Category Archives: Marine Life

Insignificant Environmental and Public Health Risk from Fukushima in North America 8 Years On

By Jay T. Cullen

Summary infographic for the Fukushima InFORM project including our measurements in North America, Japanese measurements, historical data and safety guidelines.

I am writing this post is to bring the public up to date on monitoring efforts of my research program into the impact of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident on environmental and public health here in North America. This post is part of an ongoing series summarizing work carried out by the Integrated Fukushima Ocean Radionuclide Monitoring (InFORM) project. Eight years since the peak in releases to the environment our project continues to measure radioisotopes released from the FDNPP that have the potential to present radiological health risks to living things. InFORM makes measurements of levels in seawater and common marine organisms as consumption of seafood is one of the most likely ways that residents of North America could be exposed to Fukushima derived contamination. We have found that:

  • Maximum contamination levels in seawater from Fukushima measured in waters offshore (~1500 km) and onshore British Columbia are now known to be about 8 to 10-fold lower than levels present in the North Pacific during the height of atmospheric nuclear weapons testing in the 1950’s and 1960’s.  These levels are roughly 1000-fold below the maximum allowable drinking water standards for these isotopes.
  • Levels in Pacific salmon returning to North America have not changed in a statistically significant way since before the disaster and are lower than peak levels measured in the 1960’s.
  •  As was reported in 2015 in this comprehensive study by Health Canada and backed up by measurements made by the international scientific community the release of radioisotopes from Fukushima will have no measurable impact on the health of the marine ecosystem in the northeast Pacific nor on public health in North America.

Eight years after this disaster it is important to remember those lost in the tsunami and those still displaced from their homes and communities struggling to recover.


Offshore and Onshore Citizen Science Monitoring of Seawater Contamination

The levels of radionuclide contamination in seawater is important to understand as the levels that ultimately are found in marine organisms is set by seawater levels.  InFORM recently published a peer-reviewed paper in Environmental Science and Technology summarizing our results to date. Offshore levels of Fukushima derived isotopes have peaked and are now decreasing at our westernmost stations 1000-1500 kilometers from the North American coast. The peak levels are well below levels measured in the same waters during the 1950’s and 1960’s when atmospheric nuclear weapons tests were common.  Our study area is shown in the figure below along with the prevailing currents that brought the contaminated seawater to North America.

es-2017-02712h_0001.jpeg
Study area showing the onshore-offshore sampling line occupied by the InFORM project with the support of Department of Fisheries and Oceans Canada. Station P26 is ~1500 kilometers from the coast of North America.

​Every month since about December 2014 volunteer citizen scientists in 15 coastal communities up and down the shores of British Columbia have collected seawater samples at the beach and returned them to our laboratories for analysis.  The sampling network is shown below.

mar-2016-cs-update-01.png
Coastal seawater monitoring stations in British Columbia.

Since monitoring began coastal seawater concentrations have increased as the Fukushima ​contamination plume arrives.  For the first time we can report that contamination levels have ceased increasing near the coast and are beginning to diminish. The activity of 137Cs leveled off at ~4 Bq per cubic meter of seawater which is about 2-4 times the background from weapons testing that existed here before Fukushima. Both the open ocean and coastal monitoring data are summarized in the figures below.

InFORM_trendcomp_Mar19-01.png
Monthly averaged 137Cs detected in seawater in Bq per cubic meter collected along the coast of BC from 2014-2018.

InFORMenews_Mar19-01.png
Levels of 137Cs in seawater (Bq per cubic meter) measured in samples collected by our citizen scientists along the BC coast compared to maximum levels measured offshore, weapons testing fallout maximum activities in the eastern Pacific in early 1960’s and Canada’s action level for the isotope in drinking water.

Offshore levels of 137Cs peaked at a little less than 10 Bq per cubic meter and have been diminishing as less contaminated water moves across the Pacific from the west. Coastal activities have peaked at lower levels likely because freshwater runoff from the continent is less contaminated than the seawater and dilutes the Fukushima contamination.

Monitoring of Pacific Salmon

Since 2014 we have collected and analyzed ~100 Pacific salmon and steel head trout per year returning to rivers up and down the BC coast from the Pacific Ocean.  There has been no statistically significant increase in the levels of human-made isotopes in the fish since before the Fukushima disaster. Below we plot the maximum levels we have detected in fish returning to BC from 2011-2017 compared to levels measured in Pacific salmon during the 1960’s when weapons fallout levels were highest surface waters.

Radiation%20in%20NE%20Pacific%20Salmon%20through%20time_max-01.png
Maximum levels of 137Cs detected in BC salmon post Fukushima compared to levels in Pacific salmon in the mid-1960’s owing to weapons testing fallout.

 

On average our Pacific salmon have ~0.2 Bq per kilogram wet weight and it is important to note that there is no statistically significant different in the average contamination level in the fish in years 2011-2017. We are only showing the maximum value detected in each year and have not shown how much variability exists in the yearly data for clarity. Levels of contamination in the 1960’s were >10-fold higher than our average levels in years post-Fukushima. The dose of ionizing radiation experienced by consumers of Pacific fish and shellfish is still dominated by the presence of naturally occurring radioisotopes in the Uranium and Thorium decay series (principally 210-Polonium) and remains well below levels that might represent a health risk.

We will continue our monitoring efforts likely through the end of this calendar year and continue to report our results as they are generated. As always I am happy to answer any questions related to the project and our findings.

Advertisements

Monitoring Fukushima Contamination in Pacific Salmon and Soil in British Columbia

Beautiful sockeye salmon photographed by Eiko Jones.

