"Certainly it is a very good antimicrobial product," says Zhiqiang Hu, a civil and environmental engineer at the University of Missouri–Columbia, who is studying the safety of silver nanoparticles. "But, it can kill the benign species [of bacteria] as well."

Hu says one of his major concerns is their potential effect on aquatic organisms. Many types of bacteria live in lakes and streams, and if silver nanoparticles were to get into these waters they could disrupt the aquatic ecosystem.

Hu is not the only one worried. Andrew Maynard, chief science advisor for the Project on Emerging Nanotechnologies, funded by the Woodrow Wilson International Center for Scholars and The Pew Charitable Trusts, is also concerned about the lack of research and regulation on the use of silver nanoparticles. He says this technology is cropping up in unlikely products, such as socks, kitchenware and cosmetics, to name a few.

"You have an antimicrobial agent appearing everywhere, including children's fluffy toys, with no knowledge about its health or environmental implications," Maynard says. "What are the chances of it taking out an ecologically important bacteria?"

It is this question that Maynard wants answered before the technology is applied to any more commercial products. On the other hand, Maynard acknowledges that the use of silver nanoparticles holds promise, particularly in hospital settings.

"I think there are multiple places in which it would be okay," Maynard says. Treating patients with wounds or creating a sterile environment in a hospital are two examples of what he sees as a good use.

"Silver is one of our best lines of defense against a number of microbes," he says. "And we need to think carefully before we put such a powerful agent in the market."

This article is provided by Scienceline, a project of New York University's Science, Health and Environmental Reporting Program.

4 Comments

1. 1. phred42 05:31 PM 5/3/08

   Groups File Legal Action for EPA to Stop Sale of 200+ Nano-Silver Products
   
   http://www.truthout.org/issues_06/050208HA.shtml

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2. 2. John_Toradze 12:45 AM 5/4/08

   There are negative side effects of silver.
   
   http://en.wikipedia.org/wiki/Argyria
   Discoloration of the skin seen in argyria is not the most serious health effect of silver. It has been shown to cause brain damage,[1] seizures,[2] and death or a persistent vegetative state.[3]
   
   1. Argyria: report of a case associated with abnormal electroencephalographic and brain scan findings. PMID 3112046 http://www.ncbi.nlm.nih.gov/pubmed/3112046
   
   2. Argyria and convulsive seizures caused by ingestion of silver in a patient with schizophrenia PMID 8783381 http://www.ncbi.nlm.nih.gov/pubmed/8783381
   
   3. Myoclonic status epilepticus following repeated oral ingestion of colloidal silver PMID 15111684 http://www.ncbi.nlm.nih.gov/pubmed/15111684
   
   Of course, this is all dose dependent, and I have no information on the rate of absorption of colloidal silver particles from the paint by painters or if toddlers were to eat peeling paint off of walls. It takes a fair amount of colloidal silver to cause problems.
   
   --
   Edited by John_Toradze at 05/04/2008 7:13 PM

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3. 3. Appleypie 01:41 AM 5/6/08

   Copper also kills germs just like silver. Remember silver is not toxic to humans. It used to be used for eating food. It just got too expensive! Silver is also safe to wear as jewelry. I wear silver rings to keep from getting colds. Please see RosesRings.com. However both copper and silver can kill fish. Before we condem silver socks maybe we should consider the huge amount of copper pipes in the world and weather there is any significant effect there.

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4. 4. spencerjonesy 12:25 AM 12/7/10

   Big business has been moving into silver-based antimicrobials for a long time now. See: http://thesilveredge.com/bigbus.shtml
   
   But the neo-Luddite environmentalists have opposed this from the start, claiming that silver is somehow toxic to the very environment from which it came. Recently, they even claimed that silver-impregnated socks -- worn to help kill the germs that cause stinky feet -- is a cause of global warming! See: http://thesilveredge.com/doomed.shtml
   
   Silver is probably responsible for more healing of infectious illness than any other natural substance on the face of the earth. Why environmentalists are opposing it is a mystery to me...unless they are on the payroll of Big Pharma: http://thesilveredge.com/bigdrug.shtml

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