Release, Transport and Toxicity of Engineered Nanoparticles - Reviews of Environmental Contamination and Toxicology - page 10

Transport of
nonoparticles

Cream Spray

Industry
(Nanoparticle
synthesis)

Applications of
nanoparticles

Life cycle and
release of
nanoparticles in
environment

Clothes Paint

Release of
nonoparticles in
environment

Air

Exposure of
nanoparticles to
living organisms

Water

Release of
nonoparticles in
aquatic system

Soil

Fig. 2 Schematic diagram depicting the engineered nanoparticle life cycle, including use, release,
transport, and ultimate environmental exposures

disposedoforreleasedtosoilorsurfacewater(BiswasandWu 2005 ). Accidental
release may occur during the production or transportation of nanomaterial-containing
products. Some nanomaterials are intentionally released into the environment, e.g.,
for remediation of ground- and waste-water (Nowack and Bucheli 2007 ). It is
becoming necessary that both scientists and regulators do more to understand the
different routes by which nanoparticles are released to the different environmental
compartments, i.e., air, water and soil.
Nanomaterials are released to air mainly via use of aerosol products, vehicle
emissions of gases containing nanoparticles, manufacturing and production dis-
charges,consumerproductaerosols,andreleaseofindustrialsootandsmoke.Ithas
been reported that vehicle exhaust produces aerosol concentration ranges from 10 4
to 10 6 particles per cm 3 , with most nanoparticles in the size ranges below 50 nm
diameter(BiswasandWu 2005 ).
In Table 3 we summarize literature studies that were undertaken to evaluate
nanoparticle releases to the atmosphere.
Nanoparticlesthatarereleasedtoaquaticsystemsmayresultfromlandrun-off,
andindustrialandhouseholdwastewaterefluents;moreover,amajorsourceismetal-
based nanoparticle use for water remediation (e.g., zero-valent iron nanoparticles)
(Defra 2007 ; Vaseashta et al. 2007 ).Kaegietal.( 2008 ) has shown that TiO 2 nanopar-
ticlespresentinbuildingpaints(whiteningpigments)areshedandthenreleasedto