Environ. Sci. Techno/. 1995, 29, 2801-2805
Identification and Quantification of Monobromopolychlorobiphenyls in Baltic Ringed Seal and a Technical PCB (Clophen PETER S. HAGLUND,* KARIN I. WIBERG, AND D O U G L A S R. Z O O K ' Institute of Environmental Chemistry, Umed University, S-901 87 Umed, Sweden
Monobrominated PCBs (Br-PCBs) are known to exhibit dioxin-like effects and to be more toxic than their PCB counterparts. In this study, Br-PCBs are reported, to our knowledge for the first time, in biological samples, specifically in juvenile ringed seal (Phoca hispida) from the Baltic Sea. Mass spectrometric techniques (ECNI and El) have been employed to gather structural and elemental composition information, respectively, in the absence of authentic reference standards. Quantification indicates total levels of Br-PCBs at a minimum of 20 ng/g extractable lipids. A technical PCB (Clophen A50) was investigated and also found to contain Br-PCBs, the results of which were compared to those from seal. Technical PCBs are thus possible environmental sources of Br-PCBs occurring in seal. Other potential sources are also discussed.
Introduction Polychlorinated biphenyls (PCBs) are well-studied ubiquitous environmental pollutants. Large (hundreds to millions of metric ton) productionvolumes, their continued widespread release, and their stability against biological and physical degradation have resulted in high (ppm)levels in a number of biological matrices, including marine mammals and humans. During a mass spectrometric screening of a juvenile ringed seal blubber sample, a series of compounds tentatively identified as monobromopolychlorobiphenyls (Br-PCBs)were found. Monobromotetrachlorobiphenyls (BrCb biphenyls) and monobromopentachlorobiphenyls (BrC15biphenyls) were the most abundant homologs. The effects of PCBs and polybrominated biphenyls (PBBs)on humans have been studied by the examination of accidentally exposed groups, namely, the Yusho and Michigan victims, respectively (1). A large variety of toxicological effects have been documented from these Present address: Swiss Federal Institute of Technology, Sonneggstrasse 5, CH-8092 Zurich, Switzerland.
0013-936)(195/0929-2801$09.00/0 @ 1995 American Chemical Society
cases of food poisoning. No such knowledge exists concerning the toxicity of Br-PCBs on humans. Many symptoms and clinical abnormalities arise from PCBs and PBBs, such as dermal rashes and acne, unusual pains, altered perception,respiritatory problems, headaches, some elevation of serum transmitases, and increased prophyrin excretion (1). Due to structural similarities, it is very plausible that Br-PCBs have effects simillar to the PCBs and PBBs. Several in vitro tests have been performed on Br-PCBs. The studies have mainlyfocused on dioxin-like effects, e.g., binding to the Ah-receptor protein and induction of the aryl hydrocarbon hydroxylase (A") and ethoxyresorufin 0-deethylase (EROD) enzyme systems (2-5). In these in vitro test systems, Br-PCBs proved more potent than the corresponding PCB congeners. Br-PCBshave to our knowledge never before been found in biological samples, thus the aim of the present study has been to perform an unambiguous identification and quantification (in the absence of 13C-labeled internal standards) of Br-PCBs in ringed seal from the Baltic Sea. A technical mixture (Clophen A50) has also been analyzed for the presence of Br-PCBs and used to further screen for coincident isomers to determine if technical PCBs may be a potential source of Br-PCBs found in seal.
