Big Worries About Small Particles

Companies have evidently realized that marketing anti-bacterial products to U.S. consumers is a good way to make money, and are pushing a wide array of products that claim to have bacteria-fighting properties. (I've seen socks, computer products, toys ... and even a handy hook you can use to avoid touching a potentially germ-ridden door handle.) This might seem like a good thing - bacteria cause some pretty nasty diseases, after all - except that they're using nano-sized silver particles to fight the bacteria, and we don't know nearly enough about the effects of all the nano-sized particles that are entering our environment as we wash, wear, use, and dispose of the hundreds of nano-containing products now on the market.

In the latest issue of The New Republic, Carole Bass provides an excellent overview the issue and why we should be concerned:

But those products raise multiple health and environmental questions. Do nanoparticles stay put, or do they liberate themselves? What happens if they get into the human body or the environment? Silver, for example, will kill both harmful and beneficial microbes. But little is known about the effects of nanosilver--the most frequently cited nanoparticle in PEN's consumer-products inventory, showing up in more than 20 percent of the entries. The same is true for other nanomaterials, even ones that are ordinarily harmless. Animal studies show that because nanoparticles are so small, they can travel deep into the lungs, passing into the bloodstream and other organs. They may be able to penetrate the skin. And they're much more chemically reactive, often in unpredictable ways. While consumer industries are racing to develop uses, environmental and health research lags far behind. 

Troy Benn, a doctoral candidate in environmental engineering at Arizona State University, recently conducted one of the first experiments to test the properties of nanoparticles in consumer products--with results that do not bode well for their safety. Benn and his professor, Paul Westerhoff, simulated washing seven varieties of socks advertised as using antimicrobial silver nanoparticles to help kill foot odor. When they tested the wash water, one pair--hunting socks from ARC Outdoors--lived up to the boast of its website: "It won't wash out." All the other nano-socks leaked silver. 

That's a bummer for the buyer who expected long-lasting fresh feet. But it may be even worse for the wildlife that literally lives downstream. For years, wastewater treatment plants have worked with industries to limit the silver they dump down the drain. "Now, all of a sudden, we see these consumer products with silver," says Ben Horenstein, an official at an Oakland sewage treatment plant who is active in the National Association of Clean Water Agencies. "Our ability to treat the wastewater is in jeopardy because of these antimicrobial products. ... The water bodies we discharge to have aquatic life, and silver can adversely impact that."

And, surprise, surprise, our regulatory system is ill-equipped to handle this new potential threat:

Given that nanosilver may be more toxic, molecule for molecule, than ordinary silver, it's unclear whether existing pollution laws provide enough protection. Nationally, the only law specifically governing nanotechnology is in Berkeley, California, which requires industries to report on which nanomaterials they're using. The EPA only has a voluntary reporting program. And while the National Institute for Occupational Safety and Health has issued recommendations for protecting people working with nanoparticles--who are the most likely to be exposed--it has has no enforcement power. 

Through a spokesman, the EPA says it "takes any unverified public health claims"--nano or not--"very seriously and can pursue the appropriate action." But Horenstein sees "a gap in terms of regulatory oversight. As more and more of these things are coming on the market," he says, "how much understanding do we want to have in advance, versus playing catch-up?" 

The regulation gap stems in part from the data gap. Proposed legislation, supported by the Project on Emerging Nanotechnologies and big industry players like Dupont, would require that at least ten percent of federal nanotech spending go toward environmental, health, and safety research--compared to less than five percent currently. Some environmental groups would go further. Friends of the Earth, for example, calls for a moratorium on personal-care products containing engineered nanomaterials until they're proven safe.

This isn't to say that we should scrap nanotechnology altogether; it holds promise for fighting tumors and making solar energy affordable, and curing cancer and curbing carbon emissions are certainly worthwhile goals. Endangering our health so our socks can smell fresh seems like a horribly misguided plan, though.


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The nano-silver lining in socks meant to knock off bacteria and smell is representative of a general cultural trend that grew aided by much of 20th century biomedical science: the war on germs. Never mind that without bacteria human being would not be able to live - whether we speak of soil bacteria or bacterial flora in our gut. These considerations of bacteria as an essential - nay, foundational - element of life on Planet Earth seldom make it into media or popular thought. Instead, mothers are inculcated through TV ads to protect their children by pouring buckets of Chlorox all around the house; antibacterial soaps and personal care products shout off the supermarket shelves, and now nano-silver socks explore and exploit the same fear of disease. Of course disease is best avoided; but as demonstrated by a lot of research, indiscriminate killing of all bacteria makes the world a less habitable and more disease-prone place....

By Olga Naidenko (not verified) on 05 May 2008 #permalink

All around the world unions, environmental and other groups are struggling to make governments take notice that the many questions regarding nanotechnology are not resolved, and that most regulatory regimes are ill-equipped to handle the many unknowns. Governments must begin to regulate as soon as possible. Our view is that chemicals in nano form must be considered as new chemicals - and go through rigorous testing prior to use and registration.