Environ. Sci. Technol. 1998, 32, 1747-1753
Polychlorinated Biphenyls and Nonylphenols in the Sea of Japan NARAYANAN KANNAN,* NOBUYOSHI YAMASHITA,† GERT PETRICK, AND JAN C. DUINKER Department of Marine Chemistry, Institute for Marine Research, Du ¨ sternbrooker weg 20, 24105 Kiel, Germany
Determination of polychlorinated biphenyls (PCBs) and nonylphenols (NoPhs) in the Sea of Japan not only points out the extent of marine pollution but also helps to understand the deep sea structure of that semi-enclosed “small ocean”. Using an in-situ filtration/extraction technique, two vertical profiles (deep water and shallow coastal water) and two space-integrated surface profiles were taken. Concentrations of ∑CBs (sum of 30 individual congeners) in solution were between 0.1 and 1.2 pg dm-3 and in suspension were between 0.2 and 1.5 pg dm-3; those of ∑NoPhs in solution were 2-150 pg dm-3 and below detection limits in suspension. The concentrations of ∑CBs and nonylphenols in solution as well as the compositions of the CB mixtures in solution in the vertical profile indicates a vertical structure similar to the situation in the open ocean as suggested by Kim (Biogeochemical processes in the North Pacific; Tsunogai, S., Ed.; Japan Marine Science Foundation: Tokyo 1996; pp 41-51). The concentrations of CBs in solution were determined primarily by characteristics of the water bodies involved, solution-suspension interactions playing only a minor role. Principal component analyses of the data revealed a relation between deep and bottom waters and surface waters of the nearby region.
Introduction The Sea of Japan (East Sea) is a marginal sea in the northern Pacific Ocean. Its average depth is 1700 m, and its maximum depth is almost 4000 m in the Japan Basin. The other two major basins (Ulleung Basin and Yamato Basin) are about 2200 m deep. Water exchange with the northern Pacific and the Sea of Okhotsk through the Korea, Tsugaru, Soya, and Tatar Straits is very limited because of sill depths of maximal 130 m. The major characteristics of the hydrography in the Sea of Japan are determined by the Tsushima current, carrying warm and saline waters from the south through the Korea Strait. They occupy the upper 100 m in the southern part. Early work of Uda (2) showed that the water in the entire basin of the East Sea below 300 m had quite uniform physicochemical characteristics. Gamo and Horibe (3) showed the existence of vertical structure in the water column, with similar but smaller variations in salinity and temperature than in the open ocean. Internationally coordinated studies of Kim and Kim (4) have * Corresponding author tel: +49 431 597 4028; fax:+49 431 565876; e-mail:
[email protected]. † Present address: National Institute for Resources and Environment, Hydrospheric, Environmental Protection Department, Onogawa 16-3, Tsukuba 305, Japan. S0013-936X(97)00713-X CCC: $15.00 Published on Web 05/12/1998
1998 American Chemical Society
substantiated this in considerable detail. The East Sea Proper Water consists of several distinct water massses. These were described by Kim et al. (5) as East Sea Central Water, East Sea Deep Intermediate Water, East Sea Deep Water, and East Sea Bottom Water. Studies carried out in 1993-1996 have shown that the differences in vertical structures between the eastern and western part are minor. This was partly attributed to rapid horizontal mixing of deep waters within the basin. Kim’s study has shown that the Sea of Japan is in constant change, and the present deep sea structure resembles that of open ocean. We have carried out studies in the Sea of Japan in the summer 1995 on the levels of selected organic compounds to allow a comparison with the Atlantic Ocean, where most of our work on polychlorinated biphenyls (PCBs) has been carried out in the past (6, 7). Although it is generally believed that the world ocean is the ultimate sink of these chemicals, there are only few reliable reports on the concentration of PCBs in ocean water. This is largely due to the fact that reliable sampling has proven to be difficult as their concentrations in ocean water (especially the deep) are extremely low (8). The recently developed Kiel in-situ filtration/extraction pump system (KISP; (9) allows the accurate determination of relatively apolar and polar organic compounds in seawater solution and in suspended particulate matter (SPM suspension) at even extremely low concentration levels (e.g., in the pg dm-3 and fg dm-3 range). With its help, chlorobiphenyl (CB) congener-specific analyses have been carried out in the Atlantic Ocean to study oceanic processes. The usefulness of CBs lies in the extreme persistence of many congeners, in their potential use as model substances (8), and in the fact that the main route of their entrance into the marine environment is located in the surface layer. We have found recently that the group of nonylphenols can also serve as indicators for oceanic processes. They have the additional advantage that they are transported solely in solution and may therefore be used for mixing studies. The results obtained in the Sea of Japan for chlorobiphenyls and nonylphenols are relevant to the hydrographic questions raised by Kim and Kim (4). Moreover, no recent report on the presence of hormone disrupters such as PCBs and nonylphenol in deep waters of the Sea of Japan is available to our knowledge.
