Six years after the radioactive accident in Fukushima, scientists found that the highest levels of persistent cesium in ocean waters are below the beach sands up to 100km away. This new source of radioactive waste is up to 10 times higher than levels found in seawater of the Fukushima Daiichi nuclear power plant.

The source is rather unexpected, according to researchers from the Woods Hole Oceanographic Institution (WHOI) in the United States and Japan’s Kanazawa University. Samples obtained between 2013 and 2016 revealed high levels of cesium-137 in eight beaches near the Fukushima facility.

Radioactive accident in Fukushima, Radioactive Waste, Fukusima Nuclear Plant
Fukushima Daiichi Nuclear Plant in 2012, after a tsunami wrecked it. Image credit: Tomohiro Ohsumi, Pool

Nuclear fission forms a soft, silvery-gold metal called cesium-137, a radioactive isotope of cesium that could pose a threat to humans if they are exposed to high concentrations.

“No one expected that the highest levels of cesium in ocean water today would be found not in the harbor of the Fukushima Daiichi nuclear power plant, but in the groundwater many miles away below the beach sands,” said study author Virginie Sanial, as quoted by Russia Today.

Only time and nature will wash away the radioactive content

After the reactor meltdowns, ocean currents carried the radioactive element to the sand grains located miles away from the nuclear power plant, according to the paper published Monday in the journal Proceedings of the National Academy of Sciences.

Sanial said in a press release that there is nothing to do but to wait until the cesium, which has long half-life, naturally decays and is removed from the sands to be washed out by seawater.

Although the study reveals that damaged nuclear reactors can spread radiation miles away from the meltdown site in unexpected ways, the researchers noted that the radiation levels don’t pose a threat to public health.

Still, those in charge of the management of coastal areas where nuclear power plants are located should consider this discovery and the environmental risks potential meltdowns implicate, the researchers noted. About one-half of the 440 operational nuclear reactors worldwide are located along the coastline, according to the paper.

The radioactive content found in the beach sands might have been released by nuclear weapons tests in the 1950s-60s but the team of researchers detected another form of cesium which could only be originated from the Fukushima disaster.

Radioactive accident in Fukushima, Radioactive Waste, Fukusima Nuclear Plant
A couple walks along the coast damaged by the 2011 tsunami in Fukushima. Image credit: AP

An 8.9 magnitude earthquake hit northeastern Japan in March 2011. The massive tragedy triggered a tsunami that led to meltdowns at three reactors of the Fukushima Daiichi nuclear power plant. More than 18,000 people were killed and about 160,000 victims had to flee their homes in the deadliest disaster since the 1986 Chernobyl calamity.

The other two known sources of the radioactive waste include current releases and runoff from the Fukushima plant and overflow from rivers that transports cesium from the radioactivity on land. However, none of these sources can compare with those released immediately after the radioactive accident.

Nuclear energy currently provides 1.7 percent of Japan’s nuclear energy. It declined from 30 percent before the 2011 disaster. Because the nation has very limited natural resources, the Ministry of Economy, Trade, and Industry said that nuclear energy must increase to provide at least 20 percent of Japan’s portfolio mix, according to a report by Forbes.

Source: Russia Today