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Wagner, P. J. J . Chem. Phys. 1966,45, 2335-2336. Merkel, P. B.; Kearns, D. R. J . Am. Chem. SOC.1972,94,
(41) Howard, J. A.; Scaiano, J. C. Landolt Bornstein New Series, Kinetic Rate Constants of Radical Reactions in Solution: Part d , Oxyl-, Peroxyl-, and Related Radicals; SpringerVerlag: Berlin-Heidelberg, 1984; Series II/13d. (42) Paris, D. F.; Wolfe, N. L.; Steen, W. C.; Baughman, G. L. Appl. Enuiron. Microbiol. 1983, 45(3), 1153-1155. (43) Rubin, H. E.; Alexander, M. Enuiron. Sci. Technol. 1983, 17, 104-107. (44) Subba-Rao, R. V.; Rubin, H. E.; Alexander, M. Appl. Enuiron. Microbiol. 1982, 4 3 ( 5 ) , 1139-1150. (45) Hendry, D. G.; Mill, T.; Piszkiewicz, L.; Howard, J. A.; Eigenmann, H. K. J . Phys. Chem. Ref. Data 1974, 3,
1029-1030.
Rodgers, M. A. J.; Snowden,P. T. J. Am. Chem. SOC.1982, 104, 5541-5543.
Haag, W. R.; Mill, T. Photochem. Photobiol.
1987, 45, 317-321. Haag, W. R.; Hoign6, J.; Gassmann, E.; Braun, A. M. Chemosphere 1984, 13, 631-640.
Das, P. K.; Encinas, M. V.; Steenken, S.; Scaiano, J. C. J . Am. Chem. SOC.1981, 103, 4162-4166. Das, P. K.; Encinas, M. V.; Scaiano, J. C. J. Am. Chem. SOC. 1981, 103, 4154-4162. Zepp, R. G.; Schlotzhauer, P. F.; Sink, R. M. Enuiron. Sci. Technol. 1985, 19, 74-81. Burton, G. W.; Doba, T.; Gabe, E. J.; Hughes, L.; Lee, F. L.; Prasad, L.; Ingold, K. U. J . Am. Chem. SOC.1985,107, 7053-7065.
937-978. Received for review September 23, 1986. Accepted May 29,1987. This work was supported by the Presidential Foundation of the Swiss Federal Institute of Technology under the project title “ Abiotische photochemische Oxidationsprozesse in Gewassern”.
Polychlorinated Dibenzofurans and Dibenzo-p -dioxins and Other Chlorinated Contaminants in Cow Milk from Various Locations in Switzerland Chrlstoffer Rappe, Martin Nygren, and Gunilla Lindstrom Department of Organic Chemistry, University of UmeA, S-901 87 UmeA, Sweden
Hans Rudolf Buser Swiss Federal Research Station, CH-8820 Wadenswil, Switzerland
Otto Blaser and Claude Wuthrlch Swiss Federal Office of Public Health, CH-3000 Bern, Switzerland
Six samples of cow milk from various locations in Switzerland were analyzed for polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxins (PCDDs), and other chlorinated contaminants. Sub parte per trillion levels of 2,3,7,8-substituted PCDFs and PCDDs were found in all samples. The levels were higher in samples collected in the vicinity of incinerators. Non2,3,7,8-substituted PCDDs and PCDFs were not found in the milk samples.
