Environ. Sci. Technol. 1905, 19, 736-740
Katz, U. “Communications a la gemeConference sur la Physique des Nuages”;Laboratoire Associe de Meteorologie Physique: 63170 Aubiere, France, 1980; pp 697-700. Nagamoto, C. T.; Parungo, F.; Reinking, R.; Pueschel, R.; Gerish, T. Atmos. Enuiron. 1983, 17, 1073-1082. Waldman, J. M. Ph.D. Dissertation, California Institute of Technology, Pasadena, CA, 1985. Friedlander, S. K. Environ. Sci. Technol. 1973, 7,235-240. Cooper, J. A.; Watson, J. G., Jr. J. Air Pollut. Control Assoc. 1980,30, 1116-1125.
Weast, R. C., Ed. “Handbook of Chemistry and Physics”, 56th ed.; CRC Press: Cleveland, OH, 1975; p F-199. Miller, M. S.; Friedlander, S. K.; Hidy, G. M. J. Colloid Interface Sci. 1972, 39, 165-176. Jacob, D. J. Ph.D. Dissertation, California Institute of Technology, Pasadena, CA, 1985. Unger, C. D. “An Analysis of Meteorological and Air Quality Data Associated with the Occurrence of Fogwater with High Acidity in the Los Angeles Basin”; California Air Resources Board, Sacramento, CA, July 18, 1984, memorandum. Brown, H. W. “An Analysis of Air flow over the Southern California Bight and Northern San Diego County on January 8, 1983”. San Diego Air Pollution Control District, San Diego, CA, 1983. Rosenthal, J.; Battalino, T. E.; Hendon, H.; Noonkester, V. R. Pacific Missiles Test Center, Pt. Mugu, CA, 1979, Technical Publication TP/79/33.
Atkinson, R.; Perry, R. A.; Pith, J. N., Jr. Chem. Phys. Lett. 1978,54, 14-18.
Nguyen, B. C.; Bonsang, B.; Gaudry, A. J. Geophys. Res. 1983,88, 10903-10914.
Jacob, D. J.; Munger, J. W.; Waldman, J. M.; Hoffmann, M. R. Proceedings of the 77th Annual Meeting of the Air Pollution Control Association, San Francisco, CA, Air Pollution Control Association, Pittsburg, PA, 1984, paper 24-5.
Martens, C. S.; Welosowski, J. J.; Harriss, R. C.; Kaifer, R. J. Geophys. Res. 1973, 78, 8778-8792. Hitchcock, D. R.; Spiller, L. L.; Wilson, W. E. Atmos. Environ. 1980, 14, 165-182. Eriksson, E. Tellus 1960, 12, 63-109. Robbins, R. C.; Cadle, R. D.; Eckhardt, D. L. J. Met. 1959, 16,53-56.
Finlayson-Pith, B. J. Nature (London) 1983,306,676-677. Latimer, W. D. “The Oxidation States of the Elements and Their Potentials in Aqueous Solutions”, 2nd ed.; Prentice-Hall: New York, 1952. Kritz, M. A,; Rancher, J. J . Geophys. Res. 1980, 85, 1633-1639.
Received for review September 17,1984. Accepted February 12, 1985. This research was funded by the California Air Resources Board (Contract A2-048-32).
Identification of New, Fluorinated Biphenyls in the Niagara River-Lake Ontario Area Rudolf Jaffe and Ronald A. Hltes” School of Public and Environmental Affairs and Department of Chemistry, Indiana University, Bloomington, Indiana 47405
Sediment and fish samples from the Niagara River and Lake Ontario were analyzed by capillary gas chromatographic mass spectrometry using negative ion methane chemical ionization. A series of bis(trifluoromethy1)-substituted polychlorinated biphenyls was discovered. These compounds were present in fish as well as in sediments, and their major source seems to be the Hyde Park dump in the city of Niagara Falls, NY.
