author's proof!

17 Pages·2012·0.26 MB·English

AUTHOR'S PROOF! JrnlID11356_ArtID392_Proof#1-26/08/2010
EnvironSciPollutRes
DOI10.1007/s11356-010-0392-1
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3 REVIEWARTICLE
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Applications of polychlorinated biphenyls
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5 Mitchell D. Erickson&Robert G. Kaley II
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6 Received:18May2010/Accepted:23August2010 O
7 #Springer-Verlag2010
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9 Abstract can be documented from those which cannot. Undocu- 37
10 Background, aim, and scope In the 50 years or so that mented uses may include actual minor uses as well as 38
11 polychlorinatedbiphenyls(PCBs)weremanufacturedinthe reporDted applications that are unlikely ever to have been 39
12 USA and elsewhere, they were widely used in numerous cEommercialized. 40
13 applications because of their desirable properties. The
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14 purpose of this paper is to review and summarize in one Keywords PCBs.Polychlorinated biphenyls.Aroclor. 41
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15 place the factual information about the uses of PCBs, as Capacitor.Transformer 42
16 well as to correct some misconceptions that haveEarisen
17 over the years. The focus ison applicationsin the USA for
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18 whichthereisampledocumentation.However,usepatterns 1 Introduction 43
19 were probably similar worldwide. R
20 Materials and methods Review. O In July of 1977, the sole US manufacturer of commercial 44
21 Results PCBs were used primarily as electrical insulating polychlorinated biphenyls (PCBs), the former Monsanto 45
22 fluids in capacitors and transformeCrs and also as hydraulic, Company1voluntarilyceasedmanufacturingtheproductsat 46
23 heat transfer, and lubricatingNfluids. PCBs were blended their plant in Sauget, IL (production at the Anniston, AL, 47
24 with other chemicals as plasticizers and fire retardants and plant had ceased in 1971). Starting about a decade 48
25 used in a range of prodUucts including caulks, adhesives, previously and continuing for the succeeding three-plus 49
26 plastics, and carbonless copy paper. In the USA, PCBs decades, PCBs have been among the most studied groups 50
27 were manufactured from 1929 through mid-1977, although of chemicals. Publications number in the tens of thousands 51
28 many products remained in service for decades after the and the publication rate shows no sign of slowing. PCBs 52
29 manufacture of PCBs was terminated. This article reviews remain an economic force over 30 years after the last 53
30 the historic uses of PCBs in the USA and discusses, where products were made. Issues relating to PCBs provide 54
31 possible,therelativesalesvolumes.Especiallywithsmaller professional opportunities, funding, and income to numer- 55
32 volume, military, and third-party uses, documenting a use ous regulators, academic, and government research scien- 56
33 and/or differentiating between a commercial use and an tists, consultants, remediation firms, and attorneys. 57
34 experimental test batch is not possible. Inthe40yearsorsothatPCBs havebeenintheeyesof 58
35 Discussion A major contribution of this paper is to allthesevariousparties,aswellasthoseofthepublicitself, 59
36 differentiatereportedcommercialapplications ofPCBs that much has been learned. However, some of what has been 60
“learned” is based on misunderstandings, apocrypha, and 61
Responsibleeditor:AkeBergman careless repetition of undocumented “facts” that just were 62
M.D.Erickson(*)
NewProvidence,NJ,USA
e-mail:[email protected] 1All succeeding mentions of Monsanto Company refer to the “old”
Monsanto Company, now known as Pharmacia. The company now
R.G.KaleyII known as Monsanto was chartered in 2000 and is a manufacturer of
St.Louis,MO,USA agriculturalproducts.
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63 not so. Some of these “myths” are merely amusing, for The discovery and subsequent investigations of the 113
64 example, the myth that the “12” in the names of Aroclor presence of PCBs in the environment is a tale oft-told and 114
65 products stood for the 12 carbon atoms in the biphenyl will only bequickly summarizedhere. The first mention of 115
66 molecule. Others have had more serious implications as PCBs in the environment was in the British science news 116
67 discussed below. magazineNew Scientist in December of1966 (Anonymous 117
68 Here, we review a range of factual information about 1966), reporting the findings of Sören Jensen and 118
69 the uses of PCBs, as well as to correct some of the colleagues in Stockholm. The first mention of the Swedish 119
70 misconceptions that have continued to be expounded work in the USAwas in January 1967 (Anonymous 1967). 120
71 over the years. PCB nomenclature, manufacturing, and Over the next several years, additional studies were 121
72 properties are discussed for perspective. The focus is on published, including the December 1968 publication in 122
73 applications in the USA for which there is ample Nature first reporting PCBs in US birds (Risebrough et al. 123
74 documentation. However, used patterns were probably 1968). In 1972, Jensen (1972) published The PCB Story, 124
75 similar worldwide. PCBs synthesized incidentally to doubtless thinking it impoFrtant to commemorate this 125
76 other chemistries and incorporated into products as historic tale before we Oall moved on to other scientific 126
77 inadvertent constituents are not addressed here. Also, challenges. As we know, the PCB story was far from over 127
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78 the manufacture and use of single congeners for research in 1972. 128
79 and as analytical standards are outside the scope of this By early 197R0, Monsanto had undertaken a program to 129
80 article. Finally, issues related to the presence of PCBs in address the presence of PCBs in the environment. Custom- 130
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81 the environment and associated potential exposures are erswerenotifiedofthedevelopinginformationaboutPCBs 131
82 not dealt with here. in the environment, and Monsanto introduced a label 132
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warning users to prevent environmental discharges. Mon- 133
sEanto also voluntarily withdrew PCBs from all markets 134
83 2 A brief history which were considered likely to lead to environmental 135
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discharges. Sales were restricted to a limited number of 136
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84 PCBswerefirstdescribedintheGermanchemicalliterature manufacturersofelectricalequipmentforusesinnominally 137
85 in the 1880s (Schmidt and Schultz 1881). PCBs weEre first closed systems, such as capacitors and transformers. 138
86 manufactured commercially in 1929 by the Swann Chem- Consideration was given to early cessation of manufacture, 139
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87 ical Company in Anniston, AL. Theodore Swann had butaUSGovernmentinter-departmentaltaskforcenotedin 140