Table I. Most Toxic PCDD and PCDF Isomers
Introduction
from Europe, USA, Canada, and Asia have confirmed these original findings. However, for many years the interest was focused on the analysis of fly ash samples and not on the analysis of actual emissions, probably due to sampling difficulties. Most of the analyses of emissions from incinerators have been done with nonvalidated and non-isomer-specific sampling and analytical methods. Recent studies show the presence of a multitude of PCDD and PCDF congeners, in the emission samples (6). Moreover, a striking similarity in the isomeric pattern of PCDDs and PCDFs was found between samples from different incinerators (6, 7). Various models have been used to convert a multitude of levels of more or less toxic PCDDs and PCDFs into a more simple expression like “TCDD equivalents” or “toxic equivalents” (8). In Sweden and in this paper, the approach discussed by Eadon et al. (9) has been used. Emissions from MSW incinerators operating under good condition are in the range of 1-100 ng of TCDD equivi normalized m3 (9, lo), resulting in total annual emissions of 1-100 g of TCDD equiv from a normal size MSW incinerator (50-200000 tons of waste/year). The major chlorine source in the MSW is plastic material such as
The polychlorinated dibenzo-p-dioxins (PCDDs) and the polychlorinated dibenzofurans (PCDFs) are two groups of compounds that exhibit similar chemical and physical properties; the chemical structures are given in Figure 1. The number of chlorine atoms in these compounds can vary between one and eight ( x y = 1-8, see Figure 1)to produce 75 PCDD and 135 PCDF positional isomers. Twelve of these isomers have strong toxic effects ( I ) , specifically 2,3,7,8-tetra-CDD but also other 2,3,7,8-substituted PCDDs and PCDFs with four, five, and six chlorine atoms. They are listed in Table I. In 1977, Olie et al. (2) reported on the occurrence of PCDDs and PCDFs in fly ash from municipal incinerators in The Netherlands. Although their results indicated the presence of up to 17 PCDD peaks, quantification or isomer identification was not possible because of the lack of synthetic standards. In a series of papers, Buser et al. (3-5) investigated fly ash from a municipal solid waste (MSW) incinerator and an industrial heating facility, both in Switzerland. A series of PCDDs and PCDFs were identified, and the levels in fly ash were in the range of 0.1-10 pgig total PCDDs and PCDFs. Since then, many reports
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PCDDs 2,3,7,8-tetra-CDD 1,2,3,7,8-penta-CDD 1,2,3,6,7,8-hexa-CDD 1,2,3,7,8,9-hexa-CDD 1,2,3,4,7,8-hexa-CDD
PCDFs 2,3,7,8-tetra-CDF 1,2,3,7,8-penta-CDF
2,3,4,7,8-penta-CDF 1,2,3,6,7,8-hexa-CDF 1,2,3,7,8,9-hexa-CDF 1,2,3,4,7,8-hexa-CDF 2,3,4,6,7,8-hexa-CDF
0013-936X/87/0921-0964$01.50/0
0 1987 American Chemical Society
Table 111. Ions Used for Detection and Quantification of PCDDs and PCDFs in GC/MS Analyses 4 Cly
PCDDs
* CiY
-
CIX"
'
PCDFs
Figure 1. Structures of PCDDs and PCDFs.
Table 11. Analytical Data on Milk Samples sample no.' 1 2 3 4 5 6
amount of milk, g
extracted fat, g
601.09 600.08 600.25 600.82 603.13 601.49
23.90 26.20 25.70 26.88 19.12 20.99
blank
amount of fat for g
%
21.40 23.66 23.23 24.27 16.69 18.34
89.54 90.31 90.39 90.29 87.29 87.37 92.0
OFor origin of the samole. see text.
PVC and bleached and unbleached paper. New technologies are now available to reduce these emissions. In April 1984, Rappe et al. (10) reported on a series of the toxic 2,3,7,8substituted PCDDs and PCDFs in samples of human adipose tissue from Northern Sweden. A series of reports presented at the dioxin conferences in Ottawa, Canada, in October 1984, Miami, FL, in April 1985, and in Bayreuth, West Germany, in September 1985 confirmed these observations, and it is clearly shown that there is a background of PCDDs and PCDFs in the general human population in the industrialized part of the world. In April 1984, Rappe et al. also reported on the analysis of five samples of breast milk from West Germany (10). Later data from Sweden, Denmark, The Netherlands, Yugoslavia, and Vietnam have also been published (11) indicating the same background in the general population. It is generally accepted that the major route of exposure to these compound is via food. The same 2,3,7,8-substituted PCDDs and PCDFs have been identified in ppt levels in fish from the Baltic Sea and The Great Lakes (12, 13). In this paper we report on ppt levels or below of these congeners in samples of cow milk from Switzerland. Experimental Section Milk Samples. The following six milk samples (about 1 L each) were collected by the provincial authorities: (1) Consumer's milk, pasteurized from Bern, Switzerland. This was a pooled control sample. (2) Milk from a single cow in Bowil, BE, Switzerland. Bowil is situated 9 km from the community of Langnau and 16 km from a small MSW incinerator (Krauchtal) and 20 km from a larger MSW incinerator, Bern. (3) Milk from the local dairy in Bowil, BE (13 producers). This was a pooled control sample. (4) Milk from a single cow in Hunzenschwil, AG, Switzerland. The farmland is situated 200-1000 m SE from a typical middle-sized MSW incinerator (40 000 ton/year), Buchs, AG. (5) Milk from a single cow in Suhr, Switzerland. The farmland is situated 300-1000 m SW from the same incinerator as in sample four. (6) Milk from a single cow in Rheinfelden, AG, Switzerland. The farmland is situated 1000 m SE from Rheinfelden, FRG, a production site for various chlorinated products. (7) Blank sample treated as a cow milk sample. The amount of milk analyzed is given in Table 11.
