Concern-Driven Safety Assessment of Nanomaterials - Safety of Nanomaterials along Their Lifecycle - page 357

INFORMATION BOX 16.1 DEFINITIONS RELATED TO
NONTESTING APPROACHES IN THE CONTEXT OF REACH
(Anon. 2006 (Annex XI); ECHA 2008 and 2010; German Competent
Authorities 2011; ECHA 2013)
Nontesting approaches imply not generating new data, but extending and
extrapolating existing information to facilitate the evaluation of the intrinsic
properties of chemicals.
Grouping is the process of assigning chemical substances to a “group” (or
“category”); based upon similar or regular patterns of physicochemical, bio-
logical, exposure, biokinetic, or environmental fate properties. For conven-
tional chemicals, these similarities may be due to common functional groups,
common precursors, likely common breakdown products, or a constant pattern
of a given property across the group.
Read-across is the application of the grouping concept to predict end
point-specific information for the target substance by using data for the same
end point from other substances. Thereby, the need to test every substance
for every end point is avoided. During the analogue approach , a very lim-
ited number of substances are compared, whereas the structural or category
approach implies comparing larger numbers of substances.
(Q)SAR models are mathematical models (tools) that can be used for a
qualitative (SAR) or quantitative (quantitative structure activity relationship
[QSAR]) prediction of the physicochemical, biological, and environmental
fate properties of compounds from the knowledge of their chemical structure.
Computer models are also called in silico models.
Expert systems are more complex models consisting of combinations of
SARs, QSARs, and databases.
Weight-of-evidence implies that the information obtained from several
independent sources allows assuming or concluding that a substance has a
particular property, whereas the information from each single source alone is
regarded insufficient to support this notion.
Waiving of an information requirement in the context of REACH means
that the submission of the standard information for the particular end point is
not considered necessary in a specific case.
Council's strategy for toxicity testing in the 21st century (CTTAEA and NRC 2007).
This “Tox21” initiative aims for a paradigm shift in toxicological testing that relies
less on animal studies and focuses more on in vitro methods to evaluate the effects
that chemicals can have on biological processes using cells, cell lines, or cellular
components that are preferably of human origin. It should be noted that at present
most NM risk assessments rely mostly on in vivo studies.
The development and application of integrated approaches for NM testing and
assessment should be closely linked to the grouping of NMs (Damoiseaux et al.
2011). Efficient and effective testing should enable hazard and risk assessment either