Materials and Methods Sampling. Water samples were collected during a survey of the Department of Geological Survey of Japan on the R/V Hakureimaru in June-July 1995. Surface water was taken in from 6 m depth at the bow of the ship while sailing. Water was pumped with a built-in rotary pump (20 m3 h-1). A KISP unit was connected to a pipeline that supplied seawater at 90 dm3 h-1. It was pumped through a filter unit to collect SPM, and the filtrate was extracted with XAD-2 resin. The glass fiber filter was replaced at water flow rates below 60 dm3 h-1. Deep water was sampled with KISP, using four units attached to the hydrographic wire at 50, 100, 1500, and 2500 m (Siribesi trough: 42°58′ N, 139°32′ E) and at 500, 1000, 2000, and 3000 m (Siribesi Trough: 42°55′ N, 139°32′ E). Coastal water samples (Hokkaido Coast) were collected at 50, 100, 200, and 300 m at 43°15′ N, 140°06′ E. The filters were kept in precleaned glass Petri dishes at -20 °C; the glass column containing the XAD-2 resin was kept airtight and covered with seawater in a refrigerator until analysis in Kiel. VOL. 32, NO. 12, 1998 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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TABLE 1. Sampling Positions in Japanese Waters date
location
position
depth (m)
sample vol (dm3)
20.06.95 21.06.95 25.06.95
track 1 (Pacific coast of Japan) track 2 (Sea of Japan) Siribesi Trough
36°53′ N, 141°11′ E-39°07′ N, 142°08′ E 41°29′ N, 140°36′ E-41°22′ N, 138°55′ E 42°58′ N, 139°32′ E
02.07.95
Siribesi Trough
42°55′ N, 139°32′ E
06.07.95
Hokkaido Coast
43°15′ N, 140°06′ E
6 6 50 100 1500 2500 500 1000 2000 3000 50 100 200 300
686 487 368 335 359 539 235 173 335 379 185 291 306 306
FIGURE 1. Sampling positions in the Sea of Japan and the adjacent region. The sampling time, position, and volume of water collected are given in Table 1. The sampling locations are depicted in Figure 1. 1748
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In-Situ Filtration and Extraction. The in- situ filtration/ extraction system is controlled by software. All essential data are recorded for later evaluation. The built-in computer
FIGURE 2. HRGC-ECD chromatograms of a procedural blank and a sample. CBs are identified by numbers according to Schulz et al. (11). U, unidentified compound, not belonging to the class of chlorobiphenyls. Not all the CBs that were determined in this study are shown in this figure. controls and records flow rate as well as time and duration of pumping. Extraction and Cleanup. The XAD-2 resin was extracted in a modified Soxhlet apparatus with water/acetonitrile (10: 90). The extraction procedure is given in detail in an IOC manual (8). Organics in the extracts were separated into classes [all the CBs appear in the second of four fractions collected (10)]. The GF/C filters were extracted in a modified Soxhlet apparatus with 80 cm3 acetonitrile for 4 h. This extract was treated like the XAD-2 extracts. Procedural Blanks. Three XAD-2 columns were used as blanks during the cruise. They were not used in KISP for extracting any organics. They were extracted and processed exactly like the sample columns. The chromatograms of their final extracts were taken as the procedural blanks. Individual CBs in samples were evaluated if the signal in the sample was at least three times the blank signal (Figure 2). Gas Chromatographic Separation and Detection. Gas chromatography-electron capture detection analyses were carried out with a Siemens Sichromat-1 (single column) GC and 63Ni- ECD using a programable temperature evaporator (280 °C). A SE-54 fused silica column (50 m, 0.25 mm i.d., ICT, Frankfurt) was used for identification of 30 CBs whose
elution profiles have been characterized before (11). Temperature: 140-170 °C at 30 °C min-1, then temperature ramp to 240 °C at 5 °C min-1. Carrier gas: H2 (2 mL min-1). Gas Chromatography-Mass Spectrometry. Nonylphenols were determined using a Fisons Trio 1000 mass spectrometer connected to a Fisons 8000 GC. Column: Optima 5MS, 60 m, 0.2 mm diameter, 0.15 µm film thickness. Carrier gas: helium (2.5 mL min-1). Temperature program: 70 °C (5 min), ramp to 200 °C at 20 °C min-1, then ramp to 320 °C at 5 °C min-1. Measurements were made of total ion current and selected masses (m/e 135 and 149). Mass 135 was used for evaluation of nonylphenols, using a technical mixture as standard. Principle Component Analysis (PCA). The statistical program Systat was used for PCA on normalized data.
Results and Discussion The concentrations of 30 individual chlorobiphenyls (CBs), their sum (∑CBs) in solution and suspension, and the nonylphenols (∑NoPhs) in solution are given in Tables 2 and 3. Chlorobiphenyls. The concentrations of ∑CBs in solution were between 0.1 and 1.2 pg dm-3 [0.4-3.8 fmol dm-3 those VOL. 32, NO. 12, 1998 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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TABLE 2. Concentrations (fg dm-3) of Individual CBs and Their Sums and the Sum of Nonylphenols (NoPhs) in Solution (Depth in m)a Siribesi Trough
CB no. 41 44 49 52 60 70 82 84 85 87 97 99 101 110 118 128 135 136 138 141 146 149 153 156 170 176 177 180 183 187 ∑CBs, fg dm-3 ∑CBs, fmol dm-3 ∑NoPhs, pg dm-3 a
Hokkaido Coast
Tracks 1
2
50
100
500
1000
1500
2000
2500
3000
50
100
200
300
6
6
6.6 10 14 14 4.6 10 3.9 4.8 0.6 5.8 3.2 5.0 10 10 1.9 1.6 0.7 3.6 2.7 0.30 0.26 3.6 3.1 0.3 0.36 7.2 0.2 0.2 0.2 7.8
10 16 16 18 5.5 17 5.8 15 2.1 10 6.1 7.7 16 17 7.9 1.8 1.9 4.0 7.8 1.9 0.2 7.0 4.6 1.9 1.5 4.2 1.3 1.5 0.8 2.9
40 63 66 76 31 69 14 81 18 60 30 37 110 121 58 2.6 25 32 58 18 8.6 102 56 6.4 7.2 10 7.3 10 7.0 2.3
48 75 71 70 39 76 19 43 15 57 30 34 106 121 40 11 18 25 55 15 8.0 77 43 7.5 10 15 9.5 14 6.7 16
11 15 17 16 10 19 5.5 16 3.5 10 6.3 11 12 21 10 0.6 2.5 3.5 17 3.0 1.0 17 8.6 2.7 2.9 13 3.0 3.3 1.3 3.3
9.4 16 14 17 5.5 22 22 16 6.3 24 14 11 34 53 44 11 8.6 4.4 65 13 7.3 41 45 16 18 3.9 9.2 23 8.1 24
12 21 21 22 10 24 6.6 28 5.3 18 10 11 28 37 22 5.6 7.2 6.1 35 9.0 5.4 31 30 4.3 7.2 11 4.8 11 6.2 3.8
9.4 14 18 16 5.9 10 4.3 3.8 1.6 5.8 3.2 4.0 11 11 5.5 2.8 0.76 2.8 11 1.9 0.8 6.5 8.5 2.4 3.5 6.3 3.0 5.6 2.5 0.7
2.6 43 44 48 12 41 11 30 5.6 27 16 22 46 54 28 6.9 9.1 8.5 36 6.8 3.4 40 26 5.6 7.2 7.2 2.9 19 7.8 2.9
0.29 26 30 31 8.9 25 6.8 19 2.3 11 7.0 9.4 29 23 7.3 3.5 3.0 3.6 14 2.3 0.3 12 8.7 3.2 3.5 7.1 3.2 4.2 2.7 4.9
14 25 19 22 9.0 25 4.2 14 3.7 16 9.1 11 23 30 13 3.5 5.5 2.6 15 4.0 0.8 17 13 4.0 2.5 12 3.3 5.5 2.9 3.2
13 25 31 25 8.4 18 6.1 6.4 2.3 10 5.9 7.3 18 20 7.0 2.2 2.2 2.9 12 2.0 1.0 12 6.1 2.7 3.2 2.4 3.5 5.4 2.1 4.1
5.4 8.4 10 12 4.3 9.4 1.1 3.1 1.9 6.4 4.2 5.0 10 12 6.2 1.0 1.3 1.5 7.8 1.8 0.5 6.6 4.9 1.8 2.0 2.5 3.1 2.5 0.8 1.8
10 16 15 16 11 14 2.3 7.0 1.0 9.3 8.5 7.6 16 23 12 0.9 4.9 2.8 12 1.7 0.9 16 0.9 2.2 6.4 2.7 2.1 3.3 0.9 0.8
213 0.7 2
1226 3.8 28
1176 3.7 145
265 0.8 92
604 1.8 4
452 1.4 4
330 1.0 21
266 0.9 24
138 0.4 11
228 0.7 93
136 0.4 3
183 0.6 9
619 1.9 34
312 0.9 58
Tracks indicate space-integrated sampling at 6 m depth while cruising. CBs are identified by numbers according to Schulz et al. (11).
