A team of researchers from the University of Washington's Center for Experimental Nuclear Physics and Astrophysics didn't have to go very far afield to test for airborne radiation from Japan's crippled Fukushima Daiichi Power Plant--they just examined air filters from the ventilation system in their own building on the school's Seattle campus.
Asked why they decided to test the air filters in their own building, Andreas Knecht, a co-author of the study, replies, "The biggest incentive was the curiosity whether we would be able to detect the radiation at all. In addition, we wanted to determine the impact of the additional radioactivity on our fundamental physics program, and, last but not least, confirm that the levels would be far below any health concern."
Luckily, they found that "the overall amount of the radioactivity is extremely low, at least thousands of times below [Environmental Protection Agency] limits."
"The person pointing us to the actual air filters in the physics building was Jens Gundlach," Knecht says. "[He] had been doing such kind of measurements after the Chernobyl accident. These high-volume air filters were the key to be able to see the radioactivity at all."
The study compares the recent findings with the radiation fallout from Chernobyl. The researchers note that the elements they detected in Seattle (specifically iodine-131, iodine-132, tellurium-132, iodine-133, cesium-134, and cesium-137) indicate there has not been a "complete reactor meltdown" like the one in Ukraine. They say the presence of these elements suggests the radiation came from "recently active fuel rods as opposed to spent fuel," likely from contaminated steam that evaporated into the atmosphere. By contrast, at Chernobyl there was "a direct dispersal of active fuel elements."
The study only looks at the first five days of testing, but the scientists say they will be updating their website with current air-radioactivity levels in the coming days and weeks.
All in all, it's a pretty impressive (and timely) piece of scientific research, and a fascinating look at how radiation traveled roughly 4,700 miles from the coast of Japan to an air duct in Seattle. Read the whole thing here: "Arrival time and magnitude of airborne ?ssion products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA."
As for the efforts in Japan to cool the reactors at Fukushima Daiichi and stop the spread of radiation, the news this morning is not good. According to The New York Times, "highly contaminated water" used to cool the crippled reactor could soon leak into the ocean, and plutonium from spent fuel rods has been detected in the soil around the plant. But as dire as that sounds, there's still no need to panic and stock up on iodine tablets --and hopefully there won't ever be. Says Knecht: "We do not expect any measurable amount of radioactivity in seawater to make it across the Pacific to Seattle."