2-クロロビフェニル

1.270-1.280/15.5 °C

1.44 @ 30°C

Clear oil

... Colorless mobile oil

Lower chlorinated Aroclors (1221, 1232, 1016, 1242, and 1248) are colorless mobile oils. Increasing chlorine content results in mixtures taking on the consistency of viscous liquids (Aroclor 1254) or sticky resins (Aroclors 1260 and 1262). Arclors 1268 and 1270 are white powders.

Solubility in water varies because Aroclors are variable mixtures.

In water, 1.45 mg/L at 25 °C

286 °F (NTP, 1992)

152-154 °C; Cleveland open cup

554 to 617 °F at 760 mmHg (NTP, 1992)

290-325 °C

Warning

H373 (97.7%): May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]

P260, P273, P319, P391, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 43 reports by companies from 4 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

This chemical does not meet GHS hazard criteria for 2.4% (1 of 42) of reports.

Warning

Hazard Traits - Environmental tox

Substance: Chloro-1,1'-biphenyl

Substance: 2-chlorobiphenyl

WHO; Environmental Health Criteria No. 140: Polychlorniated Biphenyls and Terphenyls (1993). EHC are designed for scientists and administrators responsible for the establishment of safety standards and regulations and provide basic scientific risk evaluations of a wide range of chemicals and groups of chemicals.[Available from, as of June 30, 2010: http://www.inchem.org/documents/ehc/ehc/ehc140.htm]

U.S. Dept Health & Human Services/Agency for Toxic Substances & Disease Registry; Toxicological Profile for Polychlorinated biphenyls (PCBs) (November 2000). The ATSDR toxicological profile succinctly characterizes the toxicologic and adverse health effects information for a hazardous substance.[Available from, as of June 16, 2010: http://www.atsdr.cdc.gov/toxprofiles/index.asp]

TSCA CHIPs present a preliminary assessment of polychlorinated biphenyl's potential for injury to human health & the environment (available at EPA's TSCA Assistance Office: (202) 554-1404

Safe S; Crit Rev Toxicol 13 (4): 319-95 (1984). Polychlorinated Biphenyls and Polybrominated Biphenyls Biochemistry Toxicology and Mechanism of Action.

/GUIDE 171: SUBSTANCES (LOW TO MODERATE HAZARD)/ Fire or Explosion: Some may burn but none ignite readily. Containers may explode when heated. Some may be transported hot. /Polychlorinated biphenyls; Polychlorinated biphenyls, liquid; Polychlorinated biphenyls, solid/

/GUIDE 171: SUBSTANCES (LOW TO MODERATE HAZARD)/ Health: Inhalation of material may be harmful. Contact may cause burns to skin and eyes. ... Fire may produce irritating, corrosive and/or toxic gases. some liquids produce vapors that may cause dizziness or suffocation. Runoff from fire control may cause pollution. /Polychlorinated biphenyls; Polychlorinated biphenyls, liquid; Polychlorinated biphenyls, solid/

/GUIDE 171: SUBSTANCES (LOW TO MODERATE HAZARD)/ Public Safety: CALL Emergency Response Telephone Number ... As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. Keep unauthorized personnel away. Stay upwind. /Polychlorinated biphenyls; Polychlorinated biphenyls, liquid; Polychlorinated biphenyls, solid/

/GUIDE 171: SUBSTANCES (LOW TO MODERATE HAZARD)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection. /Polychlorinated biphenyls; Polychlorinated biphenyls, liquid; Polychlorinated biphenyls, solid/

For more DOT Emergency Guidelines (Complete) data for Aroclor 1232 (8 total), please visit the HSDB record page.

2 - Materials that, under emergency conditions, can cause temporary incapacitation or residual injury.

1 - Materials that must be preheated before ignition can occur. Materials require considerable preheating, under all ambient temperature conditions, before ignition and combustion can occur.

0 - Materials that in themselves are normally stable, even under fire conditions.

