Skip to comments.Radioactive cesium level in fish off Fukushima not declining
Posted on 10/25/2012 6:20:47 PM PDT by DeaconBenjamin
Radioactive cesium levels in most kinds of fish caught off the coast of Fukushima havent declined in the year following Japans nuclear disaster, a signal that the seafloor or leakage from the damaged reactors must be continuing to contaminate the waterspossibly threatening fisheries for decades, a researcher says.
Though the vast majority of fish tested off Japans northeast coast remain below recently tightened limits of cesium-134 and cesium-137 in food consumption, Japanese government data shows that 40% of bottom-dwelling fish such as cod, flounder and halibut are above the limit, Ken Buesseler, a marine chemist at the Woods Hole Oceanographic Institution in Massachusetts, wrote in an article published Thursday in the journal Science.
In analyzing extensive data collected by Japans Ministry of Agriculture, Fisheries and Forestry, he found that the levels of contamination in almost all kinds of fish are not declining a year after the March 11, 2011 disaster. An earthquake and tsunami knocked out the Fukushima Daiichi plants vital cooling system, causing three reactor cores to melt and spew radiation onto the surrounding countryside and ocean.
The (radioactivity) numbers arent going down. Oceans usually cause the concentrations to decrease if the spigot is turned off, Buesseler told The Associated Press in an interview. There has to be somewhere theyre picking up the cesium.
Option one is the seafloor is the source of the continued contamination. The other source could be the reactors themselves, he said.
The safety of fish and other foods from around Fukushima remains a concern among ordinary Japanese, among the worlds highest per capita consumers of seafood.
Most fish and seafood from along the Fukushima coast are barred from the domestic market and export. In June, authorities lifted bans on octopus and sea snails caught off Fukushima after testing showed very low levels of radiation.
But the most contaminated fish found yet off Fukushima were caught in August, some 17 months after the disaster. The two greenlings, which are bottom-feeders, had cesium levels of more than 25,000 becquerels per kilogram, 250 times the level the government considers safe.
A government fisheries official, Chikara Takase, acknowledged that the figure for the greenlings was extremely high, but he added high numbers were detected only in limited kinds of fish sampled in the restricted waters closest to the plant. He acknowledged that we have yet to arrive at a situation that allows an overall lifting of the ban.
To bolster public confidence in food safety, the government in April tightened restrictions for cesium-134 and cesium-137 on seafood from 500 to 100 becquerels per kilogram. But the step led to confusion among consumers as people noticed more products were barred.
Plant operator Tokyo Electric Power Co said some radioactive water used to cool the Fukushima reactors leaked into the ocean several times, most recently in April.
Given the 30-year half-life of cesium-137, this means that even if these sources (of contamination) were to be shut off completely, the sediments would remain contaminated for decades to come, Buesseler wrote in Science.
Experts suspect that radioactive water from the plant is seeping into the ground water at the same time, and is continuing to make its way into the ocean.
Hideo Yamazaki, a marine biologist at Kinki University, agrees with Buesselers theory that the cesium is leaking from the Fukushima nuclear plant and that it will contaminate seafood for more than a decade.
He said he believes the plant will continue to leak until cracks and other damage to the three reactors that melted down are repaired. Its unclear when that work will be completed, or even how, because radiation levels in the reactors are too high for humans or even robots.
The current levels of contamination in the fish and seafood from the Fukushima coast will continue for a while, perhaps more than 10 years, judging from the progress in the cleanup process, Yamazaki said in an email.
Buesseler, who led an international research cruise off northeastern Japan in 2011 to study the spread of radionuclides from the Fukushima plant, says predicting patterns of contamination requires more than monitoring data on fish. Careful study of the ocean waters and sediments is also needed to determine how quickly the system will recover.
Stop posting pictures of my family!
Thanks! (how does that crap get online?.....)
to #2: I knew that someone would come up with a good picture of Helen Thomas. She looks a little younger in this one, say, 83.
Why complain about radioactive fish? Because they glow at night, it makes them easier to see and catch.
Cesium has a half life of about 30 years...
If cesium is there then there should be strontium along with other isotopes that last for much longer. Oh and things like some fuel (uranium,plutonium, neptunium) because it had to go somewhere.
Portland OR TV news had an article about radioactive tuna being caught off the Oregon coast. Currently the levels are extremely low but it’s here. The tuna travel between Japan and US West Coast. Scientist quoted in the article don’t know if future levels in the tuna will go up, down or cycle.
one question, as a former radiation health technician for the Navy I have been reading alot of the articles but I havent seen any reports of what the cesium levels were before the incident.
Yeah, plutonium’s half-life is about 80 million years... that could be a problem...
What's your take... is this going to be a problem that gets larger with time?
We are all getting radiation of some form or another every moment of the day. Statements like “3 times background radiation” are meaningless in most cases. People living Denver probably get at least 3 times the radiation exposure that people living in a sea level city does.
The biggest problem is consumption of heavy metals that arent processed by our bodies. Their being radioactive just increase the potential to cancer and other problems. While I am not a doctor, I believe that moderation is the answer. Dont eat too much large fish and you will avoid over exposure. The radioactivity in the ocean will solve itself as long as there is no longer a source. “The solution to pollution is dillution”
Apparently they actually have those levels because Japanese bloggers and some reporters are write (quoting a recent article I read here: http://ex-skf.blogspot.com/2012/10/greenpeace-slams-japanese.html) “3 microsieverts/hour radiation is 100 times as much as pre-nuclear-accident level in Fukushima.” and no one ever contests them in Japanese or English. (and TEPCO and the JAPANESE government are lying and covering up - the easiest cover up would be to claim that the radiation was there to begin with)
Japan’s Hiroshima and Nagasaki surivivors have been studied extensively and even those studies would require a knowledge of current geographic radiation levels (how it would impact health of study participants; it would invalidate medical studies if cesium was a significant modern presence). It stands to reason that they would map the area following the bombs. I’ve read about decreases in radiological agents in Japan from a historical perspective (x years later, regions y and z have w levels)
Another way to black box it is to note that persons exposed to x amount of radiation in the Chernobyl region experience catastrophic disease levels and genetic mutation. State of the art research on radiation levels and human health (BEIR VI) confirms that X amount of radiation in an environment causes disease and genetic mutation at x rate (how much more cancer per exposure increase). The Japanese are miraculous or have been living, prior to Fukushima, in areas with lower radiation than are detected now because they don’t evince the long term biological ills they would experience if they were living among Cesium any where near the levels they are currently detecting.
If I have the time, I’ll ask the EX-SKF blogger if he knows where to find the data you are interested in.
“The biggest problem is consumption of heavy metals that arent processed by our bodies.”
No, the problem is the energy released by radioisotopes ingested or inhaled. It’s not a question of heavy metals being processed by our bodies. It’s Strontium displacing calcium in bones and then, lodged in bones continuously irradiating tissues at close range for long periods of time> Cesium spreads out in muscle -the heart is a muscle so Cesium ingestion is related to cardiac problems. The international research done on those living in cesium contaminated regions document early dementia (radioactive elements traveling to brain tissue and irradiating tissues repeatedly for years), luekemia, genetic mutations, cancers, suppressed immune systems and many other diseases. It makes for depressing reading but it is eye opening. Here’s the research report (http://www.strahlentelex.de/Yablokov%20Chernobyl%20book.pdf) and here’s the wiki discussing the research: http://en.wikipedia.org/wiki/Chernobyl:_Consequences_of_the_Catastrophe_for_People_and_the_Environment