Investigating the environmental impact of nanosilver

When it comes to materials used in the fight against bacteria, silver may not be the first substance which comes to mind. However, the precious metal has been used in the medical industry as a biocide - a substance which can deter, render harmless, or exert a controlling effect on any harmful organism - since the 1930s.

These days, antimicrobial silver nanoparticles are used in a variety of ways, such as for preventing unpleasant odours caused by bacteria in sport shirts or socks. While silver's antibacterial properties have been appreciated, there has always been a concern over the effect nanosilver may have when it is released into wastewater during washing. Research has shown that nanosilver presents a minute risk to the environment as it is transformed into a nearly insoluble substance called silver sulphide in wastewater treatments.

In search of a definitive conclusion on the potential risks, the EU funded PROSUITE project has been set up to analyse the environmental impact of nanosilver released from sports T-shirts during their entire life cycle, from raw material extraction to end-of-life disposal.

'Nanosilver can be applied in lower quantities than other antimicrobials and hence has advantages for resource use and environmental loads,' says Tobias Walser, a researcher at the Institute for environmental engineering at the Swiss Federal Institute of Technology in Zürich. However, 'the environmental and human risk of nanosilver has yet to be fully understood', he adds.

The PROSUITE study 'is very relevant' because it 'gives a fingerprint' about the impact of such T-shirts, says Professor Anders Baun from the Department of environmental engineering at the Technical University of Denmark. However, Baun says, in general, 'it is a bad idea to distribute silver in the environment'. He points to a study that found evidence for nanosilver accumulating in the food chain based on a study of plants and animals in an experimental wetland environment. Moreover, he says, it is unknown how the coating of nanosilver influences its environmental behaviour.

More details can be found at the following link: http://cordis.europa.eu/fetch?CALLER=EN_NEWS&ACTION=D&SESSION=&RCN=35663