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

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 and Our Radioactive Ocean: Science on a Sphere Video

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.

CBC News: Fukushima nuclear pollution hasn’t hit B.C. shore, says researcher Jay Cullen

Cullen expects nuclear pollution from Fukushima will hit B.C.’s beaches eventually

By Daybreak North, CBC News Posted: Mar 11, 2015 3:33 PM PT Last Updated: Mar 11, 2015 9:57 PM PT

Ocean currents act as a conveyor, carrying debris and radiation-contaminated water from Japan towards North America. Ocean currents act as a conveyor, carrying debris and radiation-contaminated water from Japan towards North America. (NOAA)

Four years after a massive earthquake struck Japan, creating a nuclear disaster in Fukushima, research shows nuclear pollution is making its way towards B.C., but isn’t affecting fish.

“According to all the measurements that we’ve made thus far, and with our partner Health Canada who have been making measurements of fish since 2011, we’ve yet to detect that marker isotope for fish caught along the coast,” Jay Cullen, a University of Victoria professor, told Daybreak North’s Carolina de Ryk.

The earthquake that struck off the coast of the Tohoku region in northeastern Japan on March 11, 2011, set off a monster wave, up to seven metres high, that crashed over the coast, causing massive damage.

The seawater from the tsunami breached the Fukushima Daiichi nuclear plant, disabling its cooling system, causing a nuclear meltdown that the country is still trying to clean up. Altogether, the disaster killed 19,000 people and displaced more than 300,000.

Cullen, who leads a network to monitor the impact of the nuclear pollution caused by the disaster, said his team is looking for two specific cesium isotopes released from Fukushima.

“Atmospheric fallout reached the BC coast in the weeks following the meltdowns according to Health Canada monitoring stations. Transport by prevailing ocean currents was detected as early as 2012 about 1,500 kilometres offshore, and in 2014 we were detecting that contamination — fingerprint element that could only come from Fukushima on the continental shelf of British Columbia,” he said.

The team he works with is also analyzing samples sent in by residents along B.C.’s coast, which he said haven’t turned up any trace of Fukushima radiation.

He expects the nuclear pollution will hit B.C.’s beaches eventually, and he said researchers like himself will continue to monitor the impact that will have.

 

Dramatic Decrease of Fukushima Derived Radionuclides in the Northwest Pacific Ocean 2011-2012

By Jay T. Cullen

A schematic view of the formation and subduction of mode waters in the North Pacific

The purpose of this diary is to report on a recently published (Jan 2015) open-access, peer reviewed study which examined the activities of 137Cs (half life 30.2 yr), 134Cs (half life ~2.1 yr) and 90Sr (half life ~28.8 yr) in the northwest Pacific off the coasts of Japan and China. The diary is part of a ongoing effort to communicate the results of scientific research into the impact of the Fukushima Dai-ichi nuclear disaster on environmental and public health. Men and colleagues report on how activities of these fission produced isotopes changed between three research expeditions in June 2011, December 2011 and June 2012. Activities in seawater decreased dramatically through time for all three isotopes consistent with very high release rates measured from the Fukushima site in March-April 2011 followed by ongoing but many orders of magnitude (10,000 – 100,000 fold) lower releases from the site thereafter. By 2012 the impact of the Fukushima releases could be still be detected in most samples for Cs isotopes however 90Sr distributions were much more uniform with the highest measured activity only slightly above the pre-Fukushima background. These results are consistent with:

  1. the relatively small source term for 90Sr from compared with the Cs isotopes from Fukushima as determined by measurements of air, soil and water after the disaster
  2. the much lower Fukushima derived activities for these isotopes in the eastern Pacific off of North America being measured given decay and mixing of the contamination as it is transported by ocean currents

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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.
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Prince Rupert Citizen Science Monitoring Continues for February 2015

Feb. 19, 2015

Prince Rupert BC

Prince Rupert’s third sample was recently collected by our volunteer team including students from NWCC Desiree Louis (College and Career Prep program) and Michael Standbridge (Applied Coastal Ecology (ACE) program). Sampling is being coordinated by Cheryl Paavola (Instructor and Science Lab Tech) at Northwest Community College – Prince Rupert.

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