[Dauka]

Hello ! Please could you say the permissible limits (or norm) of deuterium in drinking water. And which proportion of deuterium is high (harmful) for drinking water?

Please could you add sources of information if u can?

Thank you!

[discodermolide]

Not sure if there are permissible limits. The normal concentration would be at the isotopic abundance for deuterium.
see
http://en.wikipedia.org/wiki/Deuterium

[Arkcon]

Most of the anecdotal evidence I've found seems to imply that deuterated water isn't toxic per se.  Only, when it builds up in your body, does it begin to interfere, with reactions.  So its more of a chronic toxin, and that makes it hard to give you an exact dosage.

[Borek]

http://en.wikipedia.org/wiki/Heavy_water#Effect_on_animals

[Arkcon]

I can't find it just now, but on some episode of  New Scandinavian Cooking, Andreas Viestad made a cocktail cooled with heavy water ice.  The point was that being more dense, heavy water ice cubes sink in water.  He mentioned he was making sure not to consume too much deuterated water. http://www.newscancook.com/

[lansuminc]

there is no norm (there is no defined limit for water quality purposes because deuterium is not harmful). Deuterium is simply a minor variation on the hydrogen atom that includes a neutron. Deuterium varies in water depending on a lot of factors. Because hydrogen and deuterium have different masses, there is a separation, a "fractionation" that occurs when a hydrogen-bearing compound reacts or undergoes phase change (both processes have a mass dependence).

The isotopic composition of rainwater varies considerably around the world. This is because of that process of fractionation. Most water starts as seawater, but the vapor, the evaporated water, has less deuterium than the sea water it comes from. When some of that water rains, the remaining vapor has even less deuterium. So, the further away from the ocean source of most water vapor in the air, the less deuterium will be in any rain that falls.

Drinking water is derived from rain. Thus, drinking water has deuterium at a proportion that is typical for the source area. the deuterium proportion can vary in natural waters by up to about 10-20 % (100 to 200 parts per thousand) or rarely even more.

When scientists examine deuterium contents of water and minerals, the usual standard that they compare to is sea water (actually a very specific sample of sea water).

[Borek]

deuterium is not harmful

It is definitely cytotoxic and kills in high concentrations.