Environ. Sci. Technol. 1990, 24, 1836-1841
Report, Sections 1-3. Submitted to the California Dept. Health Services, Toxics Substances Control Division, 1987. Ellis, W. D.; Bramlett, J. A.; Johnson, A. E.; McNabb, G. D.; Payne, J. R.; Harkins, P. C.; Mashni, C. I. In Proceedings of the U S . EPA Symposium of Waste Testing and Quality Assurance;US.Government Printing Office: Washington, DC, 1988; pp F-46-F-63.
(12) Simons, W. W. Sadtler Handbook of Ultraviolet Spectra; Sadtler Research Laboratories: Philadelphia, PA, 1979.
Received for review April 23,1990. Revised manuscript received July 9, 1990. Accepted July 16, 1990. W e acknowledge the partial financial support received for this project from E P A E M S L Las Vegas.
Estimation of Polychlorinated Dibenzofuran and Dibenzo-p-dioxin Contamination of a Coastal Region Using Isomer Profiles in Crabs Michael Oehme, Alena Bartonova, and Jon Knutzent Norwegian Institute for Air Research, P.O. Box 64, N-2001 Lillestr0m, Norway Compared to other marine biota such as fish, crabs lack the ability to metabolize most of the polychlorinated dibenzofuran (PCDF) and dibenzo-p-dioxin (PCDD) isomers. Therefore, they preserve nearly undisturbed the characteristic isomer profiles found in the wastewater from a magnesium production plant in southern Norway. The isomer pattern of this process shows significant differences compared to other PCDF/PCDD sources such as combustion or the pulp industry. The isomer distribution and concentration levels were determined in pooled samples of stationary male crabs, which were collected within a distance of a few kilometers and more than 100 km from the source. Two main isomer distributions could be identified, one belonging to the Mg process and one more similar to that earlier reported from the Skagerrak region. When statistical methods such as discriminant or variance analyses were employed, the coastal area contaminated by the factory could be estimated to -50 km downstream the source. Introduction
As recently shown, the production of magnesium forms substantial amounts of PCDD and PCDF as undesired byproducts ( I , 2). The main amount is produced during the reaction of coke and magnesium oxide to water-free magnesium chloride in a chlorine atmosphere at 700-1100 "C. The chlorine excess is recirculated after washing by seawater scrubbers from which the wastewater is discharged into the Frierfjord, southern Norway. The annual load was estimated to about 0.3-0.5 kg of 2,3,7,8-TCDD equivalents according to the Nordic or international model ( 3 ) . Especially the tetra-(TCDF-) and pentachlorodibenzofuran (PeCDF) isomer patterns show differences compared to other PCDD/PCDF sources such as combustion ( 4 , 5 ) and chlorine bleaching of pulp (6). The 1,3,7,8/1,3,7,9, 1,2,7,8, and 2,3,7,8 isomers are the most dominant TCDF congeners. Combustion sources show a rather even distribution of all possible isomers. 1,2,7,8- and 2,3,7,8-TCDF are also the most significant isomers in the effluents of pulp and paper mills. However, 1,3,7,8-/1,3,7,9-TCDF is only present at rather low levels in the latter source. Compared to incineration and other combustion sources as well as chlorine bleaching of pulp, the effluents from the Mg factory contain significantly higher amounts of 1,2,3,6,8-/ 1,3,4,7,9-, 1,2,4,7,8-, and 1,2,3,7,8-/ 1,2,3,4,8Norwegian Institute for Water Research, P.O. Box 33, N-0313 Oslo 3, Norway. 1836
Environ. Sci. Technol., Vol. 24, No. 12, 1990
PeCDF. In contrast, combustion processes form relatively large amounts of 1,2,6,7,8- and 2,3,4,7,8-PeCDF. These isomers are present at much lower levels in the wastewater of the Mg industry. The concentration ratio between CPCDF and CPCDD is 1O:l. This ratio is much higher than in the effluents from chlorine bleaching of pulp (7). There are also small differences between the isomer patterns for the hexa- and heptachlorodibenzofuransfrom the Mg process and other sources. However, these are, as those for all PCDD isomer groups, less conspicuous. Figure 1 compares the TCDF and PeCDF isomer distributions for some selected sources. As can be seen, only production of refined nickel gives a nearly identical TCDF pattern but there are differences in the PeCDF distribution. The reaction forming PCDF/PCDD is a process converting NiClz to NiO, which uses chlorine and a carbon source (propane) at temperatures over 700 "C ( I ) . However, the only factory in Norway producing refined Ni is placed 150 km from the Mg plant downstream on the Skagerrak coast. It stopped using this process in 1984. The recently published results of an introductory study (8) indicated that both biota such as fish and crustacea as well as sediments were considerably contaminated as far as at least 25-30 km from the Mg factory. Furthermore, it could be shown that crustacea such as crabs and shrimps bioconcentrate and preserve the emission pattern from the wastewater nearly undisturbed. This is different from fish, which enrich mainly the 2,3,7,8-tetrachloro-substituted isomers (2, 5, 9). The bioconcentration factor for crabs compared to sediments has not yet been estimated. It seems to be considerable, since PCDF/PCDD can be detected in crabs from sites far away from known sources (2, 5 ) . In addition, male crabs are rather stationary and only move within a few kilometers. Therefore, during a new and more extended project mainly male and only in some cases female crabs were collected from the sites shown in Figure 2 to answer the following questions: What are the concentrations of PCDD/PCDF in crabs down- and upstream the source? Can the area polluted by the Mg process be estimated by TCDF/PeCDF patterns in crabs? Are there any concentration differences between male and female crabs?
