Tag Archives: Ocean Currents

Interview on CBC Radio Daybreak North About InFORM with George Baker

Radio interview related to broadcast by CBC Daybreak North on Dec. 10, 2014 by George Baker.  The live radio broadcast highlights efforts of volunteer, citizen scientists Laurel Stueck (student) and Cheryl Paavola (Instructor and Science Lab Tech) at Northwest Community College – Prince Rupert collecting the first seawater sample there in November 2014.

CBC_DaybreakNorth_Dec102014Interview

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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.

Measurements to Verify Models of the Fukushima Plume: Significant Radioactivity Heading South in the Pacific

by Jay T. Cullen

Introduction

This diary is part of an ongoing series here that aims to report measurements of Fukushima derived radionuclides in the North Pacific Ocean to help determine the likely impact on ecosystem and public health in western North America. The purpose of this diary is to report the results of a recently published study by Kumamoto and colleagues in the open-access journal Scientific Reports. The study measured the activity of Fukushima derived cesium (Cs), a tracer for other radionuclides, in the upper 1000 meters of the western Pacific Ocean along the 149 degree E meridian as of winter 2012. These measurements indicate that 10-60% of the total Fukushima derived 134-Cs in the North Pacific has been transported to the south at a depth of ~300 m below the surface. This result is surprising as most models suggest that transport would be primarily to the east toward North America. The study demonstrates that the amount of Fukushima derived radionuclides being transported to the east towards North America is lower than predicted by previous models and provides important information on the circulation of the ocean.


The disaster at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), precipitated by the earthquake and tsunami on March 11, 2011, resulted in meltdowns at Units 1-3 and a massive release of radionuclides to the North Pacific Ocean by direct discharges from the plant and by deposition of radionuclides released to the atmosphere. While a suite of radionuclides were released, 134-Cs is a useful tracer of Fukushima impact. 134-Cs has a relatively short half-life (~2 years) that unequivocally fingerprints a Fukushima source. It was also released in large quantities and therefore poses a potential radiological threat to organisms. 134-Cs was released along with 137-Cs (half-life = ~30 years) in a 1:1 ratio from Fukushima.

Scientists use a variety of units to measure radioactivity. A commonly used unit is the Becquerel (Bq for short) which represents an amount of radioactive material where one atom decays per second and has units of inverse time (per second). Another unit commonly used is disintegrations per minute (dpm) where the number of atoms undergoing radioactive decay in one minute are counted (so 1 Bq = 60 dpm).

Estimates of direct release of Cs to the ocean were on the order of 11-15 PBq (10^15 Bq) while the deposition of Cs to the surface of the ocean were about 5.8-30 PBq. In 2012 the authors of the study occupied a series of stations along 149degree E as shown in the figure below:

Location of stations sampled for 134-Cs by Kumamoto et al. (2014) in the western Pacific south and east of Japan.

In addition the surface plume of radionuclides that has been modeled and detected (by InFORM team member Dr. John Smith of DFO) in surface currents heading to the east toward North America depth distributions of 134-Cs in the western Pacific show that a concentrated plume of Fukushima derived radionuclides has been transported to the south at a depth of 300 meters:

Cross sectional views of 134Cs activity (Bq/m^3) with depth and latitude along 149 degree East

Based on the integration of the activity of Cs over the depth the authors estimate that about 6 Pbq (10^15 Bq) are present in the subsurface feature being transported to the south. This represents on the order of 10-60% of the total radiocesium that was introduced to the Pacific by the disaster. This helps to explain the lower activities being measured in the eastern Pacific compared to what models predict and suggests that maximum activities on the west coast of North America will likely fall toward the lower end of model predictions that were in the range of 2-30 Bq/m^3. Simply stated more of the radioactive elements released from Fukushima to the Pacific Ocean are headed south rather than east to North America in the plume than previously thought.

More direct measurements of radioactive elements in the North Pacific Ocean through the InFORM project will help to determine what activities are likely on the west coast of North American as the plume arrives from 2013 onward. The measurements or radionuclides in seawater, combined with measurements of radioactive elements in marine organisms, will help to assess the risk of exposure of west coast residents to radionuclides from Fukushima.