Experimental Section Chemicals, Reagents, and Glassware. All solventswere of analytical grade or better. Silica (no. 7734,0.063-0.2 mm particle size) and 95-97% sulfuric acid were of analytical grade,obtained from Merck (Darmstadt, Germany). Oleinfree tetradecane was obtained from Fluka (Buchs, Switzerland). Clophen A50, a technical PCB formulation, was from Bayer (Leverkusen, Germany), batch 17012(9479D). 4'-Bromo-2,5-dichlorobiphenylwas a generous gift from Professorke Bergman of StockholmUniversity (Stockholm, Sweden). [13C1z1-2,2',4,5,5'-pentachlorobiphenyl(PCB 101) was obtained from Cambridge Isotope Laboratories (Andover, MA). Glassware was cleaned by acetone rinsing, machine washingwith alkalinedetergent, and rinsing three times with cyclohexane/ dichloromethane (1:l). Silica gel impregnatedwith 22 or 44wt%of sulfuric acid was prepared according to the procedure of Stalling et al. (6). Baltic Sea Ringed Seal Sample. Ringed seal (Phoca hispid4 carcasses were collected between 1980 and 1987 along the Swedish coastline of the Baltic Sea. After dissection, categorized tissues were grouped by age class, pooled, stored sealed, and deep frozen (-20 "C) in glass jars until the time of analysis. A composite blubber sample representing 13juvenile seals was kindly provided for the study by the Swedish Museum of Natural History (Stockholm, Sweden). Extraction and Lipid Removal. The half-thawed blubber was sampled in duplicate (4 g/sample),and the samples were blended with 200 g of sodium sulfate using a highcapacityblender. The duplicates are denoted as trial I and trial 11. The samples were column extracted with 600 mL of acetoneln-hexane (2.5:l)and 300 mLof n-hexaneldiethyl ether (9:l) to obtain a fat extract (7). The lipid content of the samples was determined gravimetrically after complete solventremoval. Bulk lipid removal was effected by means
VOL. 29, NO. 11. 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY 12801
of sulfuric acid hydrolysis. As a lirst step, the lipids were dissolved in isooctane (100 mglmL), transferred to test tubes, and gently shaken with an equal volume of sulfuric acid ( 7). To further reduce the remaining lipids, the organic layer was concentrated by rotary evaporation and was passed through a column packed with sulfuric acid impregnated silica (8). Concentration down to a total volume of 30 pL of tetradecane completed the acid hydrolysis. Cleanup by High-Performance Liquid Chromatography. The persistent organochlorine compounds were fractionated by high-performance liquid chromatography (HPLC)on a diaminopropyl silica phase (no.H3APS2-250A, Hypersil3 APS2, 4.6 x 250 mm, 3-pm particles, HiChrom Ltd., Berks, U.K.). n-Hexane was used as the mobile phase at a flow rate of 0.70 mL/min. Amino columns separate on the basis of polarity: aliphatics elute first, followed by aromatic compounds of moderate polarity, which elute according to the number of condensed aromatic rings present (9). It should be noted that aromatic compounds with polar substituents were removed during the sulfuric acid treatment described above. In separate experiments, aliquots of a Clophen A50 solution were injected onto the HPLC column to establish a time of collection window for the Br-PCBs. Ultraviolet (vv)detection at 260 nm was used to follow the separation. PCBs were seen to elute between 6.6 and 14.5 min. According to Brinkman and de Vries, PCBs and PBBs are coeluting in straight-phase (i.e.,silica and alumina) HPLC (IO). Therefore, Br-PCBs are assumed to chromatograph similarly to PCBs, and the collectionwindowwas set to the same time range. Following this calibration, the samples were quantitativelyinjected onto the amino column using a Hitachi AS-4000 autosampler (HitachiLtd, Tokyo,Japan) equipped with a 100-pL sample loop. The obtained BrPCB fractions were fortified with 750 pg of syringe spike ([l3CI2]PCB101) and were concentrated into 40 p L of tetradecane keeper. The samples were then ready for examination by gas chromatographylmass spectrometry (GUMS). GCILow-ResolutionMS. Aliquots of 2pL, corresponding to x250 mg of blubber tissue, were on-column injected into a Hewlett-Packard 5880 gas chromatograph equipped with a 60-m fused silica capillarycolumn coated with a 5% phenylmethylsilicone phase (FTE5, 0.32 mm i.d., 0.25 pm film thickness: Supelco Inc., PA). Helium was used as the carrier gas at a head pressure of 16psi (1.1bar). Separations were achieved by temperature programming the oven from 200 "C (6 min) to 300 "C at 5 "Clmin and then isothermal for 5 min. The column was connected directly to the ion source of the mass spectrometer (interface temperature 250 "C). A Finnigan 4500 quadrupole mass spectrometer (Finnigan MAT, Sunnyvale, CA)was used for analyte detection. The mass spectrometer was operated in the electroncapture negative ion chemical ionization mode (ECNI) using 0.40 Torr (5.3 x bar) of methane buffer gas. ECNI is used because of its sensitivityand selectivity for analytes bearing substituents with high electron affinity, e.g., chlorine and bromine. The ion source temperature was held low (70"C) to suppress the dissociative electron capture processes, which lead to bromide (Br-) or chloride (C1-) ion formation and thereby increase the molecular ion (M-) abundance. Full-scan spectra were recorded (mlz 30-500, 2.0 slscan, 2802 1 ENVIRONMENTAL SCIENCE &TECHNOLOGY / VOL. 29, NO. 11,1995
TABLE 1
Ions Monitored for Br=PCB, [13C1dPCB 101, and Pedluarokerosene (Lock=Masses) during Accurate Mass Experiments and Qlrantification species BrCl biphenyls (ClzHsBrCI) BrC12biphenyls (C12H7BrCId BrCl3 biphenyls (C12HsBrCId BrCld biphenyls (CIZHSB~CI~)
BrC15biphenyls (C12H4BrCM
BrCls biphenyls (C12H3BrCId BrCI, biphenyls (ClzH~BrC17) BrCls biphenyls (C12HBrCls) BrClg biphenyls (C12HBrCld [13C121PCB101 ('3CizH~C15) perfluorokerosene
accurate mass (ions monitored) naa na na 369.8100: 369.8150: 369.8200; 369.8250; 369.8300; 369.8350; 369.8400; 369.8450; 369.8500 405.7700: 405.7750: 405.7800; 405.7850; 405.7900; 405.7950; 405.8000; 405.8050; 405.8100 na na na na na 380.9760
quantification (ions monitored) 265.9498,b M' 267.9477,b (M 2)301.9079,b ( M 2)' 303.9049,b (M 4)335.8689,b ( M 2)+ 337.8659,b ( M 4)+ 369.8299,b ( M 2)+ 371.8270,b(M 4 4)-
+ +
+
+ + +
403.7909,b ( M 405.7880,b ( M
+ 2)+ 4)+ + 2)+ 4)-
437.7520,c (M 439.7490,c ( M 473.7071,c ( M 475.7071,c ( M (M 507.671 l,c 509.6681,c ( M 541.6321,c ( M 543.6291,c ( M 337.9207,b M
+ 4)+ + 6)+ + 4)+
+ 6)+ + 4)+ + 6)+ + 21'
330.9792b 492.9696c
a na means not analyzed. b,c Masses monitored during the first and second, respectively, elution window of the ion monitoring program.
unit resolution) in order to collect all available information for target identification. GCIHigh-Resolution MS. A VG 250l 70s doublefocusing magnetic sector mass spectrometer (VGhalytical Ltd., Manchester, U.K.) was used for the accurate mass determination and quantification of the Br-PCBs. The ion source was operated in the electron ionization (EI, 35 eV, 250 "C) mode. Selected ion monitoring (SIM) at a resolution of 8000 (MIAM) was used for both accurate mass determination and quantification. GC equipment and chromatographic conditions were the same as for the GCllow-resolution MS experiments described above with one exception, splitless injection was used instead of oncolumn injection(injector temperature 220 "C,splitless time 2 min). During the accurate mass experiment, nine discreet masses were monitored for both the BrC4 and BrC15 biphenyls. These channels differed by 50 millimass units (mmu) and were centered around the theoretical mlz values, cf. Table 1and Figure 2. The masses were switched by changingthe acceleratingvoltage. This type of accurate mass exercise was used since the levels of Br-PCBs were too low to allow a conventional on-line peak matching experiment. The accuracy of the method has been validated by analyzing synthetic reference standards with molecular weights ranging between 250 and 650 u. The average error was f3 mmu ( p = 0.05). Quantification of the Br-PCBs was accomplished by monitoring the two most intense ions of the molecular ion clusters of native BrCl to BrC19 biphenyls and [13C12]PCB 101, cf. Table 1. To maximize sensitivity(due to the rather large mass range), the MS ion monitoring program was divided into two elution windows: the first for BrCl to BrC15
ct*
35
8.8-
5
HC12’
.II
37
71
148
biphenyls, and the second for BrCb to Be19 biphenyls. The ion monitoring programs were changed by magnet field switching. The quantification was performed using an external standard (4’-bromo-2,5-dichlorobiphenyl) assuming equal molar response factors of all Br-PCB congeners, hence reported results are semiquantitative. The syringe spike ([13C121PCB101) was used to compensate for instrumental variations.