88 developed a commercially viable processRto manufacture May of 1972 that the continued use of PCBs in electrical 141
89 biphenyl from benzene by bubblingO benzene through equipment was essential to the safe delivery of electrical 142
90 molten lead. Chlorinationof thebiphenylwasoneofmany power in the USA (ITF 1972). 143
91 routes explored to develop coCmmercial uses for the In 1968, the Yusho incident occurred in Western Japan, 144
92 biphenyl (Penning 1930). GeNneral Electric was among the mainly in the Fukuoka and Nagasaki prefectures. “Yusho” 145
93 companies which tested this new product. They were isaJapanesewordmeaning“oildisease”;itisnotthename 146
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94 looking for a flame-retardant transformer fluid to use in of a geographical location in Japan, as is often stated. The 147
95 locations where mineral oil fires put persons or property at incident did not occur “in Yusho.” Thermally degraded 148
96 risk. General Electric recognized that PCBs were ideal Japanese PCB-containing heat transfer oil had leaked into 149
97 fluids for this application and patented various PCB- rice oil during processing. The rice oil was subsequently 150
98 containing products in the early 1930s. consumedbyresidentsinWesternJapan.Thedetailsofthis 151
99 In 1935, the Swann Chemical Company, including incident have been thoroughly covered in the scientific 152
100 Swann’s Anniston, AL, plant was purchased by the literature (Kunita et al. 1984) and in books (Erickson 1997 153
101 Monsanto Company, based in St. Louis, MO. Swann’s line and citations therein). The thermal degradation of the fluid 154
102 of polychlorinated polyphenyl products, known as Aro- had resulted in elevated levels of polychlorinated dibenzo- 155
103 clor® products, was among the product lines now manu- furans and other chemicals in the fluid and subsequently in 156
104 factured by Monsanto at Anniston. the rice oil. Although investigations continue to this day, it 157
105 In the late 1930s, a second manufacturing facility was iswidelyacknowledgedthattheprimarycausativefactorof 158
106 constructed in Sauget, IL. During World War II, the Yusho was the polychlorinated dibenzofurans, since Japa- 159
107 manufacture of PCBs was taken over by the US Govern- nese electrical workers with comparable levels of PCBs in 160
108 ment, because of their essential uses in support of the war their bodies did not exhibit the symptoms of Yusho. 161
109 effort. After the war, the uses of PCBs expanded into a After Monsanto was notified by its customers that 162
110 number of functional areas, including flame retardant heat acceptable substitute fluids for PCBs in electrical equip- 163
111 transferfluids,hydraulicfluids,andplasticizers.Theseuses ment were available, Monsanto ceased production of PCBs 164
112 are described in detail below. in1977,2yearsbeforetheEPA’sbanonthemanufactureof 165
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166 PCBs was published in May of 1979. However, PCB Table1 ComparisonofcommercialPCBmixtures t1.1
167 manufacturing in several European and Asian countries
Aroclor AverageNo. Approximate t1.2
168 continuedwellintothe1980sandprobablylater.Today,the Cl/Molecule Weight%Cl t1.3
169 intentional manufacture of PCBs is not known to be
170 occurring anywhere in the world, except for the synthesis 1221 1.15 21 t1.4
171 of small amounts for research purposes. 1232 2 32–33 t1.5
1242,1016 3 40–42 t1.6
172 2.1 PCB manufacturing process 1248 4 48 t1.7
1254 5 52–54 t1.8
173 Monsanto manufactured PCBs by the direct chlorination of 1260 6–6.3 60 t1.9
174 biphenyl (Hubbard 1964). Ferric chloride was used as a 1262 6.8 62 t1.10
175 catalyst. When the desired degree of chlorination was 1268 8.7 68 t1.11
176 attained, as determined by the specific gravity, the crude 1270 10 F 71 t1.12
177 liquid Aroclor product was pumped to a tank where O
178 residual hydrochloric acid (HCl), which was a byproduct Source:(BrinkmanandDeKok1980)
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179 of the chlorination reaction, was blown out with air.
180 Following treatment with lime to neutralize any residual well-controlled,Rthereactions willoccurinthesamewayin 217
181 acid, the crude mixtures were refined by vacuum distilla- everybatchforeverymanufacturer.Ofcourse,therewillbe 218
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182 tion. To prepare electrical grade Aroclor 1200 series minor variations, but the major components will always be 219
183 products, the distilled material was treated with attapulgus major components, and the trace components will always 220
184 earth (fuller’s earth) to remove electrically conductive be traDce components. 221
185 impurities such as traces of water and HCl and thereafter E
186 filtered. 2.2 The naming of cats: PCBs 222
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187 The complex congener composition of the various
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188 Aroclor PCB products was determined by the chemistry As we were reminded in the musical Cats, every cat has 223
189 and physics of the chlorination process. There is a fErequent threenames.ThesameistrueofPCBs,althoughsomehave 224
190 misunderstanding that Monsanto and the other manufac- even more names. For example, 3,3′,4,4′-tetrachlorobi- 225
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191 turers somehow manufactured and blended the individual phenyl is also known as PCB 77, is a non-ortho PCB or 226
192 congeners to produce the various productsR. This is simply coplanar PCB, and has CAS Registry Number 32598-13-3. 227
193 not the case. While it is not possible toOdelineate all of the Of course, it is also a congener and an isomer, and it may 228
194 reactionkinetics, a couple fairly simple considerations may be a component of a commercial mixture, such as one of 229
195 help to illustrate the consideratiCons that determined the the Aroclor products. We sort out this confusing nomen- 230
196 congener mixes. Readers whNo either enjoyed or suffered clature here. 231
197 through college organic chemistry may recall that sub- The term “congener” has come to be applied to any 232
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198 stituents on benzene rings “direct” further substitutions to single member of a class of related compounds, such as 233
199 eithertheortho/paraorthemetapositionsontherings.The PCBs, which are the class of compounds comprising 234
200 second benzene ring in the biphenyl molecule is an ortho/ molecules with 1–10 chlorine atoms attached to the two 235
201 para director, so substitution is much more common in rings of biphenyl. Despite the linguistic inconsistency, 236
202 those positions than in meta positions. Also, the chlorines monochlorobiphenyls are included in all PCB discussions. 237
203 tend to be distributed somewhat equally between the two Unchlorinated biphenyl is never included as a PCB. There 238
204 rings,sothatcongenerswiththreeormorechlorinesonone are 209 PCB congeners. These congeners can be further 239
205 ringandnoneontheotherarenotpresentinactualproduct classified according to the number of chlorines attached to 240
206 mixtures, even though such congeners frequently serve as the rings. Thus, there are 10 “congener classes,” ranging 241
