| Posted: June 22, 2009 |
Literature review - workplace exposure to nanoparticles |
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(Nanowerk News) The European Agency for Safety and Health at Work (OSHA) has published "Literature Review - Workplace exposure to nanoparticles" (pdf download, 1.6 MB) which reviews the most recent publications on nanoparticles and focuses on the possible adverse health effects of workplace exposure. The report presents the regulatory background and activities taken to manage this emerging risk.
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| Aufnahme einer Küvette mit einem Rasterelektronenmikroskop (REM). (Bild: Kompetenzzentrum Nanochem)
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From the report: The European Agency for Safety and Health at Work has published a series of expert forecasts
providing an overview of the potential emerging risks in the world of work (physical, biological,
psychosocial and chemical risks). Among the top ten emerging risks, three have in common their
physico-chemical state as insoluble particles or fibres: nanoparticles and ultrafine particles, diesel
exhaust, and man-made mineral fibres. The experts agreed that nanoparticles and ultrafine particles
pose the strongest emerging risk.
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Nanomaterials possess various new properties and their industrial use creates new opportunities, but
they also present new risks and uncertainties. Growing production and use of nanomaterials result in
an increasing number of workers and consumers exposed to nanomaterials. This leads to a greater
need for information on possible health and environmental effects of nanomaterials. This report
focuses on the possible adverse health effects of workplace exposure to engineered nanomaterials
and possible subsequent activities taken to manage the risk. Nanomaterials originating from natural
sources as well as non-intended nanoscale by-products, such as diesel engine exhaust and welding
fumes, are not included in this review. In order to provide a broad overview, information from different
sources such as scientific literature, policy documents, legislation and work programs were collected.
Documents from the EU were given priority, although national and international activities have also
been described. Studies published up to November 2008 have been considered in the report.
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When particle size is decreased to the nanoscale range, physical and chemical properties often
change with consequent new product opportunities. Thus a considerable future expansion of the
nano-market is expected. Nevertheless it should be remembered that nanomaterials are not fully new:
some established chemicals like amorphous silica or carbon black show a nanostructure. The
knowledge about the occupational exposure to new nanomaterials is very limited. In addition, the
measurement techniques to determine exposure are not fully developed. Various physical and
chemical parameters have to be considered.
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Different methods to investigate possible health effects of nanomaterials, such as in vivo- and in vitromethods
and methods to determine physico-chemical properties, are currently under discussion. The
standardised in vivo-studies represent at present the best standard to detect toxicity evoked by
nanomaterials. Effects like inflammation, fibrosis and tumours were induced by several granular
nanomaterials in the lungs after respiratory exposure. Currently the mechanism of tumour formation is
not fully understood and scientific uncertainties remain. Thus, the evaluation of toxicity is not only
influenced by results from toxicity studies but also by the policy decision to what extend the
precautionary principle is applied in case of scientific uncertainties. Skin exposure is not yet
investigated in detail. Generally, in case of insoluble substances skin exposure is not as relevant as
respiratory exposure.
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The current principles of risk assessment seem to be in general appropriate; however, the validation of
in vitro methods and the development of a testing strategy remain future tasks. Classification and
labelling as well as occupational exposure limits, which are derived from toxicological data, are
appropriate instruments for management of risks resulting from exposure to nanomaterials, but
critically depend on the availability of studies on toxicity.
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Several handling guidelines describing possible risk management activities and best practice were
published. These are mainly based on technical feasibility and some of them recommend, based on
the precautionary principle, to minimise exposure as far as possible. The protective measures that are
typically used to protect against insoluble materials, like dusts, are often recommended also for
nanomaterials. Because of the particular smallness of nanomaterials, especially the filter
materials/media used in general ventilation systems, personal respiratory protective devices and the
materials of gloves have to be examined. Preliminary studies indicate a protective effect, but further
research is needed. In relation to filtering half masks, the lack of tightness (inadequate sealing)
between face and the mask seems to be the most important risk factor. Control banding methods are
used to assess occupational exposure in the case of non-existent occupational exposure limits or
exposure measurements. First initiatives to adapt this method to nanomaterials have been developed,
but need further elaboration. An important instrument of risk management providing information about
hazards and appropriate control measures is the Material Safety Data Sheet. To what extent this
instrument considers nanospecific properties sufficiently is currently under discussion.
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Several statutory instruments are in place to ensure an appropriate level of protection of workers. The
general framework is provided by the regulation on occupational safety and health of workers (EU
Directive 89/391/EEC) and specifically for chemical safety - the directive on the protection of the
health and safety of workers from the risks related to chemical agents at work (Directive 98/24/EC).
Substance-specific regulation is intended by the biocide Directive (Directive 98/8/EC) and the
regulation No 1907/2006 (REACH – Registration, Evaluation, Authorisation and Restriction of
Chemicals). Currently it is discussed how to consider appropriately the broad variety of nanomaterials
in these regulations.
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The Community strategy on health and safety at work for the period of 2007 – 2012 includes
nanotechnology as an important topic to be worked on in the context of the identification of new,
emerging risks. Furthermore a communication from the European Commission ‘Towards a European
Strategy for Nanotechnology’ was published. The European Commission developed an “Action Plan”
to implement a safe, integrated and responsible approach for nanosciences and nanotechnologies. To
ensure a safe and ethical development and use of nanotechnologies, the European Commission
issued a Code of Conduct. There are many ongoing initiatives/activities aiming at the development of
a safe, sustainable, responsible research and development of this new technology. Large scale
research and standardisation programmes have been started and partly finalised to establish
standards, close data gaps and reduce uncertainties. European and global collaboration is recognized
as an important aspect in achieving these goals. Activities have been initiated by organisations such
as the International Organization for Standardization (ISO) and the Organization for Economic Cooperation
and Development (OECD) to support a globally harmonised development. Collaboration
between EU and US is also being developed to investigate the regulatory challenges posed by
nanotechnologies and to assess the effectiveness of existing approaches on both sides of the Atlantic.
The project takes a comparative perspective and contributes to the early identification of regulatory
methodologies and best practices that promote regulatory convergence between the EU and US.
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As the conclusion of this review of the most recent publications, the following topics are identified as
priorities for future actions and activities:
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identification of nanomaterials and description of exposure
measurement of exposures to nanomaterials and efficacy of protective measures
risk assessment of nanomaterials in line with the current statutory framework
in vivo studies for assessment of the health effects of nanomaterials
validation of the in vitro methods and methods of physico-chemical properties as methods to determine health effects
training of workers and practical handling guidelines for activities involving nanomaterials in the workplace.
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