Concern-Driven Safety Assessment of Nanomaterials - Safety of Nanomaterials along Their Lifecycle - page 365

can be used for occupational exposure control. This strategy is based upon selected
“benchmark” materials representing various MOA classes. New NMs are classi-
fied in accordance to the hazard and risk estimates of the respective benchmark
substances that exhibit the same MOA (Kuempel et al. 2012). A key challenge in
setting MOA-based classes is obtaining sufficient dose-response data to system-
atically evaluate the physicochemical factors influencing NM biological activity. In
the absence of substance-specific information, categorization processes involve both
science-based analyses and default assumptions (Kuempel et al. 2012).
Also for occupational safety assessment, the German Federal Institute for
Occupational Safety and Health (BAuA, Bundesanstalt für Arbeitsschutz und
Arbeitsmedizin) distinguishes three different groups of NMs, which combine infor-
mation on specific physicochemical characteristics and effects or kinetic properties:
(1) NMs that release granular biopersistent particles, (2) NMs that release fibrous
dusts (for these two groups, pulmonary inflammation and lung cancer are potential
health effects), and (3) NMs that have a specific “chemical” toxicity, that is, release
of toxic ions, activity of chemical functional groups, and catalytic activity (Packroff
2013).
In a position paper on NMs and REACH, the German competent authorities (BAuA,
together with the Federal Environment Agency [UBA; Umweltbundesamt] and the
Federal Institute for Risk Assessment [BfR; Bundesinstitut für Risikobewertung])
describe three conceivable scenarios for waiving of testing during NM hazard
assessment, that is, (1) use of data by referencing between the bulk and nanoform of a
substance, (2) use of data by referencing between different nanoforms of a substance,
and (3) read-across between substances with different chemical identities (possibly
various bulk and nanoforms) (German Competent Authorities 2011). Approaches for
grouping and waiving are recognized to be particularly important for substances
having a large number of different nanoforms. The German position further antici-
pates that waiving will be rare in the beginning, but has the potential to increase
as standardized tests have shown that results from substances in bulk form can be
utilized for NMs (German Competent Authorities 2011).
16.4 INTEGRATED APPROACHES FOR NANOMATERIAL
SAFETY TESTING AND ASSESSMENT
In the following, the different tiers of an initial framework for concern-driven inte-
grated approach for NM testing and assessment are summarized (for further details,
also covering IATA of NM effects on the environment, see Oomen et al. 2013).
Further work on this framework is ongoing, as well as on ways of integration of the
grouping concept.
16.4.1 i identifiCation of “nm of C onCern ”
The first step of any NM risk assessment implies determining that the material
under consideration is in fact a NM (Figure 16.3, step 1). This depends on the defini-
tion of NM used, but usually at least includes chemical characterization as well as
some particle shape characterization. The respective EU Recommendation defines