Tritium Fact Sheet |

Tritium is a radioactive contaminant of concern at Fukushima Daiichi. This contaminant does pose health risks and is present in significant quantities in the stored water at the disaster site.

The infographic below gives a quick overview of the tritium and other radioactive contaminants contained in the water TEPCO plans to dump into the Pacific Ocean. Additional documentation follows the infographic.

Fukushima Daiichi Tritium Fact Sheet


The total amount of contaminated water in some phase of treatment at Fukushima Daiichi according to TEPCO is
1,328,508 m3 or 1,328,508,000 liters as of 2023. 

The total amount of tritium contained in the contaminated water in the treatment processes is 780 Tbq or 780,000,000,000,000 Bq per METI as of 2021. As more water is brought into this system the total could increase. 

Tritium concentrations in the stored water vary greatly. Some tanks have lower levels of tritium concentrations while other tanks are incredibly high in tritium. A spot review of tritium concentrations found in the storage tanks ranged from 140,000 Bq/L to 2.5 million Bq/L per Japan’s nuclear regulator’s records

Tritium isn’t the only contaminant in this water TEPCO plans to dump into the Pacific ocean. The total of “other nuclides” that remain in the post-ALPS water is almost equal to the amount of tritium in the water. We have older reports that confirm the concentration of some of these other contaminants but don’t have specific values for some of the other ones such as Co-60, Sb-125, or the trace amounts of Cs-137 or Sr-90.

Contaminants we are able to provide an estimated total for include:
I-129  82,633,197,600 bq
Ru-106 122,886,990,000 bq
Tc-99 78,381,972,000 bq

TEPCO and other vested interests have attempted to distract from the volumes of contamination that would be dumped into the Pacific Ocean by claiming they will dilute it before dumping. This is akin to putting an equal amount of something into a tub with an eyedropper or pouring it in all at once out of a cup. The same amount ends up in the body of water. The delivery method is largely irrelevant to the concerns for the environment and public health.

Health concerns do exist. This has been a central focus of industry PR efforts to confuse and dismiss the issue. Inaccurate claims comparing it to various types of external exposure are intended to confuse the public. Here the US NRC claimed that tritium can’t penetrate human skin, while true this distracts from the actual risks. Tritium is a beta emitter, learn more about beta radiation effects here.

Tritium when ingested or inhaled poses an internal exposure risk. This is the main risk with tritium. It is capable of binding with cell constituents to form organically-bound tritium (OBT). This can pose a concentrated radiation exposure inside the body. More details about this and how tritium can cause cancer can be found here.


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