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Chemical Fact Sheet

Chemical Abstract Number (CAS #) 11141165
CASRN 11141-16-5
SynonymsPCB-1232
Aroclor 1232
Analytical Methods EPA Method 505
EPA Method 508
EPA Method 608
EPA Method 617
EPA Method 625
EPA Method 8081
EPA Method 8082
EPA Method 8270
Molecular FormulaUVCB

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use Aroclor was formerly used as hydraulic fluids, rubber plasticizer, and adhesives.
Apparent Color CLEAR OIL; Colorless mobile oil
Boiling Point 290-325 DEG C
Molecular Weight Average mol wt: 221
Density EPA 440/5-80-068] 1.270-1.280/15.5 deg C
Sensitivity Data Irritating to skin and eyes. Polychlorinated biphenyls
Environmental Impact PCBs, such as Aroclor 1232, are currently released to the environment from landfills containing PCB waste materials and products, by incineration of municipal refuse and sewage sludge, by improper (or illegal) disposal of PCB materials (such as waste transformer fluid) to open areas and by an environmental cycling process of PCBs previously introduced into the environment. Aroclor 1232 is a mixture of different congeners of chlorobiphenyl and the relative importance of the environmental fate mechanisms generally depends on the degree of chlorination. In general, the persistence of the PCB congeners increase with an increase in the degree of chlorination. In contrast to the more highly chlorinated Aroclors, Aroclor 1232 appears to be reasonably degradable in the evironment. One screening study has shown that Aroclor 1232 is biodegradable. Biodegradation is probably the ultimate degradation process in both natural water and soil systems since other degradation does not appear to be important. The PCB composition of the biodegraded Aroclor is different from the original Aroclor. If released to soil, the PCB congeners present in Aroclor 1232 will become tightly adsorbed to the soil particles. In the presence of organic solvents, PCBs may have a tendency to leach through soil. Significant volatilization of Aroclor 1232 may occur from soil surfaces. Enrichment of the low Cl PCBs occurs in the vapor phase relative to the original Aroclor; the residue will be enriched in the PCBs containing high Cl content. If released to water, adsorption to sediment and suspended matter will be an important fate process. Although adsorption may immobilize Aroclor 1232 for relatively long periods of time, eventual resolution into the water column has been shown to occur. The PCB composition in water will be enriched in the lower chlorinated PCBs because of their greater water solubility, and the least water soluble PCBs (highest Cl content) will remain adsorbed. In the absence of adsorption, Aroclor 1232 volatilizes relatively rapidly from water. However, strong PCB adsorption to sediment significantly competes with volatilization which may have a half-life ranging from 2 months to 1 year in typical bodies of water. The PCB congeners present in Aroclor 1232 have been shown to bioconcentrate significanly in aquatic organisms. If released to the atmosphere, the PCB congeners in Aroclor 1232 will primarily exist in the vapor-phase. The dominant atmospheric transformation process for these congeners is probably the vapor-phase reaction with hydroxyl radicals which has estimated half-lives ranging from 12.9 days to 3.1 months. Physical removal of Aroclor 1232 from the atmosphere is accomplished by wet and dry deposition with enrichment of the most volatile PCBs, although wet deposition will be more important than dry deposition. The major PCB exposure routes (all Aroclors and congeners) to humans are through food and drinking water, and by inhalation of contaminated air. Dermal exposure is important for workers involved with handling PCB-containing electrical equipment, spills or waste-site materials and for swimmers in polluted water.
