Category Archives: Sediment

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

Scientists Find New Source of Radioactivity from Fukushima Disaster

by WHOI Media Relations
Published 2 October 2017

Scientists have found a previously unsuspected place where radioactive material from the Fukushima Dai-ichi nuclear power plant disaster has accumulated—in sands and brackish groundwater beneath beaches up to 60 miles away. The sands took up and retained radioactive cesium originating from the disaster in 2011 and have been slowly releasing it back to the ocean. Continue reading Scientists Find New Source of Radioactivity from Fukushima Disaster

Most Recent Measurements of Plutonium in Pacific: Fukushima Fallout Undetectable

By Jay T. Cullen

@JayTCullen and @FukushimaInFORM

The purpose of this post is to report results from two recently published studies on plutonium releases from Fukushima to the Pacific Ocean. The post contributes to an ongoing series where results from peer-reviewed studies on the impact of the triple meltdowns at the Fukushima Dai-ichii nuclear power plant on the health of the Pacific ecosystem and residents of the west coast of North America are reported. A frequently asked question of those involved in monitoring the health of the North Pacific is why more measurements of the long lived, alpha-emitting isotopes of plutonium (239Pu half-life 24,100 years; 240Pu 6,570 years) are not being made given the potential for these isotopes to pose radiological health risks. Previous work indicates that 239+240Pu releases from Fukushima were about 100,000 and 5,000,000 times lower than releases from the Chernobyl disaster in 1986 and 20th century weapons testing respectively. Initial measurements of Pu isotopes in seawater and marine sediments off the coast from Fukushima indicated no detectable change occurred in Pu inventories in the western Pacific after the disaster. These two most recent studies monitored the activity and isotopic composition of Pu in seawater and marine sediments off of Japan from 2008-2013. Similar to earlier work these studies find that the release of Pu isotopes by the Fukushima accident to the Pacific Ocean has been negligible. The Fukushima signal is not detectable in the ocean off Japan relative to legacy sources from atmospheric weapons testing in the 20th century. Given these accumulating results 239+240Pu from Fukushima is unlikely to negatively impact the health of the Pacific Ocean ecosystem and levels in the environment from Fukushima will not pose a danger to the population of North America.
Continue reading Most Recent Measurements of Plutonium in Pacific: Fukushima Fallout Undetectable

Comparing the Environmental Impacts of the Chernobyl and Fukushima Disasters

Estimated total atmospheric source term for Fukushima compared to Chernobyl in PBq (PBq = 10^15 Bq). From Steinhauser et al. (2014) SciToTEnviron

By Jay T. Cullen

This post reports on a recently published peer reviewed study by Steinhauser and colleagues in the journal Science of the Total Environment (behind pay wall) comparing the Chernobyl and Fukushima nuclear accidents. The post is part of an ongoing effort to communicate the results of scientific studies into the impact of the Fukushima disaster on the environment. A majority of the radioactivity released from both Chernobyl and Fukushima can be attributed to volatile radionuclides (noble gases, iodine, cesium, tellurium). In contrast, the amounts of more refractory elements (including actinides like plutonium), released by Chernobyl was ~four orders of magnitude (10,000 fold) higher than releases from Fukushima. The most cited source term for Chernobyl is 5300 PBq (excluding noble gases) while a review of published studies of Fukushima carried out by the authors above allow an estimate for the total atmospheric source term of 520 (a range of 340–800) PBq. Monitoring of air, soil and water for radionuclides after the respective accidents indicate that the environmental impact of Chernobyl is likely to be much greater than the Fukushima accident. The post is relatively information dense as I have provided data tables for those who are interested in the estimates and the peer-reviewed studies from which they come. Apologies up front to those who find such information tedious. Continue reading Comparing the Environmental Impacts of the Chernobyl and Fukushima Disasters