Document rpJZN7YzMy7mRe4gzB4q18Eg0
CHAPTER V POLYCHLORINATED BIPHENYLS
PRODUCTION AND USE '
HONS 008974
V. Production and Use
J nt roduci. i on
iLpJj'S.y PX.LnJ! tcdJSijJher^vl s
Polychlorinated biphenyls (PCBs) constitute a large group of com pounds which are characterized by the partial or complete chlorination of the biphenyl molecule.
This report covers the production and use of four groups of poly chlorinated biphenyls with the trade name Aroclor. Each group contains a certain percentage of chlorine along with the biphenyl molecule. Their designations are Aroclor 1242, 1016, 1254 and 1221 containing 42%, 41%, 543!, and 21% chlorine respectively.
Summary An overall material balance for PCDs with estimates of reliability
of data provided by EPA is shown in Figure 1 for 1974(5).
The total amount of land destined wastes from manufacturers and producers, 536 Kkg, represents a small fraction of the total PClis entering landfills and dumps yearly (5). The estimated yearly rate of PCBs entering land disposal sites is 5,454 kkg primarily due to the disposal of capacitors (5).
The data on industrial discharges to water and sewers is based on Information supplied by Industry.
Very little has been done to control air emissions of PCBs in U.S. Industrial facilities.(2) It has been assumed by industry that the low vapor pressure of PCBs will result in very little air contamination. Therefore, data is not available for the entire industry on volumes and concentrations of Sir pollution resulting from manufacturing processes. It is known, however, that considerable air pollution may result from
1 HONS 008975
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figure I. Ovfi,'i)l tViIcr I I'.l8ncc with fsUflwtrs ofRcHl>1 M t y<*f Val'Wt
In Ug
(i>)
' HONS 008976
I
?.
paper incineration, foundaries where imported casting waxes are heated to high temperatures, and in some manufacturing processes (2).
The distribution of PCB wastes in water, incineration, and land are shown in Table 1 for 1974 (S). There is no collective data for the industry on air emissions. Incineration data as mentioned before is included instead of air emissions data.
Media distribution of wastewater volumes is shown in Figure 2. Average wastewater flow data was collected from five transformer in dustries. (b) The average of these waste flows was taken to be be the average flow for the rest of the industry. This value may be quite over estimated 40X) since two of the industries are considered to be the largest.
for the capacitor industry, wastewater data from 14 companies was available. (0) The average daily wastewater discharge for the entire industry was estimated the same as in the transformer industry (i.e., the average daily flow for 14 plants was extrapolated to 19 plants).
The location of producers and users of PCBs are shown in Figure 3 (3).
Production
,
Annual production of polychlorinated biphenyls from 1930 to 1976 in
the U.S. lias been estimated to be 636,346 Kkg (5). In 1974, the pro
duction in the ll.S. was Hi,393 Kkg (5). Figure 4 lists the quantity of
PCIis sold, exported, imported, and kept in stock during 1974.
HONS 008977 3
Table; 1. Media Distribution of Waste in 1974 in kkg With Estimates of __ _______________________ ___ReHability of Values__________________________ ___
Amount Disposed or lost
Estimated Reliability
of Values
I'CHs Disposal to Land (assume PCBs to be 30* of total solid wastes) from RCIis manufacture From capacitor industry Troin transformer industry From investment casting
Incineration of Scrap PCIls From PCBs manufacture From capacitor industry From transformer industry
Industrial Discharges to Water and Sewers (as PCIls)
From PCIls manufacture From capacitor industry From transformer industry
Spills during Transport
13.6 218 123 182
236 659 291
.5* .95* .045*
4.64
4 50* 4 50* 4 50* 4 30*
' 4 15* 4 20* 4 20*
4 40* 4 60* 4 60*
!*>jJ du) ..fn
+ 50*
)U,ui .
* Developed from data supplied by industry. Most analyses for PCBs concentrations in industrial wastewaters are probably not more accurate that - BO per cent.
HONS 008978 4
e - ESTIMATED Figure 2. Media Distribution Wastewater Volumes
MQNS 008979
HONS 008980
CAPACITOR APPLICATIONS
TRANSFORMER APPLICATIONS
Figure A. U.S. PCli Market - 1974(5) in kkg
HONS 008981 7
The sole producer of PCBs in the U.S. is Monsanto, located in Sauget, Illinois. At the end of this year, PCBs will no longer he
produced in the United States by this company.
