We Asked A Scientist To Tell Us 11 Wild Facts About Radiation

Bananas are radioactive?!

Curious to learn more about how radiation affects us (for better and worse), we spoke with Andrei Hanu, PhD, a senior scientist at Bruce Power in Tiverton, Ontario, to get the wildest facts about radiation he could offer...and, fam, we were not disappointed.

1. New York's Grand Central Terminal emits more radiation than a nuclear power plant.

"The walls of New York’s Grand Central Terminal are constructed predominantly from naturally sourced materials, such as granite and marble, which have a relatively high uranium content. As a result, employees of Grand Central Terminal are exposed to radiation doses of approximately 120 millirem (mrem) per year, which is greater than the regulatory limit of 100 mrem per year required of nuclear power plants for exposure to the public."

2. We are exposed to non-ionizing radiation all the time.

"Non-ionizing radiation refers to any type of electromagnetic radiation that does not carry enough energy to ionize a single atom or to break chemical bonds in molecules. Instead, non-ionizing radiation interacts with matter primarily through excitation or the production of heat. Non-ionizing radiation is the most common type of radiation we experience in our daily lives and includes visible light, infrared, radio waves, microwaves, and sunlight."

3. In general, ionizing radiation is created when unstable atoms or radioisotopes give off energy to reach a more stable state.

"Ionizing radiation refers to any type of electromagnetic radiation that carries enough energy to ionize a single atom or to break chemical bonds in molecules. The energy boundary for ionizing radiation is not sharply defined, since different molecules and atoms ionize at different energies, but it is accepted to be between 10 electronvolts (eV) and 33 eV. ... There are many types of ionizing radiation, but the most common ones are alpha, beta, gamma, x-ray, and neutron radiation."

4. We emit more ionizing radiation than our cellphones.

"Our cellphones work by emitting and receiving radio waves, a form of nonionizing electromagnetic radiation, from their antennas. As a result, our cellphones emit zero ionizing radiation. By comparison, our bodies are naturally radioactive due to the foods we eat and drink, as well as the air we ingest from our environment. Most of the human body’s natural radioactivity comes from an isotope of potassium, called Potassium-40, which has been around since the formation of the Earth and is a tiny fraction of all the potassium in nature. When Potassium-40 atoms undergo radioactive decay, they emit beta and gamma radiation that can either deposit its energy within the body or escape. The amount of Potassium-40 activity in a 150-pound person is about 5,000 becquerels ... and accounts for 4% of the average annual radiation dose per person in the US (NCRP Report No. 160)."

5. Everyday things like wireless routers expose us to radiation...

"Wireless routers emit and receive radio waves, a form of non-ionizing electromagnetic radiation, in the 2.4 GHz and 5 GHz frequency bands. In fact, most people do not turn off their wireless routers at night, so we are exposed around the clock." [Editor's note: Health risks around this topic are still hotly debated, so maybe try turning off your router more often jic?]

6. ...as do cigarettes.

"Cigarette smoking has been known for many years to be a leading cause of cancers of the lung and oral cavity. However, it was often attributed to the toxic chemicals in the tobacco smoke and not the naturally occurring radiation contained within. In fact, the tobacco used to make cigarettes and other tobacco products contains small amounts of radioactive materials. As cigarettes are consumed, the natural radionuclides in the tobacco become aerosolized and inhaled into the lungs, where they build up over a long period of time. The radioactivity in cigarettes comes from the fertilizer that farmers use to increase the size of their tobacco crops and which contains the naturally occurring radionuclide Radium-226. Radium decays to release Radon-222, a gas that decays with a relatively short half-life to other radioactive elements such as Lead-210 and Polonium-210 that cling to the plant."

7. Even your breakfast could be slightly radioactive!

"Bananas are rich in the naturally occurring, and radioactive, isotope Potassium-40. In about 10% of its radioactive decays, Potassium-40 will emit an energetic gamma ray that can deposit its energy within our body. The remaining 90% of the Potassium-40 decays occur via the emission of a beta (electron) particle. Due to the short range of these beta particles, they don’t contribute to our radiation dose unless the banana is ingested...which is the common thing to do with a banana. Even so, the radiation dose rates from a banana are so low that it's often used as the smallest unit of radiation dose during educational example.

"This handy chart compares the dose from eating one banana to other common radiation exposure scenarios, such as living within 50 miles of a nuclear power plant for a year (0.9 bananas) or a chest x-ray (equivalent to 200 bananas)."

