Tag Archives: Weapons Testing

More Citizen Science Seawater Monitoring Results: No Fukushima Contamination Detected

By Jay T. Cullen

@JayTCullen and @FukushimaInFORM

February 16, 2015

What we found:

The absence of any detectable 134-Cs (an unambiguous fingerprint isotope of Fukushima contamination) in the seawater samples indicates that as of November 2014 these locations covering the length of the British Columbia coast have not be affected by ocean currents carrying Fukushima contamination.

The detection limit for 134-Cs averages ~0.2 Bq m-3

Newly added results come from seawater samples collected in collaboration with citizen scientists at the following locations in British Columbia, Canada during November 2014.

  1. Bamfield
  2. Masset, Haida Gwaii
  3. Lax Kw’alaams

Samples were processed and the amount of gamma emitting isotopes determined using a high purity germanium detector.  We look primarily for radioisotopes of cesium (134-Cs half life ~2 years and 137-Cs half life ~ 30 years) for the following reasons:

  1. 134-Cs has a half life that is short enough that all other human sources to the environment have decayed away making it an ideal tracer for Fukushima contamination
  2. next to the short lived Iodine-131 (half life ~ 8 days), Cs isotopes were released in greatest activity to the environment from Fukushima and would be most likely to represent a radiological health risk given their chemistry and propensity to be taken up by the biota
  3. other isotopes were released in much lower amounts from Fukushima relative to Cs (see other posts here and search for plutonium and strontium for example) and would therefore be much more difficult to detect
  4. because they are gamma emitters (unlike Pu isotopes and 90-Sr which emit alpha and beta radiation respectively) they are relatively easy and resource efficient to detect

The absence of detectable 134-Cs indicates that waters near these locations spanning the length of British Columbia have not been contaminated with Fukushima radioactive elements transported across the Pacific by prevailing currents as of Nov 2014. The presence of 137-Cs is due to historical sources of this human made isotope owing to atmospheric nuclear weapons tests in the 20th century and contamination from the Chernobyl disaster in 1986. You can read about the levels of 137-Cs in the North Pacific pre-Fukushima here.

More results will be published as they become available.

Looking For Fukushima Contamination in Mushrooms and Soil of Western North America

By Jay T. Cullen

@JayTCullen

Chanterelle Cantharellus cibarius
 

The purpose of this diary is to report results from a recently published, peer reviewed study (behind paywall) examining the degree of Fukushima contamination in fungi and soil of western North America. The diary is the most recent contribution to an ongoing series which aims to provide evidence from scientific studies assessing the impact of the Fukushima Daiichi disaster on the environment and the health of residents of North America. Trappe and colleagues measured the activity of cesium isotopes (134-Cs half life ~ 2 years; 137-Cs half life ~30 years) in wild mushrooms, soil and leaf litter of the west coast from California up to Vancouver Island. The conclusions of the study were as follows:

  1. No activity measurements exceeded levels thought to impact human health
  2. 137-Cs activity increased in fungi and soil towards the north
  3. 134-Cs increased to the south in leaf litter
  4. Chanterelles did not significantly bioconcentrate Cs isotopes
  5. 137-Cs and 134-Cs activities were highly variable from sample to sample
  6. 137-Cs levels largely reflected non-Fukushima sources from either atmospheric weapons tests in the last century or the Chernobyl disaster in 1986

Continue reading Looking For Fukushima Contamination in Mushrooms and Soil of Western North America

Most Recent Measurements of Fukushima Derived Isotopes in the Northeast Pacific Ocean

By Jay T. Cullen

Satellite measurements of ocean temperature (illustrated by color) from July 28th to August 4th and the direction of currents (white arrows) help show where radionuclides from Fukushima are transported. Large scale currents transport water westward across the Pacific. Upwelling along the west coast of North America in the summertime brings cold deep water to the surface and transports water offshore. Circles indicate the locations where water samples were collected. White circles indicate that no cesium-134 was detected. Blue circles indicate locations were low levels of cesium-134 were detected. No cesium-134 has yet been detected along the coast, but low levels have been detected offshore. (Woods Hole Oceanographic Institution)
Satellite measurements of ocean temperature (illustrated by color) from July 28th to August 4th and the direction of currents (white arrows) help show where radionuclides from Fukushima are transported. Large scale currents transport water westward across the Pacific. Upwelling along the west coast of North America in the summertime brings cold deep water to the surface and transports water offshore. Circles indicate the locations where water samples were collected. White circles indicate that no cesium-134 was detected. Blue circles indicate locations were low levels of cesium-134 were detected. No cesium-134 has yet been detected along the coast, but low levels have been detected offshore. (Woods Hole Oceanographic Institution)