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Introduction Several hazardous waste disposal sites are located along the shores of the Niagara River. Most of these sites are located in the city of Niagara Falls and are known to pollute the Niagara River (1). This is unfortunate because the Niagara River is the major water source for Lake Ontario; 83% of Lake Ontario’s total water input and 50% of the lake’s annual suspended solid load enter through the Niagara River each year (2). As a result, anthropogenic pollutants have been found to be transported by the Niagara River to Lake Ontario and to accumulate in the sediment (3-8) and in fish and other aquatic organisms (9-14). A large percentage of the toxic wastes placed into the dumps in the city of Niagara Falls consisted of halogenated organic compounds (15), a significant (but unknown) fraction of which were fluorinated chemicals. Some of these fluorinated organic compounds have previously been identified in sediment from the Bloody Run Creek (1)and in fish from the Niagara River (9). Bloody Run is a small creek that drains the Hyde Park dump in Niagara Falls. This hazardous waste disposal site was operated by the Hooker Chemical Co. from about 1953 736
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to 1975. Approximately 55 000 tons of halogenated waste was buried at the site, and of this, about 10% was liquid and solid waste from Hooker’s production of 4-chloro(trifluoromethy1)benzene (15). Therefore, it is not surprising that a variety of fluorinated organic compounds were detected in sediments of Bloody Run Creek (1). The two most abundant were compounds 1 and 2; they were C
l
a
C
O
b
C
i
O
F
cF3 1
&
) CF3
2
shown to be byproducts from the synthesis of 4-chloro(trifluoromethy1)benzeneand seem to come from the Hyde Park dump (1). These two compounds were also detected in sediments from the western and central sedimentation basins of Lake Ontario itself (8). This paper reports on some related, potentially persistent, fluorinated organic compounds that were discovered through analyses of Niagara River and Lake Ontario sediment and fish. Experimental Section Sediments. Lake Ontario sediment cores were taken from the major sedimentation basins: the Niagara, Mississagua, Rochester, and Kingston Basins. Sampling was done in Aug 1982 by researchers at the National Water Research Institute of the Canada Centre for Inland Waters at Burlington, Ontario; sampling was carried out from the CSS Limmos. The sediment grab sample from Bloody Run Creek was obtained with the cooperation of the New York State Department of Environmental Conservation
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79"
I
78"
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77"
Figure 1. Map of Lake Ontario and Nlagara River (inset) showing sampling sites in Lake Ontarlo as well as the major dump sites near the Niagara River.
in 1979. Grab samples from the creek system adjacent to the Love Canal (Black Creek, Bergholtz Creek, Cayuga Creek, Little Niagara River, and 102nd Street Bay) were taken in June 1983. All samples were immediately labeled and refrigerated until analysis. Locations of the dumps and sampling sites are shown in Figure 1. The sediment workup procedure has been discussed in detail elsewhere
-.
I
(8).
To establish the complexity, concentration range, and presence of halogenated aromatics, the samples were first analyzed on a Hewlett-Packard 5730 gas chromatograph, equipped with a fused silica SE-54,30-m capillary column and simultaneous flame ionization-electron capture detection. Qualitative analyses were carried out on a Hewlett-Packard 5985B GC/MS modified to bring a DB-5, 30-m capillary column directly into the ion source (16). Electron impact (EI), methane chemical ionization (CI), and negative ion methane chemical ionization (NCI) modes were used for qualitative analyses. Quantitation was done in the NCI mode with the ion source at 100 "C and 0.8 torr. The GC oven temperature was programmed from 40 "C for 4 min to 280 "C for 30 min at 4 "C/min. Injector and transfer line temperatures were set a t 280 and 285 "C, respectively. Quantitation was based on an internal standard, 2-chloro-5-(trifluoromethyl)benzophenone, purchased from PCR, Inc. Since commercial standards are not available for the compounds studied, the response factors vs. the internal standard were assumed to be unity. Blanks were run through all procedures, and no significant contamination was observed. Fish. Fish from the Niagara River and Lake Ontario were sampled by the New York State Department of Environmental Conservation in the fall of 1979. Fish from the Little Niagara River were taken in June 1983. Fish samples were immediately frozen and kept frozen until analysis. All fish were sedentary species such as carp and bass (except for a few Lake Ontario salmon); thus, they serve as site-specific biological indicator organisms (17). The fish were analyzed by using the following procedure. A minimum of 30 g of fish was added to a blender. Preextracted, dehydrated sodium sulfate was added and
Flgure 2. Synthesis of 2,2'-dichioro-5,5'-bis(trifluoromethyi)biphenyl.
