1 Introduction
In recent years, the occurrence of residues of pharmaceuticals and personal care
products (PPCPs) in the environment has attracted increased attention in the scientific community. Nowadays it is a well-known fact that effluents from wastewater
treatment plants (WWTPs) are an important source for the release of these xenobiotics into surface waters. The increasing availability and use of PPCPs worldwide
have made the presence of such contaminants a global phenomenon [1]. As a matter
of fact, PPCPs are continuously introduced into the environment so that they are also
referred to as pseudopersistent pollutants. The tremendous advances in procedures
for environmental analytical chemistry [2, 3] have resulted in a significantly
increased number of PPCPs that can be monitored routinely in water samples and
have provided extended data sets to be used for a better understanding of their fate in
the environment. Although effort has been made to improve the removal rates for
PPCPs in WWTPs [4–6], the release of such xenobiotics may still be an issue
worldwide.
Typical concentrations of PPCPs in effluents of WWTPs may be up to the low μg
L
À1 range. This means that concentrations in receiving waters can be expected to be
in the ng L
À1 range. Even such low concentrations may result in negative effects on
the environment. This is well known in case of the continuous presence of residues
of antibiotics, which can lead to the development of antibiotic resistance [7]. Unfortunately, for many other classes of PPCPs, ecotoxicological effects are still poorly
understood [8]. Even less knowledge is generally available when it comes to the
presence and effects of metabolites of PPCPs possibly generated in the environment.
The presence of PPCPs in effluents of WWTPs has also raised some concerns in
the context of food safety. In arid regions, reclaimed water is nowadays frequently
employed for irrigation in agriculture as a consequence of increased water scarcity.
For example, in 2016 Israel used reclaimed wastewater for approximately 50% of the
total irrigation water [9]. Also Mediterranean countries of the European Union
depend more and more on reclaimed water in agriculture [10]. This means that
agricultural plants can be expected to get into contact with pharmaceuticals not fully
removed by WWTPs, which subsequently may result in an uptake of these xenobiotics by the plants. Considerable efforts are made to establish regulations regarding
the quality of reclaimed water, but so far comprehensive final standards have not yet
been set [11]. Another source for pharmaceuticals potentially taken up by agricultural plants is the use of biosolids [12]. Manure used as a natural fertilizer may
contain residues of veterinary drugs which can contaminate agricultural plants via
the soil [13, 14].
Various papers and reviews dealing with the uptake of intact PPCPs by plants
from the environment have been published within the last few years [15–24]. However, PPCPs taken up by plants may also be subjected to bio-transformation/
metabolization processes [25, 26]. A full risk assessment of PPCPs in the environment will require thorough investigations dealing with such transformation pathways because metabolites may show (eco)toxicities even higher than the parent
496
F. Mlynek et al.
In recent years, the occurrence of residues of pharmaceuticals and personal care
products (PPCPs) in the environment has attracted increased attention in the scientific community. Nowadays it is a well-known fact that effluents from wastewater
treatment plants (WWTPs) are an important source for the release of these xenobiotics into surface waters. The increasing availability and use of PPCPs worldwide
have made the presence of such contaminants a global phenomenon [1]. As a matter
of fact, PPCPs are continuously introduced into the environment so that they are also
referred to as pseudopersistent pollutants. The tremendous advances in procedures
for environmental analytical chemistry [2, 3] have resulted in a significantly
increased number of PPCPs that can be monitored routinely in water samples and
have provided extended data sets to be used for a better understanding of their fate in
the environment. Although effort has been made to improve the removal rates for
PPCPs in WWTPs [4–6], the release of such xenobiotics may still be an issue
worldwide.
Typical concentrations of PPCPs in effluents of WWTPs may be up to the low μg
L
À1 range. This means that concentrations in receiving waters can be expected to be
in the ng L
À1 range. Even such low concentrations may result in negative effects on
the environment. This is well known in case of the continuous presence of residues
of antibiotics, which can lead to the development of antibiotic resistance [7]. Unfortunately, for many other classes of PPCPs, ecotoxicological effects are still poorly
understood [8]. Even less knowledge is generally available when it comes to the
presence and effects of metabolites of PPCPs possibly generated in the environment.
The presence of PPCPs in effluents of WWTPs has also raised some concerns in
the context of food safety. In arid regions, reclaimed water is nowadays frequently
employed for irrigation in agriculture as a consequence of increased water scarcity.
For example, in 2016 Israel used reclaimed wastewater for approximately 50% of the
total irrigation water [9]. Also Mediterranean countries of the European Union
depend more and more on reclaimed water in agriculture [10]. This means that
agricultural plants can be expected to get into contact with pharmaceuticals not fully
removed by WWTPs, which subsequently may result in an uptake of these xenobiotics by the plants. Considerable efforts are made to establish regulations regarding
the quality of reclaimed water, but so far comprehensive final standards have not yet
been set [11]. Another source for pharmaceuticals potentially taken up by agricultural plants is the use of biosolids [12]. Manure used as a natural fertilizer may
contain residues of veterinary drugs which can contaminate agricultural plants via
the soil [13, 14].
Various papers and reviews dealing with the uptake of intact PPCPs by plants
from the environment have been published within the last few years [15–24]. However, PPCPs taken up by plants may also be subjected to bio-transformation/
metabolization processes [25, 26]. A full risk assessment of PPCPs in the environment will require thorough investigations dealing with such transformation pathways because metabolites may show (eco)toxicities even higher than the parent
496
F. Mlynek et al.