The International Atomic Energy Agency (IAEA) has today issued a comprehensive assessment of plans to begin discharging treated water into the sea from the Advanced Liquid Processing Plant (ALPS) at Fukushima. They concluded that plans “are consistent with international standards” and that discharges will have “a negligible radiological impact on people and the environment.”

The discharged water will contain tritium, a radioactive isotope of hydrogen, in the form of water (called HTO); all other radionuclides are almost completely removed by processing, but HTO remains in the water.

The IAEA verdict is entirely justifiable as the discharges of tritiated water will be similar to those from Fukushima before the accident in 2011. They are also substantially less than routine discharges from some other nuclear installations, including Sellafield in Cumbria and  Cap La Hague in France. Before discharge, the water will be further diluted to contain less than 1500 becquerels (Bq) of tritium per litre of water, less than the drinking water standard of the World Health Organisation – and hence considered safe to drink at that concentration. But, of course, the discharged HTO will also be massively diluted in the ocean.

The IAEA report contains estimates of radiation doses to the most exposed individual, based on conservative assumptions about how they might ingest HTO. These doses are less than 0.01 microsieverts; that’s 100,000 times less than the dose limit for members of the public.

As concluded by IAEA, there should be no concerns that these operations could in any way affect human health or the environment.