of individual congeners between 0.001 and 0.1 pg dm-3] and in suspension between 0.2 and 1.5 pg dm-3 [0.5-4.7 fmol dm-3 those of individual congeners between 0.01 and 0.1 pg dm-3]. Values in suspension exceeded those in solution in almost all samples. The vertical profiles of ∑CBs in solution and suspension in the Siribesi Trough were similar (Figure 3a). The surface water concentrations in solution were low, in fact lower than we have found in other near-coastal or even remote areas of the Atlantic Ocean. Another contrast with findings in the Atlantic, where concentrations in solution as well as in suspension showed maximal values at the surface and decreasing values with increasing depth, is the observation of higher concentrations in deeper water of the Siribesi Trough (for example, ∑CBs in solution: 1.2 pg dm-3 at 500 and 1000 m and 0.5-0.6 pg dm-3 at 2000 and 2500 m depth) than near the surface (0.2 pg dm-3). Values at 1500 and 3000 m depth were low (0.2-0.3 pg dm-3). A more detailed comparison of these results with those obtained in the North Atlantic may be useful, as most of our previous work was carried out in the latter area. A characteristic vertical profile of ∑CBs in the Atlantic is presented in Figure 3c, showing a concentration decrease from the surface toward the deep. The water was sampled in the Faroer Bank Channel (61°43′ N, 8°40′ W). The water at 714 m depth was identified as Iceland Scotland Overflow Water (ISOW) with ∑CBs concentration in solution of 254 fg dm-3. The water at 694 m depth was a mixture of mainly ISOW (90%) and overlying water. This sample obtained at close distance should have very similar CB concentrations. This was in fact the case (196 fg dm-3). Also the compositions of the CB mixtures were very similar (6). Both observations serve as a check on the analytical reliability of the procedure. 1750
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The other two water masses at that site were North Atlantic Central Water (NACW) (∑CBs in solution ) 1048 fg dm-3) and NACW mix (∑CBs in solution ) 490 fg dm-3). The ∑CB concentrations in suspension, except at 194 m depth, were higher than in solution. In the Sea of Japan, the concentrations in suspension were higher than those in solution in nearly all samples. Additionally, ∑CBs concentrations and CB compositions varied in deep water samples at both locations in the Siribesi Trough. It can be expected that homogeneity of the water column in the vertical profile would result in the establishment of particle-solution distribution equilibria of CBs. Plots of the ratio of measured concentrations of individual CBs in suspension and in solution against the molecular property octanol-water distribution coefficient are elegant tools to test this. This approach has resulted in linear plots in laboratory experiments (12). The success in explaining field observations has been limited, however. Linear plots have been obtained in rare cases. It has been stated that the establishment of equilibria is not fast enough to keep pace with other processes that interfere with pure physicochemical processes. For instance, primary production and remineralization processes in surface waters have been found to prohibit the establishment of equilibria, but also mixing of different water bodies and/or continuous admixture of different particles may be prohibitive (6). Also in the Sea of Japan, plots were far from being linear (results not shown). Another tool to investigate the relative roles of the mixing of water bodies and the interaction between solution and particles is found in the comparison of the compositions of CB mixtures in the interpretation of CB data. PCA may be extremely helpful in reaching this goal. It has been used