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E x p e r i m e n t a l Section
As can be seen from Figure 2, the factory is situated at the end of a fjord close to the estuary of a large river (mean annual discharge -300 m3/s). The main water transport route follows the fjord, passes its narrow mouth at Brevik, and enters a widely branched fjord system before ending
0013-936X/90/0924-1836$02.50/0
0 1990 American Chemical Society
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Figure 1. TCDF and PeCDF isomer patterns found in the emissions of different sources and in ambient air. The main isomers found in the wastewater from the magnesium process are marked.
in open Skagerrak waters. There, the main direction of the current is southwest. Crabs (Cancerpagurus)of about 13-19 cm size were collected mainly from 18 to 28 m depth (see ref 10 for more details). Pooled samples were prepared from the hepatopancreas (14 sites) or claw meat (3 sites) of 10 male crabs. In one case seven male and three female samples were mixed. In addition, from three sites, both male and female crab were analyzed separately and from one site only female crab. All samples were stored raw at -25 "C until analysis. Homogenized aliquots of 10 g of hepatopancreas or 25 g of claw meat were mixed with a 10-fold amount of sodium sulfate in a mixer with an insert made from polypropylene. After the sample was dehydrated overnight at room temperature, the dry saltlike mixture was homogenized once more in the mixer and a mixture of 13C-labeled2,3,7,8-tetrasubstituted congeners in hexane (1-4 or 10-40 pg/g of fresh weight for each isomer) was added consisting of 2,3,7,8-TCDF, 2,3,4,7,8PeCDF, 1,2,3,4,7,8-HxCDF, 1,2,3,4,6,7,8-HpCDF, 2,3,7,8T C D D , 1,2,3,7,8-PeCDD, 1,2,3,7,8,9-HxCDD, 1,2,3,4,6,7&HpCDD, and OCDD. The cleanup and quantification method is described in detail elsewhere (2), and therefore, only the following brief summary is given: (1)sample cleanup using the procedure by Smith et al. (11) with some modifications; (2) final cleanup using a combination of two Pasteur pipets, one filled with sulfuric acid coated silica and one with aluminum oxide (2); (3) separation by high-resolution gas chromatography on SP 2330 as stationary phase and quantification by electron impact (EI) (2,3,7,8-TCDD) or negative ion chemical ionization (NCI) mass spectrometry (2, 12). The following quality assurance measures were carried out to verify the reliability of the results: comparison of all employed standards with those used during a WHO intercalibration (13),parallel analysis of three samples by
another independent laboratory (IO), control of the analysis blank, which should correspond to the detection limits and regular recovery studies of the whole analysis. Recovery rates were typically within 55-105%. The reproducibility for parallels from the same pooled sample was within 25% ( n = 3). The fat determination of the samples was carried out according to the method described in ref 14. The statistical analysis was performed using the following modules of the SPSS/PC+ V2.1 package (SPSS InC., Chicago, 11,60611): CLUSTER, DSCRIM, FACTOR, MANTOVA, and TABLES. It was restricted to the results of the 2,3,7,8-tetrasubstituted isomers, the calculated 2,3,7,8 equivalents according to the Nordic model ( 3 ) ,and the summarized concentrations of the tetra, penta, and hexa isomers as well as the most dominant tetra and penta isomers marked in Figure 1 and Table I.
