2,5,6,2
0 ,4
0 ,5
0 -hexachlorobiphenyl (abbr. 4-149) as concluded in several studies
(Larsson et al. 2002, 2004a, b). The MeSO 2 -PCBs formed are persistent and only
slightly less hydrophobic than their parent compounds which make them longlasting contaminants in the biosphere (Letcher et al. 1998; Hoekstra et al.
2003a, b, c; Sandala et al. 2004; Quinete et al. 2014). From a toxicological point
of view, several of the 3-MeSO 2 -PCBs have been shown by Kato and co-workers to
induce strongly P-450 cytochrome enzymes such as P450 2B1, 2B2, 3A2 and 2C6
(Kato et al. 1995; Kato et al. 1997). In a comprehensive study on Arctic top
predators, direct associations between PCBs and thyroid hormone dysfunctions
have been found. A direct impact of methyl sulfone PCB is assumed (Braathen
et al. 2004). Based on the already reported information, we, thus, assume that at least
part of the toxic effects induced by PCBs in the environment may be subject to the
presence of major PCB metabolites. Furthermore, the main metabolites mentioned
above are chiral and, accordingly, enantioselective transformation, as well as toxic
impacts cannot be excluded. Effect-related aspects will be explained further in
Chap. 10.
In order to gain deepened insight into the enantioselective transformation of
atropisomeric PCBs, the research groups of Bergman and Hühnerfuss (Bergman
et al. 1998; Ellerichmann et al. 1998a, b, c; Larsson et al. 1999) performed several
systematic joint studies, which included:
• The separation of eight MeSO 2 -PCB standards into their enantiomers using
enantioselective cGC: 4-91, 4-95, 3-149, 4-149, 3-132, 4-132, 3-174 and 4-174
(Ellerichmann et al. 1998a, b, c)
• The enantiomer separation of MeSO 2 -PCBs in human liver sample extracts
• The enantiomer separation of MeSO 2 -PCBs in rat liver and adipose sample
extracts (Larsson et al. 2002)
• The enantiomer separation of MeSO 2 -PCBs in rat lung sample extracts (Larsson
et al. 2002)
• Structure elucidation of priority methyl sulfone PCBs (Pham-Tuan et al. 2005)
• The enantiomer separation of larger amounts of 3-132, 3-149 and 4-149 as well as
their parent PCBs by enantioselective preparative HPLC
• Investigation of enantioselective toxic effects of the MeSO 2 -PCB enantiomers
All results obtained from this joint endeavour are reported completely in the
scientific literature (Bergman et al. 1998; Ellerichmann et al. 1998a, b, c; Larsson
et al. 1999, 2002, 2004a, b; Pham-Tuan et al. 2005; Jorundsdottir et al. 2006). In total
eight out of ten atropisomeric MeSO 2 -PCBs (see above) previously found in environmental samples were separated into their enantiomers using a 10-m fused silica
capillary column coated with a 1:1 (w:w) mixture of OV 1701 and heptakis(6-Otertbutyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin (TBDMS-CD). The congener 3-95 was not included in the study because no standard compound was available
at that time. Follow-up studies, nevertheless, revealed the presence and the enantiomeric signature of this compound in various biological materials (Karásek et al.
2007). Furthermore, Ellerichmann and others (Ellerichmann et al. 1998a, b, c)
reported the successful separation of the congener 3-91. However, in the course of
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8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants
0 ,4
0 ,5
0 -hexachlorobiphenyl (abbr. 4-149) as concluded in several studies
(Larsson et al. 2002, 2004a, b). The MeSO 2 -PCBs formed are persistent and only
slightly less hydrophobic than their parent compounds which make them longlasting contaminants in the biosphere (Letcher et al. 1998; Hoekstra et al.
2003a, b, c; Sandala et al. 2004; Quinete et al. 2014). From a toxicological point
of view, several of the 3-MeSO 2 -PCBs have been shown by Kato and co-workers to
induce strongly P-450 cytochrome enzymes such as P450 2B1, 2B2, 3A2 and 2C6
(Kato et al. 1995; Kato et al. 1997). In a comprehensive study on Arctic top
predators, direct associations between PCBs and thyroid hormone dysfunctions
have been found. A direct impact of methyl sulfone PCB is assumed (Braathen
et al. 2004). Based on the already reported information, we, thus, assume that at least
part of the toxic effects induced by PCBs in the environment may be subject to the
presence of major PCB metabolites. Furthermore, the main metabolites mentioned
above are chiral and, accordingly, enantioselective transformation, as well as toxic
impacts cannot be excluded. Effect-related aspects will be explained further in
Chap. 10.
In order to gain deepened insight into the enantioselective transformation of
atropisomeric PCBs, the research groups of Bergman and Hühnerfuss (Bergman
et al. 1998; Ellerichmann et al. 1998a, b, c; Larsson et al. 1999) performed several
systematic joint studies, which included:
• The separation of eight MeSO 2 -PCB standards into their enantiomers using
enantioselective cGC: 4-91, 4-95, 3-149, 4-149, 3-132, 4-132, 3-174 and 4-174
(Ellerichmann et al. 1998a, b, c)
• The enantiomer separation of MeSO 2 -PCBs in human liver sample extracts
• The enantiomer separation of MeSO 2 -PCBs in rat liver and adipose sample
extracts (Larsson et al. 2002)
• The enantiomer separation of MeSO 2 -PCBs in rat lung sample extracts (Larsson
et al. 2002)
• Structure elucidation of priority methyl sulfone PCBs (Pham-Tuan et al. 2005)
• The enantiomer separation of larger amounts of 3-132, 3-149 and 4-149 as well as
their parent PCBs by enantioselective preparative HPLC
• Investigation of enantioselective toxic effects of the MeSO 2 -PCB enantiomers
All results obtained from this joint endeavour are reported completely in the
scientific literature (Bergman et al. 1998; Ellerichmann et al. 1998a, b, c; Larsson
et al. 1999, 2002, 2004a, b; Pham-Tuan et al. 2005; Jorundsdottir et al. 2006). In total
eight out of ten atropisomeric MeSO 2 -PCBs (see above) previously found in environmental samples were separated into their enantiomers using a 10-m fused silica
capillary column coated with a 1:1 (w:w) mixture of OV 1701 and heptakis(6-Otertbutyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin (TBDMS-CD). The congener 3-95 was not included in the study because no standard compound was available
at that time. Follow-up studies, nevertheless, revealed the presence and the enantiomeric signature of this compound in various biological materials (Karásek et al.
2007). Furthermore, Ellerichmann and others (Ellerichmann et al. 1998a, b, c)
reported the successful separation of the congener 3-91. However, in the course of
180
8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants