Radioactive material from the Fukushima Dai-ichi nuclear power plant disaster is accumulating in the sands and brackish groundwater beneath beaches up to 60 miles away from the nuclear power plant itself, according to a new study published in the Proceedings of the National Academy of Sciences on October 2.
The new study is the first to identify radioactive accumulations in this previously unsuspected place — the accumulations in question being radioactive cesium.
“Virginie Sanial, a scientist at Woods Hole Oceanographic Institution, samples groundwater beneath beaches in Japan. She plunged 3- to 7-foot-long tubes into the sand, pumped up underlying groundwater, and analyzed its cesium-137 content.” Photo by Matt Charette, Woods Hole Oceanographic Institution
“No one is either exposed to, or drinks, these waters, and thus public health is not of primary concern here,” the researchers noted in the new study, but “this new and unanticipated pathway for the storage and release of radionuclides to the ocean should be taken into account in the management of coastal areas where nuclear power plants are situated.”
The theory proposed in the new study is that high levels of radioactive cesium-137 were transported along the coast following the 2011 nuclear disaster, and subsequently got “stuck” to surfaces of grains of sand, rather than being nearly immediately dispersed and diluted as was “expected.”
“No one expected that the highest levels of cesium in ocean water today would be found not in the harbor of the Fukushima Dai-ichi nuclear power plant, but in the groundwater many miles away below the beach sands,” stated researcher Virginie Sanial of Woods Hole Oceanographic Institution.
That may well be true, but it’s also true that there people who acknowledge that accurately modeling systems as complex as those found in the natural world is essentially impossible — and who would argue that the precautionary principle should be kept in mind when dealing with something as dangerous as nuclear power. After all, predictions relating to outcomes are only ever going to be of related accuracy.
The press release provides more: “Cesium-enriched sand resided on the beaches and in the brackish, slightly salty mixture of fresh water and salt water beneath the beaches. But in salt water, cesium no longer ‘sticks’ to the sand. So when more recent waves and tides brought in salty seawater from the ocean, the brackish water underneath the beaches became salty enough to release the cesium from the sand, and it was carried back into the ocean.
“The scientists estimated that the amount of contaminated water flowing into the ocean from this brackish groundwater source below the sandy beaches is as large as the input from two other known sources: ongoing releases and runoff from the nuclear power plant site itself, and outflow from rivers that continue to carry cesium from the fallout on land in 2011 to the ocean on river-borne particles. All three of these ongoing sources are thousands of times smaller today compared with the days immediately after the disaster in 2011.
“The team sampled eight beaches within 60 miles of the crippled Fukushima Dai-ichi Nuclear Power Plant between 2013 and 2016. They plunged 3- to 7-foot-long tubes into the sand, pumped up underlying groundwater, and analyzed its cesium-137 content. The cesium levels in the groundwater were up to 10 times higher than the levels found in seawater within the harbor of the nuclear power plant itself. In addition, the total amount of cesium retained more than 3 feet deep in the sands is higher than what is found in sediments on the seafloor offshore of the beaches.”
So, what the new research does in essence is provide yet another example of the way that nuclear disasters and nuclear contamination can impact the natural environment in ways that aren’t immediately expected or intuitive to most.
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