SC/J09/JR24

Temporal trends and factors affecting PCB levels in baleen
whales and environmental samples from the western North
Pacific
GENTA YASUNAGA AND YOSHIHIRO FUJISEThe Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan.
Contact e-mail: yasunaga@cetacean.jp

ABSTRACTTo examine accumulation features and yearly changes of PCBs in the western North Pacific, PCB levels in samples
from surface seawaters, atmospheres and three baleen whales (common minke whales Balaenoptera acutorostrata;
Bryde’s whales B. edeni; sei whales B. borealis) were measured. The ranges of PCB level in surface water samples
were 3.5-11ng/L and 1.5-4.3 ng/L in 2003 and 2005, respectively. In these years PCB levels in seawater decreased with
distance from the Japanese coast. The fact that PCB levels in seawaters decreased from coastal to offshore regions wasprobably due to that PCB has been released from Japan and Eurasia continent. This result is consistent with those ofprevious studies, such as PCB monitoring in pelagic fish and squid. On the other hand, the trend in air samples was
unclear since PCB stability in the atmosphere is easily affected to a significant extent by weather conditions. PCB levelsin blubber samples of common minke, Bryde’s and sei whales exhibited ranges from 0.13-4.0, 0.04-0.21 and 0.03-0.47
ppm wet wt., respectively. To examine the temporal trend of PCB levels in whales from sub-areas 7, 8 and 9, a multiple
regression analysis was conducted having sampling years, sampling longitude, latitude, sampling date, body length andblubber thickness as individual factors. By considering the results of this and previous studies, PCB levels in baleen
whales decreased until the end of the decade of the 90’s and then it stabilized.

KEYWORDS: COMMON MINKE WHALE; BRYDE’S WHALE; SEI WHALE; NORTH PACIFIC; PCB;SEAWATER; ATMOSPHEREINTRODUCTION
Pollutants accumulate through the food chain in a marine ecosystem. Because cetaceans are located at the top of thefood chain they are frequently used for monitoring the pollutants in the marine environment. Further cetaceans aremobile and long-lived animals, and these characteristics mean that pollutants can be monitored in wide areas andintegrated in some way over time. Polychlorinated biphenyls (PCBs) are man-made chemicals and had been widelyused in the world in electrical equipments such as transformers and capacitors until 1970s. In spite of the ban ofproduction and usage in 1970s, PCBs are still being released into the environment due to its lipophilic and highly
persistent character. Especially, top marine predators such as whales tend to accumulate PCBs in fatty tissues withgrowth (Tanabe et al., 1981; Connell, 1988). The Japanese Whale Research Programme under Special Permit for North
Pacific Whales Phase II (JARPN II) was designed so that samples can be obtained for investigating the quantitative
behaviour and fate of the PCBs in the marine environment.
In the western North Pacific, yearly change of PCBs levels in marine mammals have been reported previously. Tanabe
et al., (1994) reported a study on temporal variation of PCBs in female northern fur seal. The level showed a maximum
in around 1976 and then decreased until 1988. Aono et al., (1997) reported a study of PCB in blubber of common
minke whales from the western North Pacific between 1987 and 1994. No trend in the level was observed in this period.
Kajiwara et al. (2004) reported that the PCB level and compositions were steady-stable in fat tissues of female northern
fur seals collected in the period 1972-1998 from the Japanese Pacific coast, suggesting a continuous input of PCBs into
the marine environment in significant quantities.
To examine accumulation features and yearly changes of PCBs in the western North Pacific, PCB levels in samples
from surface seawaters, atmospheres and three baleen whales (common minke whales Balaenoptera acutorostrata;
Bryde’s whale B. edeni; sei whales B. borealis), were measured.

