millisieverts. No information of how long each worker will have to stay there to assist their robot co-worker. They won’t go inside the Torus Room, as the very high radiation levels are expected inside. Instead, Survey Runner will go. The human workers will carry the robot through the narrow passage in the basement to the Torus Room door, which they will open for the robot. 8 millisieverts of radiation exposure. Before the Fukushima accident, it was rare even for the nuclear plant workers to get 1 millisievert exposure in one year. Now, the workers may get 8 years‘ worth of radiation in a day’s work at Fukushima I Nuke Plant. When the workers tried to enter the Reactor 3 Torus Room in March this year, the access door was warped and didn’t open. The workers didn’t stick around to open the door, because the radiation levels were probably too high for the work (it was 75 millisieverts/hour in front of the door). TEPCO sent workers again in June to measure the water level in the basement.
The following will be done in the Torus Room in Unit 3 Reactor Building basement.
-Visual confirmation (Acquire photos and moving images)
-Dose rate measurement
-Collect sound samples in the Torus Room
Equipments: Remote control robot (Survey runner)
Members involved: 11 TEPCO employees
Investigation date: Wednesday, July 11, 2012
Planned expose dose
8 millisievert: 6 Carrying the robot through the triangle corner, opening doors
2 millisievert: 5 Robot operation, preparation

*Robot operation control is done in Unit 3 S/B (0.1mSv/h)

Einsortiert unter:Accident, Fukushima, Radiation, Research

Bacteria a potential threat to nuclear waste repositories – Jan Overney

10.07.2012

By interacting with the radioactive waste and the materials used to contain it, underground microorganisms may affect the safety of nuclear waste repositories, for better or for worse.

Underground, time appears to stand still. That is one of the reasons why deep are considered the safest place to dispose of nuclear waste. But now, scientists are finding out that human activities such as the of tunnels can lead to a blooming of underground bacterial activity. In an ongoing research project, scientists from EPFL are cataloguing subterranean and studying its potential to affect the performance of the protective barriers – canisters, concrete and adjacent rock – that are used to contain nuclear waste.

Knowing what bacteria are present at such depths, what chemical transformations they are capable of, and even how they might evolve, have to be considered to assess the long-term safety of potential waste disposal sites. “We will use DNA sequencing and bio-informatics to identify the microbes trapped in the rock,” explains Rizlan Bernier-Latmani, head of EPFL’s Environmental Microbiology Laboratory and director of the project. The data will also provide insight on what types of molecules the microbes can produce using the substrates they grow on. “Given the long duration involved – several hundred thousand years, if the bacteria can do it, they will do it,” she says.

Bernier-Latmani has launched an experimental campaign hundreds of meters below Mont Terri, near St. Ursanne in the Swiss Jura. The Mont Terri site, which does not – and never will – hold nuclear waste, has become an international collaborative research platform looking at the suitability of argillaceous rock – in this case Opalinus Clay – for the disposal of radioactive waste. Opalinus Clay is one of the potential host rocks considered for nuclear waste disposal in Switzerland. Results from this experimental site will be largely transferrable to other similar sites.

Assessing the potential of microbes

Bernier-Latmani cites several bacterially-driven processes that have the potential to affect the safety of repositories. On the one hand, increased corrosion of metallic waste and containers and production of methane could both weaken the barriers that contain the . On the other hand, the microbes could consume gases that, over time, are likely to build up pressure in the sealed repository. Also, by altering the form of radioactive elements, their mobility could be reduced, efficiently immobilizing them in the bedrock.

 

“By furthering our understanding of what the microorganisms could do, we can take into account their activity in evaluating the long-term safety of the repository,” explains Bernier-Latmani. Using the latest DNA sequencing technology, she will be able to identify microbes even if they only represent a tenth of a percent of the microbial population. “It is very important to capture the low- abundance bacteria because they may include the genetic information that will allow them to thrive once the repository is sealed,” she says.