Products of combustion may be more hazardous than the material itself. By-products include hydrogen chloride, ... and other irritants and toxic gases ... In the range of 1112 to 1202 °F (600-650 °C) highly toxic derivatives, polychlorinated dibenzo-para-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) can be formed, which may be a greater health risk than PCBs. /Polychlorinated biphenyls/

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

Use dry chemical, carbon dioxide, or alcohol foam extinguishers. Vapors are heavier than air and will collect in low areas. Vapors in confined areas may explode when exposed to fire. Containers may explode in fire. Storage containers and parts of containers may rocket great distances, in many directions. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Notify local health and fire officials and pollution control agencies. From a secure, explosion-proof location, use water spray to cool exposed containers. If cooling streams are ineffective (venting sound increases in volume and pitch, tank discolors, or shows any signs of deforming), withdraw immediately to a secure position ... The only respirators recommended for fire fighting are self-contained breathing apparatuses that have full facepieces and are operated in a pressure-demand or other positive pressure mode. /Polychlorinated biphenyls/

If material on fire or involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Keep run-off water out of sewers and water sources. /Polychlorinated biphenyls/

Store in tightly closed containers in a cool, well-ventilated area away from strong oxidizers (such as chlorine, bromine, and fluorine). A regulated marked area should be established where this chemical is handled, used, or stored ... /Polychlorinated biphenyls/

Drums, transformers, and other containers should be frequently inspected for leakage. Store in a cool, dry, well-ventilated location. Detached storage must be used. /Polychlorinated biphenyls/

PCB material should be stored in closed containers, in ventilated areas. ... PCB's should be handled in isolated areas of the plant, where efficient ventilation systems remove airborne PCB's. ... /Polychlorinated biphenyls/

Evacuate and restrict persons not wearing protective equipment from area of spill or leak until cleanup is complete. Remove all ignition sources. Ventilate area of spill or leak. Absorb liquids in vermiculite, dry sand, earth, peat, carbon, or a similar material and deposit in sealed containers. Keep this chemical out of a confined space, such as a sewer, because of the possibility of an explosion, unless the sewer is designed to prevent the build-up of explosive concentrations. It may be necessary to contain and dispose of this chemical as a hazardous waste. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Contact your Department of Environmental Protection or your regional office of the federal EPA for specific recommendations ... Spills of one pound or more must be reported to the EPA. /Polychlorinated biphenyls/

Stop or control the leak, if this can be done without undue risk. Absorb in noncombustible material for proper disposal. /Polychlorinated biphenyls/

Environmental considerations: Land spill: Dig a pit, pond, lagoon, or holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash or cement powder, or commercial sorbents. /Polychlorinated biphenyls/

Environmental considerations: Water spill: Use natural barriers or oil spill control booms to limit spill travel. Remove trapped material with suction hoses. /Polychlorinated biphenyls/

Environmental considerations: air spill: Apply water spray or mist to knock down vapors. /Polychlorinated biphenyls/

SMALL SPILLS AND LEAKAGE: If you should spill this chemical, use absorbent paper to pick up all liquid spill material. Your contaminated clothing and absorbent paper should be sealed in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with acetone followed by washing with a strong soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

Incineration (3000 °F) with scrubbing to remove any chlorine-containing products. In addition, some chemical waste landfills have been approved for PCB disposal. More recently, treatment with metallic sodium has been advocated which yields a low molecular weight polyphenylene and sodium chloride.

Experiments on the combustion of polychlorinated biphenyls (PCB) in 1 m-long tube furnace indicated that PCB containing approx 40% Cl is destroyed within 3-4 min at 900-1000 °C using 100% excess air. Temperatures greater than 1000 °C are required to destroy PCB containing approx 60% Cl & distillation residues arising from PCB manufacturing. Domestic waste incinerators operating at 800-900 °C are unlikely to prove suitable for incinerating waste containing trace amt of PCB. Pyrolysis experiments at 900 °C with nominal residence time of 3.5 sec gave 40-60% recovery of Cl as HCl from PCB. /Polychlorinated biphenyls/

Polychlorinated biphenyls (375 g) mixed in 1242 l of #2 fuel oil was disposed of in a cement kiln incinerator with a temperature range of 1400-1450 °C. The destruction efficiency was >99.9998%. /Polychlorinated biphenyls, from table/

For more Disposal Methods (Complete) data for Aroclor 1232 (6 total), please visit the HSDB record page.

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

If material not on fire and not involved in fire: Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. /Polychlorinated biphenyls/

Personnel protection: Keep upwind. Avoid breathing vapors ... Do not handle broken packages unless wearing appropriate personal protective equipment. /Polychlorinated biphenyls/

/The worker in confined spaces/ should wear appropriate protective equipment, and be connected by a lifeline harness to an outside worker. /Polychlorinated biphenyls/

For more Preventive Measures (Complete) data for Aroclor 1232 (7 total), please visit the HSDB record page.