1

MATERIALS AND METHODS

Samples and sampling method
During the 2003 and 2005 JARPN II surveys, air samples were collected by researchers on board the research base(Nishin-Maru). Researchers also collected seawater samples on board the dedicatedf sighting vessel Kyoshin-Maru No.2.
The sampling date and location together with surface temperature are shown in Table 1. A modified version of themethod of Iwata et al. (1993) was used for sampling air and seawater.
Sampling equipment for air samples was a modification of Iwata et al. (1993). Air pump and flow meter were made in
IWAKI Co. Ltd. and pre-filter, flow line and absorbent column for collection of OCs were made from polyethylene
nonwoven fabric, polyethylene tube and PILEX glass (Asahi Co. Ltd.), respectively. The absorbent column were
packed with 5 polyurethane form plugs that were cleaned with acetone in a Soxhlet extractor for more than 7 days until
OCs had not been detected in the eluate. The system covered with stainless case was set on the upper deck at about 50
meters above sea level. Sampling equipment for surface seawater was a modification of Iwata et al. (1993). The prefilter and integral flow meters were made in ADVANTEC® and Nitto Seiko Co. Ltd., respectively. The seawater
plumbing lines from ship bottom to sampler in Kyoshin-Maru were used with stainless tube. Both samplers were madein Miura Institute of Environmental Science (Ehime prefecture, Japan), and also all column were cleaned in it.
Blubber tissues from the common minke whales (Okhotsk Sea-West Pacific stock) from sub-areas 7, 8 and 9, Bryde’s
whales from sub-area 8 and sei whales from sub-area 9 were collected by JARPN II researchers in the surveys
conducted in the period from 2002 to 2007. Table 2 shows the sample sizes and body length of the whales sampled, byspecies, sub-area and survey. The blubber tissue samples were frozen and shipped to the laboratory and stored -20˚Cuntil chemical analysis.
In order to understand the pattern of accumulation of pollutants in cetaceans, it is essential to consider some biologicalinformation from whales. In this study we considered information on the body length and maturity status of male
whales. Males of minke, Bryde's and sei whales were defined as sexually mature by testis weight (larger side) of morethan 290g, 560g and 1,090g, respectively (Bando et al., unpublished data). Only minke whales from the Okhotsk SeaWest Pacific stock as identified by the microsatellite analysis (Kanda et al., 2009), were used.

Laboratory analysis
The columns with environmental samples (air and sea water) were sent to the Miura Institute of Environmental Science(Ehime, Japan) for PCB analyses. Analyses were performed according to the Analytical Manual for Dioxin in Soils(Japan Environmental Agency, 1998). The blubber samples were sent to the Japan Food Research Laboratories (Tokyo,
Japan) for PCB analyses. Analyses were performed according to the public analytical method of Japan (Japan Ministryof Welfare, 1972).

Statistical analysis
The extent of differences in PCB levels among baleen whales and sub-areas was assessed by Mann-Whitney U test (Zar,
1999). In order to examine the yearly trend of PCB levels in blubber of whales, multiple linear regression analyses wereconducted (Zar, 1999). The following independent variables: “sampling year” , “sampling date (1 May = day 1)”,
“sampling latitude”, “sampling longitude”, “body length” and “blubber thickness”, were allowed, and all parameters
were normalized. These statistical analyses were executed by SPSS ver.11 for Windows (SPSS Co. Ltd.).
RESULTS AND DISCUSSION
Air and surface seawater
The ranges of PCB level of air samples were ND-22 pg/m3 and 8-13 pg/m3 in 2003 and 2005, respectively (Table 1, Fig.
1). Iwata et al. (1993) reported a range of 12-390 pg/m3 for air samples collected in the North Pacific in 1990. They
used a similar methodology as that used in the present study. Thus, residue levels of PCBs in atmosphere in 2003 and2005 might be lower than those in 1990. However, it should be noted that PCB stability in atmosphere is easily affected
to a significant extent by weather condition (Montone et al., 2003).
The ranges of PCB level in surface water samples were 3.5-11ng/L and 1.5-4.3 ng/L in 2003 and 2005, respectively(Table 1, Fig. 2). In both years the PCB levels in seawater decreased with distance from the Japanese coast. The factthat PCB levels in seawaters decreased from coastal to offshore region was probably due to that PCB has been released
from Japan and Eurasia continent. This result is consistent with those of previous studies, such as PCB monitoring inpelagic fish (Ueno et al., 2003) and squid (Yamada et al., 1997).
2