207 research curiosities. Although there is a consensus on the from monochlorobiphenyls (three class members) through 242
208 general homologous compositions of the major Aroclor pentachlorobiphenyl (46 class members) to decachlorobi- 243
209 products (see Table 1), characterization of the composition phenyl (one class member). When grouped by degrees of 244
210 ofthecommercialmixturesatthecongener-specificlevelis chlorination, the congener classes are often referred to as 245
211 much more complex and remains a subject of continuing “homologs,” although that term is strictly applicable only 246
212 research. to groups of chemicals with increasing carbon chain 247
213 The manufacturing process also helps explain why PCB lengths. However, the application of the term to PCBs 248
214 products of the same chlorination level are remarkably and other groups of chlorinated compounds is widespread 249
215 similar among different manufacturers and among batches in formal and informal writing and must be considered an 250
216 from the same manufacturer. As long as the processes are accepted use. 251
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252 The term “isomer” refers to one of a group of chemicals least four chlorines and with no chlorines in the ortho 305
253 that have the same molecular formula, i.e., they comprise positionscanassumetheplanarconformationnecessaryfor 306
254 thesameelementsandthesamenumbersofthoseelements. binding to the Ah receptor. These congeners (BZ numbers 307
255 Thus, the 42 members of the congener class of tetrachlor- 77, 81, 126, and 169) are thus frequently called coplanar, 308
256 obiphenyls are isomers of one another. They all have the non-ortho, or dioxin-like PCBs (note that these PCBs are 309
257 molecular formula C H Cl . (N.B., there are not 209 not “locked” into the planar conformation, but they can 310
12 6 4
258 isomers of PCBs, because PCBs as a group have 10 assume that conformation during rotation around the 311
259 possible molecular formulae.) carbon–carbon bond.) PCBs with at least four chlorines in 312
260 Ofcourse,likeeverychemical,eachPCBcongenerhasa the3,3′,4,4′,5,or5′positionsandasingle chlorine inan 313
261 precise chemical name in accordance with the system ortho position are denoted mono-ortho-PCBs. These eight 314
262 established by IUPAC. In our example above, that name congeners bind weakly to the Ah receptor. Lastly, the 315
263 is 3,3′,4,4′-tetrachlorobiphenyl. That name can only apply remaining congeners are designated as either di-ortho- 316
264 to that specific congener, and it uniquely specifies the PCBs and, more generally, aFs ortho-PCBs. 317
265 number and location of the chlorine atoms on the biphenyl It should be noted thOat the four non-ortho and eight 318
266 rings. That naming system is precise and works well for mono-ortho PCBs have been assigned TCDD toxicity 319
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267 congeners with only a few chlorine atoms, but it quickly equivalency factors by the World Health Organization 320
268 becomescumbersomeasthenumberofchlorinesincreases. (WHO) and otRher organizations to reflect the potential 321
269 Accordingly Ballschmiter and Zell (1980; corrected in relative potencies associated with binding to the Ah 322
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270 Ballschmiter et al. 1992) proposed a numbering system in receptor, compared to that of TCDD (Van den Berg et al. 323
271 which each congener was arranged in ascending IUPAC 2006). 324
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272 hierarchical order from mono- to decachlorobiphenyl and
273 given a number from 1–209 (the BZ number) to facilitate 2E.3 The naming of cats: Aroclor products2 325
274 communication of information about individual congeners.
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275 Thus, in the BZ system, 2-chlorobiphenyl is PCB 1; As noted earlier, Monsanto’s trade name for its line of 326
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276 3,3′,4,4′-tetrachlorobiphenyl is PCB 77; and polychlorinated polyphenyl products was Aroclor®. Read- 327
277 2,2′,3,3′,4,4′,5,5′,6,6′-decachlorobiphenyl is PCB 20E9. ers will please note that there is no “h” in Aroclor (the 328
278 All 209 congeners, “PCB,” the ten homologs, Aroclor trademark designation is generally omitted throughout this 329
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279 products, and other PCB-related mixture terms have a articletobeconsistentwithcommonusage).Ofcourse,the 330
280 uniquenumberassignedbytheChemicalARbstractsService, most widely known of these products were the polychlori- 331
281 whichhasassignednumberstoover50Omillionorganicand nated biphenyls, but the product line also included poly- 332
282 inorganic substances. 3,3′,4,4′-Tetrachlorobiphenyl has chlorinated terphenyls (PCTs), as well as mixtures and 333
283 CAS Registry Number 32598-13-C3. Numbers are assigned blends of PCBs and PCTs. In the broadest of terms, most 334
284 when the chemical is reportedNin the literature, so the CAS PCBs were known as liquid Aroclors, while the term solid 335
285 numbering system is not sequential. For example, the next Aroclors encompassed PCTs and the most highly chlori- 336
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286 congener on the BZ list, 3,3′,4,5-tetrachlorobiphenyl, has a nated PCBs. 337
287 CAS RN of 70362-49-1. A comprehensive list of all Ingeneral,thenamingsystemforAroclorPCBproducts 338
288 congeners with IUPAC, BZ, and CAS numbers can be is well known. The trade name Aroclor was followed by a 339
289 found in Appendix A in Erickson (1997). four-digit number (Table 1), in which the first two digits 340
290 Primarily to facilitate discussions of the toxicological were “12,” designating the product as a refined PCB. The 341
291 properties of certain PCB congeners, the ortho, meta, and second two digits specified the average percentage of 342
292 para designations are used to classify PCBs according to chlorine,byweight,intheparticularproduct.Thus,Aroclor 343
293 their potential ability to bind to the aryl hydrocarbon (Ah) 1242 was a polychlorinated biphenyl product containing 344
294 receptor in animal cells. The Ah receptor is a cellular 42% chlorine by weight. While 42% chlorine by weight is 345
295 receptor that binds planar organic compounds such as alsotheapproximatecompositionoftrichlorobiphenyls,the 346
296 polychlorinated dibenzo-p-dioxins and dibenzo-p-furans product is a complex mixture of congener classes contain- 347
297 with high affinity, leading to various toxic effects. The ing from one to six or seven chlorines. It is not 348
298 mostpotentligandis2,3,7,8-tetrachlorodibenzo-p-dioxinor “trichlorobiphenyl,” per se (this frequent misconception is 349
299 TCDD. In this classification scheme, ortho-chlorines are compounded by the naming systems of some non-US PCB 350
300 those in the 2, 2′, 6, or 6′ positions, i.e., those adjacent to products, as will be discussed below). 351
301 the carbon–carbon bond in biphenyl. Likewise, meta-
302 chlorines are those in the 3, 3′, 5, or 5′ positions, and
303 para-chlorines are those in the 4 or 4′ positions. The 2Unreferenced Aroclor and other Monsanto product information
304 significance of this scheme is that PCB congeners with at (Section2.4)isderivedfrompersonalknowledge,RGK.
