RICHLAND - The Environmental Protection Agency has detected trace amounts of radioactive iodine in Richland's drinking water this week that's believed to have come from Japan.
EPA reported finding iodine 131 in Richland and Boise drinking water about 0.2 picocuries per liter, the first traces it has detected in U.S. drinking water.
However, no radiation related to the events in Japan -- including in drinking water, milk or air -- has been detected in Washington at levels that are of any health concern, according to the Washington State Department of Health.
An infant would have to drink approximately 28,000 cups of the Richland water to receive a radiation dose equivalent to one day's worth of natural background radiation, according to EPA.
Also, the isotope has a relatively short half-life. Every eight days, half of its radioactivity decays away.
EPA samples drinking water for radiation four times a year in 50 locations across the nation, including Richland. Because of the radiation releases from the Fukushima nuclear plant in Japan, sampling stations are sending samples for analysis now.
Other sites in the West that already have been sampled include Idaho Falls, Portland and Seattle. None of them turned up any contamination.
Iodine 131 is not typically found in Richland water samples, and it was consistent with the damaged reactors, according to EPA. To get into drinking water it would need to be caught in precipitation, fall to the ground and then enter the water supply, according to EPA.
EPA stepped up monitoring of precipitation, milk and drinking water across the nation in response to the Fukushima events. The radioactive material it has detected has been expected, and all has been far below levels of public health concern, according to EPA.
The Washington State Department of Health continues to emphasize that residents should not take potassium iodide pills.
Radioactive iodine concentrates in the thyroid, but potassium iodide can prevent the thyroid from taking it up. However, the iodine 131 detected is at far too low of levels to cause a threat to health and potassium iodide can have side effects, including causing potentially severe allergic reactions, rashes and inflammation of the salivary glands.
The first airborne radiation from Japan detected in the continental United States also was discovered in Richland.
On March 16, Pacific Northwest National Laboratory's highly sensitive equipment detected xenon 133 in minute quantities. Two days later, radioactive iodine also was detected in even smaller quantities.