Environmental Fate TERRESTRIAL FATE: PCBs, such as Aroclor 1232, are mixtures of different congeners of chlorobiphenyl and the relative importance of the environmental fate mechanisms generally depends on the degree of chlorination . In general, the persistence of PCB congeners increases with an increase in the degree of chlorination. One screening test has shown that Aroclor 1232 is readily biodegradable. Since no other degradation mechansims have been shown to be important in soil systems, biodegradation may be the ultimate degradation process in soil. Estimated Koc values have shown that the PCB congeners present in Aroclor 1232 will be tightly adsorbed in soil with adsorption generally increasing as the degree of chlorination of the individual congeners increase. Aroclor 1232 should not leach significantly in most aqueous soil systems although the most water soluble PCBs will be leached preferentially. In the presence of organic solvents, which may be possible at waste sites, PCBs may have a tendency to leach through soil. Soil volatilization data for the Aroclors more highly chlorinated than Aroclor 1232 indicate that significant volatilization of Aroclor 1232 may occur from soil surfaces(2,SRC); since Aroclor 1232 isomers are more volatile than the higher chlorinated Aroclors, Aroclor 1232 should significantly volatilize from soil. AQUATIC FATE: PCBs, such as Aroclor 1232, are mixtures of different congeners of chlorobiphenyl and the relative importance of the environmental fate mechanisms generally depends on the degree of chlorination . In general, the persistence of PCBs increases with an increase in the degree of chlorination. One screening test has shown that Aroclor 1232 is biodegraded relatively rapidly. It has also been shown that the chlorinated congeners in PCBs are susceptible to reductive dechlorination by anaerobic microorganisms found in aquatic sediments . Since no other degradation processes have been shown to be important in environmental aquatic systems, biodegradation is probably the ultimate degradation mechanism in natural water. In water, adsorption to sediments and organic matter is a major fate process for Aroclor 1232(1,3). The most water soluble PCBs will be enriched in water relative to the sediment, and the leached sediment will be enriched in the higher chlorinated PCBs (lowest solubilities in water). The lower chlorinated congeners of Aroclor 1232 will sorb less strongly than the higher chlorinated congeners, but tight adsorption should occur for all congeners. Although adsorption can immobilize PCBs for relatively long periods of time in the aquatic environment, resolution into the water column has been shown to occur on an environmental level. Volatilization of dissolved Aroclor 1232 is an important aquatic process. A study conducted on Lake Michigan has indicated that volatilization may be the major removal mechanisms of total PCBs from lakes . The PCBs with the highest vapor pressures (low Cl) will be enriched in the air. Strong PCB adsorption to sediment significantly decreases the rate of volatilization; the volatilization half-life of Aroclor 1232 from typical bodies of water has been estimated to range from 2 months to 1 year when the effects of adsorption are considered. Aquatic hydrolysis and oxidation are not important processes with respect to Aroclor 1232. Aroclor 1232 has been shown to bioconcentrate significantly in aquatic orgnaisms. ATMOSPHERIC FATE: The vapor pressures of the PCB congeners present in Aroclor 1232 indicate that they will exist primarily in the vapor phase in the ambient atmosphere, and with enrichment of PCBs with the highest vapor pressures (low Cl) only minor partitioning to the pariculate-phase(1,2). Physical removal of PCBs in the atmosphere is accomplished by wet and dry deposition processes ; dry deposition will be important only for the PCB congeners associated in the particulate-phase. The vapor-phase reaction of Aroclor 1232 with hydroxyl radicals, which are photochemically formed by sunlight, may be the dominant degradation process in the atmosphere. The estimated half-life for this reaction with the dominant PCB congeners present in Aroclor 1221 has been estimated to range from 12.9 days to 3.1 months with the half-life increasing as the degree of chlorination increases.
Drinking Water Impact SURFACE WATER: An assessment of the USEPA STORET Database found Aroclor 1232 detected in 0.4% of 995 observation stations . Aroclor 1232 has been positively detected in Lake Huron . DRINKING WATER: Raw tap water in Waterford, NY, treatment plant has PCB levels 0.05-0.24 ppb . RAIN/SNOW: Levels up to 158 ng/L (1975-78) found in Canada, USA and Europe with levels decreasing to 1986 (PCBs) . In raw tap water in the Waterford, NY treatment plant, which also has the Hudson River as its source, mean PCB levels in 1976 were 0.12 ug/l (range: 0.05-0.24). Polychlorinated Biphenyls/ EFFL: An assessment of USEPA STORET Database found Aroclor 1232 detected in 1.0% of 707 observation stations . Aroclor 1232 was detected at a mean concn of 39 ppb in 14 of 20 treated wastewaters collected from the aluminum forming industries .

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