Viewpoint
t Formulating the Problems for Environmental Risk Assessment of NANOMATERIALS
D
o manufactured nanomaterials pose risks to the environment? Should we commit large amounts of funding to detailed assessments of their potential environmental risks? At a time when several countries and international organizations are considering these issues and when vocal calls are being made for significant funding allocations in this area (1, 2), we pause to reflect on how we arrived at asking these questions. We then ask what can be done to help us decide with more confidence whether this is a priority that needs to be assessed in detail. Our analysis suggests that, although many of us understand quantification of exposure and hazard as being important parts of environmental risk
5582 n Environmental Science & Technology / August 15, 2007
assessment, two initial components are critically important but sometimes overlooked: problem formulation and prioritization (3). These help us define the actual problem in the context of the environment as well as how it should be addressed for one or more nanomaterials. They also help us prioritize whether it is worth spending time and money on a more detailed quantification of environmental risk for any given material. This process, which is informed by numerous factors, including scientific evidence, public opinion, and perception of risks and benefits, forms the basis for an international approach to tiered risk assessment. It is designed to help us make better decisions about where we should invest limited resources. © 2007 American Chemical Society
images Courtesy of CBEN / RICE UNIVERSITY
RICH A RD OW EN U.K. EN V IRONMENT AGENCY UNIV ERSIT Y OF PLY MOUTH (U.K.) RICH A RD H A NDY UNIV ERSIT Y OF PLY MOUTH (U.K.)
The diversity of nanomaterials challenges us to consider how we prioritize them for environmental risk assessment. We argue that the most urgent need is to formulate the problems correctly and understand the wider context in which they are framed. Establishing a harmonized framework with guiding principles for this process can help. Such a framework can help us make better, more defensible decisions about environmental risk assessment, in terms of both the level and direction of funding allocations, and develop the evidence base required to inform appropriate controls. Continuous innovation suggests that the process needs to be iterative, inclusive, and supported by enabling tools to ensure that robust and consistent data feed into it. And these issues go beyond nanomaterials themselves. They challenge us to ask how we can consistently and transparently formulate the problems for environmental risk assessment of emerging technologies in a far wider sense, and perhaps just as importantly, who should have a role in this process.
Shaping the agenda: from gray goo to nano particles Our analysis starts with a short retrospective of how the agenda for environmental risk assessment of nanomaterials has been shaped during the past few years. It is important at the outset to emphasize (and welcome) the prospective approach to environmental risk assessment of nanomaterials. This contrasts with some notable cases in which quantitative risk assessment was prompted after adverse effects (e.g., endocrine disruption) were observed in the environment. This has not been the case for nanotechnologies. In fact, several years ago, concerns over nanotechnologies were not focused on the environment at all but rather on autonomous “nano robots” or “gray goo” self-replicating in an uncontrolled manner. Although later dismissed as highly unlikely and a distraction from the important issues (4), these fears did serve to kindle the public imagination and raise the profile of the issue. So, what are considered the important environmental issues for nanomaterials? By way of illustration, it is useful to consider what has happened in
the U.K. In 2003, its government commissioned two of its leading scientific bodies, the Royal Society and the Royal Academy of Engineering, to undertake an independent study investigating the opportunities and uncertainties associated with nanotechnologies, including environment, health, and safety aspects. Good consultation and an understanding of the need for public engagement and stakeholder dialogue were important features of this study. Their seminal report, published in July 2004 (4), established some important preliminary thinking for occupational and environmental risk assessment of nanomaterials. It highlighted something that has been confirmed subsequently: a lot is at stake. Nanotechnologies are expected to be a trillion-dollar industry within decades, bringing significant potential socioeconomic, health, and environmental benefits. The number of nano-based consumer products already on the market is considerable (5). The report concluded that realizing those benefits would require substantial investment in risk assessment and risk communication. Importantly, it also concluded that “many applications of nanotechnologies pose no new health or safety risks. . . . Currently we see the health, safety and environmental hazards of nanotechnologies as being restricted to discrete manufactured nanoparticles and nanotubes in a free rather than embedded form” (4). The focus had moved away from what seemed to be rather far-fetched concerns about gray goo. The report, through careful examination of the underpinning science, showed that particles
