Chapter 10
Chirality in Environmental Toxicity
and Fate Assessments
10.1 Introduction
In a non-chiral environment, the enantiomers of a racemate possess the same
physical and chemical properties. By contrast, metabolic and regulatory processes
mediated by biological systems are sensitive to stereochemistry and different
responses can often be observed when comparing the activities of a pair of enantiomers (Ali and Aboul-Enein 2004; Sanganyado et al. 2017). These differences can be
expressed by distribution rates, their metabolism and excretion, in antagonistic
actions relative to each other, or their toxicological properties. During the course
of the last few decades, the importance of chirality was realised in many areas of
science and technology including environmental science. Environmental awareness
and studies are very important for all of us as we are living in this environment and
our health depends entirely on the earth’s ecology. Some chiral compounds, in
particular, agrochemicals and pharmaceuticals, behave in entirely different fashion
when released into the environment. Therefore, the aspect of chirality in environmental assessments is very important for proper end reliable risk evaluation (Ali
et al. 2000; Smith 2009; Sanganyado et al. 2017; de Albuquerque et al. 2018; Qu
et al. 2019; Kaziem et al. 2020).
It is important to note that without a detailed understanding of the enantiospecific
fate and effects, redundant uncertainty is introduced into the assessment of risk
posed by chiral contaminants. Much of the environmental research on chiral contaminants has focused on legacy organochlorine pesticides (e.g. DDT) and
polychlorinated biphenyls that can no longer legally be used in most parts of the
world, but their persistence in the environment keeps them relevant as priority
pollutants in the environment. However, many currently used pesticides
(e.g. pyrethroids and organophosphate pesticides) as well as so-called emerging
contaminants such as brominated flame retardants and pharmaceutical and personal
care products are chiral. There has also recently been increasing awareness of
enantiospecific differences in fate and effects of such compounds (Ali and
© Springer Nature Switzerland AG 2021
R. Kallenborn et al., Chiral Environmental Pollutants,
https://doi.org/10.1007/978-3-030-62456-9_10
279
Chirality in Environmental Toxicity
and Fate Assessments
10.1 Introduction
In a non-chiral environment, the enantiomers of a racemate possess the same
physical and chemical properties. By contrast, metabolic and regulatory processes
mediated by biological systems are sensitive to stereochemistry and different
responses can often be observed when comparing the activities of a pair of enantiomers (Ali and Aboul-Enein 2004; Sanganyado et al. 2017). These differences can be
expressed by distribution rates, their metabolism and excretion, in antagonistic
actions relative to each other, or their toxicological properties. During the course
of the last few decades, the importance of chirality was realised in many areas of
science and technology including environmental science. Environmental awareness
and studies are very important for all of us as we are living in this environment and
our health depends entirely on the earth’s ecology. Some chiral compounds, in
particular, agrochemicals and pharmaceuticals, behave in entirely different fashion
when released into the environment. Therefore, the aspect of chirality in environmental assessments is very important for proper end reliable risk evaluation (Ali
et al. 2000; Smith 2009; Sanganyado et al. 2017; de Albuquerque et al. 2018; Qu
et al. 2019; Kaziem et al. 2020).
It is important to note that without a detailed understanding of the enantiospecific
fate and effects, redundant uncertainty is introduced into the assessment of risk
posed by chiral contaminants. Much of the environmental research on chiral contaminants has focused on legacy organochlorine pesticides (e.g. DDT) and
polychlorinated biphenyls that can no longer legally be used in most parts of the
world, but their persistence in the environment keeps them relevant as priority
pollutants in the environment. However, many currently used pesticides
(e.g. pyrethroids and organophosphate pesticides) as well as so-called emerging
contaminants such as brominated flame retardants and pharmaceutical and personal
care products are chiral. There has also recently been increasing awareness of
enantiospecific differences in fate and effects of such compounds (Ali and
© Springer Nature Switzerland AG 2021
R. Kallenborn et al., Chiral Environmental Pollutants,
https://doi.org/10.1007/978-3-030-62456-9_10
279