mixed with the fish until a powdery and free-flowing texture was obtained. This mixture was then placed in a preextracted cellulose thimble and Soxhlet extracted for 24 h with 250 mL of a 1:l solution of nanograde hexane and acetone. The final extract was reduced to about 10 mL by rotary evaporation. A 50-pL sample of this final extract was placed on a preweighed 2-cm2 piece of aluminum foil to determine the fat content of the extract. The solvent was allowed to evaporate for a period of at least 12 h before the foil was reweighed. Gel permeation chromatography was used to separate the lipids from the anthropogenic fraction (18). On the basis of the lipid content of the extract, a volume containing no more than 500 mg of lipids was injected into a 5-mL loop injector using a glass syringe. Through this injection system, the sample was loaded onto a 2.5 X 38 cm chromatographic column containing SX-2 (200-600 mesh) Biobeads which had been swollen overnight in a 3 2 solution of cyclohexane and methylene chloride. This same solvent was used for elution. The bed height was maintained at a constant level by using a Teflon plunger. Solvent flow was regulated at 4 mL/min by using a magnetic drive, Teflon gear, LC pump from Micro-pump. To be able to differentiate between the fat and anthropogenic fraction, a fixed wavelength (254 nm) UV flow detector from LDC/Milton Roy was used. The volume of the anthropogenic fraction was reduced to 0.5 mL for GC and GC/MS analysis, as described above. Synthesis of Dichlorobis(trifluoromethy1)biphenyl. This compound was synthesized by using a method similar Environ. Sci. Technol., Vol. 19, No. 8, 1985
737
to that used for polychlorinated biphenyls. The general scheme of the synthesis is shown in Figure 2. Twenty grams of 2-chloro-5-(trifluoromethyl)anilinewas dissolved in 6 M HC1. The temperature of the solution was maintained below 5 "C by using an ice bath. An ice-cooled solution of 8 g of sodium nitrite in 38 mL of water was added slowly in 2-3-mL portions to the stirred solution. The temperature of the solution was kept below 10 "C during the addition. A solution of 18 g of potassium iodide in 20 mL of water was then added slowly, while stirring, to the previous solution. The solution was allowed to stand for 3 h to eliminate the remaining N2. The mixture was then heated in a hot water bath until no more gas evolution was observed. The aqueous layer was decanted off, and the organic layer was extracted with methylene chloride. Finally, the methylene chloride extract, containing the iodo compound, was refluxed at 230 "C for 3 h in the presence of activated copper powder. The solution was analyzed by GC/MS in the NCI mode with the ion source at 100 "C and in the E1 mode. The GC retention time and the NCI and E1 spectra agreed with those found in our samples (see below). Small amounts of tri- and tetrachloro congeners were also observed in the synthetic mixture, possibly due to the presence of dichloro-5-(trifluoromethyl)aniline as a contaminant of the starting material.
1
E'
I
/
/I M-LCI
M-CI
I 200
220
240
260
I
280
300
320
340
360
4 10
380
M/Z
I
MtC2H5-HF
\
I d
1.8
Results and Discussion The concentrations of the fluorinated compounds in the various sediment and fish samples from the Niagara River-Lake Ontario system are listed in Table I. Compound 1 is the previously identified dichloro(trifluoromethy1)benzophenone, and compound 2 is the previously identified dichloro(trifluoromethy1)difluorodiphenylmethane ( I ) . Compound 3 has not been reported before. It is present
r
1
M-34
3
5
L
-J
3
in the sediment and fish samples as a series of chlorinated homologues, having from one to five chlorine atoms; there are several isomers of each homologue. The structures are analogous to a series of polychlorinated biphenyls (PCBs) except that two of the positions on the ring are occupied by two trifluoromethyl groups. The most abundant of these compounds contained two chlorine atoms. These fluorobiphenyls were identified by GC/MS using electron impact (EI), methane chemical ionization (CI), and negative ion methane chemical ionization (NCI) modes. E1 and methane CI mass spectra for the most abundant dichloro isomer are shown in Figure 3. The E1 spectrum (see Figure 3, top) clearly shows a two chlorine isotopic cluster at m/z 358. The presence of fluorine atoms is indicated by losses of 19 (F), 20 (HF), and 69 (CF,) to give ions at m / z 339,303, 254, and 219. The high abundance of the ion at m/z 358 is an indication of the aromatic nature of the compound. Molecular weight information is confirmed by the methane CI spectrum shown in Figure 3 (bottom). The formation of adduct ions such as M + H at m/z 359 and M + C2H, at m/z 387 are evidence that 358 is the molecular ion. The loss of HF from the M + H ion to give the most abundant ion at m / z 339 is characteristic of fluorine-containing compounds. It is interesting to note that this compound shows a substantial loss of HF (at m/z 367) from the M C2H6adduct ion. Several
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Envlron. Scl. Technol., Vol. 19, No. 8, 1985
3'1
70
11!1
!SO
j90
230
270
310
350
390
M/Z
Figure 4. NCI mass spectra of the most abundant dichiorobis(tr1f1uoromethyl)biphenyI at two different ion source temperatures.
dichloro congeners were present in the environmental samples; the mass spectrum and gas chromatographic retention time of the most abundant isomer found in our samples matched those of our synthetic standard. When fish samples were first analyzed for these compounds by NCI, they were not detected. During that analysis, the ion source of the mass spectrometer was at 250 "C. Lowering the ion source temperature, using NCI, has been shown to produce more abundant molecular ions, less fragmentation, and, in many cases, better sensitivity (19,20). Reanalyzing the fish samples with the ion source at 100 "C clearly showed the presence of these fluorobiphenyls. The NCI spectra at 100 and 250 "C are shown in Figure 4 for the most abundant dichloro isomer. Note the high abundance of the structurally insignificant chloride ion at 250 "C vs. the structurally important molecular anion at 100 "C. The concentrations of these fluorinated compounds in sediment are given in the top part of Table I. The con-
Table I. Fluorinated Compounds in Sediment and Fish Samples from the Lake Ontario Systema sample
1
2
compound concentration,ng/g 3-Cll 3-ci2 3-c&
3-Cl4
3416
Sediment Samples Bloody Run Creek Lake Ontario Niagara Basin 20c 23 25 587 589 591
35000
11000
2500
6200
3200
1000
80
0.18 0.38 0.38 0.19 0.14 0.004
0.21 1.40 0.48 0.40 0.24 0.05
NDb
0.03 0.06 0.005 0.14 0.07 0.008
0.005 0.006
ND
0.04 0.18 0.009 0.11 0.10 0.006
0.01 0.01 0.006
ND ND ND ND ND ND
0.54 0.16 0.13 0.04
0.98 0.57 0.36 0.40
0.008 0.007 0.008 0.04
0.08 0.08 0.07 0.09
0.08 0.08 0.08 0.10
0.02 0.02 0.02 0.02
ND ND ND ND
0.007
0.04
0.36 0.18 0.14
0.65 0.54 1.34 0.81 0.75
0.06 0.05 0.02
0.14 0.11 0.32 0.19 0.15
0.14 0.10 0.29 0.17 0.11
0.03 0.01 0.11 0.04 0.003
ND ND ND ND ND
0.009
0.07
ND
0.009
0.002
ND
ND
ND ND ND ND
140 850 310 1
180 540 290 1
60 73 41 0.3
4 14 23
ND ND ND ND
0.02
ND 0.01 0.02
ND
Lake Ontario Mississagua Basin 39 592 593 595
Lake Ontario Rochester Basin 64 69 596 597 599
ND
ND
Lake Ontario Kingston Basin 79
Lake Ontario Salmon River Niagara River at Fort Niagara Niagara River at Lewiston Little Niagara River
Fish Samples ND 2
ND ND
ND
aLake Ontario sediment concentrations are average concentrations in the first 10 cm in these cores. Fish concentrations are given in ng/g of fat. *ND = not detected. CSitenumber; see Figure 1.
