Emissions from Consumer Products Containing Engineered Nanomaterials over Their Lifecycle - Safety of Nanomaterials along Their Lifecycle - page 334

However, in contrast to all the fate and effect studies, very little is actually known
about the release of ENM into the environment (Gottschalk and Nowack 2011).
Currently, techniques are not yet available for most ENM to monitor ENM release
and quantify their trace concentrations in the environment (Hassellov and Kaegi
2009; von der Kammer et al. 2012), and thus reports on release and environmental
concentrations are very rare.
Besides knowing the amounts of ENM released into the environment, it is equally
important to investigate in what form ENM are released (Nowack et al. 2012). First
results show that most of the ENM released from products are present in matrix-
bound form, of which also some fraction is released as single, dispersed nanoparti-
cles. Almost all fate and effect studies so far have been performed with pristine ENM,
those materials that are synthesized and produced in the laboratory or by companies.
However, these ENM undergo transformation and aging reaction when incorporated
into products and when those products are used or disposed of (Nowack et al. 2012).
The materials that actually reach the environment may be completely different from
the materials originally produced by the industry. We therefore urgently need infor-
mation on the amount and characteristics of the materials that are actually released
under real-world conditions.
It is the aim of this chapter to present the available data about release of materials
from consumer products containing nanomaterials. Only those studies that report
results on release during normal use or from test mimicking normal use are included.
Release during manufacturing of the products is not covered, as this is the topic of
Chapter 12 in this topic. Also data from occupational studies Kuhlbusch et al. (2011)
(Chapter 13) and the release from disposed (Chapter 14) or incinerated product resi-
dues (Chapter 12) are included elsewhere. The available studies are reviewed here
with emphasis on the characterization of the materials released.
15.2 ANALYSIS OF EMISSION
If we would like to quantify the release of ENM from commercial products in the
real world, we are faced with problems of how to study the relevant release mecha-
nisms and especially how to identify the presence of released ENM and how to
quantify them.
15.2.1 t yPe of r elease s tudies
Release studies can be performed at different levels of complexity: batch tests with
simplified and standardized test materials allow controlling the physical and chemi-
cal conditions to a large extent and are therefore suitable to investigate the mech-
anisms of release and to develop new experimental and analytical methods. The
results from these studies may have only a limited value in estimating the amount
released into the real world.
In the next level of complexity, studies are performed that mimic the real world
but are still performed under controlled conditions. Examples include test wash-
ing machines to study release from textiles or weathering chambers to investigate
release from paints. In these tests more parameters are fixed but still a sufficient