Aboul-Enein 2004; Ali et al. 2012; Kasprzyk-Hordern and Baker 2012; Maier et al.
2013; Wang et al. 2013a, b; Zhai et al. 2014; Qian et al. 2017; Sanganyado et al.
2017; Zhang et al. 2018; Ruan et al. 2019).
10.2 Toxicity of Chiral Pollutants
In order to regulate the exact toxicity load of chiral pollutants, the information about
the different concentrations of both enantiomers is important and necessary. This
section describes the different toxicity of the two enantiomers of chiral pollutants.
About one fourth of the pesticides is chiral, and therefore, this portion represents a
sizable fraction of chiral pollutants (Ulrich et al. 2012; Ye et al. 2015; Qian et al.
2017; Basheer 2018; Jeschke 2018). Mostly pesticides are toxic and carcinogenic
thus potentially interfering or even damaging some physiological processes and also
altering enzymatic activities (Zhang et al. 2012; Qi et al. 2015; Ye et al. 2015; Yang
et al. 2017a; b; Zhou et al. 2018).
Data on the stereoselective toxicity of chiral pharmaceuticals are valued for
refining the correctness of their environmental danger assessment (Zhang et al.
2012; Qi et al. 2015; Ye et al. 2015; Yang et al. 2017a; b; Zhou et al. 2018).
However, studies on stereoselective toxicity of chiral pharmaceuticals in the atmosphere are still scarce (Bidleman et al. 2002; Asher et al. 2012). Data on fate, toxicity
and transport of distinct enantiomers are also required for a complete environmental
risk evaluation, as enantiomers may show variances in persistence, toxicity and
bioaccumulation in the environment (Kezic 2000; Smith 2009; Celis et al. 2013;
Sanganyado et al. 2017). Having in mind specific drug applications, enantiomers
may exhibit antagonistic, synergistic and additive effects; thus, future
eco-toxicological studies should consider chiral pharmaceuticals as “mixtures of
components with different effects” (Smith 2009; Stanley and Brooks 2009; Ali et al.
2012). There is also a necessity for the development of sound test system (assays and
in vitro testing) that includes chirality. Some recent studies are reporting on the
stereoselective toxicity of chiral pesticides and other contaminants (Ali et al. 2012;
Zhang et al. 2012; Ye et al. 2015; Kaziem et al. 2020). We will illustrate the current
status on enantioselective toxicity and environmental risk assessment on selected
examples outlined in the following sections.
10.2.1 Polychlorinated Biphenyls
Due to their high and well-documented environmental risk, polychlorinated biphenyls (PCBs) are currently considered among the priority chlorinated chiral contaminants worldwide. Since the early 1900s (before 1930), PCBs were commonly used
in electronics manufacture, as vehicles for pesticides, and in building materials (for
details, see earlier descriptions in Chaps. 2 and 9). Though their applications have
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10 Chirality in Environmental Toxicity and Fate Assessments
2013; Wang et al. 2013a, b; Zhai et al. 2014; Qian et al. 2017; Sanganyado et al.
2017; Zhang et al. 2018; Ruan et al. 2019).
10.2 Toxicity of Chiral Pollutants
In order to regulate the exact toxicity load of chiral pollutants, the information about
the different concentrations of both enantiomers is important and necessary. This
section describes the different toxicity of the two enantiomers of chiral pollutants.
About one fourth of the pesticides is chiral, and therefore, this portion represents a
sizable fraction of chiral pollutants (Ulrich et al. 2012; Ye et al. 2015; Qian et al.
2017; Basheer 2018; Jeschke 2018). Mostly pesticides are toxic and carcinogenic
thus potentially interfering or even damaging some physiological processes and also
altering enzymatic activities (Zhang et al. 2012; Qi et al. 2015; Ye et al. 2015; Yang
et al. 2017a; b; Zhou et al. 2018).
Data on the stereoselective toxicity of chiral pharmaceuticals are valued for
refining the correctness of their environmental danger assessment (Zhang et al.
2012; Qi et al. 2015; Ye et al. 2015; Yang et al. 2017a; b; Zhou et al. 2018).
However, studies on stereoselective toxicity of chiral pharmaceuticals in the atmosphere are still scarce (Bidleman et al. 2002; Asher et al. 2012). Data on fate, toxicity
and transport of distinct enantiomers are also required for a complete environmental
risk evaluation, as enantiomers may show variances in persistence, toxicity and
bioaccumulation in the environment (Kezic 2000; Smith 2009; Celis et al. 2013;
Sanganyado et al. 2017). Having in mind specific drug applications, enantiomers
may exhibit antagonistic, synergistic and additive effects; thus, future
eco-toxicological studies should consider chiral pharmaceuticals as “mixtures of
components with different effects” (Smith 2009; Stanley and Brooks 2009; Ali et al.
2012). There is also a necessity for the development of sound test system (assays and
in vitro testing) that includes chirality. Some recent studies are reporting on the
stereoselective toxicity of chiral pesticides and other contaminants (Ali et al. 2012;
Zhang et al. 2012; Ye et al. 2015; Kaziem et al. 2020). We will illustrate the current
status on enantioselective toxicity and environmental risk assessment on selected
examples outlined in the following sections.
10.2.1 Polychlorinated Biphenyls
Due to their high and well-documented environmental risk, polychlorinated biphenyls (PCBs) are currently considered among the priority chlorinated chiral contaminants worldwide. Since the early 1900s (before 1930), PCBs were commonly used
in electronics manufacture, as vehicles for pesticides, and in building materials (for
details, see earlier descriptions in Chaps. 2 and 9). Though their applications have
280
10 Chirality in Environmental Toxicity and Fate Assessments