TABLE 3. Concentrations (fg dm-3) of Individual CBs and Their Sums in Suspension Siribesi Trough
CB no. 41 44 49 52 60 70 82 84 85 87 97 99 101 110 118 128 135 136 138 141 146 149 153 156 170 176 177 180 183 187 ∑CBs, fg dm-3 ∑CBs, fmol dm-3 a
Hokkaido Coast
50
100
500
1000
1500
2000
2500
3000
50
100
200
300
128 143 116 88 76 116 36 40 24 60 28 32 100 108 48 4 24 12 68 12 12 100 32 10 12 24 8 16 4 8
7.0 13 15 28 33 28 12 8.4 8.2 12 3.5 8.2 18 23 17 2.8 9.4 4.2 16 6.8 4.2 4.2 10 4.7 6.8 3.5 6.3 13 4.0 2.0
32 37 34 30 34 43 19 20 37 39 19 25 54 61 29 9.0 13 17 63 17 10 34 42 15 26 6.0 10 35 7.2 49
46 32 84 94 75 104 1.6 48 1.8 62 40 1.6 96 106 106 13 1.7 30 88 36 45 62 53 13 29 28 23 39 1.6 1.6
16 14 5.8 55 14 23 8.7 8.7 4.3 17 8.7 8.7 32 32 20 5.8 5.8 2.3 29 8.7 4.3 26 27 8.7 8.7 23 4.3 14 2.9 29
8.2 16 12 11 1.7 13 1.7 1.7 1.6 8.8 6.9 1.6 1.6 12 6.9 1.6 1.5 1.5 13 2.9 1.5 12 5.2 1.4 5.2 1.4 1.4 1.4 1.5 1.4
7.0 52 36 39 61 55 25 13 44 46 15 28 69 82 58 16 24 16 124 27 13 76 66 19 45 6.6 23 61 20 14
12 10 14 27 4.8 7.7 6.5 4.3 4.3 8.6 6.0 9.1 18 19 11 1.7 13 29 17 3.6 2.9 17 28 1.9 2.2 7.2 0.7 2.6 12 10
1.9 20 20 26 20 30 14 15 10 31 10 16 47 57 40 3 18 15 50 6.9 8.9 31 37 12 21 7.9 7.9 31 2 1.9
32 8.6 29 47 57 42 11 18 35 30 15 20 48 58 24 8.6 29 29 54 4.5 7.4 11 42 10 23 5.6 7.1 30 10 4.3
33 14 40 33 1.2 41 23 10 34 40 14 21 58 58 29 5.4 21 10 95 18 9.1 20 66 7.4 27 19 1.2 4.5 12 47
27 34 34 28 23 34 18 13 88 23 10 13 41 44 28 8.8 8.8 13 43 9.4 5.6 34 27 9.4 13 11 2.5 20 6.9 2.4
1484 4.7
332 1.0
865 2.6
1362 4.2
470 1.4
159 0.5
1179 3.6
311 0.9
607 1.8
748 2.3
812 2.5
672 2.1
Sampling depths in meters are indicated at the top. CBs are identified by numbers according to Schulz et al. (11).
FIGURE 3. Sum of 30 CBs (∑CBs) and the sum of 10 nonylphenols (∑NoPhs) in solution and suspension in vertical profile of Siribesi trough (a and b) [42°55′ N 139°32′ E] and in the North Atlantic (c) [61°43′ N 8°40′ W]. before to reduce a complex data set to a few principle depths of the Siribesi Trough. In plots of this kind, similarity components that can be represented graphically, e.g., in the of the compositions results in neighboring positions. Figure form of biplots (13, 14). Figure 4 is a biplot of principal 4a shows that this applies to the sets of samples originating components 1 and 2 of the correlation matrix of mol % from (a) 50 and 100 m; (b) 500 and 1000 m; and (c) 1500, contributions of CBs in solution and suspension at the various 2000, and 2500 m. The composition of the 3000 m sample VOL. 32, NO. 12, 1998 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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FIGURE 5. Biplot of principal components 1 and 2 derived from the correlation matrix of mol % contribution of 11 dominant individual CBs in surface waters (solution) from Siribesi Trough, Hokkaido Coast, and tracks 1 and 2. Stars (f) represent scores, and the numbers refer to the depth of sampling in meters. The component loadings are represented by diamonds ((), along with corresponding CB numbers.
