The EMERGNANO project - a first global review of active research into the environment, health and safety risks of nanotechnology, provides a unique attempt to identify and assess worldwide progress in relation to nanotechnology risk issues. It was led by the UK-based SAFENANO & carried out on behalf of
Defra
, the UK Government Department for Food & Rural Affairs.
The Background
The 2004 Royal Society and Royal Academy
of Engineering review "Nanoscience and nanotechnologies: opportunities and uncertainties" highlighted the potential risks to health and the environment from exposure to nanoparticles, emphasising that there is a lack of knowledge about what these risks are and how to deal with them and revealing that more information about the toxicity, exposure and risk is required. Since publication of this report, there has been a significant increase in research activity in the UK and internationally intended to fill these gaps. Such work has been funded by both national government activity and in research programmes within each country and at an international level.
In 2005, the Nanotechnology Research Coordination Group(NRCG), chaired by Defra, was set up in the UK to determine priorities and to coordinate publicly funded research into the potential risks presented by the products and applications of nanotechnologies. Its first research progress reportset out a programme of 19 Research Objectives (ROs) to characterise the potential risks, across five main scientific areas (Task Force Areas):
i) Metrology, Characterisation, standardisation and reference materials;
ii) Exposures – Sources, pathways and technologies;
iii) Human health hazard and risk assessment;
iv) Environmental hazard and risk assessment;
v) Social and economic dimensions of nanotechnologies.
EMERGNANO - the Project Process
The EMERGNANO project, through a multidisciplinary panel of expert reviewers, has carried out a detailed review and analysis of research carried out worldwide on Environment, Health and Safety aspects of engineered nanoparticles, (NP) including issues relating to hazard, exposure and risk assessment and regulation, and made an assessment of how far 18 of these ROs have been met and which gaps still remain to be filled1. The report includes, as far as practicable, an appraisal of the research results with a view to highlighting any new information that may trigger a consideration for the need for regulation of nanomaterials, an assessment of the possibility of a qualitative risk assessment and whether there is sufficient information to invoke the precautionary principle for one or more nanomaterials, and recommendations for new research to fill gaps.
On an international basis, EMERGNANO identified more than 670 projects and, after careful selection, assessed more than 260 unique, relevant projects completed, close to completion or in progress since 2004. The greatest number of studies identified were carried out in the US, followed by the UK (fig. 1). A widespread imbalance in the work being carried out (in terms of numbers of studies) was found between the four main task force areas and within the eighteen research objectives. The largest number of studies was in the Human Health area, followed by the Exposures area; those identified in both the Environment and Characterisation areas were substantially lower. The distribution by RO was even more striking. RO14 (Research to establish a clear understanding of the deposition, distribution, toxicity, pathogenicity and translocation potential & pathways for nanoparticles in the airways and lung, and their potential impacts on the cardiovascular system and brain) had 44 studies identified as relevant, whereas RO9 (Optimisation, development and application of technologies that enable the measurement of exposure to nanoparticles in soil and water) had only one study.
Fig. 1: Geographic Distribution of studies, according to state of progress (as of October 2008)
Due to a lack of information from publicly funded studies being released into the public domain, EMERGNANO was unable to identify useful output from many of the studies involved in the programme, including studies which had already been completed. As a result, it is accepted that EMERGNANO will not have captured all of the information available on these studies.
Progress is being made...
Assessment of the available research outputs in the context of the NRCG research objectives, has revealed that some important contributions have been made. These include:
In terms of characterisation and reference materials, progress has been made in identifying candidate materials which may be used to develop characterised reference nanoparticles for toxicology. Candidate lists, along with minimum characterisation specifications, have been developed and some commercial reference materials are beginning to emerge;
In terms of exposure assessment and control, it is now clear that filters, such as those used in respiratory protective equipment and in air cleaning systems, are highly effective in removing nanoparticles from the air;
In toxicology, the lack of mass balance toxicokinetics for any nanoparticle and the patchy nature of the published toxicokinetic data is a severe impediment to identifying extra-pulmonary hazards. This feeds through to problems in utilising plausible doses, for example, in an in vitro study with liver cells or blood components. The use of only a very limited number of particle types and sizes makes it impossible to know whether all NP act the same as regards toxicokinetics, or whether there will be a structure activity relationship that highlights certain sizes and surface chemistries as factors enhancing or limiting potential of any NP to translocate or be toxic, as seems likely;
In ecotoxicology, studies have improved the understanding of kinetics of nanoparticle uptake in invertebrate and vertebrate models and have related this to toxicity. In addition, there are now a few studies focussing on microbial organisms and these provide information on effect assessment at individual level and also at community level.
In relation to the targets posed by each RO it is clear that at this point in time, based on the evidence available, progress thus far has been disappointing. Whilst many studies are undoubtedly contributing in an incremental way to the advancement of knowledge, many of the key questions are yet to be resolved. However, for those projects which are due to commence or have just started, evidence exists to support the view that the work in these projects will deliver much more in terms of output than the projects which are currently reaching completion.
...But significant gaps remain
Despite important contributions being made, it is clear that the major gaps in the knowledge base still remain. In all of the major thematic areas addressed (characterisation, exposure, toxicology and ecotoxicology), and all of the specific ROs, there is a substantial body of work remaining to be done. The programme of research has yet to deliver step changes in the knowledge base on these issues.
In assessing quality and completeness for the purpose of carrying out a risk assessment, EMERGNANO did not identify a sufficient body of evidence in any case to make a risk assessment feasible. However, three different nanomaterials have been identified that give rise to concern from the results presented within the RO reports: carbon nanotubes may have an adverse effect on human health; and both silver nanoparticles and titanium dioxide nanoparticles are detrimental to the environment. In these specific cases, further investigation as to the need to invoke the precautionary principle is required, taking into consideration all available data.
Conclusions
In conclusion, the EMERGNANO project has been a unique attempt to identify and assess worldwide progress in relation to nanotechnology risk issues. Despite a lack of available information in some cases, the project has been successful in identifying the overwhelming majority of important studies and enabled leading researchers to assess these studies as to their output and relevance. As part of the project, a comprehensive listing of projects, including detailed comments and assessment of their outputs, has been compiled. It is the authors’ view that EMERGNANO represents the best available picture currently available of current strategic research. As such, EMERGNANO presents an excellent basis for assessing progress of these and other studies in the future. Overall, EMERGANANO points to the need for a more strategic, co-ordinated agenda for nanotechnology risk research to be developed, funded and implemented.
To read the full version of the EMERGNANO report, click here.
1RO01, Nanotechnologies and public engagement, was specifically excluded from the remit of the EMERGNANO project.