SC/J09/JR24

Baleen whales
Table 2 shows the PCB level in blubbers of common minke, Bryde’s and sei whales. The ranges were 0.13-4.0, 0.040.21 and 0.03-0.47 ppm wet wt. in these species, respectively. In sub-area 8 the PCB levels in common minke whales
were significantly higher than those in Bryde’s whales (p<0.05); in sub-area 9 the levels in common minke whales weresignificantly higher than those in sei whales (p<0.05). Differences in feeding habitat and trophic levels of preys might
be one of the reasons for the differences. It is known that common minke whales selectively feed on relatively higher
trophic organisms, mainly pelagic fish such as Pacific saury and Japanese anchovy, and krills (Tamura and Fujise,2002), which are different from the prey items of Bryde’s and sei whales, which feed mainly on krill and copepod(Tamura et al., 2009).
Plots of PCB levels against sampling year in sub-areas 7, 8 and 9 are shown for common minke whales (Fig. 3a-c),
Bryde’s (Fig. 3d) and sei whales (Fig. 3e). For common minke whales in sub-area 7, sampling year, body length andsampling date were significantly selected (Table 3) with a rank order of effects of sampling date (B:-0.633 ) > year (0.372) > body length (+0.226). For those from sub-area 9, only body length (+) were significantly selected (Table 5).
For common minke whales from sub-area 8 (Table 4), Bryde’s whales from sub-area 8 (Table 6), sei whales from subarea 9 (Table 7) no factor was significantly selected in the regression equation. Primary factor to PCB levels in common
minke whales from sub-area 7 was sampling date, namely seasons. This phenomenon would reflect the dilution byincreasing of fat volume in the whale body. The year would not be important factor for PCB levels in sub-area 7,
because the sampling year was selected as secondary factor and the value in the 2003 only was apparently higher thanthe other years (Table 2 and Fig. 3a). Therefore, PCB levels in baleen whales from the western North Pacific seems to
be in a steady state since 2002.
There are some reports of temporal trend of PCB levels in the western North Pacific using marine mammals as
biological indicator. For example Tanabe et al., (1994) reported temporal variation of PCBs with a maximum in 1976
and a decreasing trend until 1988 in female northern fur seal. Aono et al., (1997) reported that the PCB levels in blubberof common minke whales from the western North Pacific (offshore) between 1987 (1.5-3.0 ppm wet wt.) and 1994
(0.62-3.1 ppm wet wt.) were stable. Kajiwara et al. (2004) reported that PCB concentrations in fat tissues of female
northern fur seals collected from off Sanriku coast in the period 1972 - 1998 continually decreased since early 1980s,
and their PCB compositions have not changed in all period. This suggest a continuous input of PCBs into the marine
environment near the Japanese coast. The PCB levels presented in this study for the period 2002-2007 is lower thanthose in 1987 and 1994. The PCB levels in marine mammals in coastal Japan had continually decreased until the end of
1990’s, and it has stabilized since at least from 2002.
There are a number of advantages of using marine organism, especially higher torophic animals, as biomonitors forresidual pollutants rather than environmental samples, such as air, seawater (Vetter et al., 1996). There were few
reports of PCB levels in environmental samples from offshore ocean, because the direct measurement of environmental
pollutants suffer from the disadvantages of the stability in the preservation until the measuring and risk of treatment
contamination due to the extremely lower levels. Predators accumulate pollutants through food chain, then they areuseful for the monitoring of marine pollutants. Predator, such as cetacean, are mobile, so pollutants will be picked up
from several food items, and they are long-lived, so pollutant burdens may be integrated in some way over time.

