Tuesday, November 3, 2009

No Silver Lining?

I just finished knitting socks for my husband that are made of an Icelandic wool and alpaca blend. These socks are special because I think I may have met the sheep that produced the wool. I bought the yarn at a Wisconsin Sheep and Wool Festival earlier this fall. The socks are going to be really, really warm this winter, which is good because my husband's feet get really, really cold. However, his feet don’t sweat, so I don’t expect the socks to get smelly, but if they did, I learned this morning in the NYT Science Section that adding silver to fibers like those used in socks can keep them odor free.

I suppose I knew that silver was an antimicrobial – after all, I do have a degree in Microbiology, but I never thought about socks and silver together. It appears that by adding a few nanoparticles of silver to textiles, the bacteria that cause unpleasant odors are eliminated. Nanoparticles, in case you don’t know, are very, very small. Picture a hair’s breadth and divide it into a trillion pieces, and you have a nanoparticle.

However, you might want to think twice about those odor-free socks because silver is not only toxic to bacteria – it’s pretty much toxic to every living thing. And remember that things like socks and clothing have to get clean. What happens to the silver when those items go through the wash? Does it go down our drains, out into our streams and our lakes, into our fish? How will effect our environment?

The Project on Emerging Nanotechnologies, a program developed by the Woodrow Wilson International Center for Scholars and Pew Charitable Trusts has issued a 72-page report called Silver Nanotechnologies and the Environment: Old Problems or New Challenge? The report says there are now over 235 products ranging from toothpaste to towels, cosmetics to clothes, appliances and paint that contain silver. It may be that some silver containing products are environmentally safe but it may also be that we just don’t know enough yet to say. Fortunately, there are people a lot smarter than I am who are thinking about this.

So here we are worried about invasive species like zebra and quaaga mussels, sea lampreys and alewives when sweet smelling socks may present just as much of a problem to our water. It seems that even smart new ideas come with a cloud. And does that cloud have as silver lining – a silver lining that’s safe for our environment? That’s the question.

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