Results and Discussion Identification of Br-PCBs. In Figure 1, the ECNI mass spectrum of a component found in the Baltic ringed seal sample with fragmentation indicative of a BrC15 biphenyl is shown. The base peak correspondsto bromide ion, with chloride ion also produced but at only half the intensity despite the fact that five chlorine atoms but only one bromine atom is present in the molecule. This observation is attributed to the relative ease of dissociativebromide ion formation (11). A moderately intense M- ion (mlz 402) with an isotope distribution characteristic of BrC15 is also observed. Major fragment ions occur at mlz324 (C15isotope distribution pattern), mlz 290 (Cl, pattern), and mlz 254 (Cb pattern). The isotope distribution patterns are in good agreement with the theoretical values, with deviations less than 5%for all clusters except C1 and Cb, which deviate by 10%. The 324 fragment can be attributed to postelectron capture reactions (M - Br + H)-of M- known to occur in ECNI sources employing a hydrocarbon-based buffer gas (12).The mlz 290 and 254 fragments are due to a similar, sequential process. The search for prospective brominated contaminants ultimately revealed the presence of BrCLBrC15-and BrCk-substitutedhomologs with characteristic BrCI, isotopic patterns.
e
c 8 e.
2000 1600 1200
800 400
04 405.770
405.780
405.790
405.800
405,810
mlz FIGURE 2. Graphical representation of the resultsfrom the accurate mass determination. The experiment indicates (a) d z 369.827 for the (M 2)+ of the BrCL compound, and (b) ndz405.790 for the (M 4)+ of the BrCls compound. Corresponding molecular weights of parent compounds are 367.830 and 401.796 u, respectively.
+
+
The accurate mass determinationof the B e l , - and B e l 5 substituted compounds indicated molecular weights of 367.830 and 401.796 u, respectively (cf. Figure 2a,b). These values are close to the theoretical molecular weights of BrCL biphenyls (367.832 u) and BrC15 biphenyls (401.794 u), respectively, with exceptional agreement particularly VOL. 29. NO. 11.1995 I ENVIRONMENTAL SCIENCE & TECHNOLOGY 12803
io
30
25
20
1‘5
min
Retention Time
TABLE 2
levels of Br=PCBs in Ringed Seal (Phoca hispida) and Technical PCB (Clophen A50)a levels in ng/gb ringed seal av (4 Clophen A50
species
trial I
XBrC12 biphenyls XBrCI3 biphenyls XBrCI4 biphenyls XBrCI5 biphenyls XBrCle biphenyls XBrC17 biphenyls XBrCIB biphenyls
ndc
nd
nd
0.62
0.80
5.4
6.5
0.71 6.0
210000
16
18
88000
1.0 0.15 nd
19 1.o nd nd
0.10 nd
nd nd nd
23
28
26
300000
total XBr-PCBs
1.o
nd nd
a A detailed description on the El/high-resolution instrumentation and conditions are given in the Experimental Section. Based on lipid weight (seal) or total product weight (Clophen A50). nd means not detected (the detection limit was 0.10 ngig).
for BrC15 biphenyl. Since both the mass spectra and the accurate mass determinations were in agreementwith the tentative structures, it was concluded that the compounds studied are indeed Br-PCBs. Retention time comparisons to reference Br-PCB standards would provide additional evidence, but unfortunately few are presently available. However, in Figure 3,the obtained GC retention times of the Br-PCBs are compared with those of PCBs. It is seen that PCB elution times increase proportionally with the number of C1 substituents added. The retention time increase due to a Br substituent is expected to be about the same as that of two C1 substituents, e.g., BrC15biphenyls are expected to elute very near to or with the C17biphenyls. Buser reported this substituent dependence in the elution temperatures for awidevariety ofbrornoIchloro-substituted aromaticcompounds, including Br-PCBs (11). Thus,mass spectral fragmentations and elemental compositionsas well as the expected GC elution behavior in the absence of authentic reference standards convincingly support the postulated structures. Quantification of Br-PCBs in Baltic Ringed Seal and Clophen A50. Table 2 gives the concentration data for Br-PCBs expressed in nanograms per gram of extracted lipid (seal)or total weight (ClophenA50). The ringed seal samples contain a series of Br-PCBs,viz., BrC12-BrC17. The total concentrations of Br-PCBsin the duplicate ringed seal sample (trials I and 11) were 23 and 28 nglg, respectively, with the BrC15 biphenyls comprising most (-70%) of the 2804
10
25 mln
Retention Time
FIGURE 3. Comparison of the ges chromatographic retention times of PCB (solid lines) and Br-PCB (broken lines).
trial II
IS
ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 29, NO. 11, 1995
FIGURE 4. Mass fragmentograms of Br-PCB found in ringed seal blubber. The peaks denoted with an asterisk (“1 showed an incorrect isotopicratio. Peeks marked with 170 and 180 are interfering signals from PCBs 170 and 180, respectively.The chromatographic and mass spectrometricconditionsare described in the ExperimentalSection.