3.0 [mg/m3]

150 [mg/m3]

890 [mg/m3]

There are no specific treatments for PCB poisoning, since it is not usually recognized until after substantial chronic exposure. Only preventing further exposure and treating the observed symptoms can be done. Acute inhalation can be treated by administering oxygen. (L4)

Acute parenteral administration of several commercial PCB mixtures (Aroclors 1242, 1248, 1254, and 1260) and a synthetic mixture of PCB congeners reflective of PCBs detected in human milk antagonized 2,3,7,8-TCDD /2,3,7,8-tetrachlorodibenzodioxin/-induced impairment of the immune response to SRBC /sheep red blood cells/ in mice at PCB:TCDD dose ratios > 1000:1 Aroclor 1232 had no effect on TCDD-induced immunotoxicity in these studies.

The most common health effects of PCBs are skin conditions such as chloracne and rashes. Chronic PCB exposure has also been shown to cause liver, stomach and kidney, damage, jaundice, edema, anemia, changes in the immune system, behavioral alterations, and impaired reproduction. (L4)

LD50; Species: Colinus virginianus (Northern bobwhite); Concentration: 3,002 mg/kg for 5 days on treated diet plus 3 days untreated /Conditions of bioassay not specified/

LD50; Species: Coturnix coturnix japonica (Japanese quail); Concentration: >5000 mg/kg for 5 days on treated diet plus 3 days untreated /Conditions of bioassay not specified/

LD50; Species: Phasianus colchius (ring-necked pheasant); Concentration: 3,146 mg/kg for 5 days on treated diet plus 3 days untreated /Conditions of bioassay not specified/

EC50; Species: Daphnia magna (water flea, age <24 hr); Conditions: freshwater, static, 18 °C, pH 7.5-8.0, hardness 44-46 mg/L CaCO3, alkalinity 40-43 mg/L CaCO3, acidity 2.4-4.0 ppm, Ca hardness 34-36 ppm; Concentration: 125 ug/L for 21 days; Effect: reproduction, general /formulated product/

For more Ecotoxicity Values (Complete) data for Aroclor 1232 (7 total), please visit the HSDB record page.

TERRESTRIAL FATE: Aroclor 1232 is a mixture of chlorinated biphenyls with the approximate distribution as follows: 31.3% mono-, 23.7% di-, 23.4% tri-, 15.7% tetra-, and 5.8% pentachlorobiphenyl(1). Based on a classification scheme(2), an estimated Koc value of 8,400(SRC) for a representative component of Aroclor 1232, determined from a structure estimation method(3), indicates that Aroclor 1232 is expected to be immobile in soil(SRC). Volatilization of Aroclor 1232 from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 6.9X10-4 atm-cu m/mole(SRC), based upon its vapor pressure, 4.1X10-3 mm Hg(4), and water solubility, 1.45 mg/L(4). However, adsorption to soil is expected to attenuate volatilization(SRC). Aroclor 1232 is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). Aroclor 1232 had 100% reported biodegradation in screening tests utilizing BOD dilution water, settled domestic wastewater inoculum, incubated for 28 days at both 5 and 10 ppm starting concentrations(5). The chlorinated congeners in PCBs have been shown to be susceptible to reductive dechlorination by anaerobic microorganisms found in aquatic sediments(6).

AQUATIC FATE: Aroclor 1232 is a mixture of chlorinated biphenyls with the approximate distribution as follows: 31.3% mono-, 23.7% di-, 23.4% tri-, 15.7% tetra-, and 5.8% pentachlorobiphenyl(1). Based on a classification scheme(2), an estimated Koc value of 8,400 for a representative component of Aroclor 1232(SRC), determined from a structure estimation method(3), indicates that Aroclor 1232 is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(4) based upon an estimated Henry's Law constant of 6.9X10-4 atm-cu m/mole(SRC), derived from its vapor pressure, 4.1X10-3 mm Hg(5), and water solubility, 1.45 mg/L(5). Using this Henry's Law constant and an estimation method(4), volatilization half-lives for a model river and model lake are 5.7 hours and 6 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 80 days if adsorption is considered(6). According to a classification scheme(7), log BCFs of the dominant PCB congeners present in Aroclor 1232 are reported as 2.95 for monochlorobiphenyl in carp to 4.63 for trichlorobiphenyl in goldfish(8), suggest the potential for bioconcentration in aquatic organisms is very high(SRC). Aroclor 1232 is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(4). Aroclor 1232 had 100% reported biodegradation in screening tests utilizing BOD dilution water, settled domestic wastewater inoculum, incubated for 28 days at both 5 and 10 ppm starting concentrations(9). The chlorinated congeners in PCBs have been shown to be susceptible to reductive dechlorination by anaerobic microorganisms found in aquatic sediments(10).

