On February 18, 2009, the European Commission (EC) Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) published its opinion on the most recent developments in the risk assessment of nanomaterials. In its opinion, SCENIHR indicates that methodologies to assess exposure to manufactured nanomaterials to humans and the environment and the identification of potential hazards require further development. For lack of a general approach, SCENIHR maintains its earlier recommendation to perform risk assessment case-by-case for each nanomaterial.
The Opinion identifies the following issues:
- Characterization of manufactured nanomaterials: There is currently a need for reference nanomaterials. The absence of well-defined parameters to measure and of standardized test protocols is identified as a major obstacle for reference material production. It should be noted that for use in biological systems certain compounds need to be added, which may have an effect on nanomaterial composition and properties resulting in changes in (toxic) behavior.
- Human exposure: Exposure estimates for consumers from food and consumer products remains difficult. Information on the presence of manufactured nanomaterials solely relies on information provided by manufacturers. In addition, exposure estimation is also hampered by lack of information on product use and use of multiple products containing manufactured nanomaterials. The main issues may be summarized as problems in replicating actual exposure conditions in laboratory tests and the lack of general availability of robust and specific measurement methods. Exposure assessment needs to consider each stage in the life-cycle.
- Human hazard: The main issues for human hazard identification may be summarized as a need to ensure that each test system is appropriate for nanomaterials and to ensure that endpoints of potential particular concern (e.g., cardio-vascular effects) are properly addressed.
- Environmental exposure: The main issues may be summarized as the development of suitable methods to assess the distribution of nanomaterials in the environment and the lack of portable monitoring equipment to measure levels of nanomaterials in different environmental media. In addition, for many manufactured nanomaterials the methods currently used (carbon dioxide production, integration into biomass) for determining biological degradation will not be applicable.
- Environmental hazard: The main issues for environmental hazard assessment may be summarized as the need for validation of laboratory test systems for characterizing the effects of nanomaterials and the need for studies of the impacts of specific nanomaterials on ecosystems.
- Risk assessment: Health and environmental hazards have been demonstrated for a variety of manufactured nanomaterials. It should be noted that not all nanomaterials induce toxic effects, however. As there is not yet a generally applicable paradigm for nanomaterial hazard identification, a case-by-case approach for the risk assessment of nanomaterials is still recommended.