Depending on whom you ask, the word “radiation” can invoke either praise of a panacea or curse on the spawn of the devil. They are not wrong; radiation can have both positive healing benefits and horrendously dangerous effects.
Some radiation may not affect you at all! And yet, the discourse surrounding this subject is polarising, with the majority quick to demonize what they don’t fully understand. Many people take advantage of this situation, to peddle snake oil or to spread even more misinformation to further their own ends. It is, therefore, important to separate fact from fiction and learn the science behind this very interesting subject.
The first thing that has to be said is that radiation is not one big bad wolf. It refers to the release -called emission- or absorption of energy by a body through space. This transfer of energy can be done in the form of either particles or waves or both. This means light, microwaves, radio waves, X rays, gamma rays and so much more. You may have noticed that quite a few members on the list are found in nature. Each of them has its own effect on our biology, and therefore must be handled in different ways and with different degrees of precaution. So, tune your EM radiation detectors (your eyes, of course!) and focus it over here, you might gather a great deal of data that helps you in the long run!
Wave Radiation and its effect on biology
When we think about radiation we tend to jump to radioactive elements and the first images to pop into our heads are those of mushroom clouds and nuclear bombs. But we tend to forget the most prevalent and common radiation in our lives: light. As radiation is the emission of energy through space, our entire planet’s energy is derived from energy emitted from a singular source: the sun. Forms of energy such as solar, coal, wind owe their origin to the sun. Food wouldn’t exist without the sun. So how can we say radiation is bad in this case? Well, the matter gets complicated when we start to consider some of the components of light.
Most readers must have heard of the mnemonic ‘VIBGYOR’ Violet–Indigo–Blue–Green–Yellow–Orange–Red) which describes the colored components of light. But light is not all visible and ‘shiny’. William Herschel ‘broke’ light down into its components using a prism (the classic experiment that we’ve all seen) but when he put a thermometer beyond red he noticed a rise in the temperature. He hypothesized that there are more ‘rays’ that are invisible. He had found the infrared rays. Further studies into light yielded the components of light, the sum total of which is the Electromagnetic (EM) Spectrum.
EM Radiation actually consists of two waves oscillating(moving) perpendicular to each other. One wave corresponds to the electric field and the other wave corresponds to the magnetic field. Both the waves are perpendicular (at 90o) to each other.
EM Radiation is wave-like in nature. We can think of wave-like motion as having a point defined on the wave move in a periodic fashion as described in the video below.
Let us define some properties of a wave that are essential to understand the wave’s effect on biology. What peaks and troughs of a wave are can be inferred from the image below. The wavelength(λ) of a wave is the distance between two successive peaks or successive troughs along with the wave. This distance is traveled in a time characteristic to the wave known as the time period(T) of the wave. Another term characteristic of the wave is the frequency(ν) which the distance traveled in unit time. The frequency(ν) comes to be equal to 1/T where T is the time period.
There is also an interesting property of waves. The speed of the wave(v) is related to the frequency and wavelength as v=λν; that is the speed is equal to the product of the wavelength(λ) and frequency(ν). Since Einstein’s relativity makes the speed of light constant at a value c(=299,792,458 m/s) the equation becomes c=λν.
An interesting observation arises. Since c is constant when the wavelength increases the frequency falls and vice versa. Also, the energy carried by the wave increases with the increase in the frequency. Think of this objectively. If you have a rope tied at one end, with the other end in your hand. Let’s say you are producing a wave by moving your hand up and down, you can increase the frequency by moving your hand faster. Clearly you will be spending more energy to maintain the higher frequency. Hence, a rise in frequency corresponds with a rise in energy carried by the wave.
Armed with this information we can look at the EM spectrum, it’s components and its properties. The EM Spectrum with its various parts is shown in the image below. Let’s delve a bit into each component and its effect on the biology of the living.
Radio waves are nonionizing radiation, which means they cannot bring about ionization. They don’t have the energy to separate electrons from atoms or molecules. They cannot break chemical bonds and hence don’t cause DNA damage.