Watching the bacteria adapt in real-time

In a close-knit microbial community where different species coexist over millennia in a constantly changing environment, bacteria are likely to evolve and acquire new functions. In a process known as horizontal gene transfer, they can take up genes from other species. To get a clearer picture of how the bacteria might evolve over thousands of years, scientists have to identify the genes expressed by the microbial community as a whole.

How can we identify all of the bacterial species present in the clay deposits beneath Mont Terri? In the past, scientists did this by extracting bacteria from water samples and culturing them until they had a bacterial population large enough to analyze. But given that only about one percent of bacterial species can be cultured, their results hardly represented the true bacterial population.

Today, new techniques allow scientists to analyze bacterial populations without having to culture them in the lab. Using these techniques, the DNA of all present in an environmental sample can be extracted, sequenced, and pieced together again using bioinformatics algorithms. This identifies all of the microbes and exhaustively catalogues their molecular machinery – the entire list of proteins that they can produce. Scientists can go even further and pinpoint the subset of these proteins that is actually in use at any given time, providing additional insight into the exact strategy the bacteria have adopted to survive, and how they might pose a threat.

Bernier-Latmani and her team use a new kind of bioreactor, basically a bacterial aquarium that can be integrated right into the bedrock in tunnels hundreds of meters below ground. By providing a means of sampling the groundwater in the rock, these bioreactors let the researchers observe the bacteria’s growth and activity in their natural habitat.

For the time being, the EPFL researchers are interested in finding out how the bacteria respond to different diets they are likely to encounter in their underground habitat, and how their presence can affect the safety of repositories. The plan is to stimulate them by enriching the groundwater with different molecules, first with hydrogen to simulate the accumulation of the gas accompanying the corrosion of steel containers. All the while, they will have access to a number of parameters – pH, dissolved oxygen, and sulfate – in real-time. Using DNA sequencing techniques, they will be able to watch the adapt to their new environment.

It is still unknown whether the bugs are native or whether they colonized the bedrock during the excavation of the tunnels, but they are there, and they are active. Deep geological repositories have been selected as the most viable option for nuclear , because, unlike on the surface of the earth, the bedrock appears to be frozen in time. But while geology may be close to standing still, human intrusion into the bedrock can bring underground biology back to its normal pace.

http://phys.org/news/2012-07-bacteria-potential-threat-nuclear-repositories.html

Einsortiert unter:Radiation, Research

Plutonium Ratio

25.03.2012

Susanne Gerber

 

Trace detection of plutonium in the city of Iwaki 2012/03/21 (Wed)

It has been detected (Pu-238, Pu-239, Pu-240) plutonium. Professor Masayoshi Yamamoto, Kanazawa University, Centre for Environmental Studies Japan Sea came to the result that Pu238/Pu239, assertive derived from Fukushima Daiichi nuclear power plant. In addition, Pu239, 240/Cs-137 radioactivity ratio has become 200 times the estimate of the government, as well as to distribution in plaques that contain radioactive iodine and radioactive silver.

(Comments of Dr. Yamamoto)

  • We will send the measurement results.
  • Pu is detected, and was surprised to be honest.
  • Pu is already widely in the nuclear test, are distributed at low levels.
  • With this Pu, Pu238/Pu239, 240 radioactivity ratio is about 0.03.
  • This ratio is 0.8 this is clearly high, and contains the primary origin of Pu.
  • Government estimates of emissions is 3.
  • Exposed in the fields of iron and to think and not the adhesion of Pu of nuclear testing,
  • you made me think why and what ratio is low.
  • It may also lower the ratio of Pu with 0.8 instead of all three has been released.
  • Pu239, 9.0E-5 in the ratio of radioactivity 240/Cs-137, 200 times the government estimate of 4.3E-7, Pu has been detected and many more. It seems that it is for Fractionation (difference of behavior) is present perhaps.
  • I think if you can analyze and Am-241 as well as uranium, if possible currently