O ', " Monsanto, however, expects a small steady growth of usage of (. u`
PCBs over the next few years (3).
Nv
*
Production I'rocosses
.X
/T1 . _
There are two main steps used in the production of PCiis; (3)
1. biphenyl is chlorinated with anhydrous chlorine in the presence of ferric chloride to produce crude PCB.
Z. The crude PCB is distilled to obtain the finished product.
figure 5 shows the steps involved in the production of PCBs (3).
There are four PCB products manufactured called Aroclors 124Z, 1016, 1254, and 1221. Their manufacture is dependent on the amount of chlorine, biphenyl and catalyst.
In order to produce PCBs, a chlorinator is first charged with the proper quantity of biphenyl and catalyst and is then heated beyond the melting point of biphenyl. Vaporized chlorine is then circulated through the chamber by means of a pump. The contact time in this chamber varies from 12-36 hours depending on the intended chlorine content of the finished product.
The crude product is held at elevated temperatures and blown witli dry air for several hours, after which it is sent to a raw Aroclor storage tank where a few tenths of IX alkali is stirred with the material to react with any remaining hydrogen chloride or ferric chloride. The raw Aroclor is then batch distilled under re duced pressure hy steam jet ejectors to remove color, and traces of
MONS 008982
8
PREPARATION OF CRUDE CHLORINATED BIPHENYLS-MONSANTO KRUMMRJCH PLANT OIS7ILLATION OF CRUDE PRODUCTS - MONSANTO KRUMMRICH PLANT
IN:i*C NATION Figure 5. Process for Production of PCBs (3)
MONS 008983
hydrogen chloride and ferric chloride. The condensate from the distil lation process is the final product. The "bottoms'' are called montars which are drummed and sent to incineration.
1 he vapors that arise in the chlorination are scrubbed with liquid Arcelor and the gaseous MCI is sent to a purification process. 1 he air from the blowers used to dry the crude product is scrubbed with water and vented to the atmosphere.
The aforementioned process is used to produce Aroclor 1254, 1242 and 1221.
In the production of Aroclor 101G, the distillation process is curried out in a gas fired retort and vacuum distillation lower. The first cut from the lower is recycled back to the retort. The overhead from the tower is the finished product. The bottoms are the montars which are sent to incineration.
Production Process Hastes Those wastes generated in the manufacturing process include
liquid from the scrubbers, condensate from steam jet ejectors, water used in drip pans and drums, and thu montars (bottom cut from stills). In the incineration process, the sources of wastewaters are the venturi scrubber 1 iquid and the water phase from the separator sump in the incineration area.
Typical quantities of water used and discharged from the plant are shown in Figure 6 (3).
Doth the process wastes and incinerator wastes are directed to the sower. The total wastewater volumes and concentration of PCBs from these sources are shown in Table 2 (3).
HONS 008984
10
IMCINTRATOR
WATER PHASE rROM TIIL' SUMP
54,432
?.%
WATER USED FOR nor GAS QUENCHING
1,034,208 .. r~ - j
tT
>1 t>n
- WATCH SCRUBBER
54,432 2t FLOOR HASH HOURS
2 7,216 1 % CONDENSATE FROM S 1 I.AM Jll EJECTORS 2%
54,432
PROCESS WAT Eli
CONDENSATE FROM STEAM TRACERS 4%
108,864
SHOWERS, EYEBATH 27,216 i*
Finm-p G. Volume of Wastewater Discharyed -
Ipd (3)
HONS 00898S 11
' Tnb Io 2 Cl) .V? LtfHi1-? r_ 01 sc ha r-ge from Monsanto Plant
Manufactur ing Process
Incineration
flow, l|)'l PCBs, ppii) I'Clls, Kg/duy
,>
i.) \'j.
Total discharge -
1 ,C>G3,000
1,000,000
./I) .Jh
rh:,.
1.23
-V
2,722,000 1 pd
f'?u.
The discharge of all wastes to the air, sewers, incineration. and landfills are enumerated in figure 7 (5). Figure 0 lists the - ' various sources of wastes and their destination in the environment (3),
i f K.