Radio waves mainly cause heating of the materials. Unlike other non-ionizing radiation which also brings about heating, radio waves are known to penetrate deeper and hence are used in medicine for deep heating of body tissue increasing blood flow, etc. Strong enough radio waves may penetrate the eye and the lens causing cataracts.
Microwaves are nonionizing radiation like radio waves and do not have sufficient energy to break chemical bonds and such. Microwaves are present in popular conscience as a result of microwave ovens.
The way microwaves work are, the oscillating electric fields of the microwaves cause vibrations in polar molecules of the substance, increasing its temperature. And hence heating it up. Another interesting case occurred during World War II, where people interacting with microwave radiation over long prolonged periods of exposure heard buzzing and clicking sounds. The research identified that this was due to the thermal expansion of parts of the inner ear.
Microwave radiation, like radio waves, may produce cataracts in the eye by mechanism of crystallizing the lens protein and thus making it cloudy and opaque. Apart from this, high-intensity microwave radiation may cause serious burns.
Infrared radiation is known as heat radiation. Almost all of its primary applications are heat-based. The strong infrared radiation of high intensity may cause blindness and damage the eye.
You might think that visible light is not harmful. Well, you are right to a certain extent.
Retinal damage (damage of the eye) might occur due to prolonged exposure to direct sunlight especially when the pupils of the eye dilated. Such a condition presents us when we look at solar eclipses directly.
Our eyes do not see the light and hence widen the ‘doors’ of the eyes (the pupils), but the same amount of light that usually leaves the sun enters our eye. This has much damaging effects and may result in decreased visual prowess or even blindness.
UV plays an important part in the production of Vitamin D in the body. Vitamin D is important for bone health as well as influences the production of serotonin. Serotonin is a chemical in the brain considered to bring about happiness and the general sense of well being.
As the age-old adage goes, that too much of something is not good, long exposure to sunlight may cause severe sunburns, as sunlight has UV components in it. Prolonged exposure to sunlight may even cause skin cancer, as the intensity of UV radiation in sunlight is pretty strong. The way UV radiation may bring about cancer is by causing DNA damage on the cellular level. UV light is known to cause cataracts. It has been hypothesized that the depletion of ozone layer, known for blocking out significant chunks of UV radiation of the sun, will result in leaking of UV radiation below the atmosphere, resulting in increased rates of cancer and cataracts in humans,
X-Rays in a sense are not bad in low-levels. Taking a typical Diagnostic X-Ray gives us the same amount of ionizing radiation we experience for about 10 days due to background sources.
That being said one doesn’t lie at risk due to low-levels of X-Rays. But at higher doses, the problems start appearing. Being ionizing in nature X-Rays will obviously result in chemical changes, translating to DNA damage and eventually cancer. Pregnant mothers are at the highest risk, as X-Rays are known to cause errors in the development of a child, resulting in deformities and other problems.
Gamma Rays are the bad boys of wave radiation. Arising from the radioactive decay of atomic nuclei, they are ionizing radiation that is very penetrating and have a lot of energy. Though they are ionizing in nature, they are still less ionizing than alpha and beta particles(something which is dealt with later on in this article).
They cause damage at the cellular level, breaking the DNA literally. Along with alpha and beta particles, gamma rays are truly one of the vicious forms of radiation, leading to radiation poisoning when exposed to high amounts for a very short time. The risks of cancer increase by 2-10%, for people who receive low-levels of exposure for longer periods, like nuclear workers,
Are nonionizing forms of radiation really not bad?
In this section, we will be focusing on the non-thermal effects of non-ionizing radiation, in particular reference to radio waves and radiation primarily emitted by mobile phones and cellular towers.
Discussions above seem to indicate that there is, in essence, no real bad effect to nonionizing radiation apart from thermal effects. In particular, the thermal effects are bad only if they are strong intense waves, and or over a prolonged period of time. There has been no significant research into areas of non-thermal effects of non-ionizing radiation.
