The flurry of recent announcements regarding reports, international cooperations, and new research activities that deal with the potential risks of manufactured nanomaterials is a clear indication that the field of nanotoxicology is gaining momentum - and not too soon. While there still is no coherent international approach to determining if and what risks are posed by what kind of nanotechnology materials, individual research groups are picking certain areas of concern and forge ahead with - often highly specific - toxicology studies. A lack of standards and definitions makes these early investigations hard to compare and sometimes they even contradict each other, a situation that is especially confusing in risk assessments of carbon nanotubes. Some studies, though, present findings that, on the face of it, are especially worrying in their potential implications and deserve much more attention to be sorted out one way or another. A recent report on the toxicity of metal nanoparticles in soil is such an example.
A new report prepared for the German Federal Ministry of Education and Research outlines an institutional model that meets the safety and security demands of human health, the environment and society. The report draws on an analysis of national and international approaches to nanotechnology regulation.
One of the key findings is that in the case of developing nanotechnologies, the place of classical regulation has been taken by precautionary measures such as observatories, voluntary codes of conduct and stakeholder dialogues. The development of an institutional model is proposed, the Scanning Probe Agency (SPA), as both a necessary and appropriate collective learning process and a means of generating public trust. Its guiding question would be: 'Is nanotechnology in good hands?'
The UK's Royal Commission on Environmental Pollution in a new report clearly states that it found no evidence of harm to health or the environment from nanomaterials but it believes that the pace at which such new nanomaterials are being developed and marketed is beyond the capacity of existing testing and regulatory arrangements to control the potential environmental impacts adequately. A major conclusion of the report is that nanomaterials are hugely variable in their nature. They are not a uniform class of materials, and attempts to regulate or legislate solely on the basis of their size or how they are made are misguided. It is the functionality of nanomaterials, i.e. what they do and how they behave, that matters and this should form the basis of governance and regulation. The report makes a number of recommendations on how to deal with ignorance and uncertainty in the area of nanomaterials, which could also be applied to other areas of fast-paced technological development.
Titanium dioxide nanoparticles have become a commercially significant nanomaterial and are being used in products around the world - in cosmetics and sunscreen lotions, paint formulations, coatings, self-cleaning additives, even in antibacterial applications. The increased use of nanomaterials such as titania goes hand in hand with a growing number of reports on the risks associated with these materials, which have arisen because insufficient information has been gathered about their reactivity and stability once they leave the laboratory. Unfortunately, pinpointing every conceivable situation that nanoparticles could interact in is an enormous multi-parameter problem and solving this by experimental testing alone is not feasible due to the huge numbers of combinatorial variations. This is where theoretical predictions can help, by rapidly and systematically sampling possibilities, and highlighting where experimentalists should focus their attention.
Adding yet another twist to the emerging debate about the potential risks of nanomaterials, researchers have demonstrated how difficult it is to map out the health effects of nanoparticles. They have shown that, even if a certain nanoparticle does not appear toxic by itself, the interaction between this nanoparticle and other common compounds in the human body may cause serious problems to cell functions. On one hand, this effect could be used to great advantage in nanomedicine for killing cancer cells. On the other hand, unfortunately, it is unknown at present whether the same effect could be observed with healthy cells as well. Since the number of possible combinations of nanoparticles and various biomolecules is immense, it is practically impossible to research them systematically. This latest example of the risk-benefit dichotomy of nanotechnology just shows how thin the line is between promising applications such as effective cancer killers and the unknown risks posed by unintentional effects of exactly the same applications.
There is a general perception that nanotechnologies will have a significant impact on developing 'green' and 'clean' technologies with considerable environmental benefits - be it in areas ranging from water treatment to energy breakthroughs and hydrogen applications. As a matter of fact, renewable energy applications probably are the areas where nanotechnology will make its first large-scale commercial breakthroughs. Conflicting with this positive message is the growing body of research that raises questions about the potentially negative effects of engineered nanoparticles on human health and the environment. However, there is one area of nanotechnology that so far hasn't received the necessary attention: the actual processes of manufacturing nanomaterials and the environmental footprint they create, in absolute terms and in comparison with existing industrial manufacturing processes. Analogous to other industrial manufacturing processes, nanoproducts must proceed through various manufacturing stages to produce a material or device with nanoscale dimensions.
The way things stand now, nanotechnology products can be sold unlabeled and the FDA regulates sunscreens only based on their sun protection factor. Cosmetic manufacturers, of course, claim that their products, including nanoparticle-based sunscreens are harmless. Indeed, nobody has demonstrated that they are unsafe - but the opposite proof, that they are perfectly safe, is missing as well. This confusing situation is due to the incomplete scientific picture created by a lack of relevant research. For instance, the question of whether or not nanoparticles can penetrate the healthy stratum corneum skin barrier in vivo remains largely unanswered. Furthermore, no studies so far have examined the impact of ultraviolet radiation on nanoparticle skin penetration. Since sunscreen is often applied to sun damaged skin, such a real world scenario, as opposed to in vitro studies in a test-tube, could go a long way in confirming or allaying fears. New research by scientists at the University of Rochester is the first to consider the effects of nanoparticle penetration through normal and barrier defective skin using an in vivo model system.
One term you hear quite often in discussion about the potential risks of nanotechnology is 'precautionary principle'. This moral and political principle, as commonly defined, states that if an action or policy might cause severe or irreversible harm to the public or to the environment, in the absence of a scientific consensus that harm would not ensue, the burden of proof falls on those who would advocate taking the action. The principle aims to provide guidance for protecting public health and the environment in the face of uncertain risks, stating that the absence of full scientific certainty shall not be used as a reason to postpone measures where there is a risk of serious or irreversible harm to public health or the environment. In 2001, an expert panel commissioned by the European Environment Agency (EEA) published a report, Late Lessons from Early Warnings: The Precautionary Principle 1896-2000, which explored 14 case studies, all of which demonstrated how not heeding early warnings had led to a failure to protect human health and the environment. It looked at controversial topics such as asbestos, Mad Cow Disease, growth hormones, PCBs and radiation - all of which demonstrated how not heeding early warnings had led to a failure to protect human health and the environment. The expert group that compiled the EEA report identified 12 'late lessons' on how to avoid past mistakes as new technologies are developed. These lessons bear an uncanny resemblance to many of the concerns now being raised about various forms of nanotechnology.