Fukushima Four Years Later: Are We Safe?

Former UH Manoa Department of Geology and Geophysics postdoctoral researcher Jan Kamenik is seen here collecting samples at Sans Souci Beach on O‘ahu.

This may go without saying, but don’t believe everything you read on the Internet. It is disheartening to see so much misinformation bleeding online.

Four years ago, after the Fukushima Daiichi nuclear power plant disaster in Japan, there was a bright red “radioactivity map” all over the Internet claiming to depict the radioactive plume on its march of death across the Pacific Ocean. Some sleuthing revealed the blatant lie it was — a model of the Tohuku tsunami waves rather than radiation.

What did really happen, and what is happening now?

When the tsunami severely damaged the Fukushima plant, four reactors released significant amounts of radiation into the atmosphere and the ocean. The radioactive isotopes released include iodine-131, cesium-137 and cesium-134. Large doses of these isotopes cause serious long-term health impacts. People closest to the site, particularly workers at the plant, are most at risk. The accident compounded the tragedy of thousands lost and displaced after the tsunami.

For Hawai‘i it is a much different story — one that requires continued monitoring to fully understand.

After the accident, Dr. Ken Buesseler from the Woods Hole Oceanographic Institute organized the first of many international expeditions to study the spread of radionuclides from Fukushima to the Pacific. I spoke with Dr. Henrieta Dulaiova, from the UH School of Ocean Science and Technology, who took part in the effort.

Dulaiova said cesium-137 and cesium-134 also come from the nuclear weapons testing in the Pacific in the 1950s and 1960s. Since cesium-137 has a 30-year half-life, if it’s detected in Hawaiian waters, it’s impossible to tell if it’s from weapons testing or Fukushima. Therefore, cesium-134, with a two-year half-life, is used as a Fukushima fingerprint.

Today, the data shows no detectible Fukushima-derived cesium isotopes in water samples around Hawai‘i. The levels of cesium-137 that are detected (less than 1.5 Bequerels per cubic meter Bq/m³) are well below the Environmental Protection Agency’s limits for human health concerns, and are likely from historical weapons tests. Dulaiova continues to monitor Hawaiian waters, but so far the coast is clear. Anything arriving in Hawai‘i is expected to be significantly diluted.

Dulaiova’s students are also monitoring mushrooms and fish, both of which can act as indicator organisms to detect radiation because it bioaccumulates in their tissues.

While the fisheries off Fukushima remain closed, the fish should be safe to eat here. This is based on the assumption that most of the fish we eat do not migrate far from their home waters. One exception to this is Pacific bluefin tuna. To be clear, the ahi readily available here in Hawai‘i is yellowfin.

Ruby Pap

There is still much to be learned about the radiation traveling from Fukushima. Also, there is increasing concern about strontium-90, which is leaking from the groundwater to the ocean at Fukushima. Strontium-90 mimics calcium and can concentrate in bones where it remains for long periods. According to WHOI, so far, strontium-90 levels in fish are far lower than cesium-137, but if the leaks continue, it will become a greater concern.

Unfortunately, government funding for a coordinated multi-national monitoring effort is not available. WHOI recently launched www.ourradioactiveocean.org where you can fund a monitoring site. Also, www.whoi.edu is a treasure trove of reliable scientific information.

Chapter of the Surfrider Foundation is tracking the issue as well: https://kauai.surfrider.org/portfolio-item/fukushima-radiation-monitored/. Perhaps you could post these links to your Facebook page?

• Ruby Pap is a Coastal Land Use Extension Agent at University of Hawai‘i Sea Grant College Program. She can be reached at rpap@hawaii.edu.