Results and Discussion Isomer Patterns and Concentration Levels. As a first step, the TCDF and PeCDF mass fragmentograms for the molecular ions M and (M + 2) were compared visually for all samples against the typical wastewater emission pattern of the Mg process. Two main isomer distributions could be identified as shown in Figure 3. Crab hepatopancreas from the sites Kl-K9 showed a TCDF and PeCDF isomer pattern that was almost the same for all samples (see pattern 1 in Figure 3) and that was in very good agreement with those from the Mg process. Hepatopancreas samples from sites K10, K11, K13, and K14 had an isomer distribution (see pattern 2 in Figure 3) that was very dissimilar to that of the Mg plant. The TCDF distribution showed some similarity with that found in crabs along the Swedish west coast not polluted by the Environ. Sci. Technol., Vol. 24, No. 12, 1990
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pulp industry ( 5 ) . However, the PeCDF pattern was somewhat different. An analogy to the Swedish samples was the low 1,2,3,7,8/1,2,3,4,8-PeCDF level compared to 2,3,4,7,8-PeCDF. The profiles in sample K12 taken from a remote area were different from all other samples. They showed some similarity with the patterns found in sediment samples from the middle of the Baltic Sea (15). On the basis of the isomer patterns found in the analyzed samples, the area contaminated by the Mg factory was defined as shown in Figure 4 as a first approximation. Tables I and I1 summarize the PCDF/PCDD results for male and female crab hepatopancreas. The concentrations expressed as 2,3,7,8-TCDD equivalents (Nordic model) were 1-2 orders of magnitude higher within the area assumed to be polluted by the Mg factory. However, the levels farther away were still in the order of 20-60 pg/g, which is comparable with the results for crab hepatopancreas from the Swedish west coast not polluted by the pulp industry (5). The reason and sources for these rather high levels in the Skagerrak region are still unknown. The TCDF and PeCDF profiles of hepatopancreas and claw meat were nearly identical. The higher 1,2,7,8-TCDF concentration compared to 2,3,6,8-TCDF is typical for the meager claw meat (see Figure 3). No significant differences could be found in the isomer distribution of male and female samples. However, though only a few samples from females were analyzed, there is an indication that the levels are considerably lower compared to males. This difference might be explained by a transfer of the deposited PCDF/PCDD to the roe maturing in the period before the samples were collected in September-October. Substantial concentration changes have also been reported for herring from the Baltic Sea between spring (higher levels) and autumn after spawning (16). 1838
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Environ. Sci. Technol., Vol. 24, No. 12, 1990
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Flgure 3. Main TCDF and PeCDF isomer patterns found in crab hepatopancreas and claw meat. Pattern 1 is caused by contamination from the Mg process.
Statistical Data Analysis. As the next step, all samples were clustered. Three separate groups of variables (individual PCDF isomers, individual PCDD isomers, summary results of PCDF isomer groups together with 2,3,7,8-TCDD equivalents) were used. Centroid and average linkage methods were applied, giving similar results. Both individual and summary PCDF variables gave dendrograms that proposed the subdivision into the following clusters: Region 1: Source area (Kl). Region 2: up to 25 km downstream (K2-K5). Region 3: up to 50 km downstream (K6-K9). Region 4: not contaminated by this source in particular (KlO-Kl4). Regions 1-3 show as earlier discussed the typical isomer distribution of the Mg process, while region 4 contains all
Table I. Concentrations of 2,3,7,8-TetrachlorosubstitutedPCDF/PCDD and Selected Source Characteristic Isomers of Crab Hepatopancrease (CH) and Claw Meat (CM) from Male Crabso
congers,' pg/g
K1 CH
1378/1379-TCDF 962 1278-TCDF 438 2368-TCDF 856 2280 2378-TCDF ETCDF 7900 12368/ 13479-PeCDF 2310 12478-PeCDF 2110 12378/12348-PeCDF 2490 23478-PeCDF 1590 ZPeCDF 14500 123478/ 123479-HxCDF 3890 123678-HxCDF 4570 123789-HxCDF 58 374 234678-HxCDF EHxCDF 13250 1234678-HpCDF 3790 OCDF 452 2378-TCDD 110 12378-PeCDD 469 12378-HxCDD 233 123678-HxCDD 387 123789-HcCDD 647 1234678-HpCDD 349 OCDD 238 2378-TCDD-EQ ( 3 ) 2451 fat content, 3'% 6.0
sample siteb K 4 C H K 5 C H K 7 C H K 8 C H K 9 C H K9CM 72 32 95 160
66 34 68 151
602 155 176 145 169 1220 259 273 2.9 64
532 147 150 174 127 1100 288 298 1.4 50 771
865 375 75 11 46 35 65 105 57 45 221 18.0
240 23 9.7 31 23 52 63 34 32 186 10.9
27 12 38 62
33 12 44 66 279 70 66 68 69 540 146 212 1.4 28
228 68 48 59 55 430 82 148 0.8 17
482 217 15 7.1 24 21 38 44 43 29 106 13.1
297 89 9.1
