Cal Baier-Anderson, Ph.D., is a Health Scientist.
In May 2008, the International Center for Technology Assessment (ICTA) submitted a petition to EPA requesting that it regulate nano-silver used in products as a pesticide under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The petition calls on EPA to take the following specific actions:
- Classify nano-silver as a pesticide.
- Determine that nano-silver is a new pesticide and require its registration as such.
- Analyze the potential risks of nano-silver to human health and the environment.
- Take enforcement actions against nano-silver-containing products being sold illegally without EPA approval under FIFRA.
EDF supports this petition. The rapid increase in the largely unregulated use of nano-silver in consumer products is alarming, especially given the lack of systematic evaluation of their possible harm to human health and the environment.
As I have explained in past posts, bulk forms of silver, while having generally low direct human toxicity, have potent anti-bacterial properties and are quite toxic to many freshwater organisms. In a recent report on nano-silver prepared for the Project on Emerging Nanotechnologies, Dr. Samuel Luoma characterized bulk-scale silver and silver ions as environmental hazards because they are toxic, persistent and bioaccumulative under at least some circumstances. He also concluded that insufficient information is available to predict whether nano-scale silver's hazards will be comparable to or greater than those of bulk-scale silver and silver ions. Baker and colleagues have described how silver nanoparticles appear to have greater antibacterial potency than larger-sized particles due to their larger surface area-to-volume ratio.
Product manufacturers are seeking to capitalize on nano-silver's antimicrobial properties by adding it to dozens of products. Many are already on the market, including nano-silver-impregnated socks and nano-silver-containing cosmetics. That means both human contact and the release of nano-silver into the environment are already occurring, yet we are unable to predict the consequences.
So it is essential for EPA to exert its authority under FIFRA to require each manufacturer using nano-silver in a product to demonstrate that the addition of nano-silver is effective in achieving any claimed benefits, that labeling is accurate and that its use is safe for both humans and the environment.
In a November 19, 2008 Federal Register Notice, EPA has solicited comments on this petition, with the comment period recently extended to March 20, 2009. See that notice for details on how you can voice your opinion on this important issue.