[clarionbell]

To answer your question. The risk is minimal to nonexistent.

Tritium, the thing ONE of the scientists is concerned about, is an isotope of hydrogen. It's barely radioactive, and it has half life of about 12 years. You may know it as the stuff that illuminates watch faces and sights. It's used in many other industrial applications and as far as radioactive elements goes

If you read the actual article you may see it's classic fear mongering:

The panel of multi-disciplinary scientists, hired by the intergovernmental Pacific Islands Forum, has not found conclusive evidence that the discharge would be entirely safe, and one marine biologist fears contamination could affect the food system.

TL;DR: They couldn't say something could happen, so they said that they can't conclude nothing will happen. Which is exactly what everybody knew before. One of them said that something COULD happen, but he doesn't know how.

[fsh]

Tritium is highly radioactive (358 TBq/g). Otherwise it wouldn't make phosphors glow in the dark.

[HPsquared]

A high number of decays per second per gram yes (it's a light element with short half-life) so a small amount of mass gives a lot of activity. The total activity of tritium in the stored water is a few hundred TBq (i.e. a few grams of tritium in all those thousands of tonnes of water).

GP was probably referring to the low energy of the decay (18 keV per decay) which is much lower than other common radionuclides found in waste. For example, Cs-137 releases 600 keV per decay, and Sr-90 releases 576 keV followed by 2274 keV. Tritium is a much lower energy decay, per atom.

[ddingus]

These things are low risk externally.

However, when made internal, as in food?