revealed even for a single exposure to CdCl 2 . The presence
or absence of nano-TiO 2 had no discernible effect on the
toxicity of CdCl 2 .
4 Interactions of Nano-TiO 2 with Plants
Although plants are the focus of attention in this chapter, one
should be aware that it is one of the myriads of living species
on earth. Prior to a brief consideration of the reported
interactions of titanium dioxide nanoparticles with some of
these other living species, knowledge of the estimated
amounts of the global production of commonly used nanomaterials would be both revealing and helpful in getting a
grasp of the issues connected with the generation and
applications of nanomaterials. In this regard, Piccinno et al.
(2012) conducted an in-depth survey on the productions and
applications of ten nanomaterials in Europe, USA and also in
the whole world. They found the following order, from
highest to lowest in terms of tons of nanomaterials:
TiO 2 > ZnO > SiO 2 > FeO x > AlO x > CeO x > CNT >
Fullerenes > AgNPs > quantum dots
It is thus clear that the probability of finding nanoparticles
in the environments of most countries would very high
indeed. Furthermore, it is more likely to be present in soil
and water than in air.
4.1 Uptake of Nano-TiO 2 from Water by Higher
Species than Plants
As mentioned elsewhere in this chapter, nanotitanium
dioxide present in water and soil. In this section, a brief
account on effect of exposure to nanoparticles of TiO 2 to
species higher than plants will be probed in view of the fact
that nanoparticles are bound to enter into higher species from
edible plants which are an integral part of the food chain for
higher species. Crustaceans and fish are more highly evolved
species than plants and are likely to have organs to deal with
toxins which enter their systems. It was thus interesting that
the effect of nanoparticles of titanium on a fish species which
thrive in river water, namely rainbow trout, was assessed by
Federici et al. (2007), in a 14-day exposure of the fish to low
concentrations of the nanoparticles. No damage to organ
tissues was reported but that the trout suffered oxidative
stress.
In a similar study to the above, land-based crustaceans
(isopods) were fed meals mixed with different amounts of
titanium dioxide nanoparticles brushed over on pieces of
hazelnut leaves of known mass (Valant et al. 2012). As
controls, leaves without any nanoparticles were used. The
experiment aimed to ascertain if the nanoparticles caused
any damage to the cell membrane of the digestive glands of
the crustaceans. It was found that there was no damage if the
concentrations were 100 µg of the nanoparticles or less per
gram of dry leaf for three days of feeding corresponding to
the consumption of about 30 µg over three days.
The results for both the projects, summarized above,
appear to indicate that animals like fish and crustaceans can
tolerate or excrete small amounts of nanoparticles which
enter their digestive systems. Rats are more highly evolved
than fish. It would be of interest to know how nanoparticles
affect them. It is common knowledge that trials on new drugs
are invariably conducted on rats. In pursuance of this practice, there are no reports thus far, in the literature on
experiments involving nanoparticles by humans. As anticipated, there is at least one study on the effect of nanotitanium
dioxide on rats. This project (Long et al. 2007) was motivated by the danger that the very high presence of nano-TiO 2
in the environment and its well-established photoreactivity,
nano-TiO 2 might interact negatively with biological targets
such as the brains of animals such as rats. A commercially
available nano-TiO 2 product with the trade name of Degussa
P25 was utilized, as the source of the TiO 2 nanoparticles
comprising 70% anatase and 30% rutile forms of TiO 2 . From
a mortified rat, microglia (BV2), rat dopaminergic (DA),
neurons (N27) and culture of rat striatum were treated with
P25 taken up in a physiological buffer medium. Measurement of physical properties of P25 was done under conditions that applied to biological specimens (Long et al. 2007).
The results showed that the nanoparticles stimulated release
of reactive oxygen species (ROS) from microglia and caused
some damage to N27 neutrons. Even if one does not comprehend the technical terms involved, one can deduce, even
tentatively, that nanoparticles of titanium dioxide are inimical to the well-being of rats (Long et al. 2007).
4.2 Uptake of Nano-TiO 2 by Plants
In the light of the brief background provided above, attention
will be focused on the principal object of this chapter,
namely to probe the interactions of nanotitanium dioxide
with plants.
In terms of the main parts of plants, it is fair to state that
nanotitanium dioxide should enter, through roots, stems and
leaves. If the ingress of nanoparticles is through the roots
and the nanoparticles are translocated to the leaves which are
stripped from the plant for safe disposal, this would be
classed as nanophytoremediation. The question which arises
is: will plants, which have fewer body parts than more
highly evolved species such as animals, be able to cope with
nanoparticles which enter their systems? It is worth noting
that a significant number of studies (Andersen et al. 2016)
have focused on seedlings rather than on fully grown plants.
