Download Organochlorine residues in marine mammals from the Northern

The Science of the Total Environment 186 (1996) 29-39
ELSEVIER
Organochlorine residues in marine mammals from the Northern
hemisphere- A consideration of the composition of
organochlorine residues in the blubber of marine mammals
Walter Vetter*a, Bernd Luckasa, Giinter Heidemannb,
“Fri~~rich-S~hillkr-UniversitLi‘r-Juno.
Instttut
hBocu
‘University
of lcehnd,
Fountlution,
Keltlur,
Institute
jiii. Erndhrung
Billbrookrieich
for
untl
210-216.
Experimentul
Umwelt.
D-22113
Puthology,
Dornhurger
Humhurg,
P. 0. Box
Karl Skirnisson”
Str. 25, D-07743
Germuny
8.540,
IS-118
Reykjusik,
Jenu.
Germuny
Icrluntl
Abstract
Levels of organochlorines
(PCBs,CDDT, lindaneand its isomers,HCB, chlordane,and toxaphene)weredetermined
in blubber of marinemammalsfrom the northern hemisphere.Differencesin both levelsand ratios of organochlorine
compoundsweredetected in different speciesof marine mammalsliving in the sameregion, e.g. blubber of harbour
seals(Phocauitulinu)
accumulatedsignificantlylower levelsof lindane, HCB, toxaphene,and DDT and its metabolites
than harbour porpoises(Phocoenuphocoenu).Comparedto suchelementarydifferencesin the organochlorinepattern
in different marine mammals,the influence of age and sex on the results was only minimal. Varying ratios of
contaminantsin individual harbour porpoiseswereexplainedby migration. Constant PCB/DDT ratios weremeasured
in harbour seals.Due to the sedentariness
of harbour seals,even local sourcesof contaminantscould be recognized.
Careful evaluation of the organochlorine levels and ratios in marine mammalsmade it possibleto monitor the
transport of PCBsfrom the Europeancontinent to EuropeanArctic regions.
Keywords:
Harbour seals;Blubber; Contaminants;PCB; DDT; Northern Europe; Arctic
1. Introduction
Organochlorine residues in marine mammals
from different regions are often used to evaluate
both distribution and levels of contaminants in the
northern hemisphere. However, such pollution assessmentsimply three variables: “organochlorine
residues” include a large number of different compounds; “marine mammals” include a number of
different seal and whale species;and the “northern
*Corresponding author.
0048-9697/96/$15.00 8 1996 Elsevier Science BV. All rights reserved
SSDI
0048-9697(96)05084-X
hemisphere” is made up of different marine regions. Generally, in equations with three variables,
two variables must be constant for an evaluation
of the third. No marine mammal speciesoccur in
all waters and thus it must be considered whether
the composition of organochlorine compounds in
different species of marine mammals is comparable. Only on this basis is a global assessmentof
organochlorine residues using marine mammals
possible. Biological parameters such as age and
sex are further important variables which must
be considered, although the influence of some
30
W. Vrtter et ul. I The Scirncr of the Totul Environment I& (1996) 29-39
biological factors on organochlorine levels is highly controversial (Holden, 1978; Reijnders, 1980;
Blomqvist et al., 1992). Variations in the organochlorine content of individuals have been reported
in the literature (Addison, 1989). In the following,
examples of organochlorine pollution in the European part of the northern hemisphere are presented. Where possible, age and sex of individuals
were considered or data from selected groups were
extracted. In some cases, such selections would
have resulted in too small a sample size, in which
case mean values, ranges, and medians are presented to support the conclusions.
column shows advanced selectivity for the separation of PCBs and chlorinated hydrocarbons (Vetter et al., 1994; Vetter et al., 1995a; Vetter and
Luckas, 1995). Column parameters were: length 63
m, internal diameter 0.25 mm, and film thickness
0.25 ,um.
It is not clear whether the CP-Select for PCBs
column will become manufactured but a capillary
column with very similar properties, the non-polar
CP-Sil 2 (Chrompack, the Netherlands), is commercially available (Estel et al., 1995). The CP-Sil
2 shows the same excellent separations of PCBs
and pesticides as the CP-Select for PCBs except
for PCB 153 and p,p’-DDE which coeluted on the
CP-Sil 2.
2. Materials and methods
Blubber samples from the North Sea and the
Baltic Sea were obtained from individuals found
dead on shore. Samples from Iceland were from
animals which had been shot.
All blubber samples were analyzed in 1988 and
1995 using the same analytical procedure. The
clean-up procedure has previously been described
in detail (Luckas et al., 1990; Vetter et al., 1995a).
Briefly, the fat layers were digested with a mixture
of perchloric acid and acetic acid. Acid-stable
organochlorine compounds were extracted twice
with n-hexane. The hexane-layer was repeatedly
treated with sulphuric acid. Finally, the remaining
fat matrix (~75 mg) was separated on 3-g silica
gel, deactivated with 30% water, by elution with
60-ml n-hexane (Vetter et al., 1995a). The recovery
was >85% for all organochlorine
compounds.
Quantification
was carried out by GC-ECD on
two capillary columns of different polarity (Luckas
et al., 1990). The accuracy of the analytical method
has been proven in an interlaboratory
study of
organochlorines in seal blubber (Rimkus et al.,
1993).