Seven years on, since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, it is useful to start to bring together information from scientific studies of the impact of the contamination on the North American environment and its people. I recently wrote to communicate the most recent results of the Integrated Fukushima Ocean Radionuclide (InFORM) project. This post summarizes a recently published, peer-reviewed paper by colleagues lead by Dr. Krzyzstof Starosta of Simon Fraser University in BC working in parallel to InFORM. The open access paper was published in the Canadian Journal of Chemistry and was recently recognized with the  “Best Paper Award” by the journal. They studied the concentrations of anthropogenic radioisotopes (134Cs half-life ~2 years, 137Cs half-life ~30 years) and naturally occurring radioisotope 40K (half-life 1.25 billion years) in Pacific salmon (sockeye, chum and chinook) and in soil and roof debris collected in southern British Columbia to determine the local impact of the FDNPP accident.  Their results were as follows:

  • 134Cs (a fingerprint of Fukushima contamination) was not detected in any of the salmon samples
  • 137Cs was not detected in sockeye or chum salmon but was detected in all chinook with an average level of ~0.2 Bq kg-1
  • Annual dose from artificial radionuclides to a human consumer of chinook salmon was estimated to be ~1/300 of the dose owing to naturally occurring isotopes in the fish and ~1/30,000 of the annual dose experienced for all other natural sources by the average Canadian
  • Most soil samples contained 134Cs and 137Cs which was delivered to the region by atmospheric transport shortly after the disaster
  • Levels of Fukushima radioisotopes in soil did not approach levels known to be harmful to living organisms

Consistent with other monitoring in the area the results of the study indicate that given the trace levels of contamination present the impact of the FDNPP accident on ecosystem and public health in North America will be insignificant. Continue reading Monitoring Fukushima Contamination in Pacific Salmon and Soil in British Columbia

IAEA Affirms Japan’s Fukushima-Related Radioactivity Monitoring

by Tim Hornyak
11 October 2017
Originally published by Eos, a periodical of the American Geophysical Union

Laboratories outside Japan have validated the results. Marine radioactivity levels from the nuclear disaster have fallen, but questions remain years after the meltdown. Continue reading IAEA Affirms Japan’s Fukushima-Related Radioactivity Monitoring

Non-native species from Japanese tsunami aided by unlikely partner: plastics

by Mark Floyd
Originally published by Oregon State University
28 September, 2017

NEWPORT, Ore. – A new study appearing this week in Science reports the discovery of a startling new role of plastic marine debris — the transport of non-native species in the world’s oceans. Continue reading Non-native species from Japanese tsunami aided by unlikely partner: plastics

How much Fukushima contamination is in migratory Pacific fish?

Proposed migration pathways of North Pacific predators.

The purpose of this post is to report on a recently published, peer-reviewed study that investigated the levels of Fukushima derived contamination in migratory Pacific predators. The post is part of an ongoing effort to inform interested members of the public what the scientific community is finding about the impact of the Fukushima Daiichi Nuclear Power Plant (FDNPP) disaster on the environmental and human health. Madigan and colleagues looked for radiocesium (134Cs, half life ~ 2 years; 137Cs, half life ~30 years) in a variety of large, predatory organisms in the North Pacific Ocean between 2012 and 2015.  Their results were as follows:

  • Fukushima derived 134Cs could not be detected in any of the organisms with the exception of a single olive ridley sea turtle with trace levels (0.1 Bq kg-1 dry weight)
  • Levels of 137Cs varied in the organisms but were generally unchanged compared with levels measured in organisms prior to the FDNPP disaster (pre-2011)
  • Levels of 137Cs were roughly 10 to 100-fold lower in the organisms than levels of naturally occurring Potassium-40 (40K)
  • Neither the levels of radiocesium or 40K approach levels known to represent a significant health risk to the animal or human consumers

These direct measurements of contamination levels in marine predators suggest that assuming that Pacific organisms will accumulate detectable FDNPP contamination is unwise.  Similarly, anxiety and speculation about the dangers of radiocesium bioaccumulation in the face of such data seems unfounded.


Between 2012 and 2015 a total of 91 different organisms from a variety of predatory marine groups were sampled and analyzed for the presence of radiocesium contamination and naturally occurring 40K.  The human made isotope 134Cs, with its relatively short ~2 year half life, serves as a fingerprint of FDNPP contamination as all other human sources are sufficiently distant in the past to have completely decayed away in the environment.  Organisms sampled and their radioisotope content are reported in the following table:

Table1_Madiganetal2017.png

 

With the exception of a single olive ridley sea turtle no detectable (<0.1 Bq kg-1 dry weight) trace of FDNPP 134Cs contamination was found.  Levels of 137Cs found in the organisms were similar to levels measured pre-Fukushima. In addition, the 137Cs levels were less than 0.2% of US FDA levels of concern (370 Bq kg-1 wet weight) and less than 0.05% of US FDA derived intervention levels (1200 Bq kg-1 wet weight).  Simply stated levels in these organisms would have to be >1600-fold higher to be designated unfit for market.  The levels and ionizing radiation dose to consumers from naturally occurring 40K dwarfed those from FDNPP radiocesium.  Radiocesium derived ionizing radiation doses were <1% of those from 40K. Neither the doses from 40K or cesium isotopes approached, even remotely, those known to affect the health of the organisms or consumers of these organisms.

These results are consistent with those of the Integrated Fukushima Ocean Radionuclide Monitoring (InFORM) project. Ongoing, scientifically rigorous, monitoring of the marine environment provides the best evidence with which to gauge the risk that the FDNPP meltdowns represent for marine and public health here in North America.