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polystyrene NPs were transferred from water to green algae (Scenedesmus) to zooplankton (Daphnia magna) and finally to top consumer fish (Carassius carassius).
NPs induced change in the behavior and fat metabolism of fish (Cedervall et al. 2012).
Trophic level transfer of NPs has also been reported in algal-zooplanktons
(Gilroy et al. 2014), simplified invertebrates (Holbrook et al. 2008), and terrestrial
(Unrine et al. 2012), pond (Marie et al. 2014), and freshwater (Zhu et al. 2010) food
chain systems.
10.5 Conclusions
NPs are absorbed by plants and transported to various plant parts in roots and shoots.
NPs can have no effect or positive or negative effect on the germination, growth,
development, and health of plants. Chemical composition, dose, size, surface covering, and used test plant all affect the response of NPs to plants. Plant response to NP
exposure has been explained using various mechanisms. Most common among
them is plant growth via enhancing chlorophyll content, photosynthesis, absorption
of micro- and macronutrients, and water uptake from soil. However, the negative
effect on plant growth and developments are due to induction of oxidative stress,
less absorption of nutrients, stress due to toxic metal ions released from NPs, and
some unknown NP-based mechanisms. The bioaccumulation and trophic transfer of
NPs is also a serious concern and should be thoroughly studied and considered
before release of waste containing NPs.
10.6 Future Perspectives
If nanotechnology has to explore its full potential, the toxicity issues associated
with NPs has to be managed. As the use of NPs in various consumer products is
going to increase in future, there should be proper toxicity evaluation procedures/
protocols and guidelines. Plants are the primary land producers, so toxicity evaluation of NPs should be made mandatory. NPs can even pass the trophic barriers,
which itself advocates to make nanotoxicity evaluation in plants compulsory.
Proper safety guidelines for using and disposing of NPs are presently lacking.
The guidelines, protocols, and reference compound used for toxicity evaluation of
macroscopic particles sometimes fail to explain the toxicity of NPs in plants as well
as in animals. Further, there are no standard NPs available that can be used as references to evaluate and compare the toxicity of variously synthesized NPs. NPs have
unique properties that are not observed in corresponding macroscopic particles.
This is due to the reason that the properties of NPs drastically change with even very
small change in size, shape, and surface covering. So, microscopic-sized particles of
even the same chemical composition cannot be used as reference for NPs. The
nanotoxicity evaluation studies are in initial phases. With more research in the plant
V. Kumar et al.
polystyrene NPs were transferred from water to green algae (Scenedesmus) to zooplankton (Daphnia magna) and finally to top consumer fish (Carassius carassius).
NPs induced change in the behavior and fat metabolism of fish (Cedervall et al. 2012).
Trophic level transfer of NPs has also been reported in algal-zooplanktons
(Gilroy et al. 2014), simplified invertebrates (Holbrook et al. 2008), and terrestrial
(Unrine et al. 2012), pond (Marie et al. 2014), and freshwater (Zhu et al. 2010) food
chain systems.
10.5 Conclusions
NPs are absorbed by plants and transported to various plant parts in roots and shoots.
NPs can have no effect or positive or negative effect on the germination, growth,
development, and health of plants. Chemical composition, dose, size, surface covering, and used test plant all affect the response of NPs to plants. Plant response to NP
exposure has been explained using various mechanisms. Most common among
them is plant growth via enhancing chlorophyll content, photosynthesis, absorption
of micro- and macronutrients, and water uptake from soil. However, the negative
effect on plant growth and developments are due to induction of oxidative stress,
less absorption of nutrients, stress due to toxic metal ions released from NPs, and
some unknown NP-based mechanisms. The bioaccumulation and trophic transfer of
NPs is also a serious concern and should be thoroughly studied and considered
before release of waste containing NPs.
10.6 Future Perspectives
If nanotechnology has to explore its full potential, the toxicity issues associated
with NPs has to be managed. As the use of NPs in various consumer products is
going to increase in future, there should be proper toxicity evaluation procedures/
protocols and guidelines. Plants are the primary land producers, so toxicity evaluation of NPs should be made mandatory. NPs can even pass the trophic barriers,
which itself advocates to make nanotoxicity evaluation in plants compulsory.
Proper safety guidelines for using and disposing of NPs are presently lacking.
The guidelines, protocols, and reference compound used for toxicity evaluation of
macroscopic particles sometimes fail to explain the toxicity of NPs in plants as well
as in animals. Further, there are no standard NPs available that can be used as references to evaluate and compare the toxicity of variously synthesized NPs. NPs have
unique properties that are not observed in corresponding macroscopic particles.
This is due to the reason that the properties of NPs drastically change with even very
small change in size, shape, and surface covering. So, microscopic-sized particles of
even the same chemical composition cannot be used as reference for NPs. The
nanotoxicity evaluation studies are in initial phases. With more research in the plant
V. Kumar et al.