GC\ECNI-MS
experiments were carried out on
an HP 5989B MS Engine (Hewlett Packard) connected to an HP 5890 II plus gas chromatograph
(Vetter et al., 1995a). The stationary phase was a
prototype of the CP-Select for PCBs (Chrompack)
column. This very non-polar phase is similar to
squalane but shows high temperature stability
(Vetter et al., 1995a). The “CP-Select for PCBs”
3. Results and discussion
3. I Composition of organochlorine compoundsin
technical mixtures and in seal blubber
The composition of organochlorine compounds
in the marine environment is often quite different
from technical mixtures (Duinker et al., 1980;
Vetter and Luckas, 1991). Even on low trophic
levels in food webs the organochlorine pattern is
different from that in technical products due to
biodegradation
and selective bioaccumulation.
Lipophilic compounds are the organics most likely
to bioaccumulate
(Connell, 1988) and the lipid
phase is the dominant phase for accumulation
of organochlorine
compounds (Mackay, 1982).
Therefore, blubber of marine mammals is an important matrix to study the accumulation of organochlorines. The octanol:water partitition coefficient (KOW) proved to be helpful in describing
factors determinating the accumulation of organochlorines (Chiou et al., 1977). A further important
factor is the metabolization
of less persistent organochlorine compounds. Accumulation of a technical product without chemical changes will only
occur in the case of single substances like hexachlorobenzene
(HCB)
and octachlorostyrene
(OCS).
A different composition compared to technical
products will be obtained by analysis of multicomponental mixtures like PCBs and toxaphene. In
blubber of marine mammals, only persistent con-
W. Vetter et ul. I The Science of the Total Environment 186 (1996) 29-39
geners are retained and less stable compounds are
eliminated. Technical PCB mixtures consist of
approx. Seventy PCB congeners each. All in all,
137 of the 209 PCB congeners were detected in
technical PCB mixtures (Frame, 1995). In seal
blubber, PCB 153 and PCB 138 reach the highest
levels of all PCB congeners. However, PCB 138
coelutes with both PCB 163 and PCB 164 on most
of the capillary column types (Larsen and Riego,
1990; Vetter et al., 1994). In seal samples, the level
of PCB 163 reaches up to 37% of PCB 138 (Vetter
et al., 1995a). Therefore, PCB 163 is one of the
most abundant PCB congeners in seal blubber.
Further high abundant PCBs in seals are PCB
149, PCB 170, and PCB 180 (Vetter et al., 1995a).
As opposed to PCB congeners of high abundance (Andersson et al., 1988; Muir et al., 1988a),
the levels of some toxic PCB congeners are lower
in seal blubber than in fish from the same region
(Asplund et al., 1990; Kannan et al., 1993; Falandysz et al., 1994). In seal blubber the biodegradation of toxaphene was even more drastic.
Technical toxaphene consists of several hundred
compounds (Jansson and Wideqvist, 1983) but
only few compounds
of technical toxaphene
(CTTs) are abundant in seal blubber (Luckas et
al., 1990; Vetter and Luckas, 1991). Less biomagnification and/or a more effective metabolism was
reported for CTTs at high trophic levels of food
webs (Andersson et al., 1988).
Metabolites play a dominant role if the persistence exceeds that of the technical product, e.g.
p,p’-DDE is more persistent than p,p’-DDT and
yields about 80% of the total-DDT content in seal
blubber (Luckas et al., 1990). Oxychlordane is a
persistent metabolite
of technical chlordane in
marine mammals (Dearth and Hites, 1991a). These
metabolites have similar polarities as the parent
compounds. However, metabolites of higher polarity which require improved clean-up procedures
(e.g. hydroxylated
PCBs, methylsulfonyl
DDE
a.s.o.) are contaminants
of high significance
(Letcher et al., 1992; Safe et al., 1995). Unfortunately, polar metabolites are not analyzed as a
matter of routine due to the lack of analytical
methods and standard compounds.
Accompanying substances in technical mixtures
become important when their persistence exceeds
31
that of the insecticidal substance, e.g. transnonachlor, which is a minor compound of technical chlordane (7 2 3% (Sovocool et al., 1977)) is
often the main chlordane compound in marine
mammals (Dearth and Hites, 1991b; Vetter et al.,
1995b). Already in the 1970s technical hexachlorocyclohexane (HCH) was replaced by pure
lindane, which is the only insecticidal active HCH
isomer (DFG, 1982). Even in the 1990s however,
levels of c(-HCH often exceed those of lindane in
seal blubber (Luckas et al., 1990). On the other
hand, high levels of /?-HCH in seal blubber are an
indication of recent applications of technical HCH
(Vetter et al., 1995a).
Transformation
products may be formed by
UV-irradiation
or even under environmental conditions and probably account for the high levels of
or-HCH compared to lindane in Arctic air samples
(Oehme and Mano, 1984). High levels of a-HCH
were also measured in seal blubber from Spitsbergen (Luckas et al., 1990).
Enantiomeric
ratios unlike 1:l are obtained
when chiral compounds are stereoselectively biodegradated or bioaccumulated. In biota, the selective enrichment of one organochlorine enantiomer
was observed for the first time for cl-HCH (Kallenborn et al., 1991). Later, enantioselective bioaccumulation
of chiral chlordanes (Buser et al.,
1992), CTTs (Buser and Miiller, 1993; Kallenborn
et al., 1994), o,p’-DDT (Oehme et al., 1994), and
atropisomeric PCBs (Glausch et al., 1994) was
reported.
