Water treated and discharged near Fukushima is harmful to the environment

Discharges into the sea of "radioactive" water containing tritium had no impact on ecosystems. The water immediately returned to concentrations consistent with guidelines for drinking water.

Following the accident, damage to the structures led to water infiltration (rain, underground, etc.) into buildings. This water, in contact with debris and the core, is loaded with radioactive elements. This water, pumped, collected, decontaminated, and then stored in large tanks on the plant site, reached its maximum volume in early 2023, i.e. 1.3 million m³ of stored water, according to various sources.

To avoid saturation of the storage site, the Japanese authorities, on the recommendation and under the supervision of international bodies, decided to discharge this water into the sea after decontamination to levels compatible with the ordinary discharges of a nuclear power plant in operation, without impact on the environment.

This water is called “tritiated water” because it contains tritium, the only element that cannot be filtered by the decontamination systems implemented upstream. Tritium is a radioactive element with little radioactivity, little radiotoxicity, and a short half-life, a constituent part of the water molecule in its own right, which can therefore not be separated from it. It is therefore included in the Fukushima discharges, in a quantity greater than the usual discharges from nuclear power plants.

Before discharge, the tritiated water is subjected to controlled dilution with seawater to lower the tritium concentration by an order of magnitude below the limit set by the World Health Organization... for drinking water. After discharge, given the natural dilution in the ocean, this concentration drops to negligible levels, up to 10,000 times lower than this drinkability limit. 

Under the discharge conditions, there is therefore no risk to health or the environment.