Philadelphia, Bakersfield and Fresno, California, are the most toxic cities in America, according to a new study that looked at air and water quality in metropolitan areas.
"Philadelphia doesn't have great air, but other cities have worst," said Morgan Brennan, of forbes.com, which conducted the report. "But the Philadelphia area has over 50 Superfund sites, really poor water quality, and a hefty amount of toxic releases."
New York City and Baton Rouge, in Louisiana rounded out the top five most toxic cities in the country.
To compile the list, forbes.com looked at 80 of America's largest metropolitan areas and examined the number of Superfund locations, unused areas which contain hazardous materials, as well as the local Air Quality Index AQI.L and Toxics Release Index, a measure of how much toxic material is released, recycled or managed by local industries.
The Philadelphia metropolitan area includes more than 50 Superfund sites.
Cities in California also have particularly poor air quality. In 2009, Bakersfield had 43 days in which the AQI passed 100 on a 500-point scale, with zero being the best possible score.
Fresno had 29 days in which the AQI passed 100, and Los Angeles had 14. Most American cities can go an entire year without seeing the AQI pass 100.
Los Angeles captured the No. 6 spot on the list, which can found on tinyurl.com/4mhhdbx.
Brennan said that high levels of toxicity do not necessarily mean increased health risks for local inhabitants.
"For the most part, just because a city ranks high for toxicity doesn't directly mean that people in those areas are being exposed to or running the risks of cancers that are related to toxicity," she said. "It's very difficult to actually measure levels of exposure."
Brennan also said that many of the cities on the list have taken steps to mitigate the hazardous effects of high toxicity levels.
"The good news is that most of these cities have some sort of initiative in place to improve air quality," she said. "A lot of cities in California have introduced clean air initiatives, for example."
New York City has plans to clean up the Gowanus Creek Canal in Brooklyn, one of the most polluted waterways in the United States.
Philadelphia had the worst water quality of the cities examined, followed by Fresno and New York City.
The Environmental Working Group EWG.L, a Washington D.C.-based nonprofit, suggests that consumers use a water filter to avoid drinking any contaminants when consuming tap water.