NOT TO BE CITED WITHOUT PRIOR REFERENCE TO THE AUTHORS

JA/J05/JR14

Spatial and temporal variation in organochlorine
contaminants in the Antarctic minke whales, Balaenoptera
bonaerensis
GENTA YASUNAGA*, YOSHIHIRO FUJISE*, RYOKO ZENITANI*, SHINSUKE TANABE*# AND HIDEHIRO KATO*+* The Institute of Cetacean Research, 4-18, Toyomi-cho, Chuo-ku, Tokyo 104-0055 Japan.
*# Center for Marine Environmental Studies (CMES), Ehime University. 2-5 Bunkyo-cho, Matsuyama, Ehime,790-8577 JAPAN.
*+ Fisheries Research Agency, National Research Institute of Far Seas Fisheries, 5-7-1, Simizu-Orido, Sizuoka 4248633, Japan.

ABSTRACTTo evaluate environmental changes in the Antarctic Ocean, concentrations of organochlorines (PCBs,DDTs, HCHs, HCB and CHLs) were determined in the blubber of the mature males of Antarctic minke
whales, Balaenoptera bonaerensis, (from 21 to 25 years) from the Antarctic Areas IV and V. The rangesof concentrations for each compound were, in ng/g fat wt: PCBs, 7.7-89; DDTs, 29-340; HCHs, 0.20-4.3;
HCB, 75-430; CHLs, 10-120. Residue levels of PCBs, and DDTs in blubbers of Antarctic minke whales
from the Antarctic Ocean were apparently lower than those levels of the other baleen whales from themiddle latitude areas. Regional significant differences between the Areas IV and V were observed inPCBs, HCHs, HCB and CHLs levels in mature male of Antarctic minke whales. And also, their HCHsand HCB levels significantly decreased during 1988/89 and 2002/03 seasons in the Areas IV and V.
Yearly changes of PCBs and DDTs were unclear during 1988/89 and 2002/03 seasons.
KEY WORDS: ANTARCTIC MINKE WHALE; ORGANOCHLORINE; MONITORING; TEMPORALTRENDINTRODUCTION
Whales tend to be in high position in the food chain of the ocean, thus they may be particularly suitable asmonitors of pollutant levels and their adverse effects (Tanabe et al., 1986; O’Shea and Brownell, 1994). The third
objective of JARPA, ‘Elucidation of the effect of environmental change on cetaceans’, was added in 1995/96
season (Government of Japan, 1995), in response to two resolutions of the IWC (IWC, 1999). It has been
continued to monitor organochlorine levels in blubbers of Antarctic minke whales, Balaenoptera bonaerensis.
Aono et al. (1996) reported that increasing trend of PCBs residue levels in Antarctic minke whales werenoted during 1984/85 and 1992/93 seasons, implying the continuous discharge of PCBs in the SouthernHemisphere. Furthermore, Niimi et al. (2000) continually analysed those samples until 1996/97 season, andreported that DDTs levels of Antarctic minke whale had decreased in 1990’s and PCBs levels could decrease inlate 1990’s, while they had increased until middle 1990’s.

We analysed organochlorine levels in blubbers of mature male of Antarctic minke whales in the Areas IV
and V during 1997/98 and 2002/03 seasons. In this paper, the yearly changes and spatial differences oforganochlorine accumulations in Antarctic minke whales in the JARPA surveys are presented.

MATERIALS AND METHODSIn this study, concentrations of PCBs, DDTs, HCHs, HCB and CHLs were determined for blubber samples of 80
Antarctic minke whales (mature males: 21-25 years) taken from the Antarctic Areas IV and V during 1987/88 and2002/03 seasons (Table 1). In the field, blubber samples were collected for organochlorines analyses, and werestored at –20°C until analysis.

1Oraganochlorine pesticides and PCBs were determined by a GC-ECD (Hewlett Packard 5890 Series)
and by GC-MS (JEOL Ltd., JMS-700; JMS-SX102A). Chemical analysis of the Organochlorines was carried out
using the standard method described by Environmental Agency of Japan, with some modifications (JapanEnvironmental Agency, 1998). Concentrations of organochlorines were expressed on a fat weight basis. Accuracy
and precision of the methods were confirmed using Organics in cod liver oil (NIST 1588a). Chemical analyses
were performed by the Miura Institute of Environmental Science.
The differences of organochlorine concentrations between areas were assessed by Mann-Whitney U test
and the temporal trends of organochlorine concentrations were assessed by linear regression analysis (Zar, 1999).
These statistical analyses were executed by SPSS ver.11 for windows (SPSS Co. Ltd.).

RESULTS AND DISCUSSION
Tables 2 shows the concentrations of organochlorines in blubbers of Antarctic minke whales taken from the Areas
IV and V. Figure 1 shows levels of PCBs and DDTs in blubbers of baleen whales in the world as previously
reported for comparison with our data. PCBs, DDTs, HCHs, HCB and CHLs were detected in all the blubbersamples of Antarctic minke whales. The ranges of concentrations for each compound were, in ng/g fat wt: PCBs,7.7-89; DDTs, 29-340; HCHs, 0.20-4.3; HCB, 75-430; CHLs, 10-120. Theses residue levels were in the order of
DDTs>HCB>PCBs>HCHs>CHLs in Antarctic minke whales from both the Areas IV and V. Aono et al. (1997)
reported these order of HCB>DDTs>CHLs>PCBs>HCHs in male of Antarctic minke whales from Area V in1990/91 and 1992/93 seasons. This difference could be due to using the CHL isomers between both studies.

PCBs and DDTs levels in blubbers of Antarctic minke and fin whales from the Antarctic were one orderof magnitude lower than those of the other whales in the middle and low latitude areas (Fig. 1). PCBs levels inblubbers of Antarctic minke and fin whales from the Antarctic were lower than those of bowhead whales, while
DDTs levels were reverse (O’Hara et al., 1999; Krone et al., 1999).

Geographical difference
Concentrations of the organochlorines, except for DDTs, in Antarctic minke whales from the Area IV during
1987/88 and 2001/02 seasons were significantly higher than those from the Area V during 1988/89 and 2002/03
seasons (p<0.05). Consequently, examination about temporal trends will be analysed in each area.

Temporal trend
Figures 2 and 3 represent plots of organochlorine concentrations in blubbers of mature of Antarctic minke whales
from the Areas IV and V during 1987/88 and 2001/02 seasons. Further, Table 3 shows simple linear correlation
coefficients and provability between year and organochlorine contaminant concentrations in blubbers in each area(p<0.05). HCHs and HCB levels in Antarctic mike were significantly decreased in both areas, however PCBs andDDTs were significantly decreased in Area-V. These differences could be attributable to differences of the vapor
pressure of each compound. However, it should be continued to monitor these levels in Antarctic minke whales
carefully, since their variances in each year of all the compound levels are relatively higher.

CONCLUSION

Volatile compounds, such as HCHs and HCB, levels in Antarctic minke whales tend to decrease, while timetrends of lower volatile compounds, such as PCBs and DDTs are not clear in JARPA surveys during 1987 and2003 seasons. These results are consistent with the previous JARPA work, suggesting a fate of organochlorines,
such as PCBs and DDTs, which may came near turning point in the Antarctic Ocean.

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