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352 One frequently reads the myth3 that the “12” in the Finally, there were also a few products containing both 401
353 product name refers to the fact that there are 12 carbon PCBs and PCTs, namely Aroclor 2565 and Aroclor 4465 402
354 atoms in the biphenyl molecule, which is decidedly not (which was refined from Aroclor 4065). The Aroclor 6000 403
355 true. In fact, for every product in the Aroclor 1200 series series of plasticizers was formulated as blends of Aroclor 404
356 (refinedPCBs),therewasacorrespondingproductinaless 5460 and Aroclor 1221. These products served as transi- 405
357 well-known 1100 series, the crude PCBs. As noted tional plasticizers between PCB-containing and non-PCB- 406
358 elsewhere, the final step in the manufacture of the 1200- containing products. In this series, the final two digits 407
359 series PCBs was the distillation of the corresponding crude indicated the amount of Aroclor 5460 in the product. For 408
360 1100-series material. Thus, Aroclor 1142 was distilled to example, Aroclor 6050 contained 50% Aroclor 5460 and 409
361 produce Aroclor 1242. Further, like PCBs, the PCTs were 50% Aroclor 1221. 410
362 marketed with a four digit specification, in which the last
363 twodigitsindicatedthepercentageofchlorinebyweightin 2.4 The naming of cats: other Monsanto PCB products 411
364 the product. However, the first two digits were “54.” Thus F
365 Aroclor 5460 was chlorinated terphenyl with an average Aroclor was the dominanOt trade name for Monsanto’s PCB 412
366 chlorine content of 60%. If the “12=12 carbon atoms” and PCT products. However, other trade names were used 413
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367 myth were true, the first two digits of the PCT line would for specific applications, sometimes because the Aroclor 414
368 have been “18,” since there are 18 carbon atoms in the product was bleRnded with other chemicals. 415
369 terphenyl molecule (the crude PCT products had desig- Therminol® was the trade name for Monsanto’s line of 416
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370 nations in the Aroclor 5000 series). heat transfer fluids. The original fluids were all in the FR 417
371 The one oft-noted exception to the naming system for series, where the “FR” referred to the flame retardant 418
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372 PCBs is Aroclor 1016. This product was developed and propertiesofthefluids.OnlytheTherminolFRseriesfluids 419
373 introduced after 1971, when it became clear that PCB cEontainedPCBs(EPRI1999;Therminol66waserroneous- 420
374 congeners containing three to four chlorines or fewer were ly noted to be a PCB-containing product at p. 3–12). In 421
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375 fairly rapidly biodegradable, while those with five or more fact, with the exception of Therminol FR-0 and Therminol 422
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376 were less so. Aroclor 1016 was produced by distilling FR-1 Lo-Temp, the Therminol FR products were 100% 423
377 Aroclor 1242 to remove the more highly chloErinated PCBs:FR-1(Aroclor 1242),FR-2(Aroclor 1248),andFR- 424
378 congeners to make a more biodegradable product. Further, 3 (Aroclor 1254). After Monsanto ceased selling PCBs for 425
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379 since it was introduced after Monsanto limited sales of open application in the early 1970s, they continued to sell 426
380 PCBs to manufacturers of electrical equipRment for use in heat transfer fluids and continued to use the Therminol 427
381 closed systems, Aroclor 1016 was preOdominantly used in tradename.TheTherminoltradenameiscurrentlyusedby 428
382 capacitors, with some limited use in transformers. SolutiaInc.towhichthebusinesswasspunoffin1997.Of 429
383 The “1016” designation was aCn outgrowth of Monsan- course, no Solutia-manufactured Therminol fluids ever 430
384 to’s system for keeping trackNof materials in the research contained PCBs. 431
385 stage of development. Each new research chemical, The situation with regard to Monsanto’s former line of 432
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386 whether PCB-containing or not, was given a sequential Pydraul® hydraulic fluids is not so straightforward. Mon- 433
387 Monsanto Chemical Substance or Sample number (MCS). santo’s early line of PCB-containing Pydraul fluids were 434
388 Thus, MCS 1016 was the designation of the Aroclor 1242 blends of PCBs along with, variously, hydrocarbon oils, 435
389 distillationproductthatwasundergoingresearchtoseeifit phosphate esters, and other chemicals, as well as additives 436
390 would be a suitable replacement for Aroclor 1242 in suchasrustinhibitors,viscositymodifiers,andcolorants.In 437
391 electrical equipment. During the product development most cases, each particular Pydraul product was developed 438
392 stage, both Monsanto personnel and customers began to for a specific application, often in association with 439
393 refertotheresearch material assimply“1016,”justasthey customers. For example, Pydraul AC was developed 440
394 referred to the other PCB products simply by their four- specifically for use in air compressors. Accordingly, there 441
395 digit name. When MCS 1016 was commercialized, it was isnosimplewaytoknoworpredictthecompositionofany 442
396 calledAroclor1016,becausethatiswhatpractitionerswere particular Pydraul fluid. 443
397 already calling it. The name was not an attempt to disguise As was the case with other “open” uses, Monsanto 444
398 the fact that it was a PCB product or to suggest that it had stopped making and marketing PCB-containing Pydraul 445
399 only 16% chlorine. Claims to that effect fail to recognize fluids in the early 1970s. In many cases, however, the 446
400 the developmental history of the product. company introduced non-PCB-containing fluids with the 447
samenamewithasuffixindicatingthatthefluidsnolonger 448
contained PCBs. In general, Pydraul fluid names with the 449
3For example, http://www.epa.gov/epawaste/hazard/tsd/pcbs/pubs/
suffix “B” indicated the fluid was a transitional fluid, often 450
aroclor.htmandhttp://en.wikipedia.org/wiki/Polychlorinated_biphenyls.
