Today, EPA released its latest RadNet results, which include the first results for drinking water. Drinking water samples from two locations, Boise, Idaho and Richland, Washington, showed trace amounts of Iodine-131 – about 0.2 picocuries per liter in each case. An infant would have to drink almost 7,000 liters of this water to receive a radiation dose equivalent to a day’s worth of the natural background radiation exposure we experience continuously from natural sources of radioactivity in our environment.

Earlier precipitation samples collected by EPA have shown trace amounts of radioactivity, so EPA has expected to find results such as these in some drinking water samples. Similar findings are to be expected in the coming weeks.