BOISE -- Trace amounts of radioactive gases from the nuclear reactor disaster in Japan began showing up in Idaho and other Western states this week.
Mark Dietrich, technology service administrator with the Idaho Department of Environmental Quality, said charcoal filter monitors in Meridian and at the Idaho National Laboratory have detected small amounts of iodine-131 and xenon-133.
The radioactive isotopes aren't part of the natural background radiation, he said. However, they are consistent with the problems taking place at the Fukushima Dai-ichi nuclear plant.
The plant lost power during a massive earthquake March 11. Three reactors experienced explosions and possibly partial meltdowns, with releases of radioactive gases and particles.
"What we're seeing here is the lighter elements that get caught up in the prevailing wind direction," Dietrich said. "The amount we're seeing is many thousands of times below what would be considered a health risk. They're right at the detection limit for this equipment."
Monitors in Washington, Alaska, Nevada, California, Hawaii, Guam and Alabama picked up trace amounts of the gases this week. Small amounts were also found in rain samples in Pennsylvania and Massachusetts.
Dietrich said this monitoring equipment is extremely sensitive. A few years ago, a single INL monitor detected a trace amount of iodine-131.
"It's such a specific isotope, we assumed someone in the area was getting treatment for thyroid cancer," he said.
The half-life for I-131 is eight days. And xenon, being a noble gas, doesn't interact with other elements. "The health issues with it are effectively nonexistent," Dietrich said.
Results from the radiation monitoring in Idaho are being posted on the Department of Health and Welfare website, at www.healthandwelfare.idaho.gov.
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