Will Miami ever have a sensible, convenient and popular public transport system? Not any time soon, but a lot of us have cars, so who cares? Well, the very soil under your feet cares. A new study out of the University of Florida finds that urban Miami has some of the most polluted soil in the world, with levels higher than Chicago, London, and Helsinki (though, not as high as New Orleans or Detroit).

The study looked at 55 square miles of Miami -- 85 percent of which is covered by "parking lots, streets, large buildings, shopping centers, houses and other impervious structures" -- and found 16 types of polycyclic aromatic hydorcarbos (PAHs), which are toxic pollutants. Most of these pollutants come from the burning of fossil fuel, i.e., driving around in our cars.

The PAHs can be absorbed by the human body through ingestion, inhalation and even through the skin, although it's not well known how much of the pollutants might be transmitted to people from soil.

However, elevated amounts of these chemicals can be harmful to soil microorganisms and may accumulate in the food chain...

All samples collected near the top of the soil contained more than 1,000 micrograms of PAHs per kilogram of soil -- the definition of heavy contamination according to an internationally used scale. Analysis of the PAHs revealed that the vast majority were most likely from vehicle exhaust.

The findings weren't exactly a surprise to the researchers, however the numbers will be used as a baseline to evaluate whether attempts to curb pollution in Miami are actually working.