Environmental Costs and Benefits of Nano-Silver Textiles: combining LCA and MCDA

Silver has been utilized for its antimicrobial properties since antiquity. Those same antimicrobial properties have produced a myriad of nano-silver (nAg) enabled products, and in particular nAg textiles. These textiles are... [ view full abstract ]

Silver has been utilized for its antimicrobial properties since antiquity. Those same antimicrobial properties have produced a myriad of nano-silver (nAg) enabled products, and in particular nAg textiles. These textiles are currently marketed as “anti-stink gear”, embracing the notion that the addition of the nAg will inhibit the growth of bacteria on the textile and reduce odor. Manufacturers of these textiles tout the ability to launder them less, and thus reduce the overall life cycle impact of the textile, as laundering has historically been found to be the greatest contributor to the overall life cycle environmental impact of textiles.

However, the addition of nAg to textiles comes at an additional environmental cost when compared to conventional textile counterparts. And a wide variability exists with respect to the concentration of silver attached to the textiles, ranging from 0.9 µg nAg per gram of textile to 21,000 µg/g. Losses of nAg due to laundering also vary significantly as a function of the attachment method of the silver, ranging from <1-100% of the initial silver content of the textile. The loss of silver not only decreases the antimicrobial efficacy of the textile, but also provides a pathway for nAg to enter the environment. The silver will eventually enter the wastewater treatment plant, and is expected to be in the form of AgCl or Ag2S. Approximately 90-95% of the silver entering the wastewater treatment plant will be removed into the biosolids, with the rest entering the aquatic environment. At the same time there are expected benefits to these textiles, which are not only limited to reduced laundering. In a medical setting, the antimicrobial benefits may vastly outweigh the increased environmental burden of nano-enabling the textile.

In order to fully investigate the environmental costs and benefits of nAg enabled textiles when compared to their conventional counterpart, life cycle assessment (LCA) is coupled with multi-criteria decision analysis (MCDA). This case study provides a framework for evaluating the benefits and costs of nano enabled products from an environmental and human health perspective. This methodology has the potential to advance the state of the field, when assessing the environmental and human health costs and benefits of nano-enabled products.