Most everyone in the world today knows that radiation exposure is bad but we have little framework for what that means. We’ve seen images of people exposed to it, but most of us have never had to experience it firsthand.
Can radiation exposure kill you? You bet. But how it damages your body is a very complex and terrifying process. And different kinds of radiation will affect your body in different ways. Gamma radiation differs from ultraviolet radiation, which is different from X-rays, microwaves, or alpha particles. There’s a lot to understand, so let’s have a look.
What Radiation Does to Living Cells
There are two different ways radiation can kill the cells in your body and, by extension, you as a living organism. The first method is something called cell apoptosis. The human body engages in cell apoptosis all the time, it’s a necessary function of life. It’s a sort of programmed cell death that is used to eliminate cells we don’t need anymore.
Apoptosis is how your body naturally prevents cancer. Your body tries to kill cells that are damaged to get rid of them. If this process is interfered with, cancer can proliferate. In the embryonic stages of development, apoptosis gets rid of webbing that would exist between your fingers as your hand develops.
Radiation exposure, even in low doses, can trigger apoptosis and cellular decay in certain types of cells. Not always, but it can. Larger doses can cause it to spread to more cell types and thus cause more damage. High enough doses of radiation can make this process fatal as your cells are unable to properly divide and replicate, causing your organs and systems to fail.
Your DNA and cell membranes are specifically damaged by radiation which causes the cell death. It can happen during mitosis, or cell division, and also during the interphase period which is between the periods of mitosis.
The other way radiation kills a cell is by preventing mitosis entirely. Your body needs to replace billions of cells every single day. These cells divide to create new cells and they can repeat this process about 50 or 60 times. A proliferating cell will divide on average about once every 24 hours. After that, the cell reaches the end of its lifespan and dies but the cells it has produced live on and continue this process for the entire life of the organism.
Radiation exposure stops the process of mitosis in some cells so that this replacement cannot occur. This is called mitotic cell death, and the result is necrosis, or the death and subsequent rotting of the cells.
How Does Radiation Affect DNA?
DNA is a molecule, and it’s made up of several compounds with a “backbone” made of sugars and phosphates. When exposed to radiation, the atoms in that DNA molecule can be affected which is what prevents cellular mitosis from happening. Radiation can break the sugar and phosphate backbone of your DNA, destroying it outright. It can also break the hydrogen bonds that hold the molecules together, altering the chemical structure of your DNA.
If radiation alters the structure of your DNA, it can lead to a mutation. The cell may not die outright but it will alter what the cell is programmed to do and how it works. This can cause your cells to operate incorrectly and the genes, programmed to perform specific functions in your body, will either do nothing or things they aren’t supposed to do. That can have a catastrophic and lethal effect.
Your body will try to repair damaged DNA but if the damage is too severe, it will not be possible.
When radiation breaks the chemical bonds holding molecules together, like water molecules that exist all throughout your body, it can create free radicals in your body. These are ions of hydrogen and hydroxyls. These ions can easily bond to other molecules. At that point, your body will start producing compounds like hydrogen peroxide or other damaging substances which also lead to DNA damage and cancer.
Symptoms of Radiation Exposure
There are two kinds of radiation that you can get exposed to. That is ionizing radiation and non-ionizing radiation. Non-ionizing radiation comes in the form of light, microwaves, radio waves, and even radar. These kinds generally don’t cause damage, but as you know exposure to ultraviolet radiation can cause a burn on your skin over time. If you put your hand in a microwave, it’s going to cause some damage eventually, so caution is still needed.
The more dangerous type is ionizing radiation. Ionizing radiation is gamma rays, x-rays, alpha particles, the kind of exposure you would get from a nuclear weapon or a nuclear reactor. This is the stuff that will kill you much more quickly and gruesomely.
Humans, and other living things, can suffer radiation sickness as a result of prolonged exposure, or even a single exposure to ionizing radiation in a large enough dose. A single chest X-ray will dose you with about 0.01 rads. A CT scan would be one rad. You would need total body exposure of 50 to 100 rads to suffer radiation sickness. A dose of over 400 will kill just about 100% of the time without some kind of medical intervention within a month. The Elephant’s Foot at Chernobyl was giving off 10,000 rads per hour. A person standing within three feet would die within minutes.
The acute health effects of radiation exposure include severe skin burns. The speed at which symptoms appear is a basic gauge for understanding the severity of the exposure. The faster you experience symptoms, the higher the dose of radiation you receive. Symptoms include hair loss, muscle weakness, vomiting, bleeding from mouth, gums, nose, and rectum, sores and sloughing skin, fever, dehydration, and more. It’s an unpleasant gauntlet of bad news. And those are just the acute ones.
Long-term exposure, as we know, can lead to numerous kinds of cancer. It may also cause liver failure, infertility and birth defects, scarred lungs, kidney issues, and more.
The Most Dangerous Kind of Radiation
With all the different kinds of radiation around, it’s worth knowing which ones you need to avoid the most. Not that you can tell the difference if you were exposed in the moment, and also not that there’s anything you can do about it once it happened. But still, you’ll have the knowledge in your head, that’s worth something, right?
Despite what the Incredible Hulk told us, gamma rays are actually the most dangerous form of radiation out there. When a nuclear weapon goes off, gamma rays are what will kill you the fastest.