The purpose of this post is to report on new results coming out the crowd-funded Our Radioactive Ocean program headed up by Dr. Ken Buesseler of Woods Hole Oceanographic Institution. This post is part of an ongoing series dedicated to scientific inquiry into the impact of the triple meltdowns at Fukushima on the health of the North Pacific Ocean and residents of the west coast of North America. Measurements of the cesium radioisotopes 134-Cs (half life ~ 2 years) and 137-Cs (half life ~30 years) were made on samples collected on a transect between Monterey Bay CA and Dutch Harbor AK this summer. Because of its relatively short half life 14-Cs serves as an unequivocal tracer of Fukushima contamination in the environment. Fukushima derived 134-Cs was detected at offshore stations with a maximum activity of ~ 2 Bq/m^3 and total 137-Cs activities of ~7 Bq/m^3 of seawater. Measurements have yet to detect 134-Cs in nearshore waters sampled up and down the North American west coast. These activities of Cs are orders of magnitude below levels thought to pose a measurable risk to human health or marine life, according to international health agencies.


For a primer on radioactivity in the ocean and the units used to discuss radioactive elements in the environment please visit this post.

A press release from WHOI regarding these new results can be found here and details about sampling locations and activities of Cs detected are available here.

At a great majority of sites sampled along the coast and offshore the activity of 134-Cs is below detection limit (~legacy contamination resulting from atmospheric weapons testing in the 20th century. Similar to previous work by Dr. John Smith of the Department of Fisheries and Oceans Canada the presence of the contaminated plume of seawater owing to releases from Fukushima can be detected in offshore stations (150 – 1500 km) with levels of 134-Cs approaching 2 Bq/m^3 and total 137-Cs (bomb + Fukushima) of about ~7 Bq/m^3. These levels of 137-Cs are similar to levels in the North Pacific Ocean that were present in 1990 owing to the combined effects of Chernobyl and weapons testing fallout as shown in the figure below.

Activity of 137-Cs in the North Pacific after Povinec and others (2013) http://www.biogeosciences.net/10/5481/2013/bg-10-5481-2013.html with arrows indicating the impact of Chernobyl, 2008 137-Cs activity in the Irish Sea and 2014 levels offshore of western North America post Fukushima for comparison.
Activities of these isotopes were about 10 million fold higher in coastal waters near the Fukushima Dai-ichi nuclear power plant off Japan in the weeks following the beginning of the disaster in March and April 2011 when rates of release and seawater concentrations were at their peak. Current releases from the plant support seawater activities on the order of 10’s-100’s of Bq/m^3 within 2 km of the plant site. The highest activities associated with the most contaminated seawater from Fukushima are predicted to travel across the North Pacific with prevailing currents and arrive in North American waters between this year and next. These offshore activities of Fukushima derived 137-Cs of ~ 5 Bq/m^3 exceed predicted activities of ~3 Bq/m^3 suggesting that offshore activities are likely reaching near peak values. The measurements being made by the international scientific community will undoubtedly help to improve our understanding of mixing and transport in the oceans.

The activities of radiocesium being detected offshore are well below levels thought to represent significant radiological health risks to marine organisms or residents of the west coast of North America. To this point no 134-Cs from the contaminated plume approaching the coast has been detected in nearshore waters. Ongoing monitoring by programs like Our Radioactive Ocean and its partner program InFORM which are making measurements of contamination in seawater and marine organisms will be key to understanding impacts of the Fukushima on our environment.

Kelp Watch 2014 Update: No Fukushima Derived Radiocesium Detected in West Coast Kelp

By Jay T. Cullen

Dan Harrison, Executive Director of InFORM partner organization Raincoast Education Society (http://raincoasteducation.org/) sampling kelp for Kelp Watch 2014 in Tofino, BC Canada.

The most recent results of Kelp Watch 2014 , a program dedicated to monitoring for the presence of Fukushima sourced radionuclides off our Pacific Coast, are reported in this post. This post is the latest contribution to a series dedicated to the dissemination of information about the impacts of the Fukushima Dai-ichi disaster on the North Pacific Ocean ecosystem and on North American public health. New results from the second sampling period (June to August 2014) of Kelp Watch 2014 were just released and can be found here. As with previously reported results here and here no radioactive isotopes from Fukushima were detected in kelp growing at sampling sites spread across the eastern Pacific coast. However, significant quantities of the short lived radioisotope 131-Iodine (half life ~8 days) continued to be found in Los Angeles County and San Diego in southern California. Rather than being transported across the Pacific these isotopes were likely released locally in waste water that carries significant 131-I because of its application in nuclear medicine to treat thyroid maladies. The absence of 134-Cs in kelp suggest that ocean transport of Fukushima contamination has yet to reach North American coastal water.


Kelp Watch 2014 is a joint initiative between Dr. Steven Manley (Department of Biological Sciences, California State University- Long Beach) and Dr. Kai Vetter (UC Berkeley and Lawrence Berkeley National Laboratory). The program involves the analysis of kelp samples collected by citizen-scientists along the Pacific coast for Fukushima derived radioisotopes. Because of their sedentary existences and propensity to concentrate isotopes in their tissues kelp are useful sentinel organisms with which to monitor the timing and extent of the Fukushima impacted plume of seawater as it progressively affects more of the North American west coast.