a
compound
mode
tetra-CDFs penta-CDFs hexa-CDFs hepta-CDFs octa-CDF penta-CDDs hexa-CDDs hepta-CDDs octa-CDD [13C,z]-2,3,7,8-tetra-CDF [ '3Cl,]octa-CDD tetra-CDDs [13Cl,]-2,3,7,8-tetra-CDD
NICI NICI NICI NICI NICI NICI NICI NICI NICI NICI NICI E1 E1
ions monitored" 304 338 372 406 442 354 353 387 423 318 435 320 332
(M-), 306 (M-), 340 (M-), 374 (M-), 408 (M- + 2), 444 (M-), 356 (M- - Cl), 355 (M- - Cl), 389 (M- + 2 - Cl), 425 (M- + 2) (M- + 2 - C1) (M') (M')
Ion used for auantification is italicized.
Extraction Procedure. The milk samples were extracted in two portions of about 300 mL each. Each milk portion was fortified with 500 pg of [ 13C]-2,3,7,8-tetra-CDD. Thereafter, 3 g of sodium oxalate dissolved in 50 mL of boiling water, 300 mL of ethanol, and 125 mL of diethyl ether were added. After vigorous shaking, 175 mL of nhexane was added, and the mixture was then shaken again. After separation of the two phases, the aqueous layer was reextracted twice with 100-mL portions of n-hexane. The combined extracts were washed twice with 200 mL of water each and dried by passage through a column of sodium sulfate. The solvent was evaporated until a constant weight was obtained, and the amount of fat was recorded (Table 11). A portion of about 10% of the dried material was removed for pesticide analyses. The remaining portion (18-24 g of milk fat, Table 11) was used for the analyses of PCDDs and PCDFs. Determination of PCDDs and PCDFs. For the analyses of milk fat we have used the cleanup method discussed in detail by Smith et al. (14). This procedure involves passing the sample through five chromatographic columns in sequence, and the key step in this procedure is a column of carbon dispersed on glass fibers. This column adsorbs most planar polynuclear polychlorinated aromatics and allows the major portion of biological coextractants to pass through. Along with similar chemicals, the PCDDs and PCDFs are then removed from the carbon column by reverse elution with toluene. Due to differences in column material and solvent quality between Europe and the U.S., some slight modifications of the Stalling-Smith sample workup methods have been introduced in our laboratory (to be published). The modified method has recently been verified by analyzing blanks and fish samples fortified at two different levels (15) and also by analyzing samples of cow milk and human milk fortified at three different levels (to be published). Before cleanup the milk fat extracts (18-24 g) were fortified with 500 pg each of [l3CI2]-2,3,7,8-tetra-CDFand ['3C,2]octa-CDD. After cleanup the extracts were analyzed by gas chromatography-mass spectrometry using high-resolution fused silica or glass capillary columns specific for 2,3,7,8substituted PCDDs (16) and PCDFs (1). The instruments, columns, and conditions were as follows: A Finnigan 4023 instrument with a 4500 ion source operating in the negative ion chemical ionization mode (NICI) was used for tetra- to octachlorinated dibenzofurans and penta- to octachlorinated dioxins. For the chromatographic separation, we used a 60-m SP 2330 fused silica column. The temperature program for the GC oven was 100 "C isothermal for 2 min, then 100-180 "C (20 deg/ min), followed by 180-260 "C (3 deg/min). The temperEnviron. Sci. Technol., Voi. 21, No. 10, 1987
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Table IV. PCDF and PCDD Content of Swiss Cow Milk from Various Locations" compound recovery of [13C]-2,3,7,8-tetra-CDF,90 recovery of [13C]-2,3,7,8-tetra-CDD, % recovery of [13C]octa-CDD,% 2,3,7,8-tetra-CDF 1,2,3,7,8-penta-CDF 2,3,4,7,8-penta-CDF 1,2,3,4,7,8-hexa-CDF 1,2,3,6,7,8-hexa-CDF 2,3,4,6,7,8-hexa-CDF 1,2,3,4,6,7,8-hepta-CDF octa-CDF 2,3,7,8-tetra-CDD 1,2,3,7,8-penta-CDD 1,2,3,4,7,8-hexa-CDD 1,2,3,6,7,8-hexa-CDD 1,2,3,7,8,9-hexa-CDD 1,2,3,4,6,7,8-hepta-CDD octa-CDD
blank 65 80 86 ND ND ND ND ND ND ND ND ND ND ND ND ND ND
(