ATMOSPHERIC FATE: Aroclor 1232 is a mixture of chlorinated biphenyls with the approximate distribution as follows: 31.3% mono-, 23.7% di-, 23.4% tri-, 15.7% tetra-, and 5.8% pentachlorobiphenyl(1). According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(2), Aroclor 1232, which has a vapor pressure of 4.1X10-3 mm Hg at 25 °C(3), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase Aroclor 1232 is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 4.6 days(SRC), calculated from a representative component's rate constant of 3.5X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(4). Although PCBs may be susceptible to photolysis, sufficient experimental data are not available to predict the relative importance of photolysis on an environmental basis(5).

The mechanism of action varies with the specific PCB. Dioxin-like PCBs bind to the aryl hydrocarbon receptor, which disrupts cell function by altering the transcription of genes, mainly be inducing the expression of hepatic Phase I and Phase II enzymes, especially of the cytochrome P450 family. Most of the toxic effects of PCBs are believed to be results of Ah receptor binding. Other PBCs are believed to interfere with calcium channels and/or change brain dopamine levels. PCBs can also cause endocrine disurption by altering the production of thyroid hormones and binding to estrogen receptors, which can stimulate the growth of certain cancer cells and produce other estrogenic effects, such as reproductive dysfunction. They will bioaccumulate by binding to receptor proteins such as uteroglobin. (A3, A4, A30, A66)

/AQUATIC SPECIES/ In channel catfish, 100% mortality was observed in an immunized group that was intraperitoneally injected with 70 mg/kg Aroclor 1232 and then challenged with the virulent bacterium Aeromonas hydrophila, while an immunized control group had no mortality. The PCB-treated group also showed significantly decreased serum beta-globulin levels, slightly elevated serum alpha-globulin levels, and decreased peritoneal macrophage activity compared to the control group

/AQUATIC SPECIES/ The 48-hr EC50 on the growth of Euglena gracilis /was determined/ to be 4.4 mg/L for Aroclor 1221 and 55 mg/L for Aroclor 1232. Aroclor 1242 showed no inhibition at 100 mg/L. Aroclor 1221, at the EC50 concentration of 4.4 mg/L, significantly depressed carbon fixation and chlorophyll levels, but did not affect oxygen consumption. Uptake of L-leucine was increased 2-fold, but incorporation was not affected. Uridine uptake was significantly decreased, but thymidine uptake and incorporation were not affected.

/OTHER TERRESTRIAL SPECIES/ Drosophila melanogaster (fruit fly) /were exposed/ to the dry residue of various PCBs ... Flies /were exposed/ to Aroclors 1221, 1232, 1242, and 1248 at 200 or 800 ug. No mortality was observed after 48 hr at 200 ug. At 800 ug, there was an increase in mortality with decreasing chlorination (after a 48 hr exposure to Aroclor 1221, 92% had died; only 45% died after exposure to Aroclor 1248 over the same length of time). No mortality was observed after a 48 hr exposure to 2000 ug of Aroclors 1254, 1260, 1262, or 1268.

An assessment of USEPA STORET Database found Aroclor 1232 detected in 1.0% of 707 observation stations(1). Aroclor 1232 was detected at a mean concentration of 39 ppb in 14 of 20 treated wastewaters collected from the aluminum forming industries(2). Aroclor 1232 was detected in waste water samples collected from Illinois at a mean concentration of 0.05 ug/L(3). A survey of the EPA priority pollutants in Illinois publically owned treatment works identified Aroclor 1232 in wastewater effluent samples at a mean concentration of 0.06 ug/L(3).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for a representative component of Aroclor 1232 can be estimated to be 8400(SRC). According to a classification scheme(2), this estimated Koc value suggests that Aroclor 1232 is expected to be immobile in soil. PCBs, such as Aroclor 1232, are readily adsorbed onto solids (especially organic matter) and are often immobilized in sediment, although eventual re-solution into the water column can occur(3).

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 1 lb or 0.454 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV.D.3.b).