/ Figure 7. 1974 Media Distribution of Wastes for Producer in kkg
Uses The major uses of PCBs arc in the manufacture of capacitors and
transformers. Imported PCBs are used in the investment casting indus try and for heat transfer fluids. The end usage of PCBs in 1974 is shown in Figure 9.
J
. Jf J-j
......
'' <
JJc.^ y '.wf
12
I*
2-
tl r /<'
HONS 008986
VAPOR FROM JET EJECTORS--------
1
EXHAUSTS FROM THE SCRUBBER GENERAL)----------- 1
SURFACE AREA EVAPORATION (IN GENERAL)
CONDENSATE FROM STEAM 'EJECTORS NON-CONTACT COOLING WATER--------------SCRUBBER LIQUOR -----------------------------------------
MONTARS ----------------------------------------------------------------BOTTOMS FROM SEPARATOR SUMP--------COLLECTION FROM ALL DRIP PANS-
RAGS FOR CLEANING------FLOOR DRY---------------------------SPENT FILTER PAPERS FULLERS EARTH --------------
ffln TO SEWERS
INCINERATION
LANDFILL
Figure 8. Non-Product PCB Discharges at Monsanto's Krummrlcb Plant
HONS 000907
OTIIFR USES
/,.l* no
I-Jr' INVESTMENT ^ CASTING WAX
1.2*
880
figure 9. End Use of PCBs (5) in Kkg
The total industrial usage of I'CBs in 1974 was 15,659 Kkg. (5).
A summary of the production and uses of PCBs over 1972-1975 is given in figure 10 (5).
There are 37 user plants in the United States - 19 capacitor plants and IB transformer plants. Their locations arc listed in Tables 3 and 4 (3).
CAJl^AorJ ndus ti'_,v In the capacitor industry, the usage of PCBs is split roughly
evenly between the production of large and small capacitors. Approxi mately 95% of the capacitors manufactured in the U.S. contain PCBs (7). Generalized flow diagrams for the manufacture of large and small capacitors are shown in Figures 11 and 12 (3). The processes involved in the manufacture of capacitors include: filling (under vacuum), sealing, deoiling, and testing.
HONS 008988 14
Figure 10. U.S. Production and Usage of PCBs Summary Over 1972-75 HONS 008989
Tab'l_e_3 U. S. Capacitor Mai ufactnring Industry_ Usjnij_ PCRs
Company IJdime ( in order of l'Clls_ ejj'OoJ
Location of_lhe_P1 an t
General Electric Company
Woslinghouso Electric Corp. Aerovox Universal Manufacturing Corp.
Cornell Dubilior
I'.R. Mallory & Co., Inc.
Sangamu Electric Co.
Sprague Electric Co.
Electric Utility Co.
Capacitor Specialists Inc.
JARI) Corp.
York Electronics
-
McGraw-Edison
Rl' Interonics
Axel Electronic, Inc.
Tobe Bcutschmann Labs.
Cine-Chrome Lab, Inc.
Hudson lalls, N.Y. ft. Edward, N.Y. Bloomington, Ind. New Bedford, Mass. Bridgeport, Conn. Totowa, N.J. New Bedford, Mass. Waynesboro, Tenn. Pickens, S. Carolina North Adams, Mass. LaSalle, 111. Escondido, Calif. Bennington, Vt. Brooklyn, N.Y. Greenwood, S. Carolina Bayshoro, L. 1., N.Y. Jamaica, N.Y. Canton, Mass. Palo Alto, Calif.
HONS 008990 16
Table 4 U.S. Transformer Manufacturing Industry Using I'CT.s
Company Nmjir
Location of the Plant
Westingbousc L'lcctric Corp.
General L'lcctric Company
llesenrch-Cottrcl1 Niagara Transformer Corp. Standard Transformer Co.
Helena Corp.
Hevi-Duty electric
Kuhlmaii Electric Co.
Electro Engineering Works
Envirotecli Buell
1
11.E. llptegraff Hfg. Co.
H.K. Porter
.
Van Tran Electric Co.
South Bo:,ton, Va. Sharon, Pa.
Rome, Ga. Pittsfield, Mass.
Finderne, N.J.
Buffalo, N.Y.
Warren, Ohio Medford, Oregon
Helena, Alabama
Goldsboro, N.C.
Crystal Springs, Miss.
San Leandro, Calif.
Lebanon, Pa.
Scottsdale, Pa.
Belmont, Calif. Lynchburg, Va.
