organochlorine pesticides in deep-sea Arctic amphipods (Bidleman et al. 2013a, b).
For this purpose, archived amphipod samples from Eurythenes gryllus were
analysed, collected between 1983 and 1998 in water depths between 2075 to 4250
from locations in the western and central Arctic Ocean. The total persistent organic
pollutants (POPs) ranged from 9750 to 156,000 ng/g (lipid weight). Enantiomerselective accumulation was found for o,p'-DDT, cis- and trans-chlordane, nonachlor MC6 and oxychlordane.
As already reported for α-HCH before, Wiberg et al. also calculated separate
biomagnification factors (BMFs) for the (+)- and the (À)-enantiomers of the oxygenated compounds. For the first step, from Atlantic cod to seal, the BMFs are
comparable for oxychlordane ((+)-OXY: BMF ¼ 152; (À)-OXY: BMF ¼ 124), and
also for the second step from seal to polar bear similar values were calculated ((+)OXY: 7.1; (À)-OXY: 6.7) As a consequence, the overall values from cod to polar
bear are also comparable ((+)-OXY: 1075; (À)-OXY: 834). The strange reversal of
the enantiomeric ratios observed for heptachlor exoepoxide up the food chain is
reflected by the following BMFs: from cod to seal for (+)-HEPX BMF ¼ 4.8 and for
(À)-HEPX BMF ¼ 9.3; from seal to bear for (+)-HEPX BMF ¼ 7.4 and for (À)HEPX BMF ¼ 2.3; from cod to bear for (+)-HEPX BMF ¼ 35 and for (À)-HEPX
BMF ¼ 21.
After the first successful separation of the enantiomers of oxychlordane and
heptachlor exoepoxide (König et al. 1991), the main metabolites of cis-/transchlordane and heptachlor, respectively, Hühnerfuss et al. performed systematic
investigations on the enantiomeric distribution of these metabolites in various
marine biota samples (König et al. 1994a, b, c; Hühnerfuss et al. 1996a, b).
Oxychlordane was found in all five sea-gull eggs investigated, while the concentrations of heptachlor exoepoxide were below the detection limit in three eggs. The
presence of heptachlor exoepoxide shows that the transformation of both
exoheptachlor and endoheptachlor to heptachlor exoepoxide is not confined to
mammalian biota like seals, but it is also the exclusive transformation pathway in
sea birds. The ER values of oxychlordane and heptachlor exoepoxide in seagull eggs
are of particular interest: in both cases, the values are larger than one, indicating a
preferential accumulation of the respective (+)-enantiomer. In contrast, the
corresponding values determined in different tissues of seals were smaller than
one. This may possibly suggest that seagulls, representing in this case a coastal
environmental food web, are reflecting rather terrestrial characteristics than marine
profiles. This holds at least for the enzymatic processes that give rise to
enantioselective accumulation of oxychlordane and/or heptachlor exoepoxide.
Oxychlordane enantiomers were also analysed by Müller et al. (1996a, b) in
harbour seals (Phoca vitulina L.) and grey seals (Halichoerus grypus (FABR.)).
They reported the notable result that higher (À)-oxychlordane levels were present in
harbour seals, while in grey seals (+)-oxychlordane was dominating (Table 8.11). A
more detailed analysis of the data set revealed that neither levels nor enantiomeric
ratios of α-HCH and oxychlordane did correlate in harbour seal or grey seals. Also in
this case (as reported from previous studies already), no trend in the enantiomeric
profiles of oxychlordane with regard to age or sex could be inferred from the data
obtained in the here-reported study.
154
8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants
For this purpose, archived amphipod samples from Eurythenes gryllus were
analysed, collected between 1983 and 1998 in water depths between 2075 to 4250
from locations in the western and central Arctic Ocean. The total persistent organic
pollutants (POPs) ranged from 9750 to 156,000 ng/g (lipid weight). Enantiomerselective accumulation was found for o,p'-DDT, cis- and trans-chlordane, nonachlor MC6 and oxychlordane.
As already reported for α-HCH before, Wiberg et al. also calculated separate
biomagnification factors (BMFs) for the (+)- and the (À)-enantiomers of the oxygenated compounds. For the first step, from Atlantic cod to seal, the BMFs are
comparable for oxychlordane ((+)-OXY: BMF ¼ 152; (À)-OXY: BMF ¼ 124), and
also for the second step from seal to polar bear similar values were calculated ((+)OXY: 7.1; (À)-OXY: 6.7) As a consequence, the overall values from cod to polar
bear are also comparable ((+)-OXY: 1075; (À)-OXY: 834). The strange reversal of
the enantiomeric ratios observed for heptachlor exoepoxide up the food chain is
reflected by the following BMFs: from cod to seal for (+)-HEPX BMF ¼ 4.8 and for
(À)-HEPX BMF ¼ 9.3; from seal to bear for (+)-HEPX BMF ¼ 7.4 and for (À)HEPX BMF ¼ 2.3; from cod to bear for (+)-HEPX BMF ¼ 35 and for (À)-HEPX
BMF ¼ 21.
After the first successful separation of the enantiomers of oxychlordane and
heptachlor exoepoxide (König et al. 1991), the main metabolites of cis-/transchlordane and heptachlor, respectively, Hühnerfuss et al. performed systematic
investigations on the enantiomeric distribution of these metabolites in various
marine biota samples (König et al. 1994a, b, c; Hühnerfuss et al. 1996a, b).
Oxychlordane was found in all five sea-gull eggs investigated, while the concentrations of heptachlor exoepoxide were below the detection limit in three eggs. The
presence of heptachlor exoepoxide shows that the transformation of both
exoheptachlor and endoheptachlor to heptachlor exoepoxide is not confined to
mammalian biota like seals, but it is also the exclusive transformation pathway in
sea birds. The ER values of oxychlordane and heptachlor exoepoxide in seagull eggs
are of particular interest: in both cases, the values are larger than one, indicating a
preferential accumulation of the respective (+)-enantiomer. In contrast, the
corresponding values determined in different tissues of seals were smaller than
one. This may possibly suggest that seagulls, representing in this case a coastal
environmental food web, are reflecting rather terrestrial characteristics than marine
profiles. This holds at least for the enzymatic processes that give rise to
enantioselective accumulation of oxychlordane and/or heptachlor exoepoxide.
Oxychlordane enantiomers were also analysed by Müller et al. (1996a, b) in
harbour seals (Phoca vitulina L.) and grey seals (Halichoerus grypus (FABR.)).
They reported the notable result that higher (À)-oxychlordane levels were present in
harbour seals, while in grey seals (+)-oxychlordane was dominating (Table 8.11). A
more detailed analysis of the data set revealed that neither levels nor enantiomeric
ratios of α-HCH and oxychlordane did correlate in harbour seal or grey seals. Also in
this case (as reported from previous studies already), no trend in the enantiomeric
profiles of oxychlordane with regard to age or sex could be inferred from the data
obtained in the here-reported study.
154
8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants