Environmental Engineering Reference
In-Depth Information
5
Nanotoxic
ity: Aquatic Organisms and Ecosystems
Ashutosh Kumar,
1
Rishi Shanker,
1
and Alok Dhawan
1,2
1
Institute of Life Sciences, School of Science and Technology, Ahmedabad University,
Navrangpura, Ahmedabad, Gujarat, India
2
Nanomaterial Toxicology Group, CSIR-Indian Institute of Toxicology Research,
Mahatma Gandhi Marg, Lucknow, Uttar Pradesh, India
CONTENTS
5.1 Bioavailability of ENPs in Aquatic Systems ..................................................................... 98
5.2 Methodological and Metrological Approaches for the Detection and
Quantiication of ENPs in Environmental Samples ..................................................... 100
5.3 Approaches and Knowledge Gaps in Aquatic Toxicity Studies ................................. 102
5.4 Conclusion .......................................................................................................................... 104
Acknowledgments ...................................................................................................................... 104
References ..................................................................................................................................... 104
Nanoscience and nanotechnology have seen an exponential growth over the past decade.
This is largely due to the advances in nanomaterial synthesis and imaging, or analysis
tools owing to funding by national and international agencies to pursue research and
innovation in this emerging area. Engineered nanoparticles (ENPs) are deined as any
intentionally produced particle that (i) has a characteristic dimension between 1 and
100 nm, and (ii) possesses properties that are not shared by non-nanoscale particles with
the same chemical composition [1]. The latter part of this deinition arises from the fact that
ENPs possess unique physicochemical properties because of their small size. Properties
such as high surface area-to-volume ratio, abundant reactive sites on the surface, and a
large fraction of atoms located on the exterior face, have made these novel materials the
most sought after materials for consumer and industrial applications. The unique charac-
teristics of ENPs derived from carbon (tensile strength of carbon nanotubes), metals (luo-
rescence properties of quantum dots; antimicrobial activity of silver nanoparticles), and
metal oxides (photocatalytic properties of TiO
2
) have proven to be the most commercially
proitable [2,3].
Naturally occurring and incidentally generated nanoparticles are heterogeneous,
whereas the ENP suspensions or powders are usually homogeneous in size, shape, and
structure [4]. ENPs have found application in diverse sectors such as energy, electron-
ics, food and agriculture, water puriication, biomedical devices, imaging, biosensing and
biochips, high-density data, detecting DNA sequence, environmental cleanup, house-
hold products, paints, consumer products, and sports [5]. According to the US National
Nanotechnology Initiative (NNI), million ton quantities of ENPs (silica, alumina and ceria,
ZnO, TiO
2
, silver, carbon nanotubes, etc.) are being manufactured for various consumer
97
