The uranium itself is not *that* radioactive, at least not the naturally occurring uranium (it has to be processed to be viable as nuclear fuel or weapons, the process is called *enrichment* because it enriches the proportion of radioactive isotope in your mix, with *isotope* being the version of atom you have, all uranium atoms have the same number of protons, but they can have different numbers of neutrons, and depending on how many neutrons they have, they are either stable or not, and non-stable isotopes split into smaller atoms, this is called radioactive decay). Anyway, your body does a lot of chemical reactions, and to those reactions an atom of Uranium actually looks a lot like some other atoms (I think it would be a lot like calcium but don’t quote me on that), so your body *could* accidentally use an atom of Uranium in chemical reaction, where it doesn’t belong, and it *could* work but down the line the product would not have chemical properties it should have. This is how most of heavy metal poisoning work on chemical level, when exposed directly to cells. But human body (and animal bodies in general) have evolved complex systems to filter out heavy metals from bloodstream, so most of uranium never reaches *most* of your cells, instead your kidneys filter it out of your bloodstream… Which means that for a time all of that uranium is concentrated in your kidneys, it gets into kidney cells and there it ends up in chemical reactions where it has no business being in.
Uranium is dangerous mostly because it’s very toxic if inhaled or eaten, similar to toxicity from other heavy metals. Uranium is often in powder form which can end up in your lungs, which is why workers wear protective equipment when working with uranium.
Refined uranium (uranium-235) is slightly radioactive, but U-235 atoms decay very slowly which means they emit very little radiation and hence toxicity generally still remains the most dangerous part of it.
Uranium is hazardous in two ways: as a source of radiation, and as a toxin.
Most uranium is not terribly radioactive unless it’s been refined to specifically the more radioactive kinds used in nuclear reactors and to make weapons.
It is, however toxic if it gets into your body, like other heavy metals. It gets wedged in enzymes and proteins on the surfaces of cells, screwing up the chemistry of the cells and their operation. It causes certain types of cells to die off by screwing up chemistry in the mitochondria (part of the cell that generates chemical energy to operate the cell), causes inflammation, and it can interfere with enzymes that do DNA repair in your body — which increases the risk of cancer as well as killing cells.
You can take uranium into your body by breathing in dust that contains it, or by eating / drinking things that have it mixed in. It’s a big concern for soldiers that may have fought in areas where “depleted” (not radioactive) uranium was used for artillery or as armor on tanks. When those things smash into stuff, microscopic bits of it are released into the air and become toxic dust.
This might be a technicality, but I don’t see anyone mentioning it yet, but it’s also incredibly dense making it an excellent material in a penetrating round in firearm ammunition. They use depleted uranium rounds as a form of ammunition and they are bad/deadly because humans are prone to being very leaky when penetrated several times with metal projectiles.
So, for a real ELI5-style answer, it’s kind of like this: why is the barrel of a rifle dangerous? Well, it’s not, unless I hit you with it, but if I put in the work to assemble the rest of the weapon, load it, lock it, and point it in the right direction, now it’s quite dangerous. That’s enrichment, basically; we take something relatively innocent and make it relatively deadly. Similar idea for the decay chain. Elements undergo alpha and beta decay which can actually turn them into different (and far less stable and safe) elements. This is not a fast process, but when it does occur or is catalyzed, the results are no joke. This is kind of like asking why a rifle in a gun safe is dangerous. Well, it’s not….until you open the safe. Decay chains open the safe.
So everything is made up of atoms….you, me, water, air, dirt, wood, metal, all matter.
These atoms pair up to form things called molecules. Like H20, O2, table salt.
Think of these molecules like 3D puzzle pieces. They interact with their surrounds based on the way that they’re shaped.
In the human body, many things happen based on how different molecules interact with each other.
The thing that unzips DNA so it can replicate, the thing that reads RNA to make proteins, the proteins that allow us to perceive light, the proteins that help us break down food, the proteins that carry oxygen in our blood, the protein channels that allow our nerves to fire.
Now, if you’ve ever gotten frustrated with a puzzle, sometimes you call it quits and just stick two pieces together. They may be slightly off, but they fit well enough that it makes it so you can’t put the *right* piece there.
Heavy metals are also molecules, and like puzzle pieces they have bits hanging off them that can connect where we don’t want them. Imagine having one puzzle with all the correct pieces, and then someone dumping a handful of EXTRA pieces in.
What if a heavy metal puzzle piece connects to the puzzle piece that helps sperm cells form? Well, you’ve not got malformed sperm cells. What it a heavy metal puzzle piece sticks its bits in the neuron puzzle pieces that help your brain cells communicate?
If you just have one or two extra pieces thrown into your original puzzle, it’s not a huge deal. But what if 100 extra pieces are thrown in? 500? Pretty soon you’ve got too many puzzle pieces for the puzzle to function the way it was supposed to.
And then the puzzle falls apart–goes to pieces, really–and dies. Its all very sad.
Latest Answers