Still within safe limits, Phila. water shows radioactive-iodine spike

Authorities are investigating why samples of drinking water from three sites in Philadelphia had a higher level of radioactive iodine than water in other cities.

Levels of Iodine-131 found April 4 in samples from treated water at the Queen Lane, Baxter, and Belmont plants were considered within federal safety standards, according to the Environmental Protection Agency.

The most common sources of Iodine-131 are nuclear reactors and weapons, but doctors also use it to diagnose and treat thyroid illnesses.

Of 69 sites it tested nationally, the EPA found the highest amount of radioactive iodine at the city's Queen Lane Treatment Plant in East Falls.

The city is working with the EPA and the Pennsylvania Department of Environmental Protection to determine the cause.

Chris Crockett, acting deputy commissioner for planning and environmental services for Philadelphia's water department, said he was not sure how long it would take to determine the reason for the relatively high levels.

The city also is adding carbon at the Queen Lane plant. Carbon works to absorb contaminants in drinking water and is removed during filtration.

The EPA released the April 4 results quicker than usual because of the ongoing problems with damaged nuclear reactors in Japan. However, Philadelphia's water department recently received data showing high levels of Iodine-131 in water in August, long before the tsunami, suggesting that Japan may not be the source.

City officials sought to reassure residents that they could drink, cook, and bathe in the water.

"The water is safe. I drank mine this morning," said Debra McCarty, deputy commissioner of operations for the Water Department.

An infant would have to drink 600 liters of water containing 2.2 picoCuries per liter a day to receive a radiation dose equal to the amount people get from natural background radiation, the EPA said. EPA spokesman David Sternberg said the agency calculated the amount for an infant because it represents "the most conservative and protective measure."

Physicians for Social Responsibility, a group of doctors opposed to nuclear weapons and power, says no level of Iodine-131 in food or drinking water is safe.

On March 23, the group issued a statement questioning reports suggesting that any radiation exposure was acceptable. No one from Physicians for Social Responsibility was available for comment Monday.

Curtis Cummings, associate professor at Drexel University's School of Public Health, said he belongs to Physicians for Social Responsibility but disagrees with its statement because radiation is everywhere.

"We are exposed to radiation every day," Cummings said. "Radon in people's basements is a far worse problem."

He said he would drink Philadelphia water but also believes the presence of iodine should be investigated.

The water test results were first reported by a blogger for Forbes magazine analyzing EPA data.