Heavy Water: Here’s Why You Shouldn’t Drink Heavy Water

Heavy water is a form of water where the hydrogen atoms are the isotope variant deuterium, that means it is slightly unstable chemically. Heavy water is used for several industrial reasons and should not be consumed.

Although most people now know that dirking heavy water is harmful they may not understand exactly why. What most people refer to as “heavy water” is actually known as deuterium oxide by scientists. Heavy water is water with the chemical formula of D2O or deuterium oxide. This water is composed of the hydrogen isotope deuterium, which is heavier and less stable than hydrogen. If you would like to know exactly why you should not drink “heavy water” then you have come to the right place.

Image source: Wikipedia

What Does “Heavy Water” Taste Like?

If you are genuinely worried about the harmful effects of drinking heavy water, you’ll probably want to know how you can recognize it.

Image source: Wikipedia

Unfortunately, there is no simple way of recognizing deuterium oxide mostly because it has no specific taste. In other words, heavy water tastes exactly like any other kind of water. So, you will never be able if you are drinking heavy water or not just for its taste.

Heavy WaterInteresting Facts
Alternate namesDeuterium oxide, Water-d2, Dideuterium monoxide
AppearanceHeavy water is a pale blue transparent liquid
Artificially producedProduced for the first time in 1932
Boiling point101.4°C
Density1.107 gm/cm3
DeuteriumA hydrogen isotope with a nucleus containing a neutron and a proton
Deuterium WeightRoughly twice as heavy as a protium atom
Harmful limitsIf 25-50% of the water in your body is heavy water it becomes harmful
Melting point3.8°C
Molar mass20.0276 g/mol
Molecular formulaH2O
Molecular weight20.0276 g/mol
Natural Abundance1 molecule in 3,200
OdorOdorless
RadioactivityNo

There is also no immediate effect. So, if you accidentally drink a little heavy water, you should not notice any effects on you.

What Is Actually Heavy Water?

But what is actually heavy water? Why is it so harmful?

According to the Encyclopedia Britannica, heavy water (also known as deuterium oxide, is:

Water composed of deuterium, the hydrogen isotope with a mass double that of ordinary hydrogen, and oxygen. (Ordinary water has a compositionrepresented by H2O.)

The only thing that sets “heavy water” apart from H2O is that, instead of having two hydrogen atoms of protium isotope, it has at least one (but often both) deuterium isotope of hydrogen. So, instead of H2O, we are dealing with D2O.

The main difference between the two kinds is that, while that a protium atom only has one proton, deuterium has both a neutron and a proton within its nucleus.

This is why D2O is so often referred to as a “heavy water”. So, although some people worry that “heavy water” might be radioactive this is actually nonsense. “Heavy water” is not radioactive. So, there is no risk whatsoever of getting radiation poisoning from it, even if you drink it.

Is Heavy Water Safe to Drink?

But, of course, the fact that “heavy water” is not radioactive doesn’t mean that it is necessarily safe for human (or animal) consumption.

In fact, you should avoid drinking “heavy water” because it is indeed harmful. And the reason why “heavy water” is harmful is that hydrogen atoms it contains and how your cells will react to that biochemically.

But, what would the harmful effects of drinking “heavy water” be? Well, that really depends on the actual amount of water ingested.

Image source: Wikipedia

Drinking just a few milliliters or anything up to a regular glass of water might not actually have any noticeable effects. However, any amount larger than that might become immediately noticeable.

The most immediate effect would probably be dizziness. If a person drank a sizable amount of D2O or “heavy water”, they might feel at least slightly busy. That dizziness would be caused because heavy water’s density being greater than regular water’s, it can affect the fluid in the inner ear. Because the fluid is essential for keeping balance, any change in density may result in dizziness.

For “heavy water” to be truly harmful (i.e., to have lasting harmful effects beyond merely making you dizzy), you would have to consistently drink large amounts of it for a continuous length of time. In other words, it would be extremely unlikely for someone to drink enough “heavy water” as to cause serious damage.

More On The Science of “Heavy Water”

Now that we have established that “heavy water” is not radioactive and that, while drinking it could be potentially harmful to people, it is highly unlikely that anyone would drink a large amount of it to be seriously affected by it, let’s look a little bit deeper into the science of “heavy water”.

