Green Living

Antimicrobial Silver Poses Wastewater Risk

Ever wonder what keeps antimicrobial socks and other textiles free of odor-causing bacteria? They contain nanoparticles of silver that gradually release ions over time, inhibiting the growth of bacteria and fungi. Antimicrobial socks are beloved by long-distance hikers and runners, as well as other athletes who wish to avoid odor and athlete's foot. Amid the H1N1 scare, antimicrobial textiles are being hailed as lifesavers for their ability to inhibit the spread of viruses.

The problem with these textiles, though, is that they have to be washed. That means those silver ions are being released into our wastewater, but too little is known about exactly how much silver runoff occurs with these fabrics and at what cost to the environment.

One study, published in the journal Environmental Science and Technology, did examine the rate at which silver is lost during laundering. Scientists from the Swiss Federal Laboratories for Materials Testing and Research tested nine silver-containing antimicrobial textiles of differing brands. They found wide variations in the amount of silver released in washing the textiles: from less than one percent to approximately 45 percent. The researchers concluded that the mechanical stress of a washing machine was responsible for the release.

So we know that at least some of this silver is entering our water system, but not what effect this might have on public and environmental health. Overexposure to silver can cause a condition called argyria, in which the skin turns blue. And who knows how aquatic life will respond to an increase in this substance.

Every metal should be suspect when it comes to human exposure; look what happened with lead and mercury, for example. The introduction of antimicrobial textiles is yet another example of marketers wanting to get a product out faster than science can test its safety. And by purchasing these products without asking questions about their impact, we allow our consumerism to trump our conscientious citizenship. Manufacturers should think before they sell items like these. We may not be able to change their behavior, but at least we can think before we buy.