Vandalia, 111. Waco, Texas
HONS 008991 17
e*xj Figure 11. Generalized Flow Diagram for the Manufacturing of Small Capacitors
HONS 008992
Figure 12. Generalized Flow Diagram for the Manufacturing of Large Caoacitors MOMS 008993
Sources of wastewater in the manufacturing process consist of scrap PCIls collected in pumps, drums and drip pans, contaminated vacuum pump oils, fractionator bottoms from trichloroethylene recovery, caustic bath (some plants), spent detergent wash and rinse water from capacitor or component cleaning operations, steam condensate from jet ejectors, seal water used in vacuum pumps, water used in phosphatizing and fluoride baths, water spray used in the paint booths, boiler blow downs and cooling tower blow down.
Solid wastes consist of scrap capacitors or capacitor interiors, floor dry and rags and newspapers used for cleaning spills, spent fuller's earth and other filtering media used for PCBs filtration and waterless cleaners used at some plants for hand cleaning purposes.
The effluent from these plants range from 9,450 - 4,762,800 lpd (3). The PCB content ranges from .0005 - 1.08 ICg/day on the average (3).
The quantities and characteristics of the individual process wastes for the industry are not available. Their nature is highly variable due to the variety of housekeeping practices provided In each plant. In many cases, process wastes are segregated, recycled or treated, and discharged to rivers or sewers. Typical treatment processes include oil/water separation, lagooning, aeration, filtration and carbon ad sorption, and incineration (5).
Typical flow rates and PCI! concentrations from capacitor plants are given in Table 5 (3). Figure 13 shows the distribution of wastes in the environment for 19/4 (5).
HONS 008994 20
Table 5 Range of flow Rt_es__f'_ PCD C o_n c_e ri t r a_t_i_on_ i
from Capacitor Mami .f u c_t u r 1ng_ _M an_t_$
uqji t s
Plant Ko. 100 101 103
104
)0!<
106 107 106'
109 110 111* 112* 113 126
Outfall:; 001
Ff fluent Flew Kite "nuTAluy"
600,000
_ - -Pfrio-nt PC?) Content wZs'iT" ' avu/r ox avn/rvo:
r//!,:,
0.1134/0.3670
Unit
9,000 161/101 0.0171/0.0171
001
007.000
9
0.0603
002
103.000
3.2
0.0044
003
30,000
3.4
0.0010
Major outfall
1,000,000
Cooling water
t, jxof drains
100,000
Leb ( i oof
fir* i ns
32,000
C't*.\5JX'si-oi cooling
water
7?,000
I'.iint strip rinse
30
21
7.8
4.4
3.7 4000
0.1850
0.0065 0.0011 0.00??. 0.0002
Major outfall 1 m jipjoy paint
IxoiJu;
Ko;w
630,000 1,300'
370 13,300
2.00r.D 0.1664
330,500 2G.G
0.075
Nckk;
130,000 1900/4000 7.3769/3.754C
CeoJ inf| vV.xr
(. Un In PWw:V..vn Cooling water l<CX>f ruins f Storm
46,000
179,000? 7,900
unlar wi
43/108
338/703 1360/2370
3/11
0.0180/0.0432
0.3636/0.7535 0.3290/0.0373
001
100,000
37/03 0.0475/0.0692
Mono
2,370 021
0.0176
No>o
16,000
8.7 ,
0.0013
None
10,224
130
0.0110
001
12,000 14.3
0.0014
None
300 GZ00'
0.03
Disposition of effluent
River
Sower
River Rj Ver River
Rj ver
River
River
Rivet River
River River
Sever
Stvvrs
River
Sever River River River
Sever
Scwr
Stwr River
!kwr
W^t/?n! '
(1) Oi r,rk uffd cure r*vo*y 4-5 vwohs.
(7) Cor.Uiins 10,000 (/ <1 sanitary scsmcto ;md
1)000
of surface w.iicv inf) lljr.it ion
farililies recycle rvr-t. of the >y.>n-cr>nlncl cooliny
Witt r vr',(\) .it U plant. 'llvt-to c! f1vents o*>nsi*.l of a ramll
fj action of Uic tooling water plus tlK-ir sanitary diselvaiyc.