But why is there a common discussion on mobile phone radiation being harmful? Most mobile phones and additional cellular devices are made as per health guidelines which are based on thermal effects of radiation.
There is no available research to gauge the long term nonthermal effects of mobile phone radiation and hence there is no specific guidelines set for this. In 2011, the International Agency for Research on Cancer (IARC), an agency under the World Health Organization, classified wireless mobile phone radiation as ‘possibly carcinogenic’. Essentially this means that long-term heavy use of wireless mobile devices may be carcinogenic(cancer-causing).
An ending statement to the above question would be that although we cannot say for sure, preliminary research seems to indicate that mobile phone radiation is ‘bad’ if used for long-term in a heavy manner. That being said we still need concrete research to confirm that wireless radiation is carcinogenic.
For duality’s sake: Particle Radiation
Just like light, there are a large number of particles that act as energy conduits. Usually, they tend to be a product of nuclear reactions. When talking about nuclear radioactivity, the most common types that are discussed are alpha radiation, beta radiation and neutron radiation.
Of course, there are more, like neutrinos and mesons and muons, but the public discourse surrounding radiation generally tends to focus on the former two rather than the latter, as those are the most commonly known, originating from radioactive decay.
Let us start with alpha radiation, or alpha particles, as it is also called. Many also call it alpha rays, as early researchers termed any energetic radiation “rays”, and it still persists.
In the simplest sense, it is a high-energy, high-speed Helium (He24 ) nucleus. What that means is, if you take an atom of Helium4 and remove its electrons, and give it loads of energy in the form of speed, you will have an alpha particle. It is a product of nuclear decay reactions, the most famous being Uranium238 to Thorium234.
You might be thinking, hey, isn’t helium one of the noble gases? So this is safe, right? Well, you’re not wrong. It’s not the particle itself that is dangerous, it is the speed with which it is ejected.
Alpha particles are ionising, that is, they can knock electrons off other atoms due to their speed and the energy they carry. But because of the particle’s relatively large size- It’s made up of two protons and two neutrons after all- it can be blocked by clothing, paper or even your skin. Since the skin consists of a layer of dead cells, alpha radiation doesn’t do much damage on the outside. The danger arises when some of it is ingested, most often in the form of Radon gas, which decays inside to give alpha particles. In this case, alpha particles can ionise molecules in the cells, causing diseases like cancer.
Alpha radiation was the first of the particle radiation to be identified, detected in 1899 by Ernst Rutherford during his investigations of radioactivity. Around 1907, it was found that alpha particles were He24 nuclei. By the late 1920s, George Gamow had established the theory of alpha decay using the newly developed principles of quantum mechanics.
The detection of beta radiation followed closely on the footsteps of that of alpha radiation, by Rutherford in 1899. Beta radiation, like alpha, is a high-energy, high-speed particle, in this case, electrons or positrons. It is produced during nuclear decay, for example when Thorium234 decays into Proactinium234. Another similarity to alpha radiation is that beta radiation is also ionising, albeit not to the degree of alpha.
The question arises; since beta is less ionising than alpha radiation, does that make it safer? No! On the contrary, beta could be considered to be more dangerous on the grounds of its ability to penetrate.
Remember, beta radiation is usually high energy electrons. This makes it approximately 8000 times smaller than the alpha particles. Studies say that a quarter-inch-thick sheet of Aluminium is required to block beta radiation. Hence, beta particles can penetrate through the skin and can cause more damage. In fact, the radiation burns that are talked about occurs due to beta radiation damaging living skin. Things get worse when beta sources are ingested, as its ionising nature can result in cancer.
Another interesting question that arises is where do the electrons released from the nucleus come from? People familiar with the structure of the atom will point out that the nucleus consists of protons and neutrons, while the electrons revolve around it. But beta nuclear decay implies the presence of electrons in the nucleus. The answer to this question lies within the neutron. Without going into details, the beta decay reaction, which occurs in neutron-rich nuclei, converts a neutron into a proton and electron. It is this electron that is ejected from the nucleus and becomes beta radiation.
