Nanotechnology for domestic water purification - Nanotechnology in Eco-efficient Construction - page 385

growth through more effi cient and durable products and new markets.
However, the applicability of such a system has to be perceived after due
consideration of the process and product in its entirety, with serious atten-
tion being paid to the probable health and environmental risks.
While it is perceived that nanotechnology will deliver cleaner production
(e.g., through green chemistry, synthesis and processing of nanoscale mate-
rials that will reduce consumption of raw materials and natural resources
such as water and energy, and improved chemical reactions and catalysis),
in reality it is very diffi cult to ensure these propositions unless there is a
proper life cycle analysis of the nanomaterials through validated nano-
specifi c risk assessment methodologies.
Although there are now only a limited number of products in the mar-
ketplace that contain engineered nanomaterials, the pace of nanotechnol-
ogy development assures that the market soon is going to be fl ooded with
nano-based products. In such a case, it is essential to have a grasp of the
attribute-related concerns, associated health and environment risks and the
extent of the population going to be affected.
The following attributes of nanoparticles create a number of unknown
exposures:

￿ size of particles: the size of nanoparticles necessitates usage of sophisti-

cated analytical tools.

￿ increased reactivity and conductivity: nanoparticles are more reactive

and conductive than the same material in bulk.

￿ routes of exposure: because of their very small size, nanoparticles can

be inhaled or ingested; in addition, they are capable of crossing the
blood-brain barrier, which protects the brain against contamination
(Oberdörster et al. , 2004).

16.6.1 Evidence for toxicity of nanomaterials

￿ ￿ ￿ ￿ ￿ ￿

Nanoparticles have the ability to induce lung injuries because of their small
size, a large surface area, and an ability to generate reactive oxygen species
(ROS). 1 The short-term pulmonary toxicity studies in rats with ultrafi ne
and fi ne carbon black, nickel and TiO 2 particles have established enhanced
lung infl ammatory strength of the ultrafi ne particles in comparison to fi ne-
sized particulates of similar composition (Warheit et al. , 2006; Grassian
et al. , 2007; Pettibone et al. , 2008). Low toxicity nanoparticles such as carbon
black and polystyrene stimulate the macrophages via reactive oxygen
species and calcium signalling, to make proinfl ammatory cytokines such as

1

Section 16.6.1 is adapted from Wani et al. , 2011: Nanotoxicity: dimensional and morphological
concerns, Advances in Physical Chemistry , Volume 2011, doi:10.1155/2011/450912.