Silver nano particles…..and the environment?

Impregnating materials with silver nano particles has been found to be a practical way to exploit the germ fighting properties of silver.
Nano particles are used because they obviously exhibit enhanced or different properties when compared with the bulk material. Their very small size results in the particles having a large surface area relative to their volume. In the case of silver nano particles, this allows them to easily interact with other particles and thus increases their antibacterial efficiency. This property has been found to be so great that one gram of silver nano particles is all that is required to give antibacterial properties to hundreds of square metres of substrate material!
Their action is surprisingly similar in different organisms. Here’s how they work:
In bacteria, structures called mesosomes are present which metabolise oxygen. Silver ions cripple the responsible enzyme and stop the take up of oxygen. This effectively suffocates any bacteria, killing them within 6 minutes and leaving surrounding tissue or material unaffected. The same principle works with fungi.
Viruses, as we know, grow by taking over another living cell and reprogramming the nucleus to replicate the virus rather than the healthy cell. As a result of this, the cell functions almost in a primitive manner, i.e. as a bacterial cell would, with the respiratory organelle assuming the function of a mesosome. Again the silver ions stop oxygen being brought into the virus-producing cell and it dies by suffocation.
Antibiotic drugs can be used to kill the same pathogens which can be attacked by these silver nano particles but bacteria and viruses are becoming increasingly resistant to drug therapies. Silver nano particles kill all types of fungal infections, bacteria and viruses, including antibiotic resistant strains but until now, no drug based antibiotic has been effective on all types of bacteria. Also, all research conducted till date has shown that bacteria have been unable to develop any immunity to silver.
Since elemental silver occurs naturally, it is considered non-toxic, non-allergic, is not cumulative and is not known to harm either wildlife or the environment.
Products made with silver nano particles have been approved by a number of accredited bodies, including the U.S. FDA, U.S. EPA, SIAA of Japan, Korea's Testing and Research Institute for Chemical Industry and FITI Testing & Research Institute.
Other potential applications for silver nano particles include diagnostic biomedical optical imaging, biological implants (like heart valves) and dressings and bandages.

Citation: http://www.azonano.com/details.asp?ArticleID=1695