REFERENCES
Aono, S., Tanabe, S., Fujise, Y., Kato, H. and Tatsukawa, R. 1997. Persistent organochlorines in minke whale(Balaenoptera acutorostrata) and their prey species from the Antarctic and the North Pacific. Environ. Pollut. 98:81-89.
Connell, D.W. 1988. Bioaccumulation behavior of persistent organic chemicals with aquatic organisms. Rev. Environ.
Contam. Toxicol. 102:117-154.
Iwata, H., Tanabe, S., Sakai, N. and Tatsukawa, R. 1993. Distribution of persistent organochlorines in the oceanic air
and surface seawater and the role of ocean on their global transport and fate. Environ. Sci. Technol. 27:1080-1098.
Japan Environmental Agency. 1998. Analytical Mannual for Dioxins in Soils. Tokyo, Japan (in Japanese;www.env.go.jp/chemi/dioxin/dojo-manual.pdf).
Japan Ministry of Welfare. 1972. Analytical Method of PCBs, Tokyo, Japan (in Japanese).
Kajiwara, N., Ueno, D., Takahashi, A., Baba, N. and Tanabe, S. 2004. Polybrominated diphenyl ethers andorganochlorines in archived northern fur seal samples from the Pacific coast of Japan, 1972-1998. Environ. Sci. Technol.
38:3804-9.
Kanda N., Goto, M., Kishiro, T., Yoshida, H., Kato, H. And Pastene, L.A. 2009. Individual identification and mixing of
the J and O stocks around Japanese waters examined by microsatellite analysis. Paper SC/J09/JR26. presented to the
JARPN II Review Workshop, Tokyo, January 2009 (unpublished). 9pp.
3

Montone, R.C, Taniguchi, S. and Weber, R.R. 2003. PCBs in the atmosphere of King George Island, Antarctica. Sci.
Total. Environ. 308:167-173.
Tamura, T. and Fujise, Y. 2002. Geographical and seasonal changes of the prey species of minke whale in the
Northwestern Pacific. ICES J. Mar. Sci. 59:516-528.
Tamura, T., Konishi, K., Isoda, T., Okamoto, R. and Bando, T. 2009. Prey consumption and feeding habits of common
minke, sei and Bryde’s whales in the western North Pacific. Paper SC/J09/JR16 presented to the JARPN II Review
Workshop, Tokyo, January 2009 (unpublished). 36pp.
Tanabe, S., Tatsukawa, R., Tanaka, H., Maruyama, K., Miyazaki, N. and Fujiyama, T. 1981. Distribution and total
burdens of chlorinated hydrocarbons in bodies of striped dolphins (Stenella coeruleoalba) . Agri. Biol. Chem. 45:25692578.
Tanabe, S., Sung, J. K., Choi, D. Y., Baba, N., Kiyota, M., Yoshida, K. and Tatsukawa, R. 1994. Persistentorganochlorine residues in northern fur seal from the Pacific coast of Japan since 1971. Environ. Pollut. 85:305-314.
Ueno, D., Takahashi, S., Tanaka, H., Subramanian, A.N., Fillmann, G., Nakata, H., Lam, P.K.S., Zheng, J., Muchtar,
M., Purudente, M., Chung, K.H. and Tanabe, S. 2003. Global pollution monitoring of PCBs and organochlorine
pesticides using skipjack tuna as a bioindicator. Arch. Environ. Contam. Toxicol. 45:378-389.
Vetter, W., Luckas, B., Heidemann, G. And Skirnisson, K. 1996. Organochlorine residues in marine mammals from theNorthern hemisphere—A consideration of the composition of organochlorine residues in the blubber of marine
mammals. Sci. Total Environ. 186,:29-39
Yamada, H., Takayanagi, K., Tateishi, M., Tagata, H. and Ikeda, K. 1997. Organotin compounds and polychlorinatedbiphenyls of livers in squid collected from coastal waters and open oceans. Environmental Pollution 96:217-226.
Zar, J. H. 1999. Biostatistical analysis, 4th ed., Prentice Hall, New Jersey, USA, 663pp.

