The Philadelphia Water Department announced yesterday that it is enhancing its testing procedures and reviewing treatment technology after federal environmental officials found radioactive iodine in the city's drinking water.

The level of Iodine-131 found at the Queen Lane treatment plant is the highest of 23 sites in 13 states where the particles have appeared following the massive radiation leaks from the Fukushima Daiichi nuclear power plant in Japan. Lower levels were found at the city's two other plants.

But the Iodine-131 in Philadelphia may have no connection to Japan, officials say.

The U.S. Environmental Protection Agency told the Daily News yesterday that Philadelphia water samples from last August contained nearly twice as much radioactive iodine as the recent samples collected after the Fukushima disaster.