 

http://enenews.com/plutonium-ratio-200-times-higher-than-govt-claims-detected-50km-south-of-fukushima-daiichi-surprises-japan-professor-who-made-finding-results

Einsortiert unter:Consequences, Danger, Fukushima, Research

All fuel has melted through, much of it into containment vessel… So where’s the rest? (VIDEO)

12.12.2011

Susanne Gerber

http://enenews.com/nhk-plant-operators-trying-to-find-nuclear-cores-all-fuel-has-melted-through-much-of-it-into-containment-vessel-so-wheres-the-rest-video

  • The fuel inside 3 reactors has melted through the bottoms of their furnaces
  • Plant operators try to identify where all the fuel has gone
  • Analysts estimate all of the fuel has melted through the furnace, much of it into the containment vessel
  • Above all, we need to know the temperature of the fuel
  • No thermometer is in place to let us know
  • Gov’t has set two conditions for declaring that the reactors are actually in cold shutdown
  • First is that the temperatures at the bottom of the reactors below 100°C
  • The other is to have greatly reduced emissions of radioactive substances
  • But if fuel has melted and reached the containment, the question arises as to the real significance of bottom temperatures of the tanks
  • The views of TEPCO is the fuel reactor was cooled. The company is indeed observed that the temperature in the containment is 40 degrees
  • The question is whether the people of Fukushima will be convinced by this argument
  • Another problem is that a temperature exceeding 100 degrees makes sense only when the vessel and the containment building were not damaged
  • The test loses its value when a reactor is damaged, which is the case at Fukushima Dai-ichi

Einsortiert unter:Accident, Consequences, Meltdown, Research

20 mSv Per Year Are Not Save

12.12.2011

Susanne Gerber

http://enenews.com/report-fukushima-safety-levels-safe-video

Title: Fukushima Safety Level NOT SAFE!

Uploaded by: Goddards Journal

Upload Date: Dec 11, 2011

 

Einsortiert unter:Danger, Radiation, Research

To Whom Does Scientific Debate Belong?