4

SC/J09/JR24
Table 1. Location of atmosphere and sea water samples collected from western North Pacific and levels of PCB.
Site
Location
Date
StartedFinished
Atmosphere03NP-A1
2003/6/16
39-35N, 157-13E
41-04N, 159-09E
03NP-A2
2003/7/28
44-48N, 162-29E
42-39N, 168-13E
03NP-A3
2003/8/10
40-59N, 155-35E
38-23N, 143-06E
05NP-A4
2005/7/7
39-59N 143-05E
37-24N 145-58E
05NP-A5
2005/7/16
39-10N 146-06E
41-02N 152-35E
05NP-A6
2005/8/15
43-28N 159-55E
39-43N 146-44E
Seawater
03NP-S1
2003/6/17
38-39N, 156-51E
39-30N, 157-29E
03NP-S2
2003/7/1
44-37N, 157-46E
44-15N, 156-45E
03NP-S3
2003/7/11
40-11N, 146-54E
40-52N, 150-21E
03NP-S4
2003/9/6
46-49N, 158-58E
44-43N, 156-09E
05NP-S5
2005/7/6
37-40N 146-20E
40-07N 143-06E
05NP-S6
2005/7/10
39-10N 146-06E
40-22N 150-50E
05NP-S7
2005/8/25
43-28N 159-55E
43-30N 154-50E

5PCBs(pg/m3)
22
ND
ND
13
11
8

(ng/L)
7.7
7.2
11
3.5
2.5
4.3
1.5

6

Table 2 PCB levels (ppm wet) in blubber of common minke , Bryde's and sei whales in the western North Pacific during 2002 and 2007.
body length
2002
2003
2004
2005
2006
species
sub area
0.75 ± 0.31
1.34 ± 0.77
0.42 ± 0.11
0.83 ± 0.44
0.91 ± 0.40
common minke whal7
ave±sd 7.48 ± 0.28
ragne ( 6.73 - 8.15 ) ( 0.35 - 1.50 ) ( 0.28 - 2.70 ) ( 0.32 - 0.60 ) ( 0.44 - 2.30 ) ( 0.22 - 1.50
126
35
12
6
17
14
n
8
ave±sd 7.54 ± 0.25
0.91 ± 0.35
1.17 ± 0.85
1.03 ± 0.76±±
) () ( 0.21 - 2.90
ragne ( 6.91 - 8.02 ) ( 0.31 - 1.40 ) ( 0.21 - 4.00 ) (
n
69
8
27
24
0.70 ± 0.24
0.60 ± 0.24
0.45 ± 0.22
0.64 ± 0.44
0.62 ± 0.43
9ave±sd 7.51 ± 0.25
ragne ( 6.77 - 8.18 ) ( 0.29 - 1.10 ) ( 0.24 - 1.20 ) ( 0.13 - 1.20 ) ( 0.14 - 2.10 ) ( 0.21 - 1.60
n
152
24
33
51
24
16
0.75 ± 0.30
0.94 ± 0.70
0.45 ± 0.22
0.71 ± 0.45
0.88 ± 0.61
total ave±sd 7.51 ± 0.26
ragne ( 6.73 - 8.18 ) ( 0.29 - 1.50 ) ( 0.21 - 4.00 ) ( 0.13 - 1.20 ) ( 0.14 - 2.30 ) ( 0.21 - 2.90
347
67
72
57
41
54
n
0.11 ± 0.06
0.13 ± 0.04
0.07 ± 0.03
Bryde's whale8
ave±sd 12.54 ± 0.41±±
) ( 0.08 - 0.19 ) () ( 0.04 - 0.11
ragne ( 11.90 - 13.11 ) ( 0.05 - 0.21 ) (
n
15
5
5
5
0.14 ± 0.18
0.12 ± 0.07
0.09 ± 0.06
Sei whale9
ave±sd 13.68 ± 0.31±±
) ( 0.04 - 0.22 ) () ( 0.04 - 0.19
ragne ( 13.23 - 14.48 ) ( 0.03 - 0.47 ) (
n
15
5
5
5
2007