One proposed molecular target for PCB disruption of calcium homeostasis that may be involved in neurological and neurodevelopmental effects is ryanodine-sensitive Ca+2 channels. Commercial PCB mixtures with intermediate to high degrees of chlorination (Aroclors 1248, 1254, and 1260) enhanced ryanodine binding to calcium release channels in sarcoplasmic reticulum membranes from skeletal or cardiac rabbit muscles, and mixtures with lower (Aroclors 1221, 1232) or higher (Aroclor 1268) chlorination showed little enhancement. Examination of selected pentachlorobiphenyls indicated that ortho substitution favored activity; 2,2',3,5',6-pentaCB induced the greatest enhancement of ryanodine binding, whereas the 3,3',4,4',5-isomer did not enhance binding. The 2,2',4,6,6'-isomer with full substitution at the ortho positions produced less enhancement than the 2,2',3,5',6-isomer, indicating that some degree of rotation about the biphenyl bond may be important for full activity. Results from studies with hippocampal slices from freshly dissected rat brains indicated that perfusion with a tri-ortho congener (2,2',3,5',6-pentaCB) enhanced ryanodine binding and inhibited electrophysiological responses to electrical pulse stimulations, but a mono-ortho congener (2,3',4,4'-tetraCB) showed no enhancement of ryanodine binding and no inhibition of electrophysiological responses to stimulation. Offspring of rats exposed to gavage doses of 8 or 32 mg/kg/day 2,2',3,5',6-pentaCB on gestation days 10-16 displayed neurobehavioral changes as adults (depressed open field locomotor activity, faster acquisition on a working memory task, and no changes in a delayed spatial alternation task) and changes in ryanodine binding to calcium channels in specific regions of the brain (e.g., decreased in hippocampus and increased in cerebral cortex). Although it is not understood how these changes in ryanodine binding are specifically related to the observed neurobehavioral changes, the results from this series of studies emphasize the potential importance of Ah receptor independent mechanisms in PCB-induced neurological and neurodevelopmental effects.

The relative potencies of the commercial polychlorinated biphenyl (PCB) mixtures Aroclors 1260, 1254, 1248, 1242, 1016 and 1232 to inhibit the murine splenic plaque-forming cell response to sheep red blood cells was determined by dose-response ip treatment of C57BL/6 mice followed by logit plot analysis of the data. The ED50 values obtained for Aroclors 1260, 1254, 1248, 1242, 1016 and 1232 were 104, 118, 190, 391, 408, and 464 mg/kg or 0.28, 0.35, 0.66, 1.5, 1.5 and 2.0 mM/kg, respectively. The higher chlorinated PCB preparations (Aroclors 1260, 1254 and 1248) were more potent than the lower chlorinated preparations (Aroclors 1242, 1016 and 1232). Previous studies have shown that the interaction of a subeffective dose of Aroclor 1254 (25 mg/kg) with an immunotoxic dose (3.7 nM/kg) of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) resulted in significant antagonism of the toxicity of the latter compound. Co-treatment of mice with a 25 mg/kg dose of all the commercial Aroclors and with a 50 mg/kg dose of a reconstituted PCB mixture (resembling a PCB extract from human milk) with TCDD (3.7 nM/kg) showed that, with the exception of Aroclor 1232, all of the commercial PCBs and the reconstituted PCB mixture significantly antagonized the dioxin-mediated inhibition of the splenic plaque-forming cell response in C57BL/6 mice.

PCBs are absorbed via inhalation, oral, and dermal routes of exposure. They are transported in the blood, often bound to albumin. Due to their lipophilic nature they tend to accumulate in lipid-rich tissues, such as the liver, adipose tissue, and skin. Metabolism of PCBs is very slow and varies based on the degree and position of chlorination. PCBs are metabolized by the microsomal monooxygenase system catalyzed by cytochrome P-450 enzymes to polar metabolites that can undergo conjugation with glutathione and glucuronic acid. The major metabolites are hydroxylated products which are excreted in the bile and faeces. The slow metabolism of PCBs means they tend to accumulate in body tissues. (L4, T6)

Summary of former end uses for various Aroclors:

PCBs were used as coolants and lubricants in transformers, capacitors, and other electrical devices (such as fluorescent lights and refridgerators) produced before 1977. PCBs may contaminate the air and water near hazardous waste sites. In addition, PCBs bioaccumulate in the environment and may be found in fish, meat, and dairy products. (L4)

PCBs /were/ ... prepared industrially by the chlorination of biphenyl with anhydrous chlorine in the presence of a catalyst such as iron filings or ferric chloride. The products are complex mixtures of chlorobiphenyls, whose degree of chlorination depends principally on the time of contact (12-36 hr) of the biphenyl with anhydrous chlorine. The crude product is blown with air, and a small amount of lime is added to remove hydrogen chloride and ferric chloride. The resulting chlorinated mixtures are batch-distilled to remove color and traces of hydrogen chloride and ferric chloride. /Polychlorinated biphenyls/

The Aroclors are characterized by four digit numbers. The first two digits indicate that the mixture contains biphenyls (12), triphenyls (54) or both (25, 44); the last two digits give the weight percent of chlorine in the mixture (e.g., Aroclor 1242 contains biphenyls with approximately 42% chlorine). /Polychlorinated biphenyls/