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Silver Nanotechnology – Round 2: SNWG comments on German BfR

On 2 May 2011 the Silver Nanotechnology Working Group (SNWG) issued a reply to the scientific opinion published by the German Federal Institute for Risk Assessment (BfR) which was made on the 12 March 2011. The response was entitled SNWG comments on BfR & nanosilver.

The original BfR's publication followed several developments that started in December 2009 when BfR published its first opinion advising against the use of nanosilver. Industry-led groups such as SNWG have repeatedly asked BfR to reconsider its position in the view of overwhelming evidence. On 17 February 2011 BfR hosted a workshop (Expert Workshop: Health Risk Assessment of Nanosilver) on nanosilver in Berlin. Despite SNWG evidence presented at the meeting BfR unilaterally published its own opinion on 2 May 2011.

The main three points of the BfR's position were:

  • BfR believes that nanosilver aims to replace conventional hygiene methods
  • BfR is concerned that the use of nanosilver has a potential for developing silver-resistant bacteria
  • BfR also claims that nanosilver has unusual effects when compared to conventional silver

Response from SNWG answered all three points with several arguments for each case. According the SNWG, the first point on general usage of nanosilver as opposed to conventional methods does not take into consideration that the real benefits and the scale of general antibacterial products: 'BfR's concern that antimicrobial treatments encourage the consumer to dispense with normal hygiene is based on a superficial understanding of the intended purpose of the treated goods'.

The second point regarding the potential of developing of a new strain of bacteria resistant to silver ions has been answered by SNWG by pointing out that bacteria in nature have been exposed to subinhibitory concentration of Ag+ ions for four billion years with no resulting resistance development.

The third point made by BfR that nanosilver behaves differently from 'macro' material was answered by pointing out that the action of nanosilver on bacteria is through silver ions and not through the particle size thus making fundamental action of nanosilver similar in all respects to the 'macro' silver.  

Having answered all the BfR's concerns the SNWG response concludes: 'BfR analysis indicates nanosilver [is] OK as long as[the] "nano" prefix is not used' and adds that 'This position indicates an illogical bias and is without scientific basis'.


For more information please follow this link to the BfR's opinion document coverage and to the NSWG response document.

News item was produced by NIA in association with BREC Solutions.

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