centrations of all the compounds are 4-6 orders of magnitude higher in the Bloody Run Creek sediment than in Lake Ontario. This agrees with our knowledge that the Hyde Park dump (drained by the Bloody Run Creek) is the source of these compounds (I). In the Lake Ontario samples, the concentration of compound 2 is always higher by (on average) a factor of 4 than that of compound 1 even though it is lower by a factor of 3 in Bloody Run Creek. This suggests that compound 2 may be more environmentally persistent than compound 1. Of the fluorobiphenyls, the dichloro and trichloro congeners are the most abundant and are present in all of the sediment samples. The highest concentration in Lake Ontario is 0.32 ng/g at site 596, a location which is about 200 km away from the source of these compounds. Figure 5 shows NCI mass chromatograms for the molecular anion of the trichlorofluorobiphenyls; these data show the isomers found in Bloody Run Creek sediments and the three major sedimentation basins in Lake Ontario. The good agreement between the relative abundances of these isomers is a further indication for a common source: Hyde Park. The concentration of these compounds in fish is given in the bottom part of Table I. It is interesting to note that while compound 2 was found in all fish samples, compound 1 was never detected. This apparent lower bioaccumulation of compound 1 could be caused either by its higher polarity or by its easier metabolism relative to compound 2. The Clzto C14fluorobiphenyls have a geometric average concentration of 60 ng/g in fish taken below the falls, but two of these compounds were also detected at very low levels (0.3-1 ng/g) in fish from the Little Niagara River. Sediment analysis from the Little Niagara, Cayuga, and Bergholtz Creek showed none of these compounds. Sediment analysis from Black Creek and the 102nd Street bay near the Love Canal storm sewer outfall showed about 0.1 ppb of compounds 1 and 2. These sediment data, taken together with the fish data, indicate that there may be
24
25
26
27
28
2’9
GC retentlon time (min)
Flgure 5. Molecular ion NCI mass chromatograms ( m / z 392) of the trichlorobis(trifluoromethyl)biphenylsin sedlments from (A) Bloody Run Creek, (6) Niagara Basin, (C) Mississaugua Basin, and (D) Rochester Basin.
another minor source for these compounds above the falls. Pollutant partitioning between water and sediment (21-23), bioconcentration (24-26), and aqueous solubility (27,28)have been correlated to the compound’s octanol/ water partition coefficients Besides experimental determinations (29, 30),partition coefficients can be estimated via calculations using fragment constants (31,32). The log KO,,,% for a variety of PCB congeners present in commercial Aroclor mixtures have been experimentally determined (33). For the mono- to tetrachloro PCB’s, these values averaged from 4.5 to 6.1, respectively. Utilizing the fragment constants reported by Rekker (321,the log Kos)sfor these fluorobiphenyls were calculated; they Environ. Sci. Technol., Vol. 19, No. 8, 1985
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range from 6.8 to 9.0. These values indicate that these compounds should partition into sediments and bioaccumulate even more effectively than the corresponding PCB’s.
Acknowledgments We express our gratitude to the Canada Centre for Inland Waters for supplying the Lake Ontario sediment samples, to the New York State Department of Environmental Conservation for supplying fish samples, and to Paul H. Chen and Ray Kaminsky for their assistance in the synthesis and sample workup procedures. Registry No. 1, 95998-69-9; 2, 95998-70-2; 3 (Cll isomer), 95998-64-4; 3 (Clzisomer), 95998-65-5;3 (C1, isomer), 95998-66-6; 3 ( C 4 isomer), 95998-67-7; 3 (CISisomer), 95998-68-8.
Literature Cited Elder, V. A,; Proctor, B. L.; Hites, R. A. Environ. Sci. Technol. 1981, 15, 1237-1243. Eadie, B. J.; Robertson, A. J. Great Lakes Res. 1976, 2, 307-323.
Frank, R.; Thomas, R. L.; Holdrinet, G.; Kemp, A. L. W.; Braun, H. E. J . Great Lakes Res. 1979,5, 18-27. Haile, C. L. Dissertation, University of WisconsinMadison, 1977. Holdrinet, M. V.; Frank, R.; Thomas, R. L.; Hetling, L. J. J . Great Lakes Res. 1978, 4, 69-74. Kuntz, K. W.; Warry, N. D. J . Great Lakes Res. 1983, 9, 241-248.
Maguire, R. J.; Kuntz, K. W.; Hale, E. J. J . Great Lakes Res. 1983, 9, 281-286. Kaminsky, R.; Kaiser, K.; Hites, R. A. J. Great Lakes Res. 1983,9, 183-189.
Yurawecz, M. P. J . Assoc. Off.Anal. Chem. 1979,62,36-40. Oliver, B.; Nicol, K. D. Environ,. Sei. Technol. 1982, 16,
Wittle, D. M.; Fitzsimmons, J. D. J . Great Lakes Res. 1983, 9, 295-302. Clark, J. R.; DeVault, D.; Bowden, R. J.; Weishaar, J. A. J . Great Lakes Res. 1984, 10, 38-47. Interagency Task Force on Hazardous Waste, Report on Hazardous Waste Disposal in Erie and Niagara Counties, March 1979, New York. Jensen, T. E.; Kaminsky, R.; McVeety, B. D.; Wozniak, T. J.; Hites, R. A. Anal. Chem. 1982,54, 2388-2390. Phillips, D. J. H. Environ. Pollut. 1978, 16, 168-229. Stalling, D. L.; Tindle, R. C.; Johnson, J. L. J . Assoc. Off. Anal. Chem. 1972,55, 32-38. Field, F. H. J. Am. Chem. Soc. 1969, 91, 2839-2842. Busch, K. L.; Norstrom, A.; Bursey, M. M.; Wilson, C. A.; Hass, J. R. Biomed. Mass Spectrom. 1979, 6, 157-161. Karickhoff, S. W.; Brown, D. S.; Scott, T. A. Water Res. 1979,13,241-248.