As we saw in the previous section the difference between H2O and D2O is the presence of deuterium. And this is precisely what makes it harmful to human beings.

Why? Mainly because the hydrogen bonds that deuterium forms are stronger than those created by protium. This could affect cell division or mitosis. Mitosis is what repairs and multiplies our cells, which is how life is preserved.

A large amount of “heavy water” will affect mitosis because D2O has a disrupting effect on it. The way in which deuterium would affect mitosis is by impairing the natural ability that mitotic spindles have to divide cells equally.

So, how much “heavy water” would one person have to drink in order for this to become a problem in terms of affecting mitosis? Well, this would depend on the person so a specific amount of D2O is not possible to state. What we can say is that a person would have to replace at least 25 to 50% of the normal hydrogen in his or her body with deuterium. Only then would their mitosis be affected.

This does not only apply to human beings but, more widely, to all mammals. It is highly unlikely that a human being or any other mammal would be harmed by drinking “heavy water” or D2O because they would have to replace a substantial amount of their body hydrogen with deuterium.

What Are The Harmful Effects

Let’s now summarize and complete the reasons why you shouldn’t drink “heavy water.”

  • Something less than a glass of it is unlikely to have any noticeable effects or cause any harm. Anything up to a glass of it might result in some dizziness but would still have no serious harmful effect.
    • In fact, even if you replaced 20% of the water in your body with “heavy water” you would still survive. But this is not recommended and should always avoid drinking any amount of “heavy water”. Replacing more than 20% of the body in your water with “heavy water” will have seriously harmful effects on your body.
  • Replacing about 25% of the water in your body with “heavy water” might cause sterilization. And, if you replaced 50% or over, this could result in death.
  • The lethal and sterilization potential of “heavy waters” are essentially the reasons why you should never drink it.
  • It is important to notice that this affects all mammals. Having said that, other species are not affected in the same way. For instance, bacteria can thrive on it.

It is also important to highlight that the occasional ingestion of “heavy water” will not cause you any harm. So, although you should strive to avoid drinking it, there is no need to panic if you accidentally drink some of it. You would have to continue drinking it (and stop drinking regular water) for several days before any harm is caused.

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8 Comments

  • This article presupposes [quite correctly] that I’d only ever be able to buy sizeable amounts of “the cheap kind” of heavy water.

    But I’m pretty sure if Bill Gates, Elon Musk, Peter Thiel & Mark Zuckerburg all chipped in for a litre of the “V.S.O.P. hi end Triple weight” heavy water (Tritium monoxide), whoever drank it ==> ..not good, might even die, iirc 😰😵

    • Could check the PH as D2O has PH of 7.41 compared to H20 at 7.0, but that seems prone to calcium/other minerals throwing off your measurement.

      I would suggest density, H20 is 89.99% density of D20, and if there’s traces of HW it would probably show.
      You’d need good quality control in your sample however.

      Final way, to take a pitcher of your well water, let it sit undisturbed for a week, and siphon off the top of it (lighter) to leave any potential HW at the bottom, and do measurements on that- or just freeze it into ice and see if the ice sinks.

      All the best.

    • get real: find a 5kg weight & see if it balances against 5litres of the water for a simpler 100x more reliable check!✅ (tiny bit of minerals drastically can change pH; almost impossible to increase weight by a factor of 150-200% dissolving anything you wouldn’t notice!)

      also, why would you think you had heavy water? does your family have a history of selling it to the government? otherwise, pretty Effin unlikely you’d have more than normal trace amts. off heavy water..

    • Supplemental: Don’t be concerned about a problem that probably doesn’t exist. Your odds of being sick from any possible HW in your well is about as much as the odds of you winning the lottery 9 times in a row, then being elected president.
      HW traces are not harmful and can even be beneficial, if you aren’t having chronic headaches as of yet it’s not anything to be concerned with. You SHOULD be concerned with bacteria, protozoa, heavy metals (lead) and calcium deposits in your water, as those are far more likely (still unlikely, but good to test anyway).

      What I suggested might work to see if you’ve got D20, you know, for science.

    • For whatever reason, the mods seemed to delete the URL I linked as a source. No fun allowed eh chaps?
      Search “Heavy water vs water density” and my source was the first result.
      Happy drinking.

  • I seem to remember that the 12 wells in the world where all the critters that drink it including us live old and healthy contain trace amounts of deuterium hmm

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