3.2 Marine mummalsas bioindicutors
Organisms on a high trophic level are able to
both metabolize and bioaccumulate organochlorine compounds. The ratio of accumulation/ biodegradation determines if a compound is either
deposited in the blubber of marine mammals or
eliminated from the species. The ratio of concentrations at one trophic level to those at the next
lowest level calculated on a lipid weight basis was
defined as biomagnification
factor (BMF) (Muir et
al., 1988a). For DDT and its metabolites (total
DDT) a BMF > 1 was detected from fish to seal
but the BMF declined from seal to polar bear
(Muir et al., 1988a). Furthermore, different species
32
W. Vcttrr et ul. I The Science of the Total Environment 186 (1996) 29-39
of marine mammals deposit different levels and
ratios of organochlorine compounds in their blubber. This fact has to be taken into account if results
from different marine regions are to be compared,
i.e. if marine mammals are utilized as bioindicators
for pollution assessments. Bioindicators are organisms or communities of organisms that react to
pollution by changes in their life functions and
accumulation of pollutants (Arndt, 1992).
To compare results obtained both from different
regions and different species, defined parameters
must be taken into account. For free-living organisms such as marine mammals, identical habits in
the uptake of food and food composition must be
guaranteed. Additionally,
the sedentariness of a
species has a fundamental influence on the accuracy of results. If feeding location and location of
sampling are identical, the residue pattern within a
region represents a defined group of marine species. Factors defining marine species are sample
data such as age, sex, condition index, seasonal
aspects, and residue distribution in different parts
of the animal (Reijnders, 1980; Addison, 1989).
However, the influence of some factors is highly
controversial. Organochlorine
levels correlating
with age were only significant for male marine
mammals (Reijnders, 1980). Levels in adult females
depend very much on their reproductive status
(Storr-Hansen and Spliid, 1993). Extremely high
levels were already detected in seal pups (see
below).
3.3 Resultsfrom marine mammalsin the sameregion
In the German part of the North Sea, harbour
seals and harbour porpoises are widespread. The
major prey of both species are the more common
species of fish (e.g. herring, mackerel) (King, 1983;
Kremer and Maywald, 1991). However, both species accumulated different levels of organochlorines. Blubber of harbour porpoises retained remarkable concentrations of HCB and lindane,
exceeding the mean levels in harbour seals by a
factor of about 50 (see Table 1). Furthermore, high
levels of p,p’-DDD account for the higher totalDDT (CDDT) levels in harbour porpoises compared with harbour seals. Low p,p’-DDD levels in
seals and high p,p’-DDD levels in harbour porpoises and several other cetaceans were already
reported in the early 1970s (Koeman et al., 1972;
Muir et al., 1988b; Kuiken et al., 1994). Analyses
of harbour seals, grey seals (Halichoerus grypus),
and harbour porpoises from western Iceland (Vetter et al., 1995b; Hummert et al., 1995) also confirm different accumulation mechanisms of organochlorine compounds in seals and cetaceans. The
Icelandic samples also showed variations in the
pollution with compounds of technical toxaphene
(CTTs). The two most abundant CTTs in biota,
TOX8/T2 and TOX9/T12, have been isolated from
seal (Vetter et al., 1992) and beluga (Stern et al.,
1992) blubber. They are now commercially available as single substances under the trade name
Parlar # 26 and Parlar # 50.
Table I
Levels of HCB, lindane, and DDT and its metabolites &g/kg) in blubber of harbour seals and harbour porpoises from the North Sea
(Schleswig-Holstein)
bkin
values
Harbour seal
(n = 32)
Harbour porpoise
(n = 16)
HCB
Lindane
XDDT
&-DDE
p,p’-DDD
p,p’-DDT
7
< I-33’
5d
808”
44-2050’
642‘+
12
<l-29
10
484
84-954
341
3903
1501-11475
2575
6347
1361-18763
4325
2869
1142-8025
1809
2983
696-8450
1757
62
14-226
48
2319
392-5263
1777
972
280-292 1
747
1283
217-3566
660
‘n = number of samples.
hmean value.
‘range.
“median.
33
W. Vetter et al. I The Science of the Totul Environment 186 (1996) 29-39
Table 2
Relative GC\ECNI-HS
signal abundances
of TOIX8 and TOX9
and PCB 153 in harbour porpoises, grey seals, and harbour
seals from western Iceland
PCB 153
TOX8
TOX9
Harbour porpoise
(n = 4)
Grey seal
(n = 8)
Harbour seal
(n = 3)
10ixI.o
478.5
432.8
1000.0
29.4
9.1
1000.0
10.6
5.5
Table 2 lists GC\ECNI-HS signal abundances
of TOX8 and TOX9 relative to the GC\ECNI-HS
signal abundance of PCB 153. The levels of TOX8
and TOX9 relative to PCB 153 were more than
ten-fold higher in harbour porpoises than in harbour and grey seals.Unfortunately, biological data
was not available for all samples,but such significant differences in the ratios cannot ble explained
by sex and age of the samples. Thus, levels of
organochlorines from different marine regions
should not be evaluated by comparison of harbour
sealsand harbour porpoises. There is strong evidence that this is also the case for other seal and
cetacean species.