total. The average concentration (3is 26 nglg. Total PCB in ringed seal is normally 1000-foldhigher (-20 pg/gl (13) in this region. However, the Br-PCB concentrations reported in Table 2 must be considered as minimum values since the EI-MS molar response factor (RF)of the internal standard (4’bromo-2,5-dichlorobiphenyl)is probably higher than the RF of the target Br-PCBspresent in the samples. The relative abundance of the Br-PCB molecular ions depend on the degree of fragmentation,which is expected to increase with increasing chlorine substitution (due to steric effects that weaken the C-C1 and especially the C-Br bonds). Thus, this effect causes a bias in the RFs and leads to an underestimation of the Br-PCB concentrations. Another factor that may bias the experimentalresults is the large number of possible congeners that exist for the Br-PCBs (837 vs 209 PCB congeners). The effect of more possible congeners is an increased detection limit for the Br-PCBs compared to the PCBs. Considering these potential sources of underestimation, the total Br-PCB levels probably exceed the presently estimated levels. The BrPCB levels found in this investigation appear intermediate between those for dioxins and PCBs and clearly contribute to the total body burden of persistent organic pollutants in seal. Mass fragmentogramsfrom the analysis of Br-PCBs in ringed seal are shown in Figure 4. As can be seen, the Br-PCBsveryoftenelute close together intime. The clusters probably originate from very similar parent PCB precursors with the bromine substituent in different positions. Eventual isomer-speci6canalysiswill be an extremelyformidable task because of the minor structural differences and the many isomeric forms possible for the Br-PCBs. In the technical PCB (Figure 51, only BrCL and BrCl5 biphenyls could be detected due to interferingsignals from the PCBs. The estimated concentrations are 210 and 88 pglg, respectively. Thus, a reversed ratio of tetra- and pentachloro homologs is observed in Clophen A50 compared to the ringed seal. The total Br-PCB concentration was 300,ug/g. Some of the chromatographicpeaks showed incorrect isotopic ratios (seeasterisks in Figure 5) and were therefore not included in the quantification. The amount of Br-PCB found in Clophen A50 is 1 order of magnitude
identity. The present study adds Br-PCB to the list of brominated compounds that are present in environmental samples, as seen bytheir presence in seal. Efforts to further characterize additional unidentified compounds that have been detected in Baltic ringed seal continue, topics that will be addressed in subsequent publications.
Acknowledgments
16
1'a
20
min
Retention Time
FIGURE 5. Mass fragmentograms of Br-PCBs found in ringed seal blubber and a technical PCB product (Clophen A50). The peaks denoted with an asterisk (") showed an incorrect isotopic ratio. The chromatographicand mass spectrometric conditions are described in the experimental section.
lower than the amount that has previously been found in Aroclor 1254 (11). No Br-PCBs could be detected in the procedural blank, and it can thus be concluded that the target compounds are not laboratory artifacts. Potential Environmental Sources of Br-PCBs. There exist a number of possible sources of Br-PCBs. Buser has reported BrClS, BrClG, and BrC1, biphenyls as trace contaminants in a technical PCB formulation,viz. Aroclor 1254 (11). The total concentrationwas estimated at 0.5% (wlw). Furthermore, a wide spectrum of mixed bromo/chloro derivatives, such as benzenes, biphenyls, dibenzofurans, and dibenzo-p-dioxins,are formed during municipal solid waste (MSW) and chemical waste incineration (14-18). Mainly monobromopolychloro derivatives of these compounds are formed duringthese processesprobablybecause of a high CUBr ratio in the waste. Motor vehicles fueled with leaded gasoline, containing dibromo- and dichloroethane as scavenger additives, also emit mixed bromo/ chloro-substituted aromatic compounds, e.g., mono- and dibromopolychlorodibenzo-p-dioxins and dibenzofurans, tribromomonochlorodibenzofurans (19, 201, and monobromomonochloro-, monobromodichloro-, and dibromomonochloro-substituted polycyclic aromatic hydrocarbons (PAH) (21). Since elevated levels of PCB have been found in traffic related samples (22, 231, Br-PCBs are potentially also formed in combustion engines. In Figure 5, mass fragmentograms from the analysis of BrC14 and BrClS biphenyls in ringed seal and Clophen A50 are compared. A number of common peaks are found in the fragmentograms. It is therefore plausible that technical PCB products are a source of Br-PCBs found in the seal blubber. Some recent investigations have shown that environmental samples contain a great number of brominecontaining compounds (21, 24, 25). Some of these have been identified as brominated flame retardants, viz. polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDPE),but most of them are of unknown
Mats Olsson of the Swedish Museum of Natural History is acknowledged for kindly providing us with the ringed seal samples. The project was financially supported by the Swedish Environmental Protection Agency "Persistent Organic Pollutants" scientific program.
