Tag Archives: Fukushima

Cesium, Fukushima, Japan, Marine Life, Peer Reviewed, Strontium

Radioactive Strontium and Cesium in Fish From the Harbor at the Fukushima Dai-ichi Nuclear Plant

1 Comment

By Jay T. Cullen

The purpose of this post is to report on a recent peer-reviewed study that investigated the radionuclide content of fish caught in the harbor of the Fukushima Dai-ichi Nuclear Powerplant (FDNPP) in 2012 and 2013. The post is also written in part to address questions like:

Why don’t you measure 90Sr in fish you catch off of North America?

This post is part of an ongoing series dedicated to summarizing results from scientific research into the impact of the FDNPP disaster on the environment. Fujimoto and colleagues measured the activity of Cesium-134 (134Cs half life ~2 years), Cesium-137 (137Cs half life ~30 years) and Strontium-90 (90Sr half life ~29 years) in fish collected from the FDNPP harbor and just outside the port in 2012 and 2013. Fish were most contaminated in the harbor and had radiocesium activity concentrations (in whole body without internal organs, Bq kg-1 – wet weight) that were ~200-330 times higher than measured 90Sr levels. The much lower 90Sr levels compared to radiocesium in the fish is consistent with much lower releases of 90Sr to the Pacific Ocean compared to radiocesium in the aftermath of the meltdowns at FDNPP (see here, here and here for example). The activity of radiocesium in fish diminishes dramatically with distance from the harbor and as of April-June 2015 none of the fish caught in Fukushima prefecture waters exceeded the stringent 100 Bq kg-1 Japanese safety standard. Across the Pacific, we have yet to detect Fukushima derived radiocesium in salmon and steelhead trout caught in British Columbian waters as part of the Fukushima InFORM monitoring effort. 90Sr is much more difficult and costly to analyze in environmental samples than are the cesium isotopes. The results of the Fujimoto study suggest that 90Sr from Fukushima is unlikely to be found at detectable levels in marine organisms in the northeast Pacific and that resources to monitor the impact of the disaster on our marine environment should focus on the detection of the cesium isotopes. Continue reading Radioactive Strontium and Cesium in Fish From the Harbor at the Fukushima Dai-ichi Nuclear Plant →

FAQ, Presentations

Question and Answer: Public Discussion of Fukushima Impact on the West Coast of North America

1 Comment

By Jay T. Cullen

Twitter follow @JayTCullen


Map showing the location of public talks for the InFORM project June 1-4, 2015.

The purpose of this post is to report on a recent public discussion tour to convey the latest results of the Integrated Fukushima Ocean Radionuclide Monitoring (InFORM) network to residents of the north coast of British Columbia. This post continues a series aimed to report the results of scientific research into the impact of the Fukushima disaster on the environment. Between June 1-4, 2015 I traveled from Victoria up to Haida Gwaii, over to Prince Rupert and up the Skeena River to Terrace and gave 8 public talks to communicate the results of the networks monitoring efforts to determine the impact of the Fukushima Dai-ichi meltdowns on the health of the northeast Pacific and residents of the North American west coast. I was able to meet three of our citizen scientist volunteers who have been collecting shoreline samples to look for Fukushima derived contamination of coastal seawater. The response to these presentations was overwhelmingly positive and the public asked very useful questions about monitoring thus far. Despite the overall usefulness of the discussions some old misinformation keeps rearing its head. Here I’ll show some of the beautiful spots on our coast and begin the process of addressing some more of the misinformation related to Fukushima impacts on the west coast. Continue reading Question and Answer: Public Discussion of Fukushima Impact on the West Coast of North America →

Cesium, Fukushima, Iodine, Japan, Peer Reviewed

Status of the Spent Fuel At Fukushima Dai-ichi: How much was released to the environment?

4 Comments

By Jay T. Cullen

The purpose of this post is to answer the question posed in the title by summarizing a recently published peer reviewed study in the journal Nuclear Engineering and Design. The diary is part of an ongoing effort to communicate results from scientific studies aimed at understanding the impact of the Fukushima Dai-ichi meltdowns on the environment. The paper by Jäckel compares measured and predicted activities of reactor products 134-Cesium (134Cs half life ~2 years) and 137-Cs (137Cs half life ~30 years) in the reactor cores and spent fuel to measurements in the spent fuel pools (SFPs) of Units 1, 2, 3 and 4 at the site to determine how much spent fuel radiocesium was released after the accident. The comparison indicates that only very minor damage to the spent fuel occurred during the accident and subsequent clearing work such that at most about 1% of the Cs inventory from a single bundle (in Unit 2 SFP) was released to the cooling water. The short answer to the question is that not very much of the spent fuel was released at all and the bulk of releases originated from the reactor fuel in Units 1, 2 and 3 at the time of the accident. This is consistent with the results of measurements made of Fukushima derived radionuclides in air, soil and water worldwide since March 2011. Continue reading Status of the Spent Fuel At Fukushima Dai-ichi: How much was released to the environment? →

Cesium, Fukushima, Japan, Marine Life, Peer Reviewed, Seawater, Strontium

Fukushima Radionuclides in Pacific: Doses to Japanese and World Public Unlikely to Cause Health Damage

1 Comment

By Jay T. Cullen

The purpose of this post is to summarize a the most recent, peer reviewed scientific study to examine the likely impact of Fukushima contamination of the North Pacific on human health. The blog is part of a continuing series that seeks to communicate the results of scientific studies aimed at determining the impact of the triple meltdowns at the Fukushima Dai-ichi nuclear power plant (FDNPP) on ecosystem and public health. Povinec and Hirose’s recent paper in Scientific Reports examined the variation in Fukushima derived 90-Strontium (90Sr half life 28.8 years), 134-Cesium (134Cs half life ~2 years) and 137-Cesium (137Cs half life ~30 years) in seawater and biota offshore of the FDNPP and in the northwest Pacific. These isotopes are most likely to represent radiologically health risks to consumers of Pacific seafood given their propensity to concentrate in organisms and, in the case of 90Sr and 137Cs, their longevity in the environment. Doses to the Japanese and world population were estimated and compared to doses attributable to naturally occurring isotopes present in food. Doses from food caught in coastal waters right next to the FDNPP to 20 km offshore were similar to doses from naturally occurring isotopes (primarily 210Po) while doses from the consumption off fish caught in the open northwest Pacific were much lower than natural doses. In each case the individual doses are well below levels where any negative health effects would be measurable in Japan or elsewhere. Continue reading Fukushima Radionuclides in Pacific: Doses to Japanese and World Public Unlikely to Cause Health Damage →

Presentations, Presentations & Media

Fukushima and Our Radioactive Ocean: Science on a Sphere Video

Leave a comment

This post simply presents a video made by Our Radioactive Ocean (ORO) for the United States of America National Oceanic and Atmospheric Administration’s Science on a Sphere program. ORO is a sister program of the InFORM network in Canada. ORO runs a large crowd funded citizen science sampling network distributed across the North Pacific dedicated to monitoring for Fukushima radionuclides in seawater. The movie has some production value and provides useful background on radioactive elements in the ocean and is designed to be shown in aquaria and other public spaces. Thanks to ORO for their continued efforts to track the arrival of the ocean borne contamination from Fukushima along the west coast of North America and in the Hawaiian Islands.