Every generation of industrial development has brought us new pollutants, and there is growing concern about the toxicity of mass-produced nanomaterials.
The New York Academy of Sciences held a fascinating symposium Monday on emerging toxic threats from nanomaterials, with a couple of speakers who covered an enormous expanse of space - from the latest science on predicting toxic effects of future materials to the policy and regulatory responses to maximize innovation and minimize negative impacts. Consider just one class of materials - there are some 50,000 types of carbon nanostructures already. Assessing the toxicity and regulating the use of each unique molecule clearly won’t work.
The Science
The session began with a fascinating talk by one of the first scientists to raise the issue of nanoparticle toxicity, Gunter Oberdorster, University of Rochester. You have to love a scientist who papers have titles such as “Effects of on-road highway aerosol exposures on autonomic responses in aged, spontaneously hypertensive rats”. But those little rats may be the only thing standing between us and whole host of nasty new toxins.
In a comprehensive look at the biological implications of nanoparticles, Professor Oberdorster described how two properties of nanoparticles - their very small size and their very large surface area per unit mass, challenge the body’s ability to defend itself. His research with rats has shown how nanomaterials that are inhaled work their way past the lung’s natural defenses quickly and in large volumes. While much of the material is passed as feces, significant amounts work their way into the liver, bone marrow and brain.
More alarming, though, was his discussion of how the olfactory nerve system - which connects the nerve network in our noses to the brain - could be a pathway for transmission of inhaled nanoparticles directly to the brain.
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He described some examples of populations that are well-known to have been exposed to nanoparticles, such as welders - who are exposed to high levels of manganese oxide nanoparticles. Welders have a high incidence of Parkinson’s disease linked to this toxic substance, and he wonders if the olfactory nerve pathway is a possibility. This would have big implications for how we think about nanoparticles.
In the end, he argued that “many nanoparticles probably do not pose a health risk to consumers, but some will. The goal of my research is to identify the highly reactive nanoparticles”
More information on his research can be found at: http://www2.envmed.rochester.edu/envmed/TOX/faculty/oberdoerster.html
The Policy Debates
The next speaker was Andrew Maynard, Chief Science Advisor for the Woodrow Wilson Center’s Project on Emergent Nanotechnologies (http://www.nanotechprojects.org). His talk was titled “Nanotechnology: Science, society and policy”.
Maynard’s talk began by pointing out the three great benefits of nanotechnology:
1) the enormous commercial potential - over the next seven years the total consumer and commercial market is projected at $3 trillion.
2) The potential for great social benefits through transformative advances in materials, medical treatments, water processing technology, and energy efficiency.
3) The interdisciplinary nature of nanotechnology means it is stimulating scientists to work together in novel, innovative ways.
Most of his talk though focused on the obstacles to fact-based policymaking around nanotechnology. He shared some public opinion polls commissioned by the Wilson Center on attitudes towards nanotechnology. It found that even when people were informed about the benefits and risks of nanotechnology a larger share became skeptical that the benefits would outweigh the risks, compared to when they were previously uninformed. Focus groups that were conducted after the surveys revealed a tremendous consumer demand for transparency and more information about nanomaterials used in products.
On the bright side, though, while there is a lot of uncertainty today paralyzing policy formation - government is uncertain, industry is conflicted, and consumers are cautious - there is a political understanding of the need to assess and manage the risks.
He thus outlined five grand challenges in assessing the risk related to nanomaterials.
1) How can we measure exposure to engineered nanomaterials in the air or water?
2) How can me characterize the potential toxicity of nanomaterials?
3) How can we understand the entire life cycle hazard - production, use, disposal?
4) How can we predict the toxicity of future materials so you can make decisions about what to pursue?
5) What government strategies need to be put in place to address these points?
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