In all examples harbour porpoises accumulated
higher levels of selected organochlorine compounds than harbour seals. But there was one
more astonishing fact. Analyses of fish revealed
significantly different PCB/DDT ratios in the
North Sea and the Baltic Sea (Luckas and Harms,
1987). This was confirmed by analyses of harbour
seals(Luckas et al., 1990). However, some harbour
porpoises which washed up dead on the German
North Sea coast (e.g. Sylt), showed ZPCB/DDT
ratios in the blubber typical to samples from the
Baltic Sea. This fact supports observations of biologists regarding migration of harbour porpoises
between the North Sea and the Baltic Sea (Kremer
and Maywald, 1991).Though this observation is of
ethological interest, harbour porpoises of the
North Sea and the Baltic Sea are no’t sedentary
and, according to the requirements presented
above, are not therefore suitable bioindicators for
monitoring the distribution of organochlorines.
Harbour seals along the German North Sea
coast are fairly sedentary. Analyses of >200 harbour seals from Schleswig-Holstein and Lower
Table 3
Levels (mean values and ranges in brackets) of organochlorine
compounds (pg/kg) in harbour seals from Schleswig-Holstein
sampled before (1987) and during (1988) the seal die-off in the
North Sea
HCB
I-HCH
Lindane
ZDDT
PCB 101
PCB 153
PCB 138/163
PCB 180
?3CB2
ZCBZ/ZDDT
Harbour seals
sampled in 1987
(I? = 18)
Harbour seals
sampled in 1988
(II = 32)
10 (<l-33)
4s (<l-103)
15 (11-40)
3161 (355-6598)
761 (111-906)
9326 (1311-26388)
6494 (1098-14444)
2266 (180-3026)
15 823 (7797-40832)
4.74 (3.6-8.8)
I (2-43)
27 (8-40)
12 ( < l-29)
3903 (1501-11475)
648 (313-1541)
10081 (3352-29972)
6983 (2367-19 947)
2224 (639-8632)
17064 (5747-49 919)
4.63 (3.0-6.2)
Saxony did not reveal one sample without the
typical North Sea pattern (Vetter and Luckas,
1991). This was of interest in connection with the
massmortality of sealsin the North Sea in 1988.
Since the measurements started before the die-off
spread, harbour seals from the same region sampled before and during the die-off could be compared (see Table 3). Biological parameters were
available and this made it possible to determine
the condition of the deceased seals according to
standard measurement procedures (McLaren,
1958; Marine Mammals Committee, 1967). The
mean condition index of 62.0 (range: 53.7-70.9)
calculated for the sealsdying during the sealdie-off
(Vetter, 1990) in 1988 was only slightly below an
average condition index of 63.9 during the years
1974-1988 (Vogel, 1989). Thus, animals with normal physical development were infected by the
virus in 1988. This is in agreement with seals in
British waters (Kuiken et al., 1994).
The organochlorine levels measured before and
during the seal die-off were also very similar, even
without division of the samples into subgroups of
equal sex and age (seeTable 3). Though the levels
in individuals ranged one order of magnitude, the
ratio of PCBs and DDT and its metabolites was
very constant.
In ratios, PCBs were given as a value called
xCB2 which is the sum of the levels of PCB 153
34
W. Vetter et cd.1 The Science of the Total Environment 186 (1996) 29-39
Table 4
Levels of DDT and PCBs @g/kg) in male and female seal pups found dead at the Wadden Sea of Schleswig-Holstein before (1987)
and during (1988) the mass mortality
Male pups, 1987 (n = 7)
Male pups, 1988 (n = 5)
ZDDT
ZCB2
ZCB2//ZDDT
ZDDT
ZCB2
XB2,‘EDDT
1509
1223
4615
1096
5161
1914
4218
9128
4238
t 7902
3955
18636
12378
14289
6.45
3.47
3.88
3.61
3.61
6.47
3.39
1657
1638
7191
1792
1501
5747
8828
26703
8213
6154
3.47
5.39
3.71
4.58
4.10
Mean: 28 19
11589
4.41
3385
10624
4.25
Female, 1987 (n = 5)
Female, 1988 (n = 6)
ZDDT
ZCB2
ZCBYZDDT
ZDDT
XB2
ZCB2/EDDT
2016
431
1386
6598
2389
6585
2010
8554
25291
11259
3.27
4.66
6.17
3.83
4.71
4985
2843
3727
4085
I505
1590
21890
11437
11308
20801
7271
5764
4.39
4.02
3.03
5.09
4.83
3.63
Mean: 2564
10740
4.53
3123
13079
4.17
and PCB 138/PCB 163. PCB 153 and PCB 138 are
the most abundant PCB congeners in the blubber
of several seal species (Luckas et al., 1990). Since
PCB 138 interfered with PCB 163 in our previous
studies (both PCB congeners coelute on phases
similar to DB-5 and OV-1701), the sum of both
congeners was considered in the CCB2 value. The
choice of PCB 153 and PCB 138/PCB 163 as
representatives also allows a calculation of CCB2
values from literature data, since these PCB congeners are commonly quantified in most publications. CDDT is the sum of p,p’-DDT, p,p’-DDE,
and p,p’-DDD.
To study the age and sex dependence of harbour
seals, levels and ratios of CCB2 and XDDT in
female and male pups found dead in October of
the year of birth (1987 and 1988, respectively) are
listed separately in Table 4. It is unlikely that the
seal pups migrated from birth to death together
with the corresponding lactating females. However, the levels of DDT and PCBs varied greatly,
even in pups. No statistically evident correlation of
levels and sex was observed (see Table 4). Though
PCB and DDT levels varied one order of magnitude, the CCB2/XDDT
ratios were constant for
both sex and sampling year. This is additional
evidence of the sedentary nature of harbour seals.