AccessedApril2010. containing PCTs. Fluids with “C” or higher designations 451
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452 contained neither PCBs nor PCTs. As with the Therminol A30,PhenoclorDP-3,andKanechlor300;ineachcase,the 481
453 name, Monsanto continued to develop and market new, “3” referred to trichlorobiphenyl, the average number of 482
454 non-PCB containing hydraulic fluids under the Pydraul chlorines on the biphenyl rings in the particular product. 483
455 trade name. Monsanto’s hydraulic fluid business was sold Each manufacturer had similar product names for products 484
456 in 1986. However, the Pydraul trade name continued to be with average percentage chlorine compositions close to 485
457 used by subsequent manufacturers. those of tetrachlorobiphenyl, pentachlorobiphenyl and 486
458 Monsanto also marketed a line of aircraft hydraulic hexachlorobiphenyl. In some cases, these naming schemes 487
459 fluids with the trade name Skydrol(R). Those fluids were have led to the incorrect inference that the products were 488
460 based on phosphate esters and never contained PCBs composed of “purely” the congener class suggested by the 489
461 (Hatton 1964). Phosphate ester-based Skydrol fluids con- number. However, all of these products were complex 490
462 tinue to be manufactured and marketed by Solutia Inc. mixtures of PCB congeners from many congener classes, 491
463 (www.skydrol.com) just like the Monsanto products. 492
As noted above, MonsanFto used the Pydraul® trade 493
464 2.5 The naming of cats: other manufacturers and products name for PCB-containinOg hydraulic fluids and Therminol 494
FR®forPCB-containingheattransferfluids.Further,many 495
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465 PCBs were manufactured worldwide through at least the users had their own trade names for PCB-containing fluids 496
466 1980s. Monsanto’s Aroclor products accounted for nearly usedintheirowRnproducts.Forexample,GeneralElectric’s 497
467 all of the US production. Foreign manufacturers sold trade name for their PCB-containing dielectric fluids was 498
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468 similar products under trade names such as Kanechlor® Pyranol®; that of Westinghouse was Inerteen®; and that of 499
469 (Japan), Clophen® (Germany), Phenoclor® and Pyralene® Kuhlman was Saf-T-Kuhl®. Many authors have tabulated 500
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470 (France), Fenchlor® (Italy), Sovol (Russia), Chlorfen and further described those products (Erickson 1997, 501
471 (Poland), and Delor® (the former Czechoslovakia). In TEable 2-VI; USEPA 2010). 502
472 addition, many use-specific PCB-containing products had
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473 identifying trade names. Manufacturers other than Mon-
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474 santo also added numerical “suffixes” to their trade names 3 Physical properties 503
475 to specify the average composition of their pEroduct
476 (Erickson 1997 Table 2-V). As noted above, Aroclor 1242 The physical properties of the various PCB mixtures have 504
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477 was a complex mixture of PCB congeners from many been discussed extensively in other publications, so they 505
478 congener classes, but the average percentRage of chlorine will only be briefly mentioned here. Table 2 shows the 506
479 closely corresponded to that of trichloOrobiphenyl. Compa- physical properties adapted from the Monsanto (2004) 507
480 rable products from other manufacturers were Clophen Material Data Safety Sheet. 508
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t2.1 Table2 PropertiesofselectedAroclorproducts
N
t2.2 PROPERTY 1U016 1221 1232 1242 1248 1254 1260 1268
t2.3 Color(APHA) 40 100 100 100 100 100 150 1.5(NPA)
molten
t2.4 Physicalstate Mobileoil Mobileoil Mobileoil Mobileoil Mobileoil Viscous Stickyresin Off-white
liquid powder
t2.5 Stability Inert Inert Inert Inert Inert Inert Inert Inert
t2.6 Density(lb/gal25°C) 11.40 9.85 10.55 11.50 12.04 12.82 13.50 15.09
t2.7 SpecificgravityatºC 1.36–1.37 1.18–1.19 1.27–1.28 1.30–1.39 1.40–1.41 1.49–1.50 1.55–1.56 1.80–1.8125º
25° 25° 25° 25° 65° 65° 90°
t2.8 Distillationrange(°C) 323–356 275–320 290–325 325–366 340–375 365–390 385–420 435–450
t2.9 AciditymgKOH/g, .010 .014 .014 .015 .010 .010 .014 0.05
maximum
t2.10 Firepoint(°C) Noneto 176 238 Noneto Noneto Noneto Noneto Noneto
boiling boiling boiling boiling boiling boiling
point point point point point point
t2.11 Flashpoint(°C) 170 141–150 152–154 176–180 193–196 None None None
t2.12 Vaporpressure(mmHg@ NA NA 0.005 0.001 0.00037 0.00006 NA NA
100°F)
t2.13 Viscosity(SayboltUniv.Sec. 71–81 38–41 44–51 82–92 185–240 1800–2500 – –
t2.14 at100°F)(centistokes) 13–16 3.6–4.6 5.5–7.7 16–19 42–52 390–540 – –
NAnotavailable
AUTHOR'S PROOF! JrnlID11356_ArtID392_Proof#1-26/08/2010
EnvironSciPollutRes
509 Individual PCB congeners are white, crystalline materi- in the chemical industry, casting waxes (decaCB), 557
510 als.However,asshowninTable2,thevariousmixturesare cutting oils, and lubricating oils) 558
511 liquids (less chlorinated) or resinous (more chlorinated)
559
512 because of the mutual melting point depression effects of These use categories had different implications for the 560
513 the congeners. As expected, the physical properties among introductionofPCBsintotheenvironment.Someuses,like 561