±
±
-

) (

) (

56

0.78 ± 0.34
) ( 0.21 - 1.60

40.76 ± 0.44
) ( 0.22 - 1.30

100.83 ± 0.38
) ( 0.29 - 1.40

42

0.76 ± 0.33
) ( 0.21 - 1.60

total

15

0.12 ± 0.11
) ( 0.03 - 0.47

15

0.1 ± 0.05
) ( 0.04 - 0.21347

0.76 ± 0.50
) ( 0.13 - 4.00

152

0.58 ± 0.31
) ( 0.13 - 2.10

69

1.04 ± 0.72
) ( 0.21 - 4.00

126

0.82 ± 0.44
) ( 0.21 - 2.70

)

)

)

)

)

)

SC/J09/JR24
Table 3 Results of multiple linear regression analyses with "PCB levels in blubbers ofcommon minke whales from sub-areas 7" as the dependent variable.
a) Model of regression
Model
1

R
0.581

R2
0.337

R2'
0.304

b) Analysis of Variance TableModel
Sum of Squares
33.132
Regression
Residual
65.140Total
98.273

DF
6
119
125

Mean Square
5.522
0.547

F value
10.088

P value
0.000c) Variables
Model
Constant
year
date
latitudelongitude
body length
blubber thickness

SE
0.509
0.126
0.154
0.287
0.485
0.064
0.053

B'

T
2.336
-2.955-4.105
0.785
1.510
3.521
1.882

P value
0.021
0.004
0.000
0.434
0.134
0.001
0.061

B
1.190
-0.372-0.633
0.225
0.733
0.226
0.082

-0.497-0.884
0.131
0.163
0.274
0.105

Table 4 Results of multiple linear regression analyses with "PCB levels in blubbers ofcommon minke whales from sub-areas 8" as the dependent variable.
a) Model of regression
Model
1

R
0.371

R2
0.138

R2'
0.054

b) Analysis of Variance TableModel
Sum of Squares
19.701
Regression
Residual
123.388
Total
143.088

DF
6
62
68

Mean Square
3.283
1.990

F value
1.650

P value
0.149c) Variables
Model
Constant
year
date
latitudelongitude
body length
blubber thickness

SE
0.401
0.177
0.889
1.082
0.831
0.192
0.293

B'

T
0.679
-0.868-0.801
0.192-0.456
2.249
0.617

P value
0.500
0.389
0.426
0.848
0.650
0.028
0.539

B
0.272
-0.154-0.7130.208-0.3790.431
0.181-0.110-0.3170.079-0.0580.277
0.084

Table 5 Results of multiple linear regression analyses with "PCB levels in blubbers ofcommon minke whales from sub-areas 9" as the dependent variable.
a) Model of regression
Model
1

R
0.314

R2
0.099

R2'
0.061

b) Analysis of Variance TableModel
Sum of Squares
5.973
Regression
Residual
54.583
Total
60.556

DF
6
145
151

Mean Square
0.995
0.376

F value
2.644

P value
0.018c) Variables
Model
Constant
year
date
latitudelongitude
body length
blubber thickness

SE
0.130
0.077
0.141
0.103
0.122
0.053
0.066

B'

