In ancient Rome, tipplers lined jars of wine with the precious metal to keep it from going bad. Millenia later we are buying refrigerators and socks, with microscopic silver particles to keep them fresh. The particles are called “nanosilver,” and they’re seeping into more and more consumer products.
Now the Environmental Protection Agency (EPA) says it plans to announce formally, in the federal registry, that it will take a look at its regulatory procedures for nanosilver. The announcement follows calls by health and environmental watchdog groups for a crackdown.
Nanosilver appears on shelves in hundreds of guises (such as Maha Corporation’s “shoe sanitizer,” pictured, which treats shoes for athelete’s foot). The question is whether escaped nanosilver particles pose a threat to human health or the environment, especially the water supply.
Silver trade groups argue that nanosilver used as a microbicide shouldn’t be regulated more strictly than colloidal silver, particles of silver in solution a well established ingredient present in including in health supplements and other products.
“Our position is there’s this history of use of colloidal silver,” said Dr. Rosalind Volpe, executive director of the Silver Nanotechnology Working Group, which advocates for industry.
The rise of nanosilver is part of the larger emergence of nanotechnology as a ubiquitous force in our lives. Nanotechnology is a set of procedures and tools used to harness the remarkable properties some materials show when shrunk to the size of molecules. Carbon nanotubes can make products like golf clubs and bike frames strong and flexible. Nanosized bubbles called liposomes can be used to deliver drugs and cosmetic products.
Silver’s germ and odor fighting properties make it the most widely used nanomaterial in consumer products.
As with most nanoparticles, the concern is that nanosilver could be ingested or cause environmental damage. The former could be a particular problem for nanosilver. Many Asian companies use it in baby products like stuffed animals and even bottles to kill bacteria.
Though nanomaterials are often defined as being between one and 100 nanometers — a nanometer is one billionth of a meter— the EPA has not established a formal definition for regulatory purposes. Instead it has the power to regulate nanomaterials under two main laws: the Toxic Substances Control Act (ToSCA) and the far more stringent Federal Insecticide Fungicide and Rodenticide Act (FIFRA).
Nanosilver is not necessarily more toxic than other nanoparticles. It’s regulated under FIFRA because of its use in killing bacteria.
Companies using nanosilver argue that as a long-established ingredient it shouldn’t be held to that standard. For example, silver particles are present in camera film (if you remember what that is), where they assist in light absorption.
Last year EPA convened a Scientific Advisory Panel on whether it should adjust how it regulates nanosilver. In February the agency released the minutes of the meeting. In the minutes the panel found that for nanosilver’s capability to carry toxins, it should be regulated more strictly than other types of silver.
“Other physiochemical properties, such as shape charge and surface coating are also likely to impact biological response and environmental fate,” the minutes stated.
Among researchers the biggest fear is that nanosilver could escape from its intended products. Once loose, nanosilver could theoretically be swallowed. Or it could find its way into the water supply where it could wreck havoc killing aquatic life or even the useful bacteria employed to treat water supplies.
Last year the journal Environmental Science and Technology published an article that found that garments containing nanosilver can shed it during normal washing.
“It’s very important to look at the whole lifecycle of products,” said Bernd Nowack, one of the researchers who authored the study. At the same time he downplayed the impact of such a tiny amount of nanosilver on the environment.
In emailed responses to questions for this article, EPA spokesman Dale Kemery said the agency expects to formally announce that it will require companies seeking to register pesticides to disclose any nanoscale ingredients.
Thus far there has not been a confirmed incident of nanosilver causing serious harm to people or the environment.
Still, “We don’t want there to be dead people before [the EPA] acts on this,” said Jaydee Hanson, a policy analyst at the Center for Food Safety. His group wants more research done on nanomaterials before they’re commercially available said “We don’t want there to be dead people before [the EPA] acts on this.”
According to Kemery the agency cracks down on nanosilver only in cases where the product claims to kill germs. Thus it’s the products advertised intention, not its ingredients, which subjects it to FIFRA regulation.
The Project on Emerging Nantechnologies at the Woodrow Wilson International Center for Scholars maintains an inventory of consumer goods which use nanotechnology. Under the manufacturer’s use guideline nanosilver products such as Blue Moon Goods’s nanosilver food containers would be regulated as would stuffed animals, which use nanosilver to fight off germs.
In 2008 EPA fined the parent company of tech outfit Iogear $208,000 for using an unregistered pesticide which contained nanosilver on a germ-fighting computer mouse.
Something similar happened to a washing machine put out by electronics giant Samsung, which incorporated silver ions until the manufacturer altered how it described the product. “Samsung stopped saying anything about the purported antimicrobial effect of nanosilver in its washing machine,” spokesman Kemery wrote. “With that, the issue was moot.”
The statement "As with most nanoparticles, the concern is that nanosilver could be ingested or cause environmental damage." is incorrect. There is very little threat to human health from silver ingestion. The real health threat from nanoparticles is inhalation.