Radiation Detected In Drinking Water In 13 More US Cities, Cesium-137 In Vermont Milk

[UPDATED 4/11 with FDA's Derived Intervention Level]

Radiation from Japan has been detected in drinking water in 13 more American cities, and cesium-137 has been found in American milk—in Montpelier, Vermont—for the first time since the Japan nuclear disaster began, according to data released by the Environmental Protection Agency late Friday.

Milk samples from Phoenix and Los Angeles contained iodine-131 at levels roughly equal to the maximum contaminant level permitted by EPA in drinking water, the data shows. The Phoenix sample contained 3.2 picoCuries per liter of iodine-131. The Los Angeles sample contained 2.9. The EPA maximum contaminant level is 3.0, but this is a conservative standard designed to minimize exposure over a lifetime, so EPA does not consider these levels to pose a health threat. The FDA, not the EPA, regulates milk.

[UPDATE: The FDA's Derived Intervention Level for iodine-131 in milk is much higher: 4700 picoCuries per liter. Read why.]

The cesium-137 found in milk in Vermont is the first cesium detected in milk since the Fukushima-Daichi nuclear accident occurred last month. The sample contained 1.9 picoCuries per liter of cesium-137, which falls under the same 3.0 standard.

Radioactive isotopes accumulate in milk after they spread through the atmosphere, fall to earth in rain or dust, and settle on vegetation, where they are ingested by grazing cattle. Iodine-131 is known to accumulate in the thyroid gland, where it can cause cancer and other thyroid diseases. Cesium-137 accumulates in the body’s soft tissues, where it increases risk of cancer, according to EPA.

Airborne contamination continues to cross the western states, the new data shows, and Boise has seen the highest concentrations of radioactive isotopes in rain so far.