via / August 18, 2014 / This diary is part of an ongoing series here that aims to report measurements of Fukushima derived radionuclides in the North Pacific Ocean to help determine the likely impact on ecosystem and public health in western North America. The purpose of this diary is to report the results of a recently published study by Kumamoto and colleagues in the open-access journal Scientific Reports. The study measured the activity of Fukushima derived cesium (Cs), a tracer for other radionuclides, in the upper 1000 meters of the western Pacific Ocean along the 149 degree E meridian as of winter 2012. These measurements indicate that 10-60% of the total Fukushima derived 134-Cs in the North Pacific has been transported to the south at a depth of ~300 m below the surface. This result is surprising as most models suggest that transport would be primarily to the east toward North America. The study demonstrates that the amount of Fukushima derived radionuclides being transported to the east towards North America is lower than predicted by previous models and provides important information on the circulation of the ocean.

The disaster at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), precipitated by the earthquake and tsunami on March 11, 2011, resulted in meltdowns at Units 1-3 and a massive release of radionuclides to the North Pacific Ocean by direct discharges from the plant and by deposition of radionuclides released to the atmosphere. While a suite of radionuclides were released, 134-Cs is a useful tracer of Fukushima impact. 134-Cs has a relatively short half-life (~2 years) that unequivocally fingerprints a Fukushima source. It was also released in large quantities and therefore poses a potential radiological threat to organisms. 134-Cs was released along with 137-Cs (half-life = ~30 years) in a 1:1 ratio from Fukushima.

Scientists use a variety of units to measure radioactivity. A commonly used unit is the Becquerel (Bq for short) which represents an amount of radioactive material where one atom decays per second and has units of inverse time (per second). Another unit commonly used is disintegrations per minute (dpm) where the number of atoms undergoing radioactive decay in one minute are counted (so 1 Bq = 60 dpm).

Estimates of direct release of Cs to the ocean were on the order of 11-15 PBq (10^15 Bq) while the deposition of Cs to the surface of the ocean were about 5.8-30 PBq. In 2012 the authors of the study occupied a series of stations along 149degree E as shown in the figure below:

Location of stations sampled for 134-Cs by Kumamoto et al. (2014) in the western Pacific south and east of Japan.

In addition the surface plume of radionuclides that has been modeled and detected (by InFORM team member Dr. John Smith of DFO) in surface currents heading to the east toward North America depth distributions of 134-Cs in the western Pacific show that a concentrated plume of Fukushima derived radionuclides has been transported to the south at a depth of 300 meters:

Cross sectional views of 134Cs activity (Bq/m^3) with depth and latitude along 149 degree East

Based on the integration of the activity of Cs over the depth the authors estimate that about 6 Pbq (10^15 Bq) are present in the subsurface feature being transported to the south. This represents on the order of 10-60% of the total radiocesium that was introduced to the Pacific by the disaster. This helps to explain the lower activities being measured in the eastern Pacific compared to what models predict and suggests that maximum activities on the west coast of North America will likely fall toward the lower end of model predictions that were in the range of 2-30 Bq/m^3. Simply stated more of the radioactive elements released from Fukushima to the Pacific Ocean are headed south rather than east to North America in the plume than previously thought.

More direct measurements of radioactive elements in the North Pacific Ocean through the InFORM project will help to determine what activities are likely on the west coast of North American as the plume arrives from 2013 onward. The measurements or radionuclides in seawater, combined with measurements of radioactive elements in marine organisms, will help to assess the risk of exposure of west coast residents to radionuclides from Fukushima.

SOURCE: Fukushima Inform

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By Broc West| 4 Comments | Featured, News


  1. An answer to fukoshimas problems,,,remove all the available nuclear materials,,,remove all the people,, put hydrogen bombs under the disabled reactors and the water tanks,,,set off the hydrogen,fusion bombs to disintergrate the atoms of the nuclear material that is currently going ‘critical’. the problem is that the highly concentrated uranium alloys that make up the reactor cores that have gone ‘critical’ will keep going ‘critical’ for a very long long time. I f they are in the water table they will send concentrated streams of radioactive water into the Pacific for a long time .No person or machine can get close enough now to seperate the rods far enough to prevent criticality.. As long as they are in disfunction they will keep sending pollution into the Pacific. and that is long enough to disrupt the life cycle on Earth. If hydrogen bombs were placed under the reactor cores and the water tanks then the resultant radiation blast would disintergrate the reactor cores and move them to super criticality ,,turning their atoms into simpler more stable forms. Their would be some atmospheric pollution shared by the whole globe,,but there would be an end to the deadly stream of radioactive water into the Pacific

    • Grow hemp/cannabis all over the planet to remove/offset the pollution and done.

  2. So??? What is the point with this kind of reports? How does it helps to all people?
    I just see an stupid title “SIGNIFICANT ……”
    What is that? OK you are a genius on atomics and things like that, you may say the radiation in one hundred or one million, so what?
    We need information from people who knows what is the danger of all this, in a very clear manner
    What is happening to the ocean water? no matter where, we all depend of it.
    What is happening to life in the ocean? we and other animals eat sea food
    How does affects the rain? the rain comes from the sea too
    How much damage is there?
    We dont need kids to tell us is not going north is going south, thanks god we will be dead last in the list.
    So please, do more than just displaying numbers and using dumb titles as “Significant”
    What would you tell me if I say a significant amount of aliens are in the earth, but though they were going south, but not, they are now going north.
    What would you tell me?
    So? are they dangerous? what they eat? how long they live? How do they reproduce? Are they contagious? is it a vaccine for that?

  3. Radioactivity “heading to Japan” ? Hello, wake up, its already there. Lets talk about the increased thyroid cancer in babies in Japan … oh wait, can’t do that because Abe will put you in jail. Only Obama is a bigger liar than Abe.

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