T
-2.060-0.6160.122-1.5550.282
2.163-0.873

P value
0.041
0.539
0.903
0.122
0.779
0.032
0.384

B
-0.268-0.0480.017-0.1590.034
0.114-0.058-0.0550.017-0.2170.023
0.173-0.087

7

Table 6 Results of multiple linear regression analyses with "PCB levels in blubbers ofBryde's whales from sub-areas 8" as the dependent variable.
a) Model of regression
Model
1

R
0.706

R2
0.498

R2'
0.121

b) Analysis of Variance TableModel
Sum of Squares
6.971
Regression
Residual
7.029
Total
14.000DF6814Mean Square
1.162
0.879

F value
1.323

P value
0.348c) Variables
Model
Constant
year
date
latitudelongitude
body length
blubber thickness

SE
0.242
0.325
1.343
1.001
1.221
0.270
0.297

B'

T
0.000
-1.6210.691-1.138
1.077
1.298
0.372

P value
1.000
0.144
0.509
0.288
0.313
0.230
0.719

B
-1.40E-10-0.5270.929-1.139
1.315
0.351
0.110

-0.5270.929-1.139
1.315
0.351
0.110

Table 7 Results of multiple linear regression analyses with "PCB levels in blubbers of
sei whales from sub-areas 9" as the dependent variable.
a) Model of regression
Model
1

R
0.624

R2
0.389

R2'
-0.069b) Analysis of Variance TableModel
Sum of Squares
Regression
5.450
Residual
8.550
Total
14.000DF6814Mean Square
0.908
1.069

F value
0.850

P value
0.567c) Variables
Model
Constant
year
date
latitudelongitude
body length
blubber thickness

SE
0.267
0.531
0.747
0.933
0.404
0.393
0.525

B'

T
0.000
-1.4471.350-1.1190.420-0.461-0.231

P value
1.000
0.186
0.214
0.296
0.685
0.657
0.823

B
-2.55E-10-0.7691.008-1.0440.170-0.181-0.121-0.7691.008-1.0440.170-0.181-0.1218

SC/J09/JR24

50°

03NP
03NP-A2
45°

03NP-A3
05NP-A640°

05NP-A505NP

03NP-A1

05NP-A4
35°

120°

125°

130°

135°

140°

145°

150°

155°

ND: Not detected

Fig. 1 Concentrations of PCBs (pg/m3) in air samples from western North Pacific Ocean in the2003 and 2005 JARPN II.

50°

03NP

03NP-S4
03NP-S2

45°

05NP-S7
40°

03NP-S3

05NP

03NP-S1
05NP-S6

35°

05NP-S5

120°

125°

130°

135°

140°

145°

150°

155°

Fig. 2 Concentrations of PCBs (ng/L3) in surface seawater samples from western North Pacific
Ocean in the 2003 and 2005 JARPN II.
9b) Common minke whale (mature male, O stock, sub area 8)a) Common minke whale (mature male, O stock, sub area 7)
5.0
PCB conc. in blubber (ppm wet)

PCB conc. in blubber (ppm wet)

5.0
4.0
3.0
2.0
1.0
0.0
2001

2002

2003

2004

2005

2006

2007

2008

4.0
3.0
2.0
1.0
0.0
2001

2002

2003

PCB conc. in blubber (ppm wet)

PCB conc. in blubber (ppm wet)

4.0
3.0
2.0
1.0
0.0
2003

2004

2005

2006

2007

2008

d) Bryde's minke whale (mature male, sub area 8)c) Common minke whale (mature male , O stock, sub area 9)
5.0

2002

2005
year

year

2001

2004

2006

2007

2008

0.5
0.4
0.3
0.2
0.1
0.0
2001

2002

2003

2004

2005

2006

2007

year

year

PCB conc. in blubber (ppm wet)e) Sei whale (mature male, sub area 9)
0.5
0.4
0.3
0.2
0.1
0.0
2001

2002

2003

2004

2005

2006

2007

year

Fig. 3a-e. PCB levels in blubber of common minke, Bryde’s and sei whales in the western North Pacific during a period
from 2002 to 2007.

10