Literature Cited (1)Safe, S. CRCCrit. Rev. Toxicol. 1984,13,319. (2) Safe, S.; Parkinson, A.; Robertson, L.; Bandiera, S.; Sawyer, T.; Safe, L.: Lambert, I.; Andres, J.; Carnubell, M. A. Deu. Biochem. 1982,23,441. (31 Bandiera, S.; Sawver, T.; CamDbell, M. A.; Fuiita, T.; Safe, S. Biochem. Pharm&ol. 1983,32;3803. (4)Andres, I.; Lambert, I.; Robertson, L.; Bandiera, S.; Sawyer, T.; Lovering, S.; Safe, S. Toxicol. Appl. Pharmacol. 1983,70,204. (5)Safe,S.;Bandiera,S.;Sawyer,T.;Zmudzka,B.;Mason,G.;Romkes, M.; Denomme, M. A.; Sparling, J.; Okey,A. B.; Fujita, T. Enuiron. Health Perspect. 1985,61,21. (6) Stalling, D. L.; Smith, L. M.; Petty, J. D.; Hogan, J. W.; Johnson, J. L.; Rappe, C.; Buser, H. R. Human and Environmental Risks of Chlorinated Dioxins and Related Compounds, 1st ed.; Plenum Press, New York, 1983;p 221. (7)Jensen, S.;ReutergBrdh, L.; Jansson, B. FA0 Fish. Tech. Pap. 1983,212,21. (8) Nygren, M.; Hansson, M.; Sjostrom, M.; Rappe, C.; Kahn, P.; Gochfeld, M.; Velez, H.; Ghent-Guenther, T.; Wilson, W. P. Chemosphere 1988,17,1663. (9)Colmsj6, A.L.; Zebiir, Y.; Ostman, C. E. Chromafographia1987, 24,541. (10)Brinkman, U.A. Th.; deVries, G. J. Chromafogr.1979,169,167. (11)Buser, H.-R. Anal. Chem. 1986,58, 2913. (12)Sears, L. J.; Campbell, J. A.; Grimsund, E. P. Biomed. Enuiron. Mass Specfrom. 1987,14,401. (13)Blomqvist, G.;Roos, A.; Jensen, S.; Bignert, A.; Olsson, M. Ambio 1992,21,539. (14)Schafer, W.; Ballschmitter, K. Chemosphere 1986,15, 755. (15)Oberg, T.; Warman, K.; Bergstrom, J. Chemosphere 1987, 16, 2451. (16)Hosseinpou, J.; Schwind, K. H.; Thoma, H. Chemosphere 1989, 19,109. (17)Tong, H. Y.;Monson, S. L.; Gross, M. L.; Huang, L. Q. Anal. Chem. 1991,63,2697. (18)Huang, L. Q.;Paiva, A.; Tong, H.; Monson S. J.; Gross, M. L. J. Am. SOC. Mass Specfrom. 1992,3,248, (19)Hagenmaier, H.; Dawidowsky, N.; Weberuss, U.; Hutzinger, 0.; Schwind, K. H.; Thoma, H. D.; Essers, U.; Biihler, U.; Greiner, R. Orgunohalogen Compounds, Vol. 2; Ecoinforma-Press: Bayreuth, Germany, 1990;p 329. (20) Schwind, K. H.; Thoma, H.; Hutzinger, 0.; Dawidowsky, N.; Weberuss. U.: Haaenmaier, H. Umweltwiss. Schadst.-Forsch. 1991,3,291. (21)Haalund. P.;Alsbera, T.; Bergman, A.; Jansson, B. Chemosphere 198u7,16,2441. (22) Granier, L.; Chevreuil, M. Chemosphere 1991,23,785. (23)Ohsaki, Y.;Matsueda, T. Chemosphere 1994,28, 47. (24)Jansson, B.; Asplund, L.; Olsson, M. Chemosphere 1987,16,2343. (25)Kuehl, D. W.; Haebler, R.; Potter, C. Chemosphere 1991,22,1071.
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I
Received for review March 3, 1995. Revised manuscript received June 7, 1995. Accepted June 7, 1995.@
ES9501474 @Abstractpublished in Advance ACS Abstracts, July 15, 1995.
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