Most of the radioactive fallout that descended upon downtown Tokyo in the days after the March 2011 accident at the Daiichi nuclear plant was concentrated and deposited in non-soluble glass microparticles -- essentially, glass-filled soot.
As a result, the fallout, which contained concentrated radioactive cesium, wasn't dissolved by rainfall, and probably lingered in the environment. Its effects remain unclear, according to a newly-published research.
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In the study, released at the Goldschmidt geochemistry conference in Yokohama, a team of Japanese geochemists analyzed samples collected from within a 142 mile (230 kilometer) radius of the stricken nuclear plant, which suffered a partial meltdown of three reactors after an offshore earthquake triggered a devastating tsunami, which in turn disabled the power supply to the reactors' cooling systems.
The accident released a plume containing cesium-137, a radioactive isotope with a 30-year half-life. Once inhaled or ingested in the body, the substance can remain in the body for weeks or months, according to the U.S. Centers for Disease Control and Prevention. Exposure can damage cells and lead to an elevated risk of cancer, according to the CDC.