The mean levels of PCBs and DDT in seal pups
(see Table 4) were below the mean values determined in harbour seals without distinguishing between age and sex (see Table 3). Harbour seals
from Norwegian waters showed the same age
dependence (Skaare et al., 1990), which is particularly due to extremely high levels of organochlorine compounds in some adult males.
High levels of PCBs correlated with DDT and,
therefore, the CCB2/XDDT
ratio was very constant. CCB2/CDDT ratios are well suited for controlling the homogeneity of the sample material.
Significant variations in the CCB;?/CDDT ratio
are an indication of migratory animals (see above).
Constant CCB2/CDDT
ratios are very useful
parameters for characterizing the organochlorine
pattern of a marine region. Already at the coast of
W. Vetter et al. I The
Table 5
Levels (@g/kg) and ratio of XB2
North Sea, Germany)
of the Total
(n = 22)
XB2
ZDDT
Mean:
Range:
Median:
Mean:
Range:
Median:
17064
(5747-49919)
12013
21407
(6831-46180)
20284
Lower Saxony, south-west of Schleswig-Holstein,
the CCB;?/CDDT ratio increased significantly from
4.6 to 8.1. This is particularly due to higher PCB
levels in Lower Saxony (see Table 5). This gradient
in PCB pollution is even more signil’lcant when
median rather than mean values are generated.
Median values are effective parameters to demonstrate the homogeneity of sample material. In seal
blubber from Lower Saxony, PCB mean values
were 20% higher and median values were 40%
higher than in harbour seals from SchleswigHolstein.
The biological and geographical data of the
samples from the Wadden Sea of Lower Saxony
allowed a selection of blubber samples from seals
living over a longer period in the mouth of the
river Elbe. Data obtained from fish samples revealed that OCS is a typical contaminant of river
Table 6
Levels of organochlorine
Environment
35
186 (1996) 29-39
and XDDT in harbour seals from the Wadden Sea of Schleswig-Holstein and Lower Saxony (both
Wadden Sea Schleswig-Holstein (n = 32)
Wadden Sea Lower Saxony
Science
CBZ2
XDDT
3909
(1501-11475)
2614
3095
(1025-5073)
2629
4.63
(3.03-6.17)
4.58
8.14
(4.16-13.84)
7.61
Elbe (Luckas and Oehme, 1990). No OCS was
detected in the blubber of seals from the Wadden
Sea of Lower Saxony but OCS was present in
samples from seals in the mouth of river Elbe. The
highest level of 600 pg/kg OCS was recorded in a
4-year-old female harbour seal. Fig. 1 shows GCECD chromatograms
of the blubber extract of
habour seals from the river Elbe and Lower
Saxony with the typical North Sea pattern. This
was a further indication of the sedentariness of the
harbour seal and its suitability as a bioindicator.
From these results it is concluded that harbour
seals are able to metabolize OCS very quickly. The
presence of OCS in some animals clearly indicates
that even in blubber, which is usually called deposit tissue, a rather active mobilization
of contaminants must take place between blubber and
tissues with high enzyme activity.
compounds (pg/kg) in grey seals from Western Iceland (Suburlond, Breiaafjiir&rr)
No.
Sex, Age
PCB 153
PCB 138
PCB 180
CDDT
HCB
r-HCH
HCB
r-HCH
#I
M, ad
M, ad
M, ad
M, ad
M, ad
F, ad
F. ad
F, ad
252
441
165
230
731
530
174
460
374
149
256’
85
143
436
292
110
321
224.
69
112
46
45
184
157
40
103
95
532
IO46
223
624
1590
948
403
688
757
13
26
9
96
12
24
79
Ii
I7
29
11
18
20
18
20
40
0.76
0.90
0.82
5.33
0.60
1.33
3.95
0.28
34
22
1.75
#2
#3
#4
#5
#6
#7
#8
Mean values
36
W. Vetter et d i The Science oJ’ the Totul Environment 186 (1996) 29-39
(a)
(b)
Fig. I. GC-ECD chromatograms of the blubber extracts of harbour seal (a) from Lower Saxony (above) (b) from the mouth of river
El be (below).
Seal samples from Iceland revealed similar results for HCB. Blubber of grey seals from Western
Iceland showed a wide range in HCB levels (see
Table 6). Two samples in particular (#4 and #7)
were highly polluted with HCB, and high HCB
levels correlated neither with sex nor levels of
PCBs, CDDT, or cr-HCH.
Surprisingly,
blubber of harbour seals from
South-Eastern Iceland showed higher levels of
DDT and PCBs but no significant variations in
the concentrations of HCB (Luckas et al., 1990). In
blubber of harbour seals and grey seals from
Faxafloi (western Iceland) similar concentrations
of PCBs, DDT and chlordane were obtained (Vetter et al., 1995b). However, variations in the HCB
levels (lo-47 pg/kg) were distinctive of grey seals
but not of harbour seals from Faxafloi. In the
blubber of harbour seals, HCB levels were generally below the a-HCH level. On the basis of these
data, it was concluded that the high HCB content
measured in several grey seals is probably caused
by a local input source (Vetter et al., 1995b).
