Radioactive material well below levels that would be considered a health concern have been found in air samples in St. Paul and two other Minnesota cities, likely from the damaged nuclear power plants in Japan, state health officials said Tuesday.
The Minnesota Department of Health said the findings were anticipated. Air samples taken in St. Paul in March detected very low concentrations of a nuclear fission byproduct called Iodine-131. Even lower concentrations were detected near nuclear power plants in Monticello and Prairie Island.
Samples taken March 29 in St. Paul found concentrations that would expose the average person to 0.011 millirem of radiation in a year. The average person is exposed to 365 millirem of radiation per year. Samples taken from the same area seven days earlier were even lower.
By contrast, a chest x-ray gives a dose of between 4 and 10 millirem of radiation. Exposure to radiation is not considered a health concern unless it reaches 10,000 millirem, said Sherrie Flaherty, radiation control supervisor with the state health department.
State officials have also started testing milk each week to ensure radiation isn't reaching local dairy farms. The department will increase frequency of testing if needed.
The U.S. Environmental Protection Agency found slightly elevated levels of iodine in Minnesota air samples last month. And the EPA announced Saturday that slightly elevated levels of radioactive material were found in St. Paul rainwater. Those levels are also not considered dangerous.
Radioactive substances exist in air, food and water. The mere presence of detectable radioactivity does not necessarily imply a health risk.
(Copyright 2011 by The Associated Press. All Rights Reserved.)