Life Cycle Aspects of Nanoproducts, Nanostructured Materials, and Nanomanufacturing: Problem Definitions, Data Gaps, and Research Needs

Chicago, Illinois: November 5-6, 2009

Synopsis for UIC Workshop on Life Cycle Aspects of Nanotechnology

Kevin C. Elliott
Department of Philosophy
University of South Carolina

I should begin with two caveats.  First, I come from the humanities rather than the natural or social sciences.  Second, my scholarship has focused primarily on the elements of life cycle assessment associated with human and environmental health.  Partly because of these limitations, I view my role in the workshop not as a source of factual information but rather as someone who can stimulate reflection about a number of the value-laden judgments involved in the life cycle assessment of nanoproducts and nanomanufacturing.  My goal is to provide suggestive examples and questions that can assist the conference participants in identifying important judgments and considering how to address them.  Some of the value judgments associated with LCA are fairly obvious, but I want to emphasize some of the implicit judgments that are intertwined with what might appear to be fairly straightforward scientific activities.

A number of the critical questions that we were asked to address in our synopsis revolve around identifying crucial bodies of information that should be collected in order to facilitate LCAs of nanoproducts and nanomanufacturing.  Because we currently face such a dramatic lack of data, especially regarding the environmental and human health effects of nanomaterials, I would encourage the workshop participants to think carefully about the subtle consequences of calling for the collection of some bodies of information rather than others.  Consider four examples:

  • If we need to choose particular nanomaterials (or nanomaterial classes) to serve as heavily studied case studies, which ones should be chosen and why?  For example, even though ceramic nanomaterials are predicted to be particularly widely used industrial materials in the near future, their toxicological effects are difficult to study, both because they tend to be photoactive and because they form aggregates and agglomerates.  Thus, one might ask whether to encourage detailed studies of ceramics (because of their potential to be widely used) or instead focus on materials that are easier to study (and therefore more likely to yield generalizable results), or pursue a compromise.
  • A similar judgment concerns how much to prioritize toxicology studies of individual, highly purified nanomaterials, as opposed to the more heterogeneous mixtures of substances that are likely to appear in waste streams from nanomanufacturing processes.  Detailed studies of individual materials may be more helpful for the purposes of developing models that can be applied to a range of contexts, but studies of mixtures are likely to uncover otherwise unknown threats that are highly relevant to LCAs.  For example, a study by Thomas Chandler and his colleagues showed little toxicity from single-walled carbon nanotubes, but some of the byproducts of the nanotube manufacturing process were toxic. 
  • What biological models would be most helpful in toxicological studies that are to be used for informing LCA?  For example, because zebrafish are a widely used model organism, toxicology studies with them could generate useful information about genetic and developmental factors associated with toxicity.  Nevertheless, because zebrafish are not native to most ecosystems where nanomaterials are likely to be released, we might obtain more realistic information about the ecological effects of nanomaterials by studying other species or even by focusing on groups of species in mesocosms.
  • Because LCAs generally cannot incorporate as much toxicological detail as risk assessments, it may be tempting to focus only on collecting information about the acute effects of nanomaterials on human or animal mortality.  Nevertheless, toxicologists are becoming increasingly concerned about more subtle, chronic toxic effects, such as developmental and reproductive abnormalities.  Deciding how much of our limited time and money to devote to these broader issues is another important question.

While these examples focus only on a few categories of LCIA (primarily those associated with environmental health and safety), my hope is that they will stimulate other workshop participants to generate similar examples that involve other aspects of life cycle assessment.   

Besides these specific sorts of value judgments, an important higher-level question is how extensive a role LCA ought to play in developing public policy for nanotechnology.  It is tempting to argue that it should play a crucial role, but policy analysts such as Dan Sarewitz have argued that it is sometimes unwise to depend too much on science to settle policy questions.  For example, in emerging areas of study such as nanotechnology, scientific analyses are plagued by uncertainties that can easily be challenged and manipulated by interest groups.  Therefore, it is important to ask where to place the burden of proof when scientific evidence is limited.  For example, should we generally start with the presumption that a conventional product is better than, equivalent to, or less environmentally friendly than a new nanoproduct?  Taking into account the limited availability of time and money, what standards of evidence should we then require for altering this initial burden of proof, and what sorts of LCAs (if any) would be best for providing this level of information?

Finally, I would encourage the workshop participants to develop a list of important questions that should be addressed in deliberative discussions that include a wider range of stakeholders.  The NRC document Understanding Risk (1996) emphasized that broadly based deliberation is normatively, substantively, and instrumentally advisable in response to the value-laden elements of risk characterization, and I think that one could formulate similar arguments in favor of broadly based deliberation about the life cycle assessment of nanomaterials.  Although expert gatherings such as the present one may be adequate for addressing fairly technical issues, there are also complicated social issues to consider, such as whether nanoproducts could replace raw materials that currently play a crucial role in some national economies.  Social scientists have already been experimenting with very creative approaches for generating public deliberation about nanotechnology, with the National Citizen’s Technology Forum based at Arizona State University being a prime example.  It would be useful to identify issues associated with LCA that could be considered in future deliberative forums of this sort.