FIGURE 4. (a) Solution and (b) suspension: Biplot of pricipal components 1 and 2 derived from the correlation matrix of mol % contribution of 11 dominant individual CBs in samples of the vertical profile in the Siribesi Trough. Stars (f) represent scores, and the numbers refer to the depth of sampling in meters. The component loadings are represented by diamonds ((), along with corresponding CB numbers. had no matching counterpart. An interesting observation is the fact that the samples split up in four groups that appear to be identical to the water mass classification of Kim et al. (5). Principal component 1, accounting for 67% of the variability between the samples, represents the degree of chlorination. The loadings (the individual CBs contributing to the result) in Figure 4a show that surface water is characterized by lower chlorinated CBs and that deep water is characterized by higher chlorinated CBs. The water samples obtained at the various depths are thus characterized by different compositions of the mixtures of individual congeners. A clear grouping of samples is absent in the biplot for suspensions (Figure 4b). The percentage contributions of principal components 1 and 2 differ from Figure 4a. PC 1 contributes only 32%, and PC2 contributes only 22%. This 1752
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(PC2) reflects most probably the variable composition of the biological material, being the main carrier of the CBs (15). As the concentrations in suspension exceed those in solution in nearly all samples, any mobilization of CBs from particulates into solution should result in corresponding modifications in both concentrations and compositions of CB mixtures in solution. All these observations indicate that the concentrations of CBs in solution as well as the composition of their mixture at any position in the Siribesi Trough can be considered as independent from the concentrations and composition in particulate suspended forms in that area and can be considered to reflect primarily the history of the water bodies concerned. It was shown in the preceding section that the different water masses as defined by Kim and Kim (4) have different and characteristic CB fingerprints as well as different CB concentration levels. Surface and bottom waters have the lowest concentrations. The different concentration regimes may be due to different source regions of the waters concerned. It was suggested by Kim and Kim (4) that the mode of deep water formation in the region has changed from bottom water formation to intermediate/deep water formation in recent years. As the anthropogenic contaminants such as chlorobiphenyls in deeper waters have their sources in the sea surface, higher concentrations at the present time would be expected in intermediate/deep waters rather than in bottom waters. This expectation is supported by observations (Figure 4a). The compositions of the CB mixtures in surface water in the Japan Sea region are quite variable. This is shown by the biplot of four samples (Figure 5). This can explain the correspondingly large differences between the CB compositions in the different water masses present in the vertical profile of Figure 4a resulting from different source regions. The low values in bottom water are similar to those in surface water and considerably higher than we observed in deep waters of the North Atlantic. The presence of surfacederived constituents may be due to mixing of deep and bottom water, but it cannot be excluded that surface water is a direct source to bottom water. These latter facts are
consistent with the estimated relatively low turnover time of total deep and bottom water of about 80 years (4), quite different from the situation in the North Atlantic. In the latter ocean, bottom water concentrations of CBs are much lower than surface water values. In fact, they are below the extremely low detection limits, in agreement with the much longer turnover time of the Atlantic deep waters. Nonylphenols (NoPhs). Supporting evidence for the existence of different water masses with different fingerprints of chlorobiphenyls, suggesting the existence of different source regions of water and its dissolved constituents, is found in the distribution of nonylphenols. These are breakdown products of alkylphenol (poly)ethoxylates (surfactants with detergent or oil dispersing properties). Their presence in deep waters can be attributed completely to advective transport in solution; their source is located exclusively in the sea surface. We have investigated this class of compounds in several coastal and open oceanic regions of the North Atlantic. Their concentrations in suspended particles have been below detection limits in all cases, even in the presence of high concentrations in solution (unpublished