Samples were collected June to August of this year at various sampling locations along the coast with some kelp obtained from Chile and Tasmania (where little Fukushima impact is expected) to serve as reference locations.

Stations where samples of kelp were obtained for Kelp Watch 2014
Full results for the second sampling period can be found here along with details about the goals and approach of Kelp Watch 2014.

Because of its relatively short half life of ~2 years radioactive 134-Cs serves as a useful tracer of Fukushima impact as it was released in significant quantities, with many other isotopes, into the environment after the disaster in March 2011. All other legacy sources of the human produced isotope have occurred far enough in the past that any 134-Cs present in the environment faithfully reflects release from Fukushima. Similar to previous work by this program all samples of kelp collected from the Pacific by Kelp Watch 2014 in June to August of this year had no detectable (detection limit ~ 0.04 Bq/kg dry weight of kelp) levels of 134-Cs suggesting that isotopes from Fukushima are not significantly affecting radioisotope activities in these organisms to date.

The authors summarize findings about 134-Cs and its longer lived cousin 137-Cs (half life ~30 yr) as follows:

Cesium-137 was detected in all West Coast samples at very low levels. This isotope is still detectable in the marine environment due to above-ground nuclear weapons testing that took place mostly in the 1950s and 1960s. The very low limits set on the shorter-lived Cesium-134 mean that the Cs-137 cannot be directly tied to the Fukushima releases and is more likely due to these “legacy” sources.

Significant Iodine-131 (131-I, half life ~8 days), which can represent a significant radiological health risk given its propensity to concentrate in the thyroid gland and induce cancer, activities continue to be detected (up to 251 Bq/kg at Long Beach CA) in southern California kelp samples. This 131-I is not likely from Fukushima given that ocean transport is quite slow relative to 131-I decay. Kelp Watch 2014 attributes the presence of 131-I to local sources which are likely waste water inputs to the coastal ocean that contains 131-I from nuclear medical applications in hospitals and clinics in the area.

Ongoing monitoring of seawater and marine organism activity concentrations of radioisotopes from Fukushima will help to determine the likely impacts on the ecosystem and public health along North America’s Pacific coast resulting from the disaster. As always, I will report new results as they are made available and we look forward to more work from this quality monitoring program.

Powell River Peak Covers the InFORM Project

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Link to the article here

Seawater testing project ramps up
Citizen scientists aid in tracking coastal radiation
by Chris Bolster | reporter@prpeak.com

Published: Wednesday, October 8, 2014 12:42 PM PDT
A seawater testing project on BC’s coast is ramping up to record the arrival of Japanese radiation leaked into the sea from the Fukushima Daiichi nuclear power plant disaster.

On March 11, 2011, the plant on the north east coast of Japan was hit by a tsunami triggered by a 9.0 magnitude earthquake. Three of the six nuclear reactors at the plant went into meltdown and a day later started to leak radioactive material into the Pacific Ocean. It is known as the largest nuclear incident since Chernobyl in 1986.

Dr. Jay Cullen is a chemical oceanographer at the University of Victoria who is leading the three-year project.

Starting this month, Cullen and his team will be coordinating about 600 citizen scientist volunteers in 14 coastal communities who will be collecting seawater samples monthly to send to the lab.

“The project itself is building on the success of more modest testing programs the Department of Fisheries and Oceans (DFO) and Health Canada have been carrying out since the triple meltdown at Fukushima Daiichi in March 2011,” said Cullen.

DFO and Dr. John Smith have been making measurements in the north east Pacific and the Arctic oceans looking for radionuclides from Fukushima in seawater, he said.

Cesium-137, a signature isotope of Fukushima, was first detected about 1,500 kilometres offshore in 2012. In June 2013 it was detected off the west coast of Vancouver Island.

Cullen’s project will track the arrival of the plume of contaminated seawater being transported on North Pacific ocean currents.

“It’s to track its arrival and look for the maximum activities of these isotopes which will dictate what the risk is to the public,” Cullen said, adding that estimates suggest peak levels will reach BC during the next three years.

Scientist have measured low levels of radioactive material in seawater for decades.

“If you look at the activity of some of the isotopes which present the greatest health risks like Cesium-137 or Strontium-90 those levels peaked in the mid-1960s as a result of weapons testing,” said Cullen.

Currently there is only a slight trace of the chemicals from the disaster, he said.

“If you lived here in the 1970s or 80s the radioactivity of seawater and fish was likely greater than what we expect to be resulting from Fukushima,” he added.

Readers interested in the most recent scientific studies on the radiation-contaminated seawater or more information on the project, can visit Cullen’s blog or the study’s website.