8. Pilots/flight attendants are sometimes called “radiation workers.”

"Pilots and flight attendants working for North American–based airlines average a minimum of between 70 and 85 flight hours per month. A significant portion of these flight hours are spent at high altitude, between 35,000 and 40,000 feet, where the dose rates from galactic cosmic radiation are typically 100 times greater* than those experienced at ground level. The Canadian Aircrew Radiation Environment Study (CARES) conducted by the Royal Military College of Canada (RMC) and the Defence Research Establishment Ottawa (DREO) between August 1996 and January 1998 determined that aircrew radiation dose rates increase with altitude, latitude, and duration of flight. In fact, the average radiation dose received by aircrew during the CARES study was greater than that which is typically received by workers who are monitored for occupational radiation exposure, such as medical workers and nuclear energy workers. In the US, the National Council on Radiation Protection and Measurements (NCRP Report No. 160) reported that aircrew have the largest average annual effective dose (307 mrem) of all US radiation workers. Despite these studies, neither Transport Canada nor the Federal Aviation Administration (FAA) require mandatory tracking and reporting of aircrew radiation dose.

"For the curious ones, the FAA has developed a program called CARI that calculates the effective dose of cosmic radiation received by those flying between two airports in the world. However, the program does not consider the increased radiation caused by solar flares."

9. Radiation from the sun has turned formerly red, white, and blue American flags on the moon white.

"The American flags, planted on the moon during the Apollo missions of the late 1960s and early 1970s, were made from a pre-dyed nylon base fabric. During the last 50 years, the flags have been continuously exposed to the harsh surface environments on the moon and the intense and unfiltered ultraviolet (UV) radiation from the sun. Prolonged exposure to the intense UV radiation has photobleached the dyes or pigments, which gave the flags their colour, and, as a result, the flags have taken on the natural white colour of the nylon base fabric."

10. The average yearly radiation dose per person in the US is 620 mrem (or just over 6 mSv).

[Editor's note: 620 mrem is equivalent to just over 6 mSv, and 100 mSv is the lowest level at which there's any increased risk of cancer — aka this amount of radiation is normal and harmless.]

"Half of this dose comes from natural background radiation. Radon and thoron gases account for two-thirds of the natural background radiation exposure, while cosmic, terrestrial, and internal radiation account for the rest. The other half of the average yearly radiation dose comes from medical, commercial, and industrial activities. Among the largest of these sources is a computed tomography (CT) scan, which accounts for about 150 mrem. Other medical procedures make up another 150 mrem or so each year. Some consumer products such as tobacco, fertilizer, welding rods, exit signs, luminous watch dials, and smoke detectors contribute about 10 mrem per year. The pie chart here shows the sources that make up the average annual US radiation dose of 620 mrem.

"A mrem becomes harmful when a large dose is delivered acutely and to the whole body. For example, if a person receives 100,000 mrem of whole body dose within 24 hours, they may experience radiation sickness symptoms, such as tiredness and nausea."

11. Not all radiation is harmful — in fact, some types are saving lives!

"The three most commonly used radioisotopes are Cobalt-60, Technetium-99m, and Iodine-131.

"Cobalt-60 is a synthetic radioisotope that is produced as a byproduct of typical nuclear power plant operation. Cobalt-60 is a high-energy gamma emitter used to sterilize ... single-use medical devices, including sutures, syringes, surgical gowns, and masks. Cobalt-60 is also used to sterilize pharmaceutical wares, cosmetics, irradiated spices, and other consumer products that include fruit, seafood, poultry and red meat.

"Technetium-99m is another synthetic gamma-emitting radioisotope that is commonly used to image the skeleton and heart muscle, as well as image the brain, thyroid, lungs (perfusion and ventilation), liver, spleen, kidney (structure and filtration rate), gall bladder, bone marrow, salivary and lacrimal glands, heart blood pool, infection, and numerous other specialized medical studies.

"Iodine-131 is widely used to treat hyperactive thyroid glands, to treat thyroid cancer, and in imaging the thyroid. It is a beta emitter, making it useful for therapy."

*1. Canadian Aircrew Radiation Environment Study (CARES) Report, Volumes 1, 2 and 3, Royal Military College of Canada and Defence Research Establishment Ottawa, March 1998
2. Cosmic Radiation Exposure of Aircrew Project Report, Volumes 1 and 2, Royal Military College of Canada, March 2000

All images courtesy of Getty Images

Keep learning about radiation by checking out how Bruce Power is helping fuel the future of nuclear medicine.