MGNS 000995 21
UK - UNKNOWN Mgurel3. Distribution of Wastes in Environment
for Capacitor Industry in 1974 i n kkg
HONS 008996 22
Trans forum r 1 n du st ry
In the transformer industry, PCHs are used in the manufacture of new transformers and in the repair of old transformers. Flow diagrams for the manufacture of transformers are shown in Figures 14, 15, and 16 (3). Only 5% of the transformers manufacture in the II.S. contain I'CPs (7). Typical manufacturing operations include a predrying step for removal of moisture from the transformer interiors, several stages of askarel filling and topping, addition of electrical connections and bushings, electrical testing and sealing.
Water is not an essential component of the transformer manufacturing process (3). It is primarily used for non-contact cooling purposes. PCBs, consequently, reach water streams by occasional losses during handling and residuals accumulated around drainage .systems from past operations where no precautions were taken in the handling and disposal of.PCBs (3).
Wastewater sources include waste askarel collected in sumps or pans at filling stations, contaminated vacuum pump seal oil and con taminated kerosene like petroleum distillate (3). Solid wastes in clude rags and floor dry used for cleaning purposes and spent clay from Aroclor filtration operations (3).
HONS 008997 23
SOUP AlKARCl
SPCNT
FUU. CR'l CARTH
SCRAP 0*CS '
Figure 14. Transformer Filling Operation With Oven Predrying of Assembled Hardware
HONS 008998
Figure 15
Transformer Filling With Oven or Vacuum Chamber Predrying of Transformer Internals
(IONS 008999
Figure 16 Transformer Filling With Vapor Phase Predrying of Interiors HONS 009000
One plant, does have a PCB related process where water is used in the waste incineration system for quenching hot gases.
No wastewater treatment methods are used in the transformer industry for the removal of PCBs.
Most plants report that their water usage is minimal (3). Data from a few plants is given in Table 6 (3). Figure 17 shows the distribution of wastes in the environment (5).
In the repair of transformers, sources of wastewater include accidental spills, junked transformers, cleaning drums used to transport PCBs, and scrap TCBs disposed of in landfill. It was esti mated that the repair industry used 7% of the total, usage of PCBs by the transformer manufacturing industry in 1974 (5).
Processes used in maintaining and repairing transformers are shown in Figures 18 and 19 (5).
jnvestmcnt__Cas1.iny Industry. The sole supplier of PCB blended waxes is Yates Manufacturing
Cu. in Chicago, Illinois. PCBs are imported by this company in the form decachlorobiphenyl (deka) at the rate of 136 - 227 Kkg/year (6).
A typical manufacturing process used by this industry is shown in Figure 20 (6). Waste streams arc shown in Figure 21 (6).
In the manufacturing process, a wax pattern is made and a ceramic mold is formed on the wax. The wax is melted out, and the mold, after baking in a furnace is ready for use. PCB loss to the atmo sphere could be significant during the melting out process and in the furnace.
HONS 009001
27
Table 6
PCB _C oncen t ra t i_on i n E_f fl_u en ts__ fro m Transformer Ma nu_Tn c tti r i ng_P1 a n t. s
Want No. W1' 134
111.
116(3)
117
Affluent Flew Hate
(ial/buy
Effluent. I*ai Content
nri> lb /d<w
Avg/lVix .
hvtj'/i to<
I>i r.fooition of Kffluent.
1,3)0,000 560,000
4.9/120 7/75
0.0535/1.311 0.0321/0.344
River River
50,000,,. 2,000l '
Unkriewt Unknown
UnJaio-n Unknown
Sewer River
30,000
24,000 150,000
<1/2 2/113
<1/3
<0.0003/0.0006 0.0004/0.022G 0.0013/0.0039
River River River
252,000 / n ^l 3.4/11 370,720 #2 2.3/3.0 504,000 \ yI 0/19.1
0.0071/0.0231 0.0066/0.0120 0.03J6/0.0003
oo
2D.G/iuiknown 0.0032/unknasn
River Ri.vtr River
Sever
NyUr.,*
(1) Vhi% plant h.i.\. other discharges out of Uicir pro|xn;tioj. Pisclmrcjc lifted nLove are Uxarc associated with PCH related operations.
(2) list invited .
(3) bischuges designated os #1, 12, and <3 rue Uie cunbinuJ effluents
fitn their p:j.*er house, and one each frcu lheir two i vmufacturiivj
areas,' levi'ceiively. /vxoiding to Uie plants' Co:j>s of rjvjim.Mr
permit
ion foira, filed in duly 1971, this plant lias 13
ouLfalls.