With regard to the enantioselective enrichment
of a-HCH, the preferential accumulation of (+)-
W. Vetter et al. I The Science of the Total Environment 186 (1996) 29-39
c(-HCH was measured in blubber of harbour seals
and northern fur seals (Callorhinuis
minus)
(Milller et al., 1992; Mossner et al., 1992). However, it
was recently shown that not all marine mammals
show higher levels of (+)-c(-HCH
than (-)-aHCH in the blubber (Hummert et al., 1995). Progress is ongoing to explain these phenomena.
4. Conclusions
The investigations confirm that pollution from
organochlorine compounds measured in different
species of marine mammals from different marine
regions must be evaluated very carefully.
However, a proper consideration, including all
factors which are important for the utilization of
marine mammals as bioindicators from different
marine regions, allows an assessment of the risks
to seal species from contamination with organochlorines.
PCB levels in harbour seals are highest in the
Dutch Wadden Sea (Reijnders, 1986). This is
therefore the major source of inputs of PCBs into
the North Sea and North Atlantic. PCB levels
decrease along the continental line of the North
Sea from the Dutch Wadden Sea along the German Wadden Sea of Lower Saxony and Schleswig-Holstein to the Danish North Sea coast. From
the German Wadden Sea, PCB levels decrease
towards Great Britain and Iceland (Law et al.,
1989; Luckas et al., 1990; Mitchell and Kennedy,
1992) and along the Norwegian coast (Skaare et
al., 1990) towards Spitsbergen (Luckas et al.,
1990). Harbour seals are not present at Spitsbergen and therefore ringed seals (Phoca hispida) had
to be used for comparison. The trend offdecreasing
PCB levels from the North Sea towards Arctic
waters was confirmed by ringed seals from Spitsbergen. However, analysis of ringed seals (Phoca
hispida botnica) and harbour seals from the same
region in the Baltic Sea revealed differences in the
organochlorine
levels (Blomqvist et al., 1992).
Thus, further investigations are necessary to confirm that harbour seals can generally be compared
to ringed seals for the assessment of the global
distribution of organochlorine compounds.
31
References
Addison, R.F., 1989. Organochlorines and marine mammal
reproduction. Can. J. Fish. Aquat. Sci., 46: 360-368.
Andersson, ij, C. Linder, M. Olsson, L. Reutergardh, U.
Uvemo and U. Wideqvist, 1988. Spatial differences and
temporal trends of organochlorine compounds in biota
from the northwestern hemisphere. Arch. Environ. Contam.
Toxicol., 17: 755-765.
Arndt, U., 1992. Einftihrung in die Bioindikation. In: A. Kohler
and U. Amdt (Eds), Bioindikatoren fur Umweltbelastungen, Verlag Josef Margraf, Weikersheim.
Asplund, L., B. Jansson, C. de Wit, S. Bergek, M. Hjelt, C.
Rappe, T. Odsjii and M. Olsson, 1990. Polychlorinated
Dibenzo-p-dioxins (PCDD) and Dibenzofurans (PCDF).
Compared to other Organohalogen Pollutants in Biological
Samples from Swedish Ecosystems. Dioxin 90, Ecoinforma
Press, Bayreuth; Short Papers Vol. 1: 405-408.
Blomqvist, G., A. Roos, S. Jensen, A. Bignert and M. Olsson,
1992. Concentrations of sDDT and PCB in Seals from
Swedish and Scottish Waters. Ambio, 21: 5399545.
Buser, H.R., M.D. Miiller and C. Rappe, 1992. Enantioselective
determination of chlordane components using chiral highresolution gas chromatography-mass spectrometry with application to environmental samples. Environ. Sci. Technol.,
26: 15333 1540.
Buser, H.R. and M.D. Miiller, 1993. Isomer- and enantiomerselective analyses of toxaphene components using chiral
high-resolution gaschromatography and detection by mass
spectrometry/mass spectrometry. Environ. Sci. Technol., 28:
119-128.
Chiou, CT., V.H. Freed, D.W. Schmelling and R.L. Kohnert,
1977. Partition coefficients and bioaccumulation of selected
organic chemicals. Environ. Sci. Technol., 11: 475-478.
Connell, D. W., 1988. Bioaccumulation behavior of persistent
organic chemicals with aquatic organisms. Rev. Environ.
Contam. Toxicoi., 102: 117-160.
Dearth, M.A. and R.A. Hites, 199la. Chlordane accumulation
in people. Environ. Sci. Technol., 25: 1279- 1285.
Dearth, M.A. and R.A. Hites. 1991b. Complete analysis of
technical chlordane using negative ionization mass spectrometry. Environ. Sci. Technol., 25: 245-254.
DFG (ed.), 1982. Hexachlorcyclohexan-Kontamination:
Ursachen, Situation und Bewertung. Mitteilung IX, Harald
Boldt Verlag, Boppard.
Duinker, J.C., M.T.J. Hillebrand, K.H. Palmork and S. Wilhelmsen, 1980. An evaluation of existing methods for quantification of polychlorinated biphenyls in environmental
samples and suggesting for an improved method based on
measurements of individual components, Bull. Environ.
Contam. Toxicol., 25: 956-964.
Estel, D., M. Mohnke, F. Biermans and H. Rotzsche, 1995. The
analysis of C&-C,, hydrocarbons in naphtha and reformate
with a new apolar fused silica column. J. High Resol.
Chromatogr., 18: 4033412.
38
W. Vetter et al. I The Science of the Total Environment 186 (1996) 29-39
Falandysz, J., N. Yamashita, S. Tanabe, R. Tatsukawa, L.
