Biomedical Engineering Reference
In-Depth Information
The
use
of nanomaterials and nanoproduct spans a vast range of applica-
tions and functions that lead to a similarly large range of emission pathways
and quantities depending on usage and handling of the respective product,
which cannot be fully covered here. Some examples for typical applications
and disposal treatment of nanoproducts and specific issues related to their
emissions are discussed in Table 11.8.
The
end-of-life
treatment options for nanoproducts are currently the same
as for conventional products—see Table 11.9 for examples of causes of poten-
tial nanoparticle releases in waste management systems. However, the dra-
matic increase in the utilization of nanoproducts inevitably results in an
increased generation of nanowaste—although the latter may be delayed
in time depending on the nanoproduct lifetimes. At the same time, waste
management policies put a strong emphasis on the implementation of recy-
cling and reusing strategies (e.g., the legally binding EU Waste Framework
Directive 2008/98/EC). In such context, the recycling of nanowaste may
appear as a situation of increasing concern, pertaining to occupational
TABLE 11.8
Examples (Nonexhaustive List) of Causes of Potential Releases for Selection of
Nanoproducts during Th
eir Use Stage
Type of Applications
Causes of Potential Releases
Paints and coatings (e.g.,
nano-TiO
2
as white
pigment, nano-Ag as
biocide)
Aging or weathering of the original manufactured nanoparticles
due to the influence of rain, wind, atmospheric pollution, UV
radiation, and the like might significantly alter their physico-
chemical and toxicological properties, as well as influence the
emission rate over time.
77
The application technique might influence the amount, pathway,
and state of the particles emitted (e.g., aerosol, suspension)
Various processes related to the paint/coating carrier (e.g.,
abrasion, washing, renovation, sanding, demolition) may
influence emission rates.
93,94
Nanoparticles might not only be emitted in their pure form but
rather as part of a mixture that may or may not interact with
the particles (inducing, e.g., adsorption, chemical reactions,
alteration of physico-chemical properties)
Fuel additives (e.g., CeO
2
in diesel added to
decrease harmful
emissions and increase
fuel efficiency)
Nanoparticle characteristics may change significantly during
combustion, so that the original particle cannot be assumed to
be emitted directly
Exhaust emissions might enter the atmosphere or the surface
water via runoff from the road surface
Cosmetics (e.g., ZnO in
sunscreen)
Emission into surface water due to wash-off during swimming
Emission into surface water via incomplete removal from final
effluent due to wash-off during showering
Biocides (e.g., Ag-
nanosilver applied to
packaging, clothing,
detergents)
Leakage from products through normal wear and tear (e.g.,
abrasion,
93
heating/cooling, washing
95
) might lead to a release
into surface water via incomplete removal in a sewage
treatment plant, or into air via abrasion or other processes
