(conc ¼ 6.2–7.5 μg/g lipid; ER trans ¼ 0.55–0.66; ER cis ¼ 1.07–1.24), tench (conc ¼
150–160 μg/g lipid; ER trans ¼ 0.88–1.10; ER cis ¼ 0.95–1.00), crucian carp (conc ¼
39–91 μg/g lipid; ER trans ¼ 0.10–0.19; ER cis ¼ 0.41–0.54), eel (conc ¼ 4.6–4.8 μg/g
lipid; ER trans ¼ 0.79–0.98; ER cis ¼ 1.15–1.27), mussel (conc ¼ 120 μg/g lipid;
ER trans ¼ 0.91; ER cis ¼ 1.26). Similar clusters can be inferred from Table 8.21: for
concentrations and enantiomeric ratios for AHTN, trans-ATII and AHDI,
respectively.
The authors assumed that high concentrations and enantiomeric ratios close to
racemic, that is, ER % 1, indicate a low metabolisation potential of a species for the
respective polycyclic musk derivative. On the other hand, caution has to be applied
when inferring metabolisation potentials exclusively from lipid-based concentrations: low concentrations may reflect a stronger metabolisation, but it cannot be
excluded that specific matrix effects, for example, high lipid contents like in eel, may
pretend a stronger metabolisation than actually encountered. As unequivocal evidence for an enantioselective transformation process, however, are ER values clearly
different from one. On the basis of these assumptions, rudd appears to exhibit a
strong enantioselective metabolisation potential for trans-HHCB.
Tench shows a low enantioselective metabolisation potential for trans- and cisHHCB, and a moderate one for AHTN and AHDI. Very strong enantioselective
metabolisation can be concluded for trans- and cis-HHCB, as well as for trans-ATII
in crucian carp, while for AHDI a moderate metabolisation was observed. With ER
values 0.1 for trans-HHCB and trans-ATII, the highest enantioselectivity in the
study by Gatermann et al. was observed. In eel the high lipid content gives rise to
low lipid-normalised concentrations, but the ER values indicate low to moderate
enantioselective metabolisation for trans- and cis-HHCB, and AHTN, while for
trans-ATII and AHDI a stronger enantioselective metabolisation capability was
found. For a more detailed discussion of the results obtained herein for crucian
carp and tench, the reader should refer to the next section on polycyclic musks.
The values for the pooled Zebra mussel sample, known for a low metabolisation
capability, reflect the water values, which were also determined in the study carried
out by Gatermann et al. (2002a, b). By the way of contrast, in the liver the metabolic
capacity is higher than in other organs. As a consequence, lower concentrations of
the polycyclic musks and larger deviations from racemic were determined in the
tench and crucian carp liver extracts (with the exception of trans-HHCB in the tench
sample) compared to the corresponding muscle tissues (8.2.15.).
As stated above, the lipid-based concentrations for the assignment of
metabolisation potentials may be misleading. However, in those cases, where both
low concentrations and significant deviations of the enantiomeric ratios from one are
being encountered, it is justified to assume strong metabolisation capacities. This
assumption is in line with previous conclusions drawn by Wiberg et al. from
enantioselective analyses of chlordanes in different fish species (Wiberg et al.
1998a, b, c).
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8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants
150–160 μg/g lipid; ER trans ¼ 0.88–1.10; ER cis ¼ 0.95–1.00), crucian carp (conc ¼
39–91 μg/g lipid; ER trans ¼ 0.10–0.19; ER cis ¼ 0.41–0.54), eel (conc ¼ 4.6–4.8 μg/g
lipid; ER trans ¼ 0.79–0.98; ER cis ¼ 1.15–1.27), mussel (conc ¼ 120 μg/g lipid;
ER trans ¼ 0.91; ER cis ¼ 1.26). Similar clusters can be inferred from Table 8.21: for
concentrations and enantiomeric ratios for AHTN, trans-ATII and AHDI,
respectively.
The authors assumed that high concentrations and enantiomeric ratios close to
racemic, that is, ER % 1, indicate a low metabolisation potential of a species for the
respective polycyclic musk derivative. On the other hand, caution has to be applied
when inferring metabolisation potentials exclusively from lipid-based concentrations: low concentrations may reflect a stronger metabolisation, but it cannot be
excluded that specific matrix effects, for example, high lipid contents like in eel, may
pretend a stronger metabolisation than actually encountered. As unequivocal evidence for an enantioselective transformation process, however, are ER values clearly
different from one. On the basis of these assumptions, rudd appears to exhibit a
strong enantioselective metabolisation potential for trans-HHCB.
Tench shows a low enantioselective metabolisation potential for trans- and cisHHCB, and a moderate one for AHTN and AHDI. Very strong enantioselective
metabolisation can be concluded for trans- and cis-HHCB, as well as for trans-ATII
in crucian carp, while for AHDI a moderate metabolisation was observed. With ER
values 0.1 for trans-HHCB and trans-ATII, the highest enantioselectivity in the
study by Gatermann et al. was observed. In eel the high lipid content gives rise to
low lipid-normalised concentrations, but the ER values indicate low to moderate
enantioselective metabolisation for trans- and cis-HHCB, and AHTN, while for
trans-ATII and AHDI a stronger enantioselective metabolisation capability was
found. For a more detailed discussion of the results obtained herein for crucian
carp and tench, the reader should refer to the next section on polycyclic musks.
The values for the pooled Zebra mussel sample, known for a low metabolisation
capability, reflect the water values, which were also determined in the study carried
out by Gatermann et al. (2002a, b). By the way of contrast, in the liver the metabolic
capacity is higher than in other organs. As a consequence, lower concentrations of
the polycyclic musks and larger deviations from racemic were determined in the
tench and crucian carp liver extracts (with the exception of trans-HHCB in the tench
sample) compared to the corresponding muscle tissues (8.2.15.).
As stated above, the lipid-based concentrations for the assignment of
metabolisation potentials may be misleading. However, in those cases, where both
low concentrations and significant deviations of the enantiomeric ratios from one are
being encountered, it is justified to assume strong metabolisation capacities. This
assumption is in line with previous conclusions drawn by Wiberg et al. from
enantioselective analyses of chlordanes in different fish species (Wiberg et al.
1998a, b, c).
224
8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants