By Cindy Folkers
When reactors exploded and melted down at the Fukushima nuclear power complex in March 2011, they launched radioactivity from their ruined cores into the unprotected environment. Some of this toxic radioactivity was in the form of hot particles (radioactive microparticles) that congealed and became airborne by attaching to dusts and traveling great distances.
After the Fukushima nuclear disaster began, one highly radioactive specimen, a particle small enough to inhale or ingest, was found in a private home where it should not have been, hundreds of miles from its source, in a vacuum cleaner bag containing simple house dust.
This “high activity radioactively-hot dust particle” came from a house in Nagoya, Japan – after it had traveled 270 miles from Fukushima. The only radioactive particle found in the home’s vacuum cleaner bag, it was an unimaginably minuscule part of the ruined radioactive core material from Fukushima – many times smaller than the width of a human hair. We know it came from Fukushima because it contained cesium-134, meaning that the particle came from a recent release, and we know it is a piece of core material specifically because it was so radioactive that it could not have come from any other material.
Most of the particle’s radioactivity came from cesium-134 and cesium-137. By the time it was collected, some of the particle’s radioactivity, mostly from iodine-131, had already decayed. Named “corium” by scientists, it was still thousands of times more radioactive (5,200,000,000,000,000 disintegrations per second per kilogram — that’s 5.2 quadrillion more than the average activity (26,000 disintegrations per second per kilogram) found in dust and soil samples collected through community volunteer efforts from across Japan — with a focus on areas around Fukushima — since the 2011 nuclear disaster began. By way of comparison, in the U.S., average soil and dust activity is thousands of times lower.
Due to privacy concerns, we are not permitted to know the identities of the Nagoya residents who participated in the dust sampling collection and in whose home the particle was found. Nor do we know how many people lived in the home; if there were children or babies present; or pets; or pregnant women. And we will never know if there were any other radioactive microparticles in the home that did not make it into that vacuum cleaner bag.
We do not know how the particle got there. No one in the home (nor the vacuum cleaner) had any connection to the Fukushima reactors or the exclusion zone. Was the particle transported by a car tire into their city? On someone’s shoes? Did it fly in through a window after being lofted by air currents? Did it arrive by a combination of forces? We do not know if other particles like this travelled just as far in all directions, or who may have taken a breath at just the wrong moment, so that a similar microparticle might be lodged in their lungs.
We do know the residents in Nagoya were notified about the particle’s presence, and that if it had been inhaled or ingested, it could have proven lethal over time. This corium particle would have destroyed tissue near it, potentially threatening the function of any organ that tissue was part of. But the particle’s additional danger would come from what it didn’t destroy – that is tissue that is damaged but survives and can go on to mutate into cancer or non-cancer diseases.
In addition to catastrophic releases from nuclear power facilities, these particles come from atomic detonations, other nuclear industry processes such as mining and atomic fuel fabrication, and nuclear facility releases of radioactivity, as well as leaking atomic waste dumps. Nuclear workers, First Nations Tribes, and local residents have submitted samples for testing around such facilities. Particles have been detected in the environment and in house dusts in communities around weapons facilities in Los Alamos, NM; Hanford, WA; and Rocky Flats, CO. Thorium, plutonium, and uranium from nuclear facilities were found “outside of radiation protection zones,” including workplaces, workers’ homes and cars. “Given the small respirable size of these radioactive microparticles, they are a potential source of internal exposure from inhalation or ingestion,” according to Dr. Marco Kaltofen of Worcester Polytechnic Institute.