SIX SECONDS--that is how long 95% of people spend washing their hands. However, to kill germs effectively, you need to spend at least 20 seconds scrubbing, about the time it takes to sing "Happy Birthday" twice through, according to the Centers for Disease Control and Prevention. Many people buy soaps containing antimicrobial chemicals like triclosan (TCS) and triclocarban (TCC) in the hopes of cleaning more efficiently. However, studies show that these products are no more effective than plain soap and water--and the 20-second rule still applies.
In our zest for cleanliness, we not only fail to kill germs correctly, but unwittingly may be contributing to an environmental and human health mess. "Most people don't use personal care products correctly and are unaware of the legacy that they are leaving behind, which lasts decades or longer," says Rolf Halden, director of the Center for Environmental Security at Arizona State University. "The widespread use of antimicrobial compounds offers no measurable benefit for the average consumer, yet creates a legacy of pollution that can be traced back for half a century in the sediments of our drinking water resources."
Every day, those scant seconds send the active ingredients from thousands of products--antimicrobial soaps, cosmetics, disinfectants, and sanitizers--cascading out of our homes into sewers. From there, a significant fraction breaks through wastewater treatment units eventually to settle into lakes and rivers.
Halden, a professor in the School of Sustainable Engineering and the Built Environment, studies the broad interconnectedness of the water cycle and human health, with special emphasis on the role of man-made products and human lifestyle choices on environmental quality. It has led him on a journey from scientific discovery to reforming public policy. "It's very powerful to look into water, and to understand what is left over after treatment, and to trace the fate of what happens," explains Halden, whose "follow the water" mantra has served as a guidepost to his scientific career.
Halden's team was the first to find significant concentrations of TCC and TCS dating back to the 1950s in sediments of Baltimore's Chesapeake Bay and New York's Jamaica Bay, where they were discharged in treated domestic wastewater. More recently, Halden found the same antimicrobial ingredients contaminating Minnesota's freshwater lakes, released into nearby waters from various human activities. "We...