is radioactive water more dangerous than radioactive air?

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is radioactive water more dangerous than radioactive air?

In: Biology

Air isn’t radioactive, it’s the dust in the air that is radioactive. I would say the air borne radioactivity is more dangerous because when it gets in your lungs it doesn’t get out. Radioactive water isn’t so bad as long as you don’t drink it. If the water gets on your skin, it can be washed off.

There are 3 main types of radiation.

Alpha radiation is a particle made of 2 protons and 2 neutrons; basically just a helium nucleus. Relative to other radiation types, it’s very big and the fact it has 2 protons means it has a net charge of +2.

Alpha radiation can be blocked by paper, because it’s so big. It can’t get past your skin and the outer layers of your skin are comprised of dead cells that aren’t damaged significantly by the absorption of the alpha particle.

Alpha particles can do a lot of damage once they’re inside you though. This +2 positive charge means that they tear away electrons willy-nilly, causing significant ionising damage. Alexander Litvinenko, a KGB agent, was famously poisoned by polonium, an alpha radiation emitter. Initially, doctors were confused at his symptoms of radiation poisoning, because the alpha particles emitted by the consumed polonium didn’t make it out of his body to be detected, so they didn’t detect much radiation.

Beta particles are electrons. An electron is almost 2000 times smaller than a proton, so a beta particle is tiny compared to an alpha particle. An electron has a -1 charge, so it’s possible for it to cause ionisation damage. The fact it’s so small means it’s so small means it can fit between the gaps of atoms and can travel further than alpha particles. They can be blocked by a few milimetres of aluminium foil.

Gamma radiation isn’t a particle, so it’s highly penetrating. When you see multiple feet of lead shielding, it’s gamma radiation we’re trying to block here. Gamma radiation is electromagnetic radiation, which means it’s very similar to the light we see, or radio waves, or X rays. The difference between all these radiation types is their wavelength and frequency. X-rays, for example, have a shorter wavelength and higher frequency than visible light, so they are higher energy. Gamma rays are even higher frequency so hold even more energy. Gamma rays aren’t as ionising as beta or alpha particles, but they can still do damage if biological tissues absorb them. The biggest concern is their penetration, they just keep on going.

A radioactive isotope might emit one of these types of radiation, or all of them. We can guess what’s most likely to happen, but there’s a degree of randomness. It’s why nuclear waste is so dangerous: even if we start out with pure Uranium-235, it’ll decay in many different ways, producing a mixture of different radioactive isotopes.
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With that background, let’s consider your specific question. Radioactive water isn’t necessarily worse than radioactive air. Radioactive isotope dust in the air is very dangerous to breathe in, because the dust will irritate lungs and any beta or alpha radiation emitted can do more damage once it’s inside you.

I think the danger of radioactive water isn’t necessarily in the consumption, but in overall ecological damage. Let’s imagine there’s a lake that’s had nuclear waste dumped in it. People might cordon off that lake and not drink from it or swim in it. Except that’s not enough. Radioactive materials could leech into groundwater, contaminating all neighbouring water sources. Animals that live in and around the lake will consume radioactive isotopes and so will anything that eats *those* animals. Once it’s distributed, radiation can be hard to control.

This is a much more complex question than you may realize.

An element defined by the number of protons in the atom. Each of these atoms can then have various number of neutrons, an isotope of the same element. Each element can have many isotopes. There are currently 118 elements on the periodic table but there are over 1000 isotopes and the vast majority of them are radioactive, each one decaying differently, giving off different types of particles with different energies.

A lot of them are artificially created and have half-lives so small they’re insignificant. But there are probably a couple hundred isotopes that are significant.

Since radioactive isotopes are still the same element as their stable version they still have the same chemical properties, they can still create the same chemical bonds. So one thing needing clarified is what are you referring to when you say radioactive air and radioactive water. Do you mean the actual air and water is radioactive or do you mean radioactive particles contaminating it?

Also what isotopes are you referring to because each type absorbs into the body at different rates. Some absorb very quickly, some not at all.

Radioactive dust in air is very bad because when breathed in it becomes trapped in the deeper part of the lungs and the body has no good mechanism to get rid of it so it stays there causing damage. Or in some cases it gets absorbed into the body. Radioactive air such as radon or hydrogen or helium or nitrogen is not as serious because you breathe it in then you breathe it right back out before it causes a big issue. But chronic exposure to radioactive gas accumulates damage over time.

Water is made of hydrogen and water. Hydrogen has only one radioactive isotope, tritium. Tritium decays via a very weak beta decay, it is just barely high enough energy to be ionizing. The only real concern is if you consume it in large quantities. Our bodies are 70 percent water. Some of it gets expelled but consumed tritiated water would go everywhere in your body. However the one upside is that our bodies turn over rate of water is very fast. 10 days after consumption half the tritium would be gone, expelled in urine or perspirated through your skin. Considering tritium has a 12 year half life that means very little, about 1 in 650 atoms, will decay while inside you.

Oxygen has several radioactive isotopes but they are all very short lived with the longest being Oxygen-15 with a half-life of 2 minutes. In very large quantities radioactive oxygen would be quite dangerous due to the higher energy decay products and the high activity. But a radioactive oxygen atom bound in water would decay very quickly, breaking the chemical bonds when it transitions to a different element. That element would either be stable or also decay very quickly. Ultimately this would never be a big issue as far as water consumption is concerned.

Radioactive dust consumed in water is a concern based on what isotope it is and in what concentration. For example Iodine-131 is a concern because when consumed a lot of it gets absorbed very quickly and gets concentrated in the thyroid. So even though it only has an 8 day half-life with 50% clearing the body in 5 days, it can still cause lots of damage. However uranium for example, if ingested only about .5% to 5% will actually get absorbed in the body. The rest will pass straight through and be excreted. Of the percentage that gets absorbed about 70% of it will be cleared quickly in the urine. The rest will get deposited in soft tissues throughout the body. A single small exposure would have little impact on the body but due to the super long half-life it’ll always be there, so chronic exposure would cause it to build up leading to serious impacts on health, not just from the radiation but also from the chemical properties since it is a heavy metal.