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US EPA Scientific Advisory Panel has mixed Opinions on Nanosilver

Published: Saturday 6 February 2010

The US Environmental Protection Agency has released the minutes of its recent EPA Scientific Advisory Panel (SAP) Meeting on the topic ‘Evaluation of Hazard and Exposure Associated with Nanosilver and Other Nanometal Oxide Pesticide Products’ (held in Arlington VA, on the 3rd to the 5th November 2009).

The minutes highlight the Panel’s following findings:

  • The Panel was not aware of any information that suggested that silver ions released from silver nanomaterials would behave different than silver ions generated by any other source. However, the Panel believed that the rate of silver ion production, as well as the distribution of silver in tissue, may differ substantially between silver nanomaterials and other forms of silver.
  • The panel agreed that particle size has a substantial impact on particle properties, [...]. The effects of size are generally most observable in particles below 20 nm and largely below 10 nm, [...].
  • The Panel indicated that they were not aware of studies which definitely answered the question whether or not agglomerated silver nanoparticles in the range of 100 nm to 1000 nm pose different hazards than larger sized particles. [...]
  • Regarding the exposure from ‘realistic use’ scenarios, the Panel indicated that there are limited data available. [...]
  • Environmental fate of released silver nanomaterials is somewhat unclear, though ‘down-the-drain’ disposal will result in introduction to sewage treatment plants, [...].
  • The Panel stated that most existing models are not appropriate for use with silver nanomaterials and will not accurately predict nanosilver exposure scenarios. [...]
  • The Panel strongly believed that in addition to current data requirements under FIFRA, additional assays which compared nanoscale and bulk materials would be most beneficial in addressing the question. [...]
  • The Panel believed that the lack of existing data suggests that it would be necessary to conduct research on a case-by-case basis to evaluate whether silver nanomaterials remain associated with a substrate.[...]
  • The panel disagreed that nanosilver applied to a substrate will permanently bind with the substrate and concluded that, given the state of science and measurement standards currently available, it will be especially challenging to determine that there is no release of nanomaterials from a substrate. [...]
  • The Panel agreed that additional data are needed before the scientific community can conclude whether or not particles at the smaller end of the size scale (e.g., 1 nm) are likely to behave like particles at the larger end of the scale (e.g. 100 nm). [...]
  • The Panel cautioned about extrapolating from one nanosilver formulation to another when assessing hazards. [...]
  • The Panel believed that environmental conditions can affect the properties of nanoparticles, including silver. [...]
  •  Finally, the Panel acknowledged that data gaps about potential exposure and hazard related to nanosilver are board and there is very little information about nanosilver in the environment related to fate, transport and transformation, [...].

Follow these links to find out more about the SAP meeting, or to download the Minutes of the SAP meeting.

 
Related Links:
The Dutch National Institute for Public Health and the Environment has published a report entitled Nanomaterials under REACH – Nanosilver as a case study; according to the report’s preface, it describes ‘a hypothetical registration of nanosilver under the new EU REACH regulation on chemicals, taking into account the ongoing discussions within the REACH Competent Authorities and its Subgroup on Nanomaterials on how REACH applies to nanomaterials [...]. (15th December 2009)
 
The US Silver Nanotechnology Working Group (SNWG), has issues a press release on its contribution to the recent EPA Scientific Advisory Panel (SAP) Meeting on the topic ‘Evaluation of Hazard and Exposure Associated with Nanosilver and Other Nanometal Oxide Pesticide Products’ (held in Arlington VA, on the 3rd to the 6th November 2009). (11th December 2009)
 
The journal Environmental Science and Technology has published a paper entitled ‘The Behavior of Silver Nanotextiles during Washing’ (Environ. Sci. Technol., DOI: 10.1021/es9018332), reports the results of an experimental study that investigated 9 commercially available fabrics (with silver contents varying between 0.003 and 21.6 mg/g), into or onto which silver had been incorporated in different ways. (9th October 2009)
 
Meeting Reports (by the NIA Delegate):
3rd - 4th November 2009: 3rd Safety for Success Dialogue: Building Trust in Nanotechnology (Renaissance Hotel, 19 Rue du Parnasse, 1050 Brussels)