Tritium Q&A

Publication - April 1, 2008
Tritium is radioactive water or water vapour. It’s not something in the water, but the water molecules themselves that are radioactive. Tritium is the radioactive isotope of hydrogen. That means tritium is unstable and gives off radiation when it disintegrates. In the environment, the most common kind of tritium is tritiated water — that is, water molecules in which one (or both) of the hydrogen atoms is radioactive.

Is it dangerous?

Yes, tritium is hazardous when you drink it, eat it, breathe it or absorb it through your skin. Tritium is not considered an external hazard, but an internal one. It has a radioactive half-life of about 12 years, which means it stays around in the environment for a long time. It has the unusual properties of rapid transport in the environment, quick uptake by humans, fast exchange mechanisms with other hydrogen atoms and the ability to bind with organic molecules during cell formation and cell metabolism.

What are the effects of exposure to tritium?

Tritium is a radionuclide, which gives radiation when ingested or inhaled. Radiation causes cancers, congenital malformations and genetic effects. Radiation is known to be a carcinogen, teratogen and mutagen, and effects are thought to occur at the lowest possible exposures.

Why is Greenpeace concerned about tritium in Canada?

Huge amounts are pumped into Lake Huron and Lake Ontario and released into the air every day from Canada’s nuclear power stations. Tritium discharges from Canadian reactors at civil nuclear power stations are by far the largest in the world. They are 100 to 1,000 times greater than tritium discharges from other kinds of nuclear reactors.

Should I be concerned?

The closer you live to a nuclear power station, the more you should inform yourself about tritium. Near nuclear power stations, rivers, wells, vegetation, animals and humans have raised levels of tritium.

What do nuclear industry and nuclear regulators think?

They think tritium isn’t dangerous and that the amounts released are below health limits. The Canadian Nuclear Safety Commission and the nuclear industry rely on models for estimating the radiation doses from tritium that Greenpeace believes contain serious scientific inaccuracies and result in very low doses being estimated. These estimates allow the continued operation of nuclear power stations.

What do government scientists think?

Most tow the nuclear industry line. Government officials and politicians are advised on radiation matters largely by the nuclear industry and its regulators. Many independent scientists consider tritium to be more dangerous than is officially recognized. Over the years, the more scientists have learned about tritium, the more hazardous it has been perceived. Greenpeace thinks government officials and politicians should consult more widely and listen to a balance of views on radiation matters.

How can I decide between differing scientific views? It’s too complicated.

Yes, it’s complicated. To help, ask yourself whom you think is likely to be more precautionary — nuclear scientists or independent ones? Of course, all scientists who work on radiation issues are concerned about public health, but there is a tendency for nuclear scientists not to be too critical about radiation’s effects in public.

Doesn’t tritium occur naturally?

At low levels, yes, but that doesn’t justify making huge amounts and releasing them near large populations. Background tritium is created in the upper atmosphere by cosmic ray bombardment.

If it’s so dangerous, why are there no deaths?

Because no one is counting them. Initial epidemiology studies in the 1990s found raised levels of leukemia and congential malformations, but no follow-up studies were commissioned.

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