Rucinska and K. Sk&a, 1994. Congener-specific data on
polychlorinated biphenyls in tissues of common porpoise
from Puck Bay, Baltic Sea. Arch. Environ, Contam. Toxico]., 26: 267-272.
Frame, G., 1995. A comprehensive, multicenter study of PCB
elution on capillary GC columns. Presented at Pittcon ‘95,
New Orleans, March 8, 1995, Paper 717; submitted to
Fresenius J. Anal. Chem.
Glausch, A., G.J. Nicholson, M. Fluck and V. Schurig, 1994.
Separation of enantiomers of stable atropisomeric polychlorinated biphenyls by multidimensional gas chromatography on Chirasil-Dex. J. High Resol. Chromatogr., 17:
347-349.
Holden, A.V., 1978. Pollutants and seals-a review. Mamm. Rev.,
8: 53-66.
Hummert, K., W. Vetter and B. Luckas, 1995. Levels of
alpha-HCH, lindane, and enantiomeric ratios of alphaHCH in marine mammals from the northern hemisphere.
Chemosphere, 31: 3489-3500.
Jansson, B and U. Wideqvist, 1983. Analysis of toxaphene
(PCC) and chlordane in biological samples by NC1 mass
spectrometry. Intern. J. Environ. Anal. Chem., 13: 309-321.
Kallenborn, R., H. Hiihnerfuss and W.A. K&rig, 1991. Enantioselektiver Metabolismus von (+/-)-cc-1,2,3,4,5,6-Hexachlorcyclohexan in Organen der Eiderente. Angew. Chem.,
103: 328-329.
Kallenborn, R., M. Oehme, W. Vetter and H. Parlar, 1994.
Enantiomer selective separation of toxaphene congeners
isolated from seal blubber and obtained by synthesis.
Chemosphere, 28: 89-98.
Kannan, K., S. Tanabe, A. Borrell, A. Aguilar, S. Focardi and
R. Tatsukawa, 1993. Isomer-specific analysis and toxic
evaluation of polychlorinated biphenyls in striped dolphins
affected by an epizootic in the western Mediterranean sea.
Arch. Environ. Contam. Toxicol. 25: 227-233.
Koeman, J.H., W.H.M. Peters, C.T. Smit, P.S. Tjioe and J.J.M.
de Goeij, 1972. Persistent chemicals in marine mammals.
TNO-nieuws 27: 570-578.
King, J.E., 1983. Seals of the World, Oxford University Press.
Kremer, H. and A. Maywald, 1991. Der Schweinswal in Nordund Gstsee. WWF Panda-Fordergesellschaft fur Umwelt.
Kuiken, T., P.M. Bennett, C.R. Allchin, J.K. Kirkwood, J.R.
Baker, C.H. Lockyer, M.J. Walton and M.C. Scheldrick,
1994. PCBs, cause of death and body condition in harbour
porpoises (Phocoena phocoena) from British waters. Aquat.
Toxicol., 28: 13-28.
Larsen, B. and J. Riego, 1990. Interferences from 2,3,5,6-3’,4’hexachlorobiphenyl (CB 163) in the determination of 2,3,42’,4’,5’-hexachlorobiphenyl (CB 138) in environmental and
technical samples. Int. J. Environ. Anal. Chem., 40: 59-68.
Law, R.J., CR. Allchin and J. Harwood, 1989. Concentrations
of organochlorine components in the blubber of seals from
eastern and north-eastern England, 1988. Marine Poll. Bull.,
20: 110-115.
Letcher, R., R. Norstrom, A. Bergmann and D.C.G. Muir, 1992.
Methylsulfone-PCB and-DDE metabolites in polar bears-
comparison to parent compounds in diet. In: Dioxin’92,
12th International Symposium on Dioxins and Related
Compounds. 24-28 August Tampere, Finland. Extended
Abstracts, 8: 357-360.
Luckas, B. and M. Oehme, 1990. Characteristic contamination
levels for polychlorinated hydrocarbons, dibenzofurans and
dibenzo-p-dioxins in Bream (Ahrontis hum)
from the river
Elbe. Chemosphere, 21: 79-89.
Luckas, B. and U. Harms, 1987. Characteristic levels of chlorinated hydrocarbons and trace metals in fish from coastal
waters of North and Baltic Sea. Intern. J. Environ. Anal,
Chem., 29: 215-225.
Luckas, B., W. Vetter, P. Fischer, G. Heidemann and J. PI&z,
1990. Characteristic chlorinated hydrocarbon patterns in
the blubber of seals from different marine regions. Chemosphere, 21: 13-19.
Mackay, D., 1982. Correlation of bioconcentration factors.
Environ. Sci. Technol., 16: 274-276.
Marine Mammals Committee, 1967. Standard measurements of
seals.J. Mammal., 48: 459-462.
McLdren, LA., 1958. The biology of the ringed seal in the
eastern Canadian Arctic. Bull. Fish. Res., 118: 97.
Mitchell, S.H. and S. Kennedy, 1992. Tissue concentrations of
organochlorine compounds in common seals from the coast
of Northern Ireland. Sci. Total Environ., t 15: 163-177.
Mossner, S., T.R. Spraker, P.R. Becker and K. Ballschmiter,
1992. Ratios of enantiomers of Z-HCH and determination
of x-, /I-, and y-HCH isomers in brain and other tissues of
neonatal northern fur seals (Cahrhinus
ursinus). Chemosphere, 24: 1171-1180.
