Field and Laboratory Measurements Related to Occupational and Consumer Exposures - Safety of Nanomaterials along Their Lifecycle - page 276

Information Database (NECID) is currently constructed under the umbrella of the
European partnership of Occupational Health and Safety research (PEROSH * ). The
NECID template is currently been used in all EU projects where exposure data are
generated and facilitates the population and use of the database.
The NECID database requires that data were determined according to measurement
strategies that support a harmonized comprehensive exposure assessment. Several mea-
surements strategies have been developed as described in Chapter 11 by Asbach et al.
Such strategies are pragmatic decision schemes in order to avoid comprehensive, time-
consuming, and expensive exposure measurements. In the case of nano-objects, their
agglomerates, and aggregates (NOAA, EN ISO 2012), it reflects the lack of analytical
capabilities and the costs of employing scientific instruments in the field. In these tiered
approaches, information is collected in each successive tier at a more detailed level in
order to reduce the uncertainty in the exposure estimates. The NEAT approach as devel-
oped by NIOSH (Methner et al. 2010) was one of the first tiered approaches applied
for nano exposure scenarios. Presently, a number of tiered-approach strategies have
been published: the one proposed by a number of institutions in Germany on which the
German nanoGEM project based their closely related proposal (Asbach et al. 2012), a
French approach (Witschger et al. 2012), and the tiered approach proposed by McGarry
and coauthors (McGarry et al. 2012). All approaches start with a relatively simple and
limited set of measurements and/or gathering basic information on processes, jobs,
and materials in a first tier followed by extended assessment in subsequent tiers. The
decision criteria to enter the next tier are key factors for such approaches; for example,
nanoGEM uses a situational-driven criterion: An emission or exposure concentration at
a workplace is considered to be significantly increased above background if it exceeds
the background concentration plus its threefold standard deviation (Asbach et al. 2012).
A slightly different approach has been proposed by The British Standards Institution
(BSI 2010), and adopted by van Broekhuizen et al. (2012), respectively, that makes use
of benchmark levels or nano reference values. If the exposure exceeds an “action level,”
actions are required, for example, for more detailed measurements or control measures.
The nonsubstance specific reference values are expressed as particle size integrated
total particle number concentration and could as well be used in the framework of a
tiered approach. Recently, some projects have started to evaluate the decision crite-
ria proposed in the various tiered approaches, for example, the Business and Industry
Advisory Committee within OECD WPMN SG8 and CEN project on Guidance and so
on, see also Chapter 11 (Asbach et al., this topic).
Occupational exposure limits have not yet been derived for any NOAA, neither by
the European SCOEL (the Scientific Committee on Occupational Exposure Limits)
nor by any national OEL-setting authority. However, NIOSH (2011, 2013) has pro-
posed mass-based recommended time-weighted exposure limits for two materials,
that is, nanoTiO 2 and nanocarbon nanotubes (CNTs). The German MAK (maximale
Arbeitsplatzkonzentrationen) Committee is currently discussing a general limit
value for airborne nano-objects and nanomaterials as described in the BegKS 527. †
* http://www.perosh.eu/research-projects/perosh-projects/exposure-measurements-and-risk-assess-
ment-of-manufactured-materials-nanoparticles-devices/.
† http://www.baua.de/en/Topics-from-A-to-Z/Hazardous-Substances/TRGS/Announcement-527.html;j
sessionid=26C257784F8C77E286DD99E15D507CFD.1_cid389.