Talking of neutrons, free, high-energy neutrons are a form of ionising radiation, called neutron radiation. They may be emitted in nuclear fission or fusion reactions and are also found in cosmic rays that hit the Earth. Because they are uncharged, they are much more penetrating than alpha or beta radiation. Not only that, but some stable nuclei also tend to absorb these neutrons and turn unstable, for example, the formation of Carbon14 from Nitrogen14, when neutron radiation from cosmic rays hits the nitrogen in the atmosphere.
Many know that neutrons were discovered by James Chadwick, a British physicist working in the Cavendish Laboratory, in 1932. The discovery established the nature of the atomic nucleus, and the uncharged nature of the neutron made it an excellent probe to look into the structure of other atomic nuclei. This was a game-changer in the field of atomic physics, and if you’ve read about the nuclear fission reactors and the reactions that occur over there, you’ll understand how it changed history.
As mentioned above, neutron radiation has the ability to penetrate through most things, including clothes and skin. The danger is the ionising part, where it knocks off a proton off an atom’s nucleus. Another facet of the danger is when the neutron is absorbed into the nucleus, and makes the atom unstable.
Hence, neutron radiation can damage soft tissue like the corona of the eye, and like alpha and beta radiation, can cause cancers and burns. Neutron radiation can also damage and cause defects in structural elements like metal. This is the reason why equipment in radioactive environments need to be replaced often. Recently, the Chernobyl reactor 4 got a new sarcophagus that is supposed to last a hundred years. But it will still have to be constantly monitored for damage caused by the neutron radiation from the exploded core, for a long time to come.
In most reactors and research centres, lead and concrete are commonly used to block neutron radiation, but in this case, water acts as a good shield against it! The hydrogen in the water molecule can absorb the neutron very well and become stable deuterium. This makes storing spent nuclear fuel in a pool of water a very safe way to store it till it becomes inert, to the extent where it’s perhaps safe enough to swim at the top of said pool! (Don’t do it, though.)
This might be a good time to bring up a common- but perhaps harmless- myth regarding particle radioactivity.
I am sure many of you have seen radioactive substances depicted as glowing green in most TV shows, movies, and books.
Unfortunately, this does not happen in real life; at least not by itself. Radiation by these substances is invisible to the human eye. What can be done, though, is the conversion of this invisible energy into visible light. Many substances, called fluors or scintillators, emit visible light when ionizing radiation hits them. So a little bit of a radioactive substance mixed in with fluors is what is used to make the “glow in the dark” clocks, watches and other devices. The green is because of the fluor used and is not the natural glow of radioactivity.
But it might not be all lies.
What you see in the picture, is a nuclear reactor running in a pool. Clearly, it glows blue. Are there any fluors, I hear you ask. No. This is due to Cherenkov radiation. Basically, it is a sonic boom, but with light instead of sound. The radiation particles travel so fast, that they travel faster than the speed of light in the medium- water in this case. This releases light, and it is that light that we see as an eerie glow in this pool reactor.
Remember the time when there was a hullabaloo about how cellphones were causing cancer? What about the time we were asked not to heat food in the microwave because, cancer? There is a lot of misunderstanding of how radiation works, and hopefully, this blog helped you navigate that forest a little easier. Keep in mind, radiation can have both good and bad effects. Radiotherapy is used for the treatment of diseases like cancer, and radio tagging is an efficient method to track and study many molecules or cells. In short, radiation in itself can be considered a tool. How we interact with it and how we use it determines if it will give us cancer or if it’ll cure us.
One thing to keep in mind is that everything you see around you is radioactive. Bananas, smoke detectors, ceramic tiles, your fancy “glow in the dark” toys, even you are radioactive! And to borrow a phrase from Orwell, some things are more radioactive than others. The best thing to do if someone tries to talk about the dangers of radiation, is to find out what specific radiation they are talking about, see how dangerous it is, and take the necessary steps to protect yourself from it. Stay safe, stay healthy.Recommended1 recommendationPublished in