Keeping a close eye on radiation
Radiation is all around us in our natural environment. From rocks in the ground, to cosmic radiation, it is typically harmless, despite our daily exposure to this emission of energy as electromagnetic waves or moving subatomic particles. So how do we know that tiny radioactive particles floating around us aren’t causing us harm? Health Canada’s Radiation Protection Bureau is constantly monitoring radiation in Canada and around the world.
As a basic safeguard, we monitor stability of background radiation levels across the country. If there are any changes, our experts can take the appropriate actions to ensure Canadians remain safe.
Canadian Radiological Monitoring Network
Dr. Laura Chaloner works with Health Canada’s Canadian Radiological Monitoring Network (CRMN), which includes 26 stations located across Canada to measure the particles in the air and in rainwater. The equipment in each station provides weekly measures of the total radiation in air, and allows scientists to monitor the levels to which the population is exposed.
“We establish trends in the background radiation across Canada. We can’t avoid background radiation from soil or cosmic rays, but we can quickly identify abnormal events such as man-made radioactive particles,” explains Laura. “There is no danger in being exposed to background radiation, because the levels are so low. Our role is to verify that the levels remain within the normal range.”
The health effects of low levels of ionizing radiation on the human body is measured in sieverts. In an average year, Canadians are exposed to about 2 millisieverts of radiation, which poses no danger. The worldwide average is 2.4 millisieverts and some countries, depending on the geological area, can be much higher.
In addition to the detailed analysis offered by the CRMN, the Fixed Point Surveillance Network provides real-time updates every 15 minutes in order to alert experts as soon as an incident occurs.
Comprehensive Nuclear-Test-Ban Treaty Monitoring Stations
Canada is also part of a global network of 80 stations established to detect minute emissions from illicit nuclear explosions forbidden under the Comprehensive Nuclear-Test-Ban Treaty (CTBT).
“The equipment at these stations is more sensitive than a regular monitoring station,” explains Dr. Kurt Ungar, Head of the Verification and Incident Monitoring Section of the Radiation Protection Bureau. “They provide measurements more frequently – while a typical sample is collected over a week, these are collected over 8, 12 or 24 hours.”
Together, these networks ensure Health Canada gets all the information needed to detect any significant fluctuations in radiation exposure, even for locations quite distant from the monitoring stations. “The actual fluctuation can be quite small. In fact, it takes very specialized techniques to be able to estimate their size,” says Kurt.
Monitoring radiation around the world
But radiation isn’t something that can be examined in isolation by a single country. When Canadian scientists detect something abnormal, they work with international partners to determine where it comes from.
For example, in 2017, the Radiation Protection Bureau was involved in examining the origin of ruthenium-106 in Europe. Through various tests, Dr. Michael Cooke, a Research Scientist in the Radiation Protection Bureau, was able to reveal a chemical signature that determined how it was produced and supported other evidence as to where it came from.
“Typically, in nuclear forensics, you are looking for a signature because it tells you a story. But we wanted to get more than circumstantial evidence,” explains Michael. “We can now say conclusively that it was caused by a nuclear waste processing activity. We can produce tangible evidence that speaks to exactly what happened. That is a world first, and Canada figured it out!” Read the full scientific paper at https://www.pnas.org/content/early/2020/06/09/2001914117.
Following the Fukushima-Daiichi nuclear accident in 2011, experts were quickly able to confirm that the exposure to Canadians was minimal and that it did not pose a risk to health.
“Concern shifted to the migration of a radioactive ocean plume toward the west coast of Canada. Through our involvement with the Integrated Fukushima Ocean Radionuclide Monitoring project, the National Monitoring Section has analyzed hundreds of samples for radioactive content.
Only a few of these had detectable quantities of cesium-134, a relatively short-lived marker for contamination derived from the Fukushima accident that allows us to distinguish new from old radioactive content.
This was additional confirmation that there was no health impact, and became more of an academic interest into how radioactivity propagates in the environment. We really had to look closely and push the limits to be able to see this stuff,” says Michael.
“During the Fukushima incident, we had a wealth of information about what was going on around the world. We wanted to understand the nature of the impact and inform people abroad about the potential risks,” adds Kurt. “The general plans and practices were sufficient given the enormity of the accident, but we were able to confirm that independently.”
Most of Health Canada’s systems are looking at particles present in the air. In several locations, including those that are part of a global network developed in the context of the Comprehensive Nuclear-Test-Ban Treaty, scientists can also examine radioactive gasses emitted by most nuclear facilities, in Canada and around the world.
Canada has agreements with other countries and programs initiated through the United Nations. These agreements make it easier for scientists to understand what is going on in the environment and determine health concerns.
Ensuring the safety of Canadians
“There is very little that escapes our ability to detect, but the fact that we see it doesn’t make it dangerous,” reassures Kurt. “It’s important for us to see it, because we often want to assess the situation at the point of origin.”
The Radiation Protection Bureau is dedicated to ensuring the safety of Canadians through the detection of radioactivity in the environment. “I try to look at things through a different lens. I look at our surveillance activities and am always asking if can we do them better. I’m not trying to reinvent the wheel, but there are sometimes opportunities for innovation,” says Michael.
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