Environmental Engineering Reference
In-Depth Information
30
EnvironmEntal risks of nanotEchnology:
Evaluating thE Ecotoxicity of nanomatErials
Miguel A. Méndez-Rojas
1
, José Luis Sánchez-Salas
1
, Aracely Angulo-Molina
2
,
and Teresa de Jesús Palacios-Hernández
3
1
Departamento de Ciencias Químico-Biológicas, Universidad de las Américas Puebla, Puebla, Mexico
2
Departamento de Ciencias de la Salud, Universidad de las Américas Puebla, Puebla, México
2
Departamento de Ciencias Biológicas, Universidad Popular Autónoma del Estado de Puebla, Puebla, México
30.1
introduction
Ecotoxicology is a young, multidisciplinary field of science concerned with the study of contaminants (chemicals or biological
organisms) in the biosphere and the understanding of their effects on the population, community, and ecosystem level, including
humans [1, 2]. It is a multidisciplinary field that uses tools and concepts from biology, chemistry, medicine, toxicology, and
ecology. In that sense, nano-ecotoxicology is an emergent branch of ecotoxicology specifically dedicated to engineered and
natural nanomaterials (NMs). For such a specialized field of interest, it is important to make a complete assessment of the life
cycle of the product, in order to understand the potential environmental and health hazards of such materials.
Ultrafine particles (UFPs) suspended in the air have been traditionally included as a topic of interest in toxicology, and their
sizes range in the nanometer scale; when present in water or soil, they are referred to as colloids. In the normal toxicological
terminology, particles with diameters less than 0.1 µm (100 nm, 0.1 µm) are called UFPs, although they can be grouped into
three general categories: (1) those with diameters less that 100 nm; (2) those with sizes between 100 and 2500 nm (resulting
from aggregation of UFPs); and (3) coarse-mode particles larger than 2500 nm. On the other hand, the term colloid is applied
to particles with sizes in the 1-1000 nm range (0.001-1 µm). This kind of extremely fine and small materials may be the product
of natural processes, they may be produced as by-products of anthropogenic activities, or inclusively they may be specifically
manufactured for very specific applications.
Natural nanostructured materials have been around us for a long time. Humans and living beings have been exposed to nat-
urally produced NMs since the beginning of life sources (soil erosion, ocean water evaporation, forest fires, photochemical
reactions, volcanic eruptions, viruses, biogenic magnetite biosynthesized by magnetotactic bacteria, mollusks, arthropods, fish,
birds, or from disintegration of iron meteorites when entering into the atmosphere) [3, 4]. They are also artificially produced,
both intentionally for very specific applications (pigments, quantum dots, magnetic nanoparticles, catalysts, coatings, cos-
metics, among several more examples) and as by-products of several manufacturing and industrial processes (fuel and charcoal
combustion, mineral processing, cooking, welding, smoking, building demolition, consumer products containing NM degrada-
tion, etc.), many of them potentially toxic (Fig. 30.1).
Engineered nanomaterials (ENMs), on the other hand, are sources of concern as they have not been around us for a long time
and living beings may have not developed appropriate biological barriers or trapping systems to avoid undesirable interactions
that may harm individuals. There are several reports of toxicological studies of NMs which suggest that several of them may be
dangerous, although the results are sometimes not conclusive and even contradictory [1] (Fig. 30.2).
