Syndicated from post here.
You may not know exactly what nanosilver is, but you’ve definitely used it. In a way, nanosilver is like the Jetsons: it’s sort of futuristic, but has also been around for ages. And because nanosilver is both of those things, while we’ve come to accept it as part of our everyday lives, there are still a lot of new things we’re learning about it, for better and for worse. Before we get to what we don’t know about nanosilver, though, let’s start with some solid facts.
Nanosilver (or colloidal silver, as it’s otherwise known), is essentially extremely tiny particles of silver that have been suspended in liquid. How small exactly? For perspective, a strand of human hair is between 50,000 to 80,000 nanometers wide. A nanosilver particle is typically no bigger than 100 nanometers. Due to this, one of the most prized properties of nanosilver is its ability to be used as an antimicrobial agent.
The first time humans actually encountered nanosilver was way back in the late 1800s, when the particles were used to develop some of the first photographs. Not too long after that, once it was discovered that nanosilver had the ability to kill bacteria, we started employing it for a whole range of other uses, from swimming-pool algaecides in the 1950s, to drinking-water filters two decades later.
In more recent years, science has developed a way to synthesize nanosilver particles, opening the floodgates for potential uses.
“What we’ve learned how to do is bundle silver atoms into minuscule little particles, and then we’re able to take these particles and put them in places that they’ve never been able to get before,” said Samuel Luoma, a U.S. Geological Survey researcher working on nanosilver technology, explaining the developments in an article on Environmental Health Perspectives.
Due to these developments, nanosilver has begun to appear in an increasing number of products. There are now over 400 products on the market that employ nanosilver technology, many of which involve direct contact with our bodies and our food, including clothing, sheets, blankets, cosmetics, soaps, nasal spray, hair straightener, ink, air purifiers, vegetable and fruit cleaners, cutting boards, vacuum cleaners and in Korea, even toothpaste.
A paper by the Silver Nanotechnology Working Group explains why this has come to be the case:
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Nanosilver antimicrobial treatments can bring a number of functionalities to consumer articles, including longer shelf life (e.g., cosmetics) giving more safety, less waste and ultimately lower prices for consumers; plastics that are protected against the degrading action of bacteria (e.g., discoloration); and textiles that are protected against colonization of bacteria that can lead to odors (e.g., sports clothing), ultimately giving greater comfort and prolonged use. Additional benefits such as reduced washing frequency at lower temperatures can give significant water and energy savings.
Sounds too good to be true, right? It may be. Because the very thing that makes nanoparticles so effective—their size—is also what makes them a potential hazard. We still don’t fully know how nanosilver behaves when it's released into the environment or absorbed by our bodies. A growing number of studies show that products containing nanosilver can shed these particles, which subsequently end up in wastewater or our bloodstream.
These rogue nanosilver particles pose a number of potential problems. As we’ve established, silver nanoparticles are highly toxic to bacteria and fungi. This is not good news for soil. Quoted in an article on Scientific American, Ben Colman, a research scientist at Duke University who conducted a study into the effects of nanosilver on soil systems, explained how these particles, “significantly altered [..] plant growth, microbial biomass and microbial activity.”
On the flipside, nanosilver toxicity poses a different threat to our own biology. The Center for Food Safety’s senior policy analyst Jaydee Hanson, quoted in an article on Civil Eats, noted that over time, overexposure to nanosilver, “may lead to bacteria becoming increasingly resistant to antibiotics.” A study conducted by the Norwegian Institute of Public Health further found that silver nanoparticles had a “toxic effect on cells, suppressing cellular growth and multiplication and causing cell death depending on concentrations and duration of exposure.”
In 2014, the European Commission and its non-food Scientific Committee on Emerging and Newly Identified Health Risks published findings under the comprehensive title, “Final Opinion on Nanosilver: safety, health and environmental effects and role in antimicrobial resistance.” SCENIHR found that in order to truly ascertain any potential hazards, more data was “needed to better understand bacterial response…to silver nanoparticles exposure.”
Turning to the EPA
Nanosilver is defined by the EPA as a pesticide. As a result, only products that explicitly use nanosilver as a measure against germs and bacteria need to be registered and approved by the agency. Here is the main problem. Due to the more recent explosion of nanosilver present in consumer goods, most products are getting past EPA’s approval as they don’t fit the bill of being a pesticide. Perhaps most concerning, as Civil Eats pointed out, some manufacturers have “simply changed their product labels to remove germ-killing claims, in an effort to avoid EPA enforcement or product scrutiny.”
Just last year, the scientific journal Environmental Health published a study looking at the potential health and environmental hazards contained in nanosilver-related products that had been overlooked by the EPA. “The demonstration study proves,” said Elizabeth Crowe, director of the environmental health network Coming Clean, who helped conduct the study, “that both regulators and companies don’t have to wait for new assessment methods in order to determine the potential harm of nanomaterials. They can act now to protect the health of workers and the public by making better choices on what to include in their products.”
In other words, society needs to be more alert. That’s not to say we should throw the baby out with the bathwater. As Greg Lowry, a nanosilver particle researcher at Carnegie Mellon University, points out: “There’s a tremendous potential benefit to the use in some of these products. What one has to do is to ask yourself whether the benefits outweigh the risk.”
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