514 themixturesvaryaccordingtotheamountofchlorineinthe carbonlesscopypaper,resultedinenvironmentaldischarges 562
515 products. Specific gravity, boiling point, and viscosity through the recycling of the paper. Other uses, such as 563
516 increase as the chlorine content increases, while the water caulks, were intended to remain in place for extended 564
517 solubility and vapor pressure decrease. periods. The majority of the PCBs were sealed in electrical 565
518 Ashasbeenoftennoted,theverypropertiesthatmadePCBs equipment, where the only environmental impact would 566
519 desirablefornumerousindustrialapplicationswerethosethat have been from accidents, maintenance, or disposal after 567
520 contributedtotheenvironmentalpersistenceofthemorehighly the original PCB-containing materials had remained in 568
521 chlorinated congeners. PCBs were resistant to chemical and service for years or even decFades. 569
522 thermaldegradation,aswellastobiodegradation. With increased interesOt in the environmental impact of 570
523 Ofcourse,themostimportantpropertyofPCBswastheir PCBs, the sale of PCBs for so-called “open” uses, which 571
524 fire resistance or, alternatively, their flame retardant proper- could lead to near-teOrm release into the environment if not 572
525 ties.WhenPCBswereinvolvedinfires,theprimaryproduct managedproperRly, were voluntarilycurtailed byMonsanto. 573
526 ofcombustionwashydrochloricacid,whichisnotflammable, By 1972, Monsanto had restricted PCB sales to electrical 574
P
527 sotheproductsofcombustionservedtoquenchthefire.Thus, equipment applications. 575
528 PCBswerehighlydesirableforapplicationswherefirewasa Durfeeetal.(1976)prepareda489-pagereport,“PCBsin 576
529 threattolifeandproperty,suchasinelectricalequipmentin the UDnited States—Industrial Use and Environmental Dis- 577
530 commercial buildings and hospitals, in hydraulic systems in tEributions,” that was published by EPA. This report is cited 578
531 foundries,andinheattransfersystems. frequently in this article and a famous table on the “End- 579
T
Uses of PCTs and PCBs by Type” has been extensively 580
C
referenced(ATSDR2000;Johnsonetal.2006;WHO1978). 581
532 4 Uses E Durfee’s end-use table summarized the report’s text and 582
provided a good synopsis of mid-1970s public information 583
R
533 4.1 General use categories on PCB use. Since that time, additional documentation and 584
R additional perspectives allow us to improve upon Durfee’s 585
534 Commercial PCB mixtures were usedOin a wide variety of classic work, as discussed in this paper. 586
535 applications, including dielectric fluids in capacitors and A Subpanel on PCBs under an Ad Hoc Committee on 587
536 transformers, heat transfer fluids, Chydraulic fluids, lubricat- Environmental Health Research under the apparent auspic- 588
537 ing oils, and as additives Nin paints, carbonless copy es of the National Institute of Environmental Health 589
538 (“NCR”) paper, adhesives, sealants, and plastics. By far, Sciences reviewed the environmental impact of PCBs in 590
U
539 the preponderance of the PCBs was used in capacitors and 1972 (Hammond et al. 1972). This list of uses was 591
540 transformers.Theircommercialutilitywasbasedlargelyon important, given the 1972 publication date and the 592
541 their chemical stability, including low flammability, and communicationswithMonsantoofficialsforotherusedata. 593
542 desirable physical properties, including electrical insulating Durfee et al. (1976) also tabulated the US PCB 594
543 properties. PCB production and use has been thoroughly production and sales as adapted in Table 3 and Fig. 1. 595
544 reviewed (Durfee et al. 1976; EPRI 1999; Erickson 1997, Other publications documented similar use patterns in 596
545 2001; Johnson et al. 2006; WHO 1993). Japan (Hammond et al. 1972), six European countries 597
546 As reviewed by the WHO (1993), PCB use can be (Brinkman and De Kok 1980), and in 23 Organization for 598
547 divided into three categories: Economic Cooperation and Development countries as well 599
as the USA (WHO 1978). In aggregate, the foreign 600
548 & Completelyclosedsystems(electricalequipmentsuchas manufacturers accounted for nearly 50% of worldwide 601
549 capacitors and transformers) production (Bletchly 1983). In all cases, capacitor use 602
550 & Nominally closed systems (hydraulic and heat transfer dominated, followed by transformers, and then the other 603
551 systems, vacuum pumps) applications. 604
552 & Open-ended applications (Major: plasticizer in PVC, Clearly capacitor and transformer fluids dominated the 605
553 neoprene, and other chlorinated rubbers. Other: surface sales with a combined 75% of US sales. We discuss these 606
554 coatings, paints, inks, adhesives, pesticide extenders, acknowledged and major uses of PCBs in this article, but 607
555 and microencapsulation of dyes for carbonless copy we also delve into other uses that may have comprised 608
556 paper. Also: immersion oils for microscopes, catalysts smaller amounts,unknowntoMonsantoorEPAatthetime 609
AUTJrnlHID11O356R_Art'IDS39 2P_PRroof#O1-O26/0F8/2!010
EnvironSciPollutRes
t3.1 Table3 EstimatesofcumulativeUSproductionandusageovertheperiod1930–1975inmetrictons(g×10E6)
t3.2 Commercialproduction Commercialsales Industrialpurchases %ofProduction %ofDomesticsales
t3.3 USPCBProduction 635,000
t3.4 USImports 1,360 0.2
t3.5 USDomesticUsage 538,000
t3.6 TotalUSExports 68,000 11
t3.7 UseCategory
t3.8 PetroleumAdditive 450 0.07 0.08
t3.9 HeatTransfer 9,100 1 2