Susanne Gerber

10.11.2011

That was a central question raised by many of the 200-plus people who attended a citizens’ forum in Tokyo on Oct. 12, as they criticized the ways in which the Japanese government and radiation specialists working for it are assessing and monitoring the health effects of the ongoing nuclear disaster at the Fukushima no. 1 nuclear power plant. The daylong conference, organized by the Japanese citizens’ groups SAY-Peace Project and Citizens’ Radioactivity Measuring Station (CRMS), featured experts who dispute much of the evidence on which the government has based its health and welfare decisions affecting residents of Fukushima Prefecture and beyond. Organizers of the event were also demanding that the government take into consideration the views of non-experts — and also experts with differing views from those of official bodies such as the International Commission on Radiological Protection (ICRP). the Japanese government has constantly referred to the ICRP’s recommendations in setting radiation exposure limits for Fukushima residents. One of the driving forces for the citizens’ forum was a desire to challenge the conduct and much of the content of a conference held Sept. 11-12 in Fukushima, titled the “International Expert Symposium in Fukushima — Radiation and Health Risk.” That conference, sponsored by the Nippon Foundation, involved some 30 scientists from major institutions, including the ICRP, the World Health Organization, the International Atomic Energy Agency and the United Nations Scientific Committee on the Effects of Atomic Radiation. Although the proceedings were broadcast live on U-stream, the event itself was — unlike the Tokyo forum — closed to the public. Some citizens and citizens’ groups claimed that this exclusion of many interested and involved parties — and the event’s avowed aim of disseminating to the public “authoritative” information on the health effects of radiation exposure — ran counter to the pursuit of facilitating open and free exchanges among and between experts and citizens on the many contentious issues facing the nation and its people at this critical time. In particular, there was widespread criticism after the Fukushima conference — which was organized by Shunichi Yamashita, the vice president of Fukushima Medical University and a “radiological health safety risk management advisor” for Fukushima prefectural government — that its participants assumed from the outset that radioactive contamination from the plant’s wrecked nuclear reactors is minimal. Critics also claimed that the experts invited to the conference had turned a collective blind eye to research findings compiled by independent scientists in Europe in the aftermath of the 1986 Chernobyl nuclear disaster in present-day Ukraine — specifically to findings that point to various damaging health consequences of long-term exposure to low-level radiation. So it was that those two citizens’ groups, angered by these and other official responses to the calamity, organized the Oct. 12 conference held at the National Olympics Memorial Youth Center in Shibuya Ward. among the non-experts and experts invited to attend and exchange their views were people from a wide range of disciplines, including sociology, constitutional law and pediatrics. On the day, some of the speakers took issue with the stance of the majority of official bodies that the health damage from Chernobyl was observed only in a rise in the number of cases of thyroid cancers. Eisuke Matsui, a lung cancer specialist who is a former associate professor at Gifu University’s School of Medicine, argued in his papers submitted to the conference that the victims of Chernobyl in the neighboring present-day country of Belarus have suffered from a raft of other problems, including congenital malformations, type-1 diabetes and cataracts. Matsui cited a lengthy and detailed report of research by the Russian scientists Alexey V. Yablokov, Vassily B. Nesterenko and Alexey V. Nesterenko that was published in 2007, and republished in English in 2009 by the new York Academy of Sciences under the title “Chernobyl: Consequences of the Catastrophe for People and the Environment.” Matsui stressed that, based on such evidence, the Japanese government should approve group evacuations of children — at the expense of the plant’s operator, Tokyo Electric Power co. — from certain parts of Fukushima Prefecture. he cited some areas of the city of Koriyama, 50 to 60 km from the stricken nuclear plant, where soil contamination by radioactive cesium-137 has reached 5.13 Curies per sq. km. That is the same as in areas of Ukraine where residents were given rights to evacuate, Matsui said. In fact in June, the parents of 14 schoolchildren in Koriyama filed a request for a temporary injunction with the Fukushima District Court, asking it to order the city to send their children to schools in safer areas. In the ongoing civil suit, those parents claim that the children’s external radiation exposure has already exceeded 1 millisievert according to official data — the upper yearly limit from all sources recommended by the ICRP for members of the public under normal conditions. Following a nuclear incident, however, the ICRP recommends local authorities to set the yearly radiation exposure limit for residents in contaminated areas at between 1 and 20 millisieverts, with the long-term goal of reducing the limit to 1 millisievert per year. Meanwhile, Hisako Sakiyama, former head researcher at the National Institute of Radiological Sciences, delved into the non-cancer risks of exposure to radiation. In her presentation, she referred to a report compiled in April by the German Affiliate of International Physicians for the Prevention of Nuclear War (IPPNW). Titled “Health Effects of Chernobyl: 25 years after the reactor catastrophe,” this documents an alarmingly high incidence of genetic and teratogenic (fetal malformation) damage observed in many European countries since Chernobyl. Sakiyama also pointed out that the German report showed that the incidence of thyroid cancer due to radiation exposure was not limited to children. For instance, she cited IPPNW survey findings from the Gomel district in Belarus, a highly-contaminated area, when researchers compared the incidence of thyroid cancer in the 13 years before the Chernobyl explosion and the 13 years after. these findings show that the figures for the latter period were 58 times higher for residents aged 0-18, 5.3 times higher for those aged 19-34, 6 times higher for those aged 35-49, and 5 times higher for those aged 50-64. “In Japan, the government has a policy of not giving out emergency iodine pills to those aged 45 and older (because it considers that the risk of them getting cancer is very low),”‘ Sakiyama said. “But the (IPPNW) data show that, while less sensitive compared to children, adults’ risks go up in correspondence with their exposure to radioactivity.” Further post-Chernobyl data was presented to the conference by Sebastian Pflugbeil, a physicist who is president of the German Society for Radiation Protection. Reporting the results of his independent research into child cancers following the Chernobyl disaster, he said that “in West Germany … with an exposure of 1 millisievert per year, hundreds of thousands of children were affected.” He noted, though, that any official admissions regarding health damage caused by the 1986 disaster in the then Soviet Union came very slowly and insufficiently in Europe. Indeed, he said the authorities denied there were health risks for years afterward. In response, an audience member who said he was a science teacher at a junior high school in Kawaguchi, Saitama Prefecture, asked Pflugbeil to exactly identify the level of exposure beyond which residents should be evacuated. While acknowledging that was a very difficult question, the German specialist noted later, however, that he would think pregnant women should probably leave Fukushima — adding, “I have seen many cases over the years, but I come from Germany and it’s not easy to judge (about the situation in Japan).” At a round table discussion later in the day, as well as discussing specific issues many participants made the point that science belongs to the people, not just experts — the very point that underpinned the entire event. As Wataru Iwata, director of the Fukushima-based citizens’ group CRMS, one of the forum’s organizers (which also conducts independent testing of food from in and around Fukushima Prefecture) put it: “Science is a methodology and not an end itself.” In the end, though the citizens’ forum — which ran from 9:30 a.m. to 10 p.m. — arrived at no clear-cut conclusions, organizers said that that in itself was a good outcome. and another conference involving citizens and scientists is now being planned for March 2012.

