Tag Archives: Martin A. Philbert

Nanosilver risk assessment in Germany and a new approach to risk assessment suggested at Univ. of Michigan

There’s a move to ban the use of nanosilver in food and articles used daily (think of the socks you don’t have to wash very often because they don’t smell) in Germany until there’s been a full risk assessment. From the April 14, 2011 news item on Nanowerk,

In its opinion on toxicity aspects of nano silver, the Federal Institute for Risk Assessment (BfR) had recommended to waive the use of nano silver in foods and articles of daily use until the data situation allows for a final assessment of the health risks. Mainly industry objected to this assessment by BfR that enough data were available for the evaluation of the health risks of nano silver in consumer products and foods. For that reason BfR had invited experts from research and science as well as representatives of associations and industry to a workshop in order to discuss existing risks and possible options for a comprehensive consumer protection. “The discussion confirmed the words of caution of BfR”, said BfR President Professor Dr. Dr. Andreas Hensel, “because the situation continues to be characterised by the fact that not enough secured scientific findings about the specific effects of nano-sized silver particles are available.

” Metallic silver and different silver compounds are used, for instance, in cosmetic agents as well as in different consumer products, mainly because of their anti-microbial effect. For textiles not only medical/therapeutic applications but increasingly also hygiene aspects play a role. The anti-microbial finishing of textile fibres is mainly to act against odour formation as a result of the microbial decomposition of sweat. In the meantime nano-sized silver particles are increasingly being used. Nano particles are particles with a diameter of less than 100 nanometres.

This is interesting in light of yesterday’s April 14, 2011 posting about the European Commission’s attempts to establish a definition for nanomaterials before any attempts to regulate their use. Then today I came across a posting by Dr. Andrew Maynard, Director of the Risk Science Center at the University of Michigan, Ann Arbor titled Why we don’t need a regulatory definition for nanomaterials. His comments represent a significant shift in opinion since I first started following his work in 2007,

Engineered nanomaterials present regulators with a conundrum – there is a gut feeling that these materials present a new regulatory challenge, yet the nature and resolution of this challenge remains elusive. But as the debate over the regulation of nanomaterials continues, there are worrying signs that discussions are being driven less by the science of how these materials might cause harm, and more by the politics of confusion and uncertainty.

Yet the more we learn about how materials interact with biology, the less clear it becomes where the boundaries of this class of materials called “nanomaterials” lie, or even whether this is a legitimate class of material at all from a regulatory perspective.

In an evidence-driven society, now would be the time to take stock – to ask what the science tells us about risks associated with exposure to materials more generally, and to reformulate the problems we are trying to address when it comes to nanomaterials. But increasingly, evidence is taking a backstage role in the process of developing definitions for regulatory purposes. This was highlighted recently by Henrik Laursen [quoted in my April 14, 2011 posting] , coordinator of the nano team in the European Commission’s environment department, who was reported on Euractiv.com as stating that ultimately, the decision on a regulatory definition of nanomaterials would be a policy decision.

This should ring alarm bells throughout the scientific community.

Andrew has been heavily involved with the nanotechnology effort and discussion for many years. This is the biographical information available from his faculty page (it is by no means comprehensive),

Prof. Maynard is a leading authority on the responsible development and use of emerging technologies. His research interests span identifying, assessing and managing emergent risks, to exploring innovative solutions to established and emerging human health and environmental risks, to equipping people with the tools they need to make informed decisions in the face of risk and uncertainty. Prof. Maynard is a member of the World Economic Forum Global Agenda Council on the Challenges of Emerging Technologies, serves on numerous review and advisory panels around the world, and has testified on a number of occasions before U.S. Congressional committees.

Andrew explains why his ideas about regulation changed and how he wants to approach it,


Five years ago, the state of the science was such that it still seemed feasible that a regulatory definition of nanomaterials could be crafted. Today, that hope is looking increasingly tenuous. We know that size matters when it comes to understanding the risks presented by materials generally – and particles more specifically – and that characteristics such as physical form and chemistry are also important. But these are relevant from diameters of tens of micrometers – where particles begin to be able to penetrate organisms – down to the nanometer size range. At different length scales, different material-biology interactions lead to different mechanisms of action that have the potential to cause harm in different ways. But there are no rules that are generalizeable to the nanoscale specifically – that much the science is clear on. And this alone calls into question the scientific-basis of enforcing nanoscale-specific regulations.

Rather, the science suggests that we have a bigger task in hand – how do we develop a better understanding of how any particle capable of entering or otherwise interacting with an organism might cause harm, and how do we codify this in evidence-based guidelines that will inform regulation?

Here’s his proposal in a nutshell,

Difficult as it may be given the momentum of current efforts to define nanomaterials for regulatory purposes, now is the time to shift toward evidence-based regulation of sophisticated materials.

Andrew has written a paper about this proposal along with David B. Warheit and Martin A. Philbert, The New Toxicology of Sophisticated Materials: Nanotoxicology and Beyond (behind a paywall), in the journal Toxicological Sciences, (2011) 120 (suppl 1): S109 – S129, doi: 10.1093/toxsci/kfq372, in 50th Anniversary Issue.

I am intrigued but not yet convinced. I really must make time to read the paper. In any event, I encourage you to read Andrew’s full posting on the topic.