HONS 009002 20
UK - UNKNOWN igtire 17. Distribution of Wastes In the Environment
for Transformer Industry in 1974 in kkg
29 HONS 009003
Figure 18. Transformer Repair
HONS 009004 30
figure 19. Transformer Maintenance & Servicing
31 HONS 009005
IMPORTED PCBs
WAX --------
PATTERN WAX
_JSTEAM
CLARIFIED
________ /HAX
DEWATERING IN / USED WAX
OPEN KETTLES
STORAGE
Mfr- BOTTOMS TO DISPOSAL
PATTERN WAX PRODUCTION:
WAX PRODUCTION
DIE PATTERNS
^PACKAGING AND SHIPMENT (30* PCBs,IN PLASTIC BAGS
REMOVAL OF PATTERNS FROM DIES
ADDITION OF SPRUES AND GATES
HEAT
HOT SPRUES AND GATES
EXCHANGER WAX
FORMATION
COATING WITH 01P SEAL WAX
INVESTMENT CASTING PROCESS Figure 20. Flow Chart of PCB's Usage In Investment Casting
HONS 009006
OtSFOSAl
SCMOC
Figure 21. Idealized Flow Chart for an Investment Casting Foundry* Showing Haste Streams
HONS 00900?
Solid wastes include unreclaimed used wax, bottoms from reclama tion, waste spills, and equipment cleanout. These wastes are sent to landfills arid were estimated to be 182 Kkg in 1974 (5).
Process water docs not appear to be used except possibly for cooling purposes.
Non-Industrial Waste Sources and Quantities There are no natural sources of PCBs in the environment. Those
PCBs found in the environment are a result of previous discharges of the material.
It is believed that much of the PCBs measured in streams and rivers arc a result of fallout from the air (2).
Over the past few years studies have been done on various drainage basins in the U.S. Hater data indicates PCB levels of .2-3.0, .1 -.3 .1-1.0, and .1-.8 Ppm over the years 1971-1974 respectively (1). PCBs measured in ho(tom sediments over that period of time ranged from 1.2 64.0, 2-30, 0-00, and 2-1 CO mg/Kg respectively (1).
Inadvertent discharges of PCBs into the environment have been recognized from the following sources: paper recycling facilities where effluent recycle streams were contaminated with PCBs, effluents from plants which were engaged in the manufacture of machinery and mechanical products, chlorination of biphenyls in wastewater treat ment plants, discharges from paper mills and aluminum foundaries, and runoff from sewage sludges on the land.
It has been estimated that over the period 1930-1975, only 25,000 Kkg (t 70?) or 4.4? of the total quantity of PCBs purchased have been destroyed (5). It is believed that 60? of the total purchase or 344,040 Kkg (1 202) are still in service and 200,000 Kkg (1 40") are currently in the environment (0).
HONS 009008 34
Reftrren ce s_
1. Dennis, D.S., "PCBs in the Surface Waters and Bottom Sediments of the Major Drainage Basins of the U.S. USEPA, March 1976, EPA-560/6-75-004, National Conference on Polychlorinated Biphenyls, pg. 183-194.
?. Kleincrt, S.J., "Sources of PCBs in Wisconsin," USEPA, March 1976, EPA-560/6-75-004, National Conference on Polychlorinated Biphenyls, pg. 124-126.
3. USEPA, January 1976, Assessment of Wastewater Management Treatment Technology, and Associated Costs for Abatement of PCBs Concentrations in Industrial Effluents, Task II, Prepared by Versar, Inc.
4. USEPA, Criteria Document, EPA 440/9-76-021. 5. USLPA, Office of Toxic Substances, February 25, 1976, EPA 560/
6-76-005, PCBs in U.S. Industrial Use and Environmental Distribution
Task b
6. Versar, Inc., January 1976, PB231842, Development of a Study Plan for Definition of PCBs Usage, Wastes, and Potential Substitution in the Investment. Casting Industry, Task III.
7. Durfce, R.L., "Production and Usage of PCBs in the United States," . USEPA, March 1976, EPA-560/6-75-004, National Conference on Polychlorinated Biphenyls, pg. 103-107.
MOMS 009009
35