Gamma rays are incredibly high energy and powerful. You’d need a couple of inches of pure lead to shield yourself from them. They pass directly through a human body which is what makes them so dangerous as they cause the ionization we talked about earlier that leads to DNA damage and cell death.
Alpha particles are some of the least dangerous kinds of radiation outside the body. They can’t penetrate your skin and they are also very heavy. So heavy that they use up most of their energy just getting away from the atom that created them. They’re produced as a result of nuclear decay from things like uranium and plutonium.
All that said, if you inhale substances emitting alpha particles, they can damage you internally. Internally, alpha particles are some of the most dangerous.
Beta particles can be stopped by a layer of clothing, which seems like they are not a big deal. But flesh does not stop them and they will penetrate your skin. They cause radiation burns and if you inhale fallout or particles that emit beta radiation, it could be fatal.
X-rays, despite the fact we use them in medicine, are also potentially dangerous. Like gamma rays, they are pure energy photons and not particles like alpha or beta particles. The main difference between them is that gamma rays come from the cell’s nucleus while x-rays come from outside the nucleus. They are less powerful than gamma rays and don’t penetrate as well.
The Least Dangerous Kinds of Radiation
It’s not really correct to say that any kind of radiation is safe. The amount and type of exposure is what you need to worry about. That’s why an X-ray is potentially deadly, but we can still use it safely in medicine. You’re limiting the amount of exposure to something that the human body can tolerate.
Generally speaking, any kind of ionizing radiation is going to be especially dangerous to the human body. Non-ionizing radiation is considered less dangerous, but that doesn’t mean it’s totally safe.
Non-ionizing radiation can excite atoms in a molecule but it does not have the power to strip electrons away like ionizing radiation does. Things like power lines, your cell phone, light bulbs, and radio waves are all examples of non-ionizing radiation that we encounter every day and generally don’t have a problem with.
Officially, non-ionizing radiation has not been found to cause cancer in humans. That said, for decades people have insisted that those living near power lines have suffered cancer at higher than normal rates, even though no link has been found. Likewise, some people have concerns about 5G cell phone towers or even just keeping a cell phone in their pocket causing cancer. Again, we don’t have any real evidence to back these fears up.
What Nuclear Weapons Do To Living Things
When a nuclear weapon goes off, there are several ways it can cause destruction and death. In just ten seconds, the fireball formed in the blast can reach its full size. The force of the blast alone is enough to level buildings, pop eardrums, and cause internal bleeding even in people far from the blast site.
The thermal radiation that happens in the blast site is so intense it can vaporize anything living or otherwise. Even people hidden in an underground bunker would risk death as fires consume everything above and burn up all the available oxygen.
The most powerful nuclear weapon ever tested was Russia’s Tsar Bomba in 1961. Its 50-megaton yield made it 3,800 times stronger than the bomb dropped on Hiroshima. The power and devastation of the weapon was almost unimaginable.
When it detonated, it produced a mushroom cloud 37 miles high that was visible 620 miles away. It completely destroyed a town 34 miles away and windows in Norway and Finland were shattered. There were reports of damage as much as 100 miles away and third-degree burns felt 62 miles away.
Beyond the initial blast, electromagnetic interference from the weapons would destroy electronics over a wide area. Whole power grids would fail. A single modern warhead is at least 5 times more powerful than those used in WWI and has enough power to level an entire city. A 100-kiloton warhead, 5 times more powerful than the strongest of the two used in Japan, could kill just shy of 600,000 people in New York City.
The initial thermal flash from a blast only lasts seconds but can start fires and can burn people up to 20 miles away. The ensuing blast wave could level buildings for several miles in all directions around the blast. A 10-megaton warhead could essentially destroy all of New York from Long Island to Newark.
Fallout
The uniquely devastating power of nuclear weapons is the fallout. This refers to all the particles that fall to Earth after a nuclear incident. Anything exposed to that radiation during the blast, from dirt to bits of the buildings and other things destroyed by it. They are all shot into the air during the initial explosion where they become irradiated and then fall down to earth again.
Fallout is dangerous over the short term and long term. Much of the radiation in fallout will dissipate over a matter of days. This is why you’re told to stay inside for at least 24 hours after an explosion. In 24 hours much of the radiation will have gone. The longer you can avoid exposure, however, the better. Some fallout can remain radioactive for years.
One of the dangers of fallout exposure relates to what we said earlier about alpha and beta particles. They’re most dangerous when they’re inside your body and if you go out into the world after a nuclear blast, you can ingest or inhale fallout.
Recovering from Radiation Exposure
Initial treatments for radiation exposure are focused on decontamination. Your clothes need to be stripped and your body cleaned to remove any particles that can make exposure worse.
Recovering from radiation sickness is possible but there may be long-term damage. Also, it’s not an easy process. It can take years to recover in some cases. Treatment can include things like blood transfusions, marrow transplants, and medications to stave off infections as you will be susceptible to many of them.
You may need to take things like potassium iodide. This can help prevent your thyroid from absorbing radioactive iodine. Prussian blue can bind to radioactive particles so your body can excrete them. Diethylenetriamine pentaacetic acid binds to radioactive metals so those too can be excreted.
The process is complex and, as we said, long. But it can potentially work if you haven’t been too badly exposed. That said, long-term effects are almost guaranteed. That’s why limited exposure to radiation in the first place is always the best bet.