Muir, D.C.G., R.J. Norstrom and M. Simon, 1988a. Organochlorine contaminants in Arctic marme food chains: Accumulation of specific polychlorinated biphenyls and chlordane
related compounds. Environ. Sci. Technol., 22: 1071-1079.
Muir, D.C.G., R. Wagemann, N.P. Grift, R.J. Norstrom, M.
Simon and J. Lien, 1988b. Organochlorine chemical and
heavy metal contaminants in white-beaked dolphins (hyenorhynchus
ulhirostris)
and pilot whales (Globicephula
ntelaenu) from the coast of Newfoundland, Canada. Arch.
Environ, Contam. Toxicol., 17: 613-629.
Miiller, M.D., M. Schlabach and M. Oehme 1992. Fast and
precise determination of r-hexachlorocyclohexane enantiomers in environmental samples using chiral high reolution gas chromatography. Environ. Sci. Technol., 26: 566569.
Oehme, M. and S. Mano, 1984. Long-range transport of
organic pollutants to the Arctic. Fresenius 2. Anal. Chem.,
319: 141-146.
Oehme, M., R. Kallenborn, K. Wiberg and C. Rappe, 1994.
Simultaneous enantioselective separation of octachloro
chlordanes and o,p’-DDT in environmental samples using a
tandem capillary column. J. High Resol. Chromatogr., 17:
583-588.
Reijnders, P.J.H., 1980. Organochlorine and heavy metal residues in harbour seals from the Wadden sea and their
possible effects on reproduction. Neth. J. Sea Res., 14:
30-65.
W. Vet&r et al. IThe Scirnce of’ the Totul Environment 186 (1996) 29-39
Reijnders, P.J.H., 1986. Reproductive failure in common seals
feeding on fish from polluted coastal waters. Nature, 324:
456-457 and 418.
Rimkus, G., L. Rexilius, G. Heidemann, A. Vagts and J.
Hedderlich, 1993. Results of an interlaboratory study on
orgdnochlorine compounds (PCB, DDT, DDE) in seal
blubber (Phoca vitulina). Chemosphere, 26: 1099-I 108.
Safe, S., K. Washburn, T. Zacharewski and T. Philips, 1995.
Synthesis and characterization of hydroxylated polychlorinated biphenyls (PCBs) identified in human serum.
Chemosphere, 31: 3017-3023.
Sovocooi, G.W., R.G. Lewis, R.L. Harless, N.K. Wilson and
R.D. Zehr, 1977. Analysis of technical chlordane by gas
chromatography/mass spectrometry. Anal. Chem., 49: 734740.
Skadre, J.U., N.H. Markussen, G. Norheim, S. Haugen and G.
Holt, 1990. Levels of polychlorinated biphenyls, organochlorine pesticides, mercury, cadmium, copper, selenium, arsenic, and zinc in the harbour seal, Phoca uitulinu, in
Norwegian waters, Environ. Poll., 66: 3099324.
Stern, G.A., D.C.G. Muir, CA. Ford, N.P. Grift, E. Dewailly,
T. F. Bidleman and M.D. Walla, 1992. Isolation and identification of two major recalcitrant toxaphene congeners in
aquatic biotd. Environ. Sci. Technol., 26: 18381840.
Storr-Hansen, E. and H. Spliid (1992). Distribution patterns of
polychlorinated biphenyl congeners in harbosr seal (Phow
vitulina) tissues: statistical analysis, Arch. Environ. Contam.
Toxicol.. 25: 328-345.
39
Vetter, W., 1990. Riickstandsanalytik am Beispiel der Bestimmung chlorierter Kohlenwasserstoffe in Meeressaugern. Diplomarbeit, Universitat Stuttgart.
Vetter, W. and B. Luckas, 1991. Meeressauger als Bioindikatoren.UWSF -2. Umweltchem. ijkotox., 3: 324-327.
Vetter, W. and B. Luckas, 1995. Ratios of PCB 138, PCB 163
and PCB 164 in Aroclor mixtures. Fresenius J. Anal. Chem.,
352: 612-613.
Vetter, W., B. Luckas and M. Oehme, 1992. Isolation and
purification of the two main toxaphene congeners in marine
organisms. Chemosphere, 25: 164331652.
Vetter, W., B. Luckas, F. Biermans, M. Mohnke and H.
Rotzsche, 1994. Gas chromatographic separation of polychlorinated biphenyls on a new apolar capillary column. J.
High Resol. Chromatogr., 17: 851-858.
Vetter, W., C. Natzeck, B. Luckas, G. Heidemann, B. Kiabi and
M. Karami, 1995a. Chlorinated hydrocarbons in the blubber of a seal (Photo caspicu) from the Caspian Sea. Chemosphere, 30: 1685- 1696.
Vetter, W., K. Hummert, B. Luckas and K. Skirnisson, 1995b.
Organochlorine residues in two seal species from western
Iceland. Sci. Total Environ., 170: 159- 164.
Vogel, SC., 1989. Speckdicke als Konditionsparameter bei 1988
an der Kuste Schleswig-Holsteins tot aufgefundenen
Seehunden; In: Zoologische und Ethologische Untersuchungen zum Robbensterben. Vorliufiger Endbericht zum FEVorhaben das BMU (Vorh. Nr. 108 05 017/06) pp. 39-60.