http://www.thyroiddiseasetreatment.com/citizens-forum-queries-nuclear-experts.html

Einsortiert unter:Consequences, Danger, Fukushima, Radiation, Reflection, Research

The Forth Reactor and the Destiny of Japan

Susanne Gerber

28.10.2011

In his recent blog, entitled “The Fourth Reactor and the Destiny of Japan”, Akio Matsumura correctly identifies the spent fuel pool in Unit 4 as the most serious potential threat for further massive radioactive releases from the Fukushima Daiichi nuclear power plant.

The Fourth Reactor and the Destiny of Japan, Akio Matsumura, September 29, 2011:

“I, along with many eminent scientists, are emphasizing the precarious situation of the fourth reactor that contains 1,535 nuclear fuel rods in the pool and is balanced on the second floor, outside of the reactor containment vessel. If the fuel rods spill onto the ground, disaster will ensue and force Tokyo and Yokohama to close, creating a gigantic evacuation zone. All scientists I have talked with say that if the structure collapses we will be in a situation well beyond where science has ever gone. The destiny of Japan will be changed and the disaster will certainly compromise the security of neighboring countries and the rest of the world in terms of health, migration and geopolitics. The Japanese government should immediately create an independent assessment team to determine the structural integrity of the spent fuel pool and its supporting structure. This is of the highest importance: the structure’s security is critical to the country’s future.”

Akio Matsumura
worked together with European members of parliament, was First Secretary-General of International Green Cross and Earth Summit Conference in Rio de Janeiro and worked as an Advisor to United Nations Program.

