Environmental Engineering Reference
In-Depth Information
6 Possible Mechanisms by Which Nanoparticles Induce Toxicity.......................................... 35
6.1 GenerationofROS ...................................................................................................... 35
6.2 Interaction with Proteins ............................................................................................. 36
6.3 DNA Damage .............................................................................................................. 37
7 Summary .............................................................................................................................. 38
References .................................................................................................................................. 39
1
Introduction
Nanotechnology is associated with the design and application of nanoscale particles
(viz.,1-100nm)thatpossesspropertiesthatarequitedifferentfromtheirbulkcoun-
terparts. The Royal Society and Royal Academy of Engineering offer the following
deinitionforthisterm:“Nanotechnologiesarethedesign,characterization,produc-
tion and application of structures, devices, and systems by controlling shape and
sizeatnanometerscale”(RoyalSocietyandRoyalAcademyofEngineering
2004
).
Differenttypesofengineerednanoparticles(ENPs)arepresentlysynthesizedand
utilized for multiple applications.These include particles that are made of carbon,
metalandmetal-oxideandquantumdots(QDs)(seeTable
1
for a list of abbreviations
andacronyms).ENPshavespeciicphysico-chemicalpropertiesthatareutilizedfor
applications that have social and economic benefit. Metal nanoparticles are used in
medicineandhavegreatantibacterialpotential(Chopra
2007
). ZnO and TiO
2
nanopar-
ticles have light-scattering potential and are used to protect against harmful UV
light(Rodr￭guezandFern￡ndez-Garc￭a
2007
). ENPs have also proved to be poten-
tialdrugdeliveryagents(Alivisatos
2004
;Gibsonetal.
2007
; Huber
2005
; Tsai et al.
2007
).ENPsareeficientscrubbersofgaseouspollutantlikecarbondioxide(CO
2
),
nitrogenoxides(NO
x
),andsulphuroxides(SO
x
)(SchmitzandBaird
2002
). Moreover,
ENPsareusedforapplicationsinenvironmentalremediation(Zhang
2003
).
Scientists and economists have predicted that ENP-based processes and technol-
ogywillincreasinglybeusedinnanotechnologyresearchanddevelopment(Guzman
et al.
2006
). It has been estimated that the value of nanotechnology products will
reach $1 trillion by 2015 and will employ about two million workers (Nel et al.
2006
; Roco and Bainbridge
2005
).
The increased growth of nano-based products for multiple applications will ulti-
matelybethesourceoftheirexpandedreleasetoair,waterandsoil(Nowackand
Bucheli
2007
). Nanomaterial wastes are released into the environment from operat-
ing or disposing of nanodevices and during nanomaterial manufacturing processes.
Suchreleasesmaybedangerousbecauseofthesmallsizeoftheparticlesinvolved,
i.e., such particles can float into the air, be chemically transformed, and can affect
waterqualityand/oraccumulateinsoils.Moreover,ENPscanbeeasilytransported
toanimalandplantcells,eitherdirectlyorindirectly,andcauseunknowneffects.
The dearth of information on environmental transport and safety has raised con-
cernsamongthepublicandamongscientiicauthorities.Thereisadesiretoknow
much more about the fate and behavior of ENPs in the environment and in biologi-
cal systems. Nanotechnology is still in its infancy, and it is critical that action be
takentoevaluatethepotentialadverseeffectsthatENPsmayhaveonorganismsand
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