Nanotechnology for domestic water purification - Nanotechnology in Eco-efficient Construction - page 390

et al. , 2006; Chang et al. , 2007; Jin et al. , 2007). Unfortunately, silica nanopar-
ticles also tend to agglomerate and have been demonstrated to lead to
protein aggregation in vitro at a dose of 25 g/mL (Barik et al. , 2008). Oxi-

dative stress has been implicated as an explanation behind silica nanopar-
ticles cytotoxicity both in vitro and in vivo (Chen and von Mikecz, 2005;
Yang et al. , 2009; Wang et al. , 2009). All these studies have reported cyto-
toxicity and oxidative stress, as determined by increasing lipid peroxidation
(LPO), reactive oxygen species (ROS), and decreasing cellular glutathione
(GSH level), but no similarity exists regarding dose response.
Very little is known about the safety risks presented by engineered nano-
materials. Given their unique properties, particularly their increased reac-
tivity and electrical conductivity, safety concerns are focusing on whether
nanomaterials could cause fi res or explosions. Because nanoparticles behave
differently from larger particles, questions have arisen about whether they
can pollute the water supply or damage crops during processes that release
these particles into the air, soil or water. Again, studies in this area are in
their infancy.
In the short term, the major health and safety risks will be to researchers
in laboratories and production staff exposed during the manufacture of
nanomaterials. People in these occupations must be aware of the potential
hazards of using materials that have unknown properties, and they
must take measures to mitigate their risks. However, their activities are
contained and generally do not pose a threat to the public or to the
environment.
Owing to the highly interdisciplinary nature of nanotechnology, it can be
viewed as an enabling technology that is a sincere augmentation of the
existing technologies in the fi eld of water purifi cation, textile, aerospace,
health care and electronics. Keeping in view the unknown behaviour and
fate of nanomaterials in the environment, nanotechnology may pose tre-
mendous challenges to the existing waste management systems. Knowledge
on the mobility, persistence and bioaccumulation potential in the environ-
ment is hardly available. Hence risk assessment on the possible impact of
nanowastes is critical and needs to be made.
Regulators in the United States, the European Union and elsewhere
around the world believe that nanoparticles represent an entirely new
risk and that it is necessary to carry out an extensive analysis of the risk.
Such studies then can form the basis for government and international
regulations. As a proper and comprehensive risk and life cycle analysis,
encompassing production, application and waste management strategies of
nanomaterials, is of urgent need for a successful commercialization of a
technology with proven societal benefi ts, otherwise environmental costs
could be high and the technology as a whole could be distrusted or rejected
by the public.

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