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 resources to monitor the impact of the disaster on our marine environment should focus on the detection of the cesium isotopes. Continue reading
By Jay T. Cullen
The purpose of this post is to review how the background dose of ionizing radiation has changed through geologic time until the present. I was motivated to write this by questions and misinformed statements made to me regarding the likelihood that the low levels of ionizing radiation now added to the Pacific Ocean might harm marine microbes and effectively kill the base of the oceanic food chain – given levels being measured this is for all intents and purposes impossible. This post is part of an ongoing series that summarizes the results of scientific research into the impact of the Fukushima Dai-ichi nuclear disaster on the health of the marine environment and residents of the west coast of North America. Life on Earth has been exposed to ionizing radiation since the first organisms began leaving chemical signs of their existence almost 4 billion years ago. In a paper published in 1999 Karam and Leslie calculated how the dose experienced by organisms from naturally radioactive geological and biological materials has changed over time. They find that overall the beta and gamma dose experienced by organisms has dropped from about 7 millisievert (mSv = 0.001 Sv) 4 billion years ago to about 1.4 mSv today. Given the similarity of repair mechanisms that organisms use to cope with damage from ionizing radiation it is likely that these mechanisms evolved early in Earth’s history which may explain why organisms are capable of dealing with higher than background doses in the environment today. Continue reading
Prince Rupert BC
Prince Rupert’s July 2015 sample was recently collected by our volunteer team at Northwest Community College including visiting science teacher Sandy Humphrey from SD 91. Sampling is being coordinated by Cheryl Paavola (Instructor and Science Lab Tech) at Northwest Community College – Prince Rupert.
Sandy Humphrey of SD 91 collecting the InFORM seawater sample in a very sunny Prince Rupert harbour.
Sandy Humphrey and Cheryl Paavola at Prince Rupert.
The sample will be processed and analyzed for radiocesium and naturally occurring radionuclides.
The Integrated Fukushima Ocean Radionuclide Monitoring (InFORM) project is a network involving academic, governmental, and non-governmental organizations, as well as citizen scientists. InFORM is acquiring data to support a thorough radiological impact assessment for Canada’s west coast stemming from the Fukushima Dai-ichi nuclear power plant (FD-NPP) accident, and to effectively communicate these results to the public. The measurements undertaken as part of the InFORM project to look for Fukushima derived radionculides in fish during our first of three years of monitoring are now complete. Sockeye salmon (Oncorhynchus nerka) and Steelhead Trout (Oncorhynchus mykiss) (as well as some Chinook, Chum and Pink Salmon) were caught off the west coast of Canada in Summer 2014 as they were returning to 9 different streams and rivers up and down the coast of British Columbia Canada. These results add to the first 19 fish which we reported on in December of 2014.
What we have found so far:
- None of the fish from 2014 were found to contain detectable levels of 134Cs. What this means is that radioactivity from Fukushima cannot be detected in fish caught in BC waters as of August 2014
- Nuclear weapons testing fallout (137Cs) can be detected in BC fish at levels that represent a fraction of Health Canada guidelines (1000 Bq kg-1) and a fraction of the radiation exposure owing to naturally occurring radionuclides
- Neither the 137Cs nor the naturally occurring radioisotopes in fish represent a measureable health risk to consumers in Canada
Summary of the amount of radioactive cesium isotopes in sockeye salmon and steel head trout harvested from BC waters in 2014 (Figure by Jonathan Kellogg email@example.com).
By Jay T. Cullen
The purpose of this post is to address common questions related to Fukushima monitoring efforts being conducted by the Integrated Fukushima Ocean Radionuclide Monitoring (InFORM) network in the northeast Pacific Ocean and coastal waters of Canada. This diary continues a series aimed to report the results of scientific research into the impact of the Fukushima disaster on the environment. I am asked routinely why we do not measure contamination in marine microalgae, the base of the marine foodweb, given that they concentrate radionuclide contamination from Fukushima found in seawater into their cells as they grow. The extremely low levels of contamination found from Fukushima in the northeast Pacific Ocean combined with the very small amounts of microalgae present in oceanic waters make such monitoring logistically infeasible. Follow below the fold for the detailed answer. Continue reading
By Jay T. Cullen
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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
By Jay T. Cullen
In an effort to communicate the results of our investigation into the impact of the Fukushima disaster on Canadian ocean ecosystems and the public our data is now being shared through the British Columbia Centre for Disease Control. The BCCDC is an agency under the Provincial Health Services Authority and their website is a fantastic resource for those concerned about a multitude of health issues. In particular they have a very information rich section devoted to radiation in the environment and health of BC residents. This Frequently Asked Questions (FAQ) page regarding the Fukushima Dai-ichi disaster is particularly useful and well presented. InFORM and partner organization Our Radioactive Ocean’s citizen science seawater monitoring data can be found on the BCCDC website here. Thanks to our colleagues at BCCDC for their continued work guarding the health of BC residents.