Tritium is not particularly dangerous.

Tritium is a low-energy beta emitter with a half-life of about 12 years. It does not bioaccumulate.

Tritium forms naturally from cosmic rays hitting the upper atmosphere. It has a concentration of about 1e-18 in rainwater.

@FearlessFly Quoting the link: " TEPCO drafted a plan to dilute the water to below the legal limit for concentration of radioactive materials before releasing it in the sea." It could be a lot worse. We have plenty of radioactivity around us from brick and cosmic radiation. However, the nuclear daughter products continue to have no socially or politically acceptable disposal solution in our own country.

The real question is whether the water contains anything besides tritium.