Much of this has been driven by the expectation that
78
K. G. Moodley and V. Arumugam
or absence of nano-TiO 2 had no discernible effect on the
toxicity of CdCl 2 .
4 Interactions of Nano-TiO 2 with Plants
Although plants are the focus of attention in this chapter, one
should be aware that it is one of the myriads of living species
on earth. Prior to a brief consideration of the reported
interactions of titanium dioxide nanoparticles with some of
these other living species, knowledge of the estimated
amounts of the global production of commonly used nanomaterials would be both revealing and helpful in getting a
grasp of the issues connected with the generation and
applications of nanomaterials. In this regard, Piccinno et al.
(2012) conducted an in-depth survey on the productions and
applications of ten nanomaterials in Europe, USA and also in
the whole world. They found the following order, from
highest to lowest in terms of tons of nanomaterials:
TiO 2 > ZnO > SiO 2 > FeO x > AlO x > CeO x > CNT >
Fullerenes > AgNPs > quantum dots
It is thus clear that the probability of finding nanoparticles
in the environments of most countries would very high
indeed. Furthermore, it is more likely to be present in soil
and water than in air.
4.1 Uptake of Nano-TiO 2 from Water by Higher
Species than Plants
As mentioned elsewhere in this chapter, nanotitanium
dioxide present in water and soil. In this section, a brief
account on effect of exposure to nanoparticles of TiO 2 to
species higher than plants will be probed in view of the fact
that nanoparticles are bound to enter into higher species from
edible plants which are an integral part of the food chain for
higher species. Crustaceans and fish are more highly evolved
species than plants and are likely to have organs to deal with
toxins which enter their systems. It was thus interesting that
the effect of nanoparticles of titanium on a fish species which
thrive in river water, namely rainbow trout, was assessed by
Federici et al. (2007), in a 14-day exposure of the fish to low
concentrations of the nanoparticles. No damage to organ
tissues was reported but that the trout suffered oxidative
stress.
In a similar study to the above, land-based crustaceans
(isopods) were fed meals mixed with different amounts of
titanium dioxide nanoparticles brushed over on pieces of
hazelnut leaves of known mass (Valant et al. 2012). As
controls, leaves without any nanoparticles were used. The
experiment aimed to ascertain if the nanoparticles caused
any damage to the cell membrane of the digestive glands of
the crustaceans. It was found that there was no damage if the
concentrations were 100 µg of the nanoparticles or less per
gram of dry leaf for three days of feeding corresponding to
the consumption of about 30 µg over three days.
The results for both the projects, summarized above,
appear to indicate that animals like fish and crustaceans can
tolerate or excrete small amounts of nanoparticles which
enter their digestive systems. Rats are more highly evolved
than fish. It would be of interest to know how nanoparticles
affect them. It is common knowledge that trials on new drugs
are invariably conducted on rats. In pursuance of this practice, there are no reports thus far, in the literature on
experiments involving nanoparticles by humans. As anticipated, there is at least one study on the effect of nanotitanium
dioxide on rats. This project (Long et al. 2007) was motivated by the danger that the very high presence of nano-TiO 2
in the environment and its well-established photoreactivity,
nano-TiO 2 might interact negatively with biological targets
such as the brains of animals such as rats. A commercially
available nano-TiO 2 product with the trade name of Degussa
P25 was utilized, as the source of the TiO 2 nanoparticles
comprising 70% anatase and 30% rutile forms of TiO 2 . From
a mortified rat, microglia (BV2), rat dopaminergic (DA),
neurons (N27) and culture of rat striatum were treated with
P25 taken up in a physiological buffer medium. Measurement of physical properties of P25 was done under conditions that applied to biological specimens (Long et al. 2007).
The results showed that the nanoparticles stimulated release
of reactive oxygen species (ROS) from microglia and caused
some damage to N27 neutrons. Even if one does not comprehend the technical terms involved, one can deduce, even
tentatively, that nanoparticles of titanium dioxide are inimical to the well-being of rats (Long et al. 2007).
4.2 Uptake of Nano-TiO 2 by Plants
In the light of the brief background provided above, attention
will be focused on the principal object of this chapter,
namely to probe the interactions of nanotitanium dioxide
with plants.
In terms of the main parts of plants, it is fair to state that
nanotitanium dioxide should enter, through roots, stems and
leaves. If the ingress of nanoparticles is through the roots
and the nanoparticles are translocated to the leaves which are
stripped from the plant for safe disposal, this would be
classed as nanophytoremediation. The question which arises
is: will plants, which have fewer body parts than more
highly evolved species such as animals, be able to cope with
nanoparticles which enter their systems? It is worth noting
that a significant number of studies (Andersen et al. 2016)
have focused on seedlings rather than on fully grown plants.
Much of this has been driven by the expectation that
78
K. G. Moodley and V. Arumugam