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Engineered Nanoparticles: Review of Health and Environmental Safety

Final Report Summary - ENRHES (Engineered nanoparticles: review of health and environmental safety)

The project presents a comprehensive and critical scientific review of the health and environmental safety of four classes of nanomaterials: fullerenes, carbon nanotubes (CNT), metals and metal oxides. The report includes an illustration of the state-of-the-art as well as on-going work, while identifying knowledge gaps in the field. Prioritised recommendations have been developed and set in the context of informing policymakers in the development of methods to address exposure as it relates to the potential hazards posed by engineered nanoparticles, and in the development of appropriate regulation.

The review provides context for the materials chosen, in term of the production techniques, applications and market value. This is supplemented with the findings of an industry survey carried out in an attempt to gather up to date information on the quantities of various types of nanomaterials produced and used, the type of products in which they are used, any exposure data gathered and risk assessment practices employed. The review highlights the essential role which nanoparticle characterisation plays in a variety of overlapping contexts ranging from fundamental and applied research, through process and product quality control and commercialisation, to health and environmental protection. In the context of exposure assessment, the review shows that there is, in general, a paucity of published data.

A wide range of instruments and approaches were used and exposures were reported in terms of number, mass and surface area concentrations, as totals and differentiated as a function of size. Similarly, the review highlights the general paucity of data in the area of environmental fate and behaviour, which represents a major obstacle in developing a holistic view of the fate and transport of nanomaterials within the environment and therefore environmental exposure. A substantial appraisal of the toxicity of nanoparticles is presented for each nanomaterial class, identifying the underlying mechanisms driving each of their toxicities, and determining whether any generalisations can be made regarding nanomaterials as a whole. When appraising the available epidemiology and human studies, the paucity of data relating to CNT, fullerene, metal and metal oxide nanoparticles, has required a broader approach. This draws upon the depth and breadth of knowledge available for a small number of nanoparticles which have been manufactured at the industrial scale for decades.

The review of the literature on the ecotoxicity of nanoparticles has addressed aquatic toxicity, terrestrial toxicity, bioaccumulation, and degradability. A special effort has been put into translating the effects, found in the reviewed papers, into the terminology traditionally used in risk assessment, e.g. ECx- and LCx-values and NOEC/LOEC-values. The penultimate chapter presents a basic risk assessment, inspired by the REACH guidance, for the four types of nanomaterials under review based on the information provided by preceding chapters of the review.

In conclusion, the review's findings strongly supports the further development of thorough characterisation (including proper considerations of agglomeration/aggregation) of the nanoparticles in exposure media when conducting exposure assessment, as well as in the generation of data for determining exposure to both humans and the environment as well as assessing hazardous properties. Further testing strategies are required to be established to cover all relevant endpoints needed for a risk assessment. At present, carrying out risk assessment of nanoparticles can only sensibly be done on a case-by-case basis. Only when more data becomes available may it be possible to group nanomaterials according to their physical, chemical and/or biological properties or mode of action, so that testing could be done for representatives of each group.