Karickhoff, S. W. Chemosphere 1981, 10, 833-846. Schwarzenbach, R. P.; Westall, J. Environ. Sei. Technol. 1981, 15, 1360-1367. Veith, G. D.; DeFor, D. L.; Bergstedt, B. V. J . Fish Res. Board Can. 1979, 36, 1040-1048. Neely, W. B.; Bronson, D. R.; Blau, G. E. Environ. Sei. Technol. 1974,8, 1113-1115. Mackay, D. Environ. Sci. Technol. 1982, 16, 274-278. Mackay, D.; Bobra, A.; Shiv, W. Y.; Yalkowsky, S. H. Chemosphere 1980,9, 701-711. Banerjee, S.; Yalkowsky, S. H.; Valvani, S. C. Environ. Sei. Technol. 1980,14, 1227-1229. Veith, G. D.; Austin, N. M.; Morris, R. T. Water Res. 1979, 13,43-47.
McDuffie, B. Chemosphere 1981, 10, 73-83. Leo, A.; Hansch, C.; Elkins, D. Chem. Rev. 1971, 71, 525-616.
Rekker, R. F. In “Pharmacochemistry Library”; Elsevier: Amsterdam, 1977; Vol. 1. Rapaport, R. A.; Eisenreich, S. J. Environ. Sci. Technol. 1984, 18, 163-170.
532-536.
Suns, K.; Craig, G.; Crawford, G.; Rees, G.; Tosine, H.; Osborne, J. J . Great Lakes Res. 1983,9, 335-340. Kuehl, D. W. Chemosphere 1981, IO, 231-242.
Received for review September 20,1984. Accepted January 22, 1985. This research was supported by the US.Environmental Protection Agency under Grant 808961.
Reaction/Removal of Polychlorinated Biphenyls from Transformer Oil: Treatment of Contaminated Oil with Poly(ethy1ene glycol)/KOH Daniel J. Bruneile,” Ashok K. Mendiratta, and Daniel A. Singleton+
General Electric Corporate Research and Development, Schenectady, New York 12301 Polychlorinated biphenyls (PCBs) in transformer oil react with poly(ethy1eneglycols) and potassium hydroxide under relatively mild conditions. Complete reaction with PEG occurs at 60-120 “C in under 2 h to produce aryl polyglycols, the products of nucleophilic aromatic substitution. The reactants and aryl polyglycol products are insoluble in transformer oil and are easily removed. Process optimization, demonstration of batch and continuous processes, and an engineering evaluation have been completed. The treated oil has been tested for its chemical and electrical properties and meets all the specifications reauired for reuse.
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Introduction The production of polychlorinated biphenyls (PCBs) began in 1929 and peaked in the late 1960s ( I , 2). The
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Present address: Department of Chemistry, 1Tniversity of Minnesota, Minneapolis, MN 55455. 740
Environ. Sci. Technol., Vol. 19, No. 8 , 1985
properties of PCBs that led to their widespread utilization in transformers and capacitors are their thermal stability, their flame retardant capability, their resistance to oxidation, reduction, acids, and bases, and their excellent dielectric properties (1, 2). In 1972, the EPA issued a report stating that PCB contamination was ubiquitous and that PCBs represented an unquantified threat to the environment (3). In 1976, Congress passed the Toxic Substances Control Act, which specifically regulates manufacture, use, and disposal of PCB-contaminated materials ( 4 ) . At the inception of our work, no method existed for removal of PCBs from contaminated oil (Facilities are currently available for burning PCBs or PCB-contaminated fluids. Solvent extraction processes have been patented (5, 6).) At the present time, the only methods available for chemical destruction of PCBs, which permit reuse of the oil, require the use of metallic sodium (7-14). Hence, we undertook a program of research with the goal of identifying a safe, inexpensive, and simple means of
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