t3.10 MiscIndustrial 12,000 2 2
t3.11 CarbonlessCopyPaper 20,000 3 4
t3.12 HydraulicsandLubricants 36,000 F6 6
t3.13 OtherPlasticizerUses 52,000 O 8 9
t3.14 Capacitor 286,000 45 50
O
t3.15 Transformers 152,000 24 27
t3.16 Total 636,000 636,000 R
P
AdaptedfromTable1.2-1,p.7inDurfeeetal.(1976)byconversionfrompoundstometrictonsandcalculationofpercentages
610 ofDurfee’stabulation.Wealsodiscussundocumenteduses. tionsDfor capacitor askarels. As with transformers, General 637
611 Table 4 presents an overview of commercial uses; Table 5 EElectricusedthetradenamePyranolandWestinghouseused 638
612 lists published PCB applications with no known commer- thetradenameInerteen;bothhadcodenumberstodesignate 639
T
613 cial use; the sections that follow provide additional detail. the specific type of askarel (Erickson 1997). 640
C
Small capacitors contained as little as 2 mL and large 641
614 4.2 Electrical equipment E capacitorscontainedupto27LPCB(ITF1972).From1957– 642
1971, capacitors accounted for most of the PCB use in the 643
R
615 The vast majority of PCBs were used in capacitors and USA(Durfeeetal.1976).Thestartdateof1957isbasedon 644
616 transformers and other electrical equipmeRnt as dielectric availabilityofMonsantorecordsandthestatementmayapply 645
617 fluids. PCBs were used in electrical eqOuipment because of toearlieryearsaswell.In1968,95%ofallUSproductionof 646
618 performance and safety attributes. For example, one of the capacitor liquidswasPCBs (ITF 1972). In1976, 90–95% of 647
619 most important factors was theirCfire resistance or flame all impregnated capacitors manufacturedin the USAwere of 648
620 retardancy. The UnderwriterNs Laboratories flammability the PCB type (Durfee et al. 1976). In 1979, EPA estimated 649
621 rating for Aroclor 1242 was 2–3, while that for mineral that “9.56 million pieces of equipment...contain PCB 650
622 oil was 10–20, comparedUto gasoline, with a flammability capacitors”(WestinandWoodcock1979).Unliketransformer 651
623 rating of 90–100 (ITF 1972). askarels, capacitor askarels were generally pure PCB. 652
Twoimportanttypesofcapacitorswerephase-correcting 653
624 4.2.1 Capacitors capacitors for power lines and fluorescent light ballasts. In 654
capacitor manufacture, the PCBs were used to impregnate 655
625 The properties of the dielectric liquid impregnating the the paper dielectric and fill air voids. Other applications 656
626 cellulosic paper are: non-flammability, dielectric constant included a wide variety of uses of small capacitors in 657
627 matching that of paper, low dissipation factor, high appliancesandotherproducts,suchasairconditionerpump 658
628 dielectric strength, high chemical stability, low vapor motors,submersiblewaterpumps,automobiles,televisions, 659
629 pressure, inert decomposition products in an electric arc, light fixtures, clothes washers, clothes driers, refrigerators, 660
630 lowtoxicityofthematerial,anditsdecompositionproducts freezers, and microwave ovens (EPRI 1999). The fluores- 661
631 and low cost (ITF 1972). cent light ballasts contained a PCB capacitor and/or 662
632 PCBs fit those criteria. The industry term for this PCB petroleum-asphalt insulating material (“potting”) contami- 663
633 dielectricfluidwascapacitoraskarel.4 The capacitor askarels nated with PCBs (USCFR 1999). 664
634 include neat Aroclors 1221, 1242, 1254, and 1016, as well
635 as a mixture of 75% Aroclor 1254 and 25% trichloroben- 4.2.2 Transformers 665
636 zene. The ASTM (1991a) has published standard specifica-
Mostpowertransformersusealiquidtoelectricallyinsulate 666
4Notethat“askarel”isnotatradenameandisnotcapitalized. and remove heat from the core and windings. The desired 667
AUTHOR'S PROOF! JrnlID11356_ArtID392_Proof#1-26/08/2010
EnvironSciPollutRes
Fig.1 ApplicationsintheUSA 50
basedonsalesrecords1930–
1975(Erickson2001)
40
nt 30
e
c
r
e
P 20
10
0
Capacitor Transformer Export Plastic Hydraulic Copy Misc. Heat Transfer
Lube
F
668 properties are: non-flammability, high dielectric strength, & “Rectifier transformerOs used for large rolling mills and 704
669 low viscosity, high chemical stability, compatibility with DC [direct current] industrial power supplies... contain 705
670 other materials, inert decomposition products, low toxicity about 8600 kg oOf askarel...” 706
671 of the liquid and its decomposition products and low cost & “Railroad trRansformers used on-board in electric loco- 707
672 (ITF 1972). PCBs fit those criteria, except that if the motives or multiple unit electric railroad cars...contain 708
673 appropriate Aroclor fluid was too viscous, it was blended 300–11P00kgofaskarelineachunit...sinceatunnelfire 709
674 withtrichlorobenzene5toachievethedesiredviscosity.The in 1940 caused by an oil filled locomotive transformer, 710
D
675 industry term for this PCB-containing dielectric fluid was Penn Central will not allow any oil containing trans- 711
676 transformeraskarel.Themostcommontransformeraskarels E former equipped locomotive into New York City.” 712
677 were 60% Aroclor 1260/40% trichlorobenzene (Type A) & Reactors: “During power surges they choke the voltage 713
T
678 and 70% Aroclor 1254/30% trichlorobenzene (Type D). and deliver the normal output.” 714
C
679 The transformer askarels contain other minor components & Grounding Transformers 715
680 used as free radical scavengers. The ASTM (1991Eb) has
In large transformers, hundreds of liters of PCB fluid 716
681 published standard specifications for transformer askarels.
