Add Cleveland to the list of places where iodine 131 - probably released from the damaged nuclear plant in Japan - has been detected.
Case Western Reserve Geology Professor Gerald Mattisoff says he's detected a small amount of the radioactive substance in rainwater while monitoring the movement of particles into Lake Erie.
Since the calamity at the Fukushima Daiichi plant, Iodine 131 has been detected in rainwater on both US coasts, as well as Colorado and inland Pennsylvania.
Mattisoff says the level of radiation poses no health threat.
"My estimate is that it's about 10 percent of the amount of radioactivity that we see normally in the rain anyway," he says. "So it's just a slightly elevated above the natural level that we normally measure. But there's still the concern because this is still an ongoing problem in Japan. They have not solved that problem yet."
Mattisoff says the radiation half-life of iodine 131 is about 8 days, compared to about 85 thousand years for plutonium.
The U.S. Environmental Protection Agency, which regularly monitors radiation, says levels in Cleveland are thousands of times lower than levels that would cause any concern.