Survey Reveals Dirtiest Surfaces

There are a lot of dirty places in D.C.

The Anacostia River has been cited as "one of the most polluted waterways in the nation" by environmental advocacy group D.C. Appleseed. Not the best place to go swimming.

News4's Tom Sherwood has often called Freedom Plaza the most rat-infested open space in District -- which probably did not make it a very hygienic camping ground for anti-corporate protesters.

While some might impugn the cleanliness of Metro, the system is cleaned on a daily basis. Metro's station equipment gets washed with disinfectant every day, and the agency says trains and buses are disinfected weekly.

But unless you're licking the poles on Metro (and please don't do that), you may not think about the cleanliness -- or lack thereof -- of common items you encounter every day.

Health product manufacturer Kimberly-Clark teamed up with the University of Arizona to review the contamination factor of some of the most heavily trafficked surfaces.

Researchers swabbed surfaces like countertops, doorknobs and keyboards to measure the level of Adenosine Triphosphate (ATP), a substance present in bacteria, yeast and mold cells. The study says that objects with ATP readings of 300 or above are considered to be high-risk for illness transmission.

The study tested common surfaces in several metropolitan areas, producing the following list of surfaces with the highest percentage of "high contamination" (i.e., the dirtiest):

• 71 percent of gas pump handles
• 68 percent of mailbox handles 
• 43 percent of escalator rails
• 41 percent of ATM buttons
• 40 percent of parking meters/kiosks
• 35 percent of crosswalk buttons
• 35 percent of vending machine buttons