Biomedical Engineering Reference
In-Depth Information
• Effects on living organisms are highly dependent on the specific
nanoparticle properties and will differ significantly between dif-
ferent particle types (nanotubes, fullerenes, TiO
2
, polyacrylamide
nanoparticles, etc.).
Applying this matrix to the nanosilver T-shirt case study yields Table
11.4. It already preidentifies that the impact during use phase will directly
depend on the consumer behavior: if the nanosilver T-shirt is used one or
several more days before being washed than a conventional T-shirt (assum-
ing that bacterial growth and therefore odors are delayed), all impacts linked
to washing and drying will be reduced when considered per day of T-shirt
use. This leads to a trade-off between reduced indirect impacts of washing
versus additional direct impacts due to, for example, impacts of dissolved
nanosilver on ecosystem quality.
11.3.1.2 Nano-Specificities of LCA Goal Definition
The goal definition is not intrinsically different from other LCAs; however,
certain features are even more important to consider to avoid strong biases:
- Functional unit
: It is crucial to address impacts per functional unit
rather than per kilogram of material. With nanomaterials and
nano-based products, despite the often high impact per kilogram
of nanomaterials, the overall impact per functional unit can be lim-
ited compared with other conventional materials, since quantities of
nanomaterial purchased per functional unit are often limited.
- Nanomaterial versus nano-based product
: From an LCA perspective,
it is not possible nor desirable to judge the intrinsic environmental
performance of a nanomaterial or in fact of any material as such. A
(nano-)material assessment can only be assessed within the context
of its application to a given product with its corresponding function
and functional unit (e.g., for a nanosilver T-shirt).
- System boundaries
: Including direct nanomaterial releases during
nanoproduct manufacturing, use, and disposal is crucial to ensure a
fair comparison with other traditional chemicals.
11.3.2 Nano-Specificities for Life Cycle Inventory
When quantifying and collecting emission data to build an LCI for
nanomaterial-embedded products, a number of specific aspects need to be
considered, adding to the complexity this task already demands for any
LCA. In general, the inventory database to be built for nanoproducts can be
divided into three major groups of data, comprising (i) the indirect resources
and emissions associated with the supply of inputs into the life cycle of the
