Environmental Engineering Reference
In-Depth Information
Organic
matter
Metal
asso-
ciation
CdTe
Salt ion
NP
Cd and Te
Disso-
ciation
Toxin A
CdTe
Aggre-
gation
Toxin B
FIGURE 5.1
Factors affecting the behavior of nanoparticles and their bioavailability in aquatic ecosystems. Organic matter
(OM), salt ions (SI), toxicants (ToxA and ToxB), nanoparticles (NP), cadmium telluride (CdTe), cadmium (Cd),
and tellurium (Te).
depending on the properties of the pollutant. A schematic about the fate of ENPs in aquatic
system and their increased/decreased bioavailability is represented in Figure 5.1.
ENPs have also been demonstrated to adsorb other pollutants on their surface owing to
their high surface area-to-volume ratio and complex-forming ability. Baun et al. [33] showed
in Daphnia magna that the toxicity of phenanthrene in the presence of C60 aggregates was
signiicantly higher (60%) than the parent compound owing to increased bioavailability.
Similarly, the bioavailability of phenanthrene to plant roots also increased upon its adsorp-
tion to alumina nanoparticles. In contrast, Knauer et al. (2007) have reported that the pres-
ence of carbon black ENPs reduced the toxicity of diuron to green algae [34]. This could be
due to the adsorption of diuron on carbon black, thereby reducing its bioavailability. Also,
fullerenes were found to decrease the toxicity of various chemicals to algae as a result of
their decreased bioavailability [35].
5.2 Methodological and Metrological Approaches for the Detection
and Quantification of ENPs in Environmental Samples
The detection of ENPs' internalization in any aquatic organism is a crucial step for under-
standing their behavior and toxicity. Lack of methodological and metrological approaches
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