observations). This was also found in the present study for the Sea of Japan. The vertical profile of dissolved ∑NoPhs in the Siribesi Trough is very similar to that of ∑CBs (Table 2; Figure 3b) with lowest and practically equal values in surface and bottom water, very high values in central water, and intermediate values in deep water. As particulate matter can be excluded as a source of the higher concentrations in subsurface waters, the only possible explanation is that the different water masses in the vertical profile have different source regions at the surface, with different concentrations of both CBs and nonylphenols. The relative change of concentrations between different depths in the vertical profile differs between CBs and nonylphenols. For instance, the ratio between the concentrations at 1000 m depth and the surface is 50 for nonylphenols and 9 for ∑CBs. Such differences are a logical consequence if the source water for the 1000 m level has different concentration levels from those of the local surface water. Sources of Contamination. The ultimate sources of chlorobiphenyls are industrially produced technical mixtures of various overall chlorine content (in the 30-60% range). They have been produced under different names, e.g., Aroclors and Phenoclors. Of particular relevance for the area under consideration are the Russian (Sovol) and Japanese (Kanechlor) formulations. A comparison between their compositions of the CB mixtures with those found in the Sea of Japan may be interesting for identifying sources. The score plots of the PCA involving water samples and the four major Kanechlor (KC) and Clophen (A) formulations (eg., KC 300, 400, 500, and 600 with 30, 40, 50, and 60% chlorine, respectively) and Sovol (50-60%) (16) are represented in Figures 6. The surface water resembles KC400; the deep water and bottom water resemble Sovol and KC500, respectively. Gamo et al. (17) suggested that surface water in the northern or northwestern part of the Sea of Japan gets dense enough in strong winters to sink to the bottom. The newly formed bottom water would have sufficient kinetic energy to maintain active vertical mixing. The resemblance betweeen the CB compositions in these deep and bottom waters and Sovol supports this. Samples from intermediate depths resemble both KC400 and KC500, a common phenomenon, from which no conclusions can be derived. It can be concluded that these first findings on the distribution of both chlorobiphenyls and nonylphenols are
FIGURE 6. Score plots of principal components 1 and 2 derived from the correlation matrix of % contribution of 30 CB congeners to sum CBs (∑CBs) in Clophen A30-A60, in Kanechlor KC300KC600, in Sovol, and in vertical samples (solution) of Siribesi Trough. in agreemeent with the presence of different water masses in the Sea of Japan, as suggested by Kim and Kim (4) and characterized by different concentrations of chlorobiphenyls and different compositions of their mixtures as well as different concentrations of nonylphenols.
Literature Cited (1) Kim, K.-R. In Biogeochemical processes in the north Pacific; Tsunogai, S., Ed.; Japan Marine Science Foundation: Tokyo, 1996; pp 41-51. (2) Uda, M. J. Imp. Fish. Exp. Stat. 1934, 5, 57-190. (3) Gamo, T.; Horibe, Y. J. Oceanogr. Soc. Jpn. 1983, (4) Kim, K.-R.; Kim, K. J. Korean Soc. Oceanogr. 1996, 31, 164-172. (5) Kim, K.; Kim, K.-R.; Kim, Y.-G.; Cho, Y.-K.; Chung, J.-Y.; Choi, B.-H.; Byun, S.-K.; Hong, G.-H.; Takematsu, M.; Yoon, J.-H.; Volkov, Y.; Danchenkov, M. J. Korean Soc. Oceanogr. 1996, 31, 155-163. (6) Schulz-Bull, D. E.; Petrick, G.; Bruhn, R.; Duinker, J. C. Mar. Chem. 1998, 61, 101-114. (7) Schulz-Bull, D. E.; Lembrecht, A.; Petrick, G.; Duinker, J. C. Deep Sea Res. Submitted for publication. (8) Intergovernmental Oceanographic Commission. Manuals and Guides 27; 1993; 34 pp. (9) Petrick, G.; Schulz-Bull, D. E.; Martens, V.; Scholz, K.; Duinker, J. C. Mar. Chem. 1996, 54, 97-105. (10) Petrick, G.; Schulz, D. E.; Duinker, J. C. J. Chromatogr. 1988, 435, 241-248. (11) Schulz, D. E.; Petrick, G.; Duinker, J. C. Environ. Sci. Technol. 1989, 23, 852-859. (12) Chiou, C. T.; Porter, P. E.; Schmedding, D. W. Environ. Sci. Technol. 1983, 17, 227-231. (13) de Boer, J.; Stronck, C. J. N.; Traag, W. A.; van der Meer, J. Chemosphere 1993, 26, 1823-1842. (14) Gabriel, K. R. Biometrika 1971, 58, 453-467. (15) Lenz, J. Ber. Wiss. Kommn. Meeresforsch. 1974, 23, 209-225. (16) Kannan, N.; Schulz-Bull, D. E.; Petrick, G.; Duinker, J. C. Int. J. Environ. Anal. Chem. 1992, 47, 201-215. (17) Gamo, T.; Nozaki, Y.; Sakai, H.; Nakai, T.; Tsubota, H. J. Mar. Res. 1986, 44, 781- 793.
Received for review August 11, 1997. Revised manuscript received April 1, 1998. Accepted April 2, 1998. ES970713Q
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