SOURCE: worldbusiness.org

Einsortiert unter:Consequences, Danger, Fukushima, Research

To Deal With Future Desasters

Susanne Gerber

10.10.2011

Experts from the International Atomic Energy Agency arrived in the Japanese city of Fukushima on Sunday to observe the massive decontamination effort following the world’s worst nuclear disaster since Chernobyl. Local doctors also began a long-term survey of children for thyroid abnormalities, a problem associated with radiation exposure. Officials hope to test some 360,000 people who were under the age of 18 when the nuclear crisis began in March, and then provide follow-ups throughout their lifetimes. The 12-member IAEA group was to visit farms, schools and government offices throughout Fukushima prefecture in northeastern Japan to observe the cleanup process. It is the U.N. atomic agency’s second major mission to Japan since the crisis at Fukushima’s Dai-ichi nuclear power plant began. Nearly 20,000 people were killed when the earthquake and tsunami hit Japan on March 11, and the disaster severely damaged the Fukushima complex. Officials say the plant is now relatively stable, but tens of thousands of people still cannot — or choose not to — return to their homes because of the radioactive contamination. No one has died from radiation in the nuclear crisis, but concerns remain high over how the lingering contamination will impact the safety of Fukushima’s children. The thyroid testing program is intended to allay those fears and build a database that might help deal with future disasters. On its opening day Sunday, more than 100 children, whose thyroid glands are more susceptible to radioactive iodine than adults, were checked. The results were not made public, but officials have said that if any abnormalities are discovered, the children — to be tested every two years until age 20, and then every five years after that — will be provided with further care. More than 6,000 cases of thyroid cancer have been detected in people who were children or adolescents when exposed to high levels of radioactive fallout in the period immediately after the 1986 Chernobyl disaster. A 12-mile (20-kilometer) no-go zone remains in effect around the Fukushima nuclear plant. Japan recently lifted other advisories that warned residents just outside of that zone to be prepared to evacuate at any time, a move largely aimed at reassuring evacuees that it is safe to return. To further bring down contamination levels, towns outside of the no-go zone have begun washing down public areas and removing the top soil in parks and schoolyards. The task is a daunting one because the nuclear accident spread radiation unevenly over a broad swath of Fukushima, leaving some areas near the plant relatively safe, while creating dangerous hotspots farther away. Japan’s government has acknowledged that the effort could take years.

http://mdn.mainichi.jp/mdnnews/news/20111010p2g00m0dm015000c.html

Einsortiert unter:Consequences, Danger, Politics, Research

Off the Coast

Susanne Gerber

29.09.2011

SOURCE: NCOM Japan

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. Japanese officials have detected elevated radiation levels in rice near the crippled reactors. Worrying radiation levels had already been detected in beef, milk, spinach and tea leaves, leading to recalls and bans on shipments.

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. Ken Kostel, Woods Hole Oceanographic InstitutionKen Buesseler, a marine chemist, paid his respects at Namiwake Shrine outside Sendai, Japan, before departing on a cruise to study radiation releases into the ocean from the Fukushima power plant. 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. Chernobyl-induced radiation in the Black Sea peaked in 1986 at about 1,000 becquerels per cubic meter, he said in an interview at his office in Woods Hole, Mass. By contrast, the radiation level off the coast near the Fukushima Daiichi plant peaked at more than 100,000 becquerels per cubic meter in early April. Before Fukushima, in 2010, the Japanese coast measured about 1.5 becquerel per cubic meter, he said. Working with a team of scientists from other institutions, including the University of Tokyo and Columbia University, Mr. Buesseler’s Woods Hole group in June spent 15 days in the waters off northeast Japan, studying the levels and dispersion of radioactive substances there and the effect on marine life. The project, financed primarily by the Moore Foundation after governments declined to participate, continued to receive samples from Japanese cruises into July. 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.’’ Mr. Buesseler took samples of about five gallons, filtered out the naturally occurring materials and the materials from nuclear weapon explosions, and measured what was left. The scientists had expected to find ocean radiation levels falling off sharply after a few months, as radioactive substances were dispersed by the currents, because, he said, “The ocean’s solution to pollution is dilution.’’ The good news is that researchers found the entire region 20 to 400 miles offshore had radiation levels too low to be an immediate threat to humans. But there was also 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. ‘‘We also don’t know concentrations in sediments, so benthic biota may be getting higher doses and if consumed (shellfish), could be of concern,’’ he wrote later in an e-mail, referring to organisms that dwell on the sea floor. The study also found that the highest cesium values were not necessarily from the samples collected closest to Fukushima, he said, because eddies in the ocean currents keep the material from being diluted in some spots farther offshore. The overall results were consistent with those previously found by Japanese scientists, Mr. Buesseler said. He said more research was urgently needed to answer several questions, including why the level of contamination offshore near the plant was so high. “Japan is leading the studies, but more work is needed than any one country, or any one lab, can possibly carry out,” he said.

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

Einsortiert unter:Fukushima, Radiation, Research