"There's something unusual here and we need to figure out what's going on," said Chris Crockett, the department's acting deputy commissioner of environmental services.
You may ask: Does this have anything to do with the radioactive emissions from the Fukushima Dai-ichi power plant in Japan?
The answer is no.
Although trace amounts of Iodine-131 have blown over to the United States from Japan, Philadelphia has a more serious - and mysterious - problem with an unidentified local source that predates Japan's March nuclear disaster.
U.S. Environmental Protection Agency data show that the iodine in Philly's water has exceeded federal drinking-water limit at least nine times since 2007 at two of the city's three water-treatment plants.
And Philadelphia's water has the highest iodine level among dozens of water systems in the U.S. tested by the EPA since the Japanese disaster.
'That's insane'
Water Department officials tell the Daily News that they were not aware of the data until about the time that the Japanese crisis raised concerns about nuclear particles contaminating U.S. air and rainwater, an issue that turned out to be unrelated to the iodine in Philadelphia.
The Water Department is working with state and federal environmental officials to find the local source of Iodine-131, which can cause cancer in high or prolonged doses and is believed to be responsible for thousands of thyroid cancers following nuclear-bomb tests in the Nevada desert in the 1950s and '60s.
"It's not the type of thing you want to hear when you have kids," said Bettina Berg, who lives in the city's Bella Vista section and is worried about the health of her boys, ages 4 and 20 months. "That's insane if it's been at least four years and they haven't done anything about it."