R provided insulation between the high voltage core and the 717
682 General Electric used the trade name Pyranol and Westing-
tank, which would be grounded. 718
683 house used the trade name Inerteen, bRoth with code
684 numbers to designate the type of askarOel (Erickson 1997). 4.3 Air and gas compressor lubricants 719
685 Only about 5–10% of transformers were ever manufac-
686 turedwithPCBsduringtheperiodCwhenPCBswereusedin
The use of PCBs in air compressor lubricants was driven 720
687 this application (Durfee et alN. 1976; ITF 1972). The vast primarilybytwoconsiderations;reducedfireandexplosion 721
688 majority (96% in 1968) used mineral oil for the dielectric
U hazardandlowermaintenancecostsduetothereductionof 722
689 fluid,becauseanaskareltransformercost1.3timesasmuch
carbon deposits on air compressor valves. The first 723
690 as a mineral oil transformer. The cost of askarel was cited
consideration was particularly attractive to customers 724
691 as $1.80/gal and the cost of mineral oil was $0.25/gal, a 7-
operating natural gas pipelines and in other operations 725
692 fold premium for the fluid. (ITF 1972). Fire underwriters
where high ambient temperatures made the introduction of 726
693 required the use of non-flammable dielectric fluids in
mineral oil-based lubricants especially dangerous. PCB 727
694 indoor transformers unless the transformers were in a
uses included “gas-transmission turbines, Aroclors 1221 728
695 fireproof concrete vault (ITF 1972).
and 1242” (Hammond et al. 1972). 729
696 Askarel dielectric fluids were used in network, pad-
EPA published a synopsis of the use of PCBs in natural 730
697 mounted, pole-mounted, and precipitator power supply
gas pipelines, quoted in part here (USEPA 2004). 731
698 transformers containing 200–2,000 kg in each unit with
699 an average of about 1,400 kg (ITF 1972). Specifically Majorinterstatenaturalgaspipelinestransportnatural 773323
700 (Durfee et al. 1976): gas from production areas on the Gulf Coast and 734
western US to local distribution companies that 735
701 & “Furnacetransformersusedinthehot,dirtyatmosphere
distribute the natural gas to industrial and urban 736
702 in proximity to glass-melting and induction furnaces...
customers. PCBs were used in turbine and air 737
703 contain 900–1800 kg of askarel each...”
compressorsasahydraulic/lubricant andaplugvalve 738
sealant. As part of the normal operation of large 739
5The term “trichlorobenzene” is used generically herein for various turbine compressors, PCB compressor lubricants 740
combinationsoftri-andtetrachlorobenzenesusedinaskarelfluids. could leak or blow by pressure seals and enter the 741
AUTJrnlHID11O356R_Art'IDS39 2P_PRroof#O1-O26/0F8/2!010
EnvironSciPollutRes
t4.1 Table4 CommercialPCBuses
t4.2 Application Aroclor(s) MetricTons Referencea
(g×106)
t4.3 Electricalequipment
t4.4 Capacitors(large,small,fluorescentlightballasts) 1242,1016,(1254)b 286,000 Durfeeetal.1976
t4.5 Transformers 1254,1260(1242,1016) 152,000 Durfeeetal.1976
t4.6 Transformerequipment EPRI1999
t4.7 -slipgears EPRI1999
t4.8 -phaseconverters EPRI1999
t4.9 Slipmotors EPRI1999
t4.10 Electromagnets EPRI1999
t4.11 Hydraulics/Lubricants/HeatTransferFluids F
t4.12 AirCompressor/Gas Pydraul G,A HOammondetal.1972;USEPA2004
TransmissionTurbineLubricants
t4.13 Turbinol O
t4.14 Santovac
R
t4.15 1221,1242
t4.16 HeatTransfer 1242,1248,1254 9P100 Durfeeetal.1976
t4.17 HydraulicFluids(andotherlubricants) 1232–1260 36,000 Durfeeetal.1976;Hammondetal.1972
t4.18 VacuumPumps D EPRI1999
t4.19 Motorcoolants(miningequipment) Frenchimport Durfeeetal.1976
E
t4.20 Heattransfersystems 1242 9,100 Durfeeetal.1976;Hammondetal.1972
T
t4.21 Vacuumpumps 1248,1254 A Hammondetal.1972
t4.22 Vapordiffusionpumps C EPRI1999
t4.23 Immersionoilsformicroscopes 12E60&PCT McCrone1985
t4.24 Opticaloilsintelescopes EPRI1999
R
t4.25 Cuttingoils 1254 A Hammondetal.1972
t4.26 PCBsIncorporatedintoProductsandMaterials R
t4.27 MiscellaneousIndustrial O 12,000 Durfeeetal.1976
t4.28 Plasticizers 52,000 Durfeeetal.1976
t4.29 CarbonlessCopyPaper(microencapsuClationofink) 1242 20,000 Durfeeetal.1976;Hammondetal.1972
t4.30 Inks N 1254 Hammondetal.1972
t4.31 Thermographicandxerographiccopying P ITF1972
U
t4.32 Paints,varnishes,lacquers,andothersurfacecoatings Many Noinfo ITF1972
t4.33 Flooringandfloorwax/sealants G,A USCFR1999
t4.34 Coal-tarenamelcoatings USCFR1999
t4.35 PipelineValveGrease 1268 G USEPA2004
t4.36 Adhesives 1221–1254 P Hammondetal.1972;EPRI1999
t4.37 AdhesiveTape USCFR1999
t4.38 CaulkandJointsealants 1254&other Multiple(seetext)
t4.39 Gasketsealers PowerResInst1999
t4.40 Insulationandotherbuildingmaterials 1254,1268 Multiple(seetext)
t4.41 Rubberproducts 1232–1254,1268 A Hammondetal.1972;EPRI1999
t4.42 Wireandcablecoatings 1254,1260 A,G Cleghornetal.1990;EPRI1999;
USCFR1999
t4.43 Dieorinvestmentcastings DecaCB(Imported) 13–22/year Durfeeetal.1976
t4.44 PetroleumAdditive 450 Durfeeetal.1976
aIngeneral,wehavecitedtheoldestprimaryreferenceforuses,assumingthatnewerreferencesgenerallyusedthefirstasasource
bAroclorsinparenthesesareknownminoruses
Ppatentliterature,Aarticleinpublishedjournal,GUSGovernmentPublication,MMonsantoMarketingLiterature