An activist from the group, Choi Kyoungsook, said it could not be trusted that the water is safe to dump in the ocean.

Japan began releasing water from the wrecked nuclear power plant on Thursday (August 24), despite objections both at home and abroad from fishing communities and others worried about the environmental impact.

Japan and scientific organisations say the water is safe. Plant operator Tokyo Electric Power has been filtering it to remove isotopes, leaving only tritium, a radioactive isotope of hydrogen that is hard to separate.