SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 11104282
CASRN 11104-28-2
SynonymsPCB-1221
Aroclor 1221
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 Formerly used in gas-transmission turbine hydraulics, rubber plasticizers, adhesives, and electrical capacitors. Although the production and sale was discontinued in late 1977, it is still present in many of the capacitors now in use.
Apparent Color Colorless mobile oil.
Odor PRACTICALLY ODORLESS
Melting Point 1 DEG C
Molecular Weight Average mol wt: 192
Density 1.182-1.192/15.5 deg C
Sensitivity Data Irritating to skin and eyes.
Environmental Impact PCBs such as Aroclor 1221, are currently released to the environment from landfills containing PCB waste material 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 1221 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 1221 appears to be reasonably degradable on an environmental basis. Screening studies have shown that Aroclor 1221 is readily biodegradable. Biodegradation is probably the ultimate degradation process in both natural water and soil systems since other degradation processes do 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 1221 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 1221 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 1221 for relatively long periods of time eventual resolution into the waste column has been shown to occur. The PCB composition in water will be enriched tin 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 1221 volatilizates 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 1221 have been shown to bioconcentrate significantly in aquatic organisms. If released to the atmosphere, the PCB congeners in Aroclor 1221 will exist primarily in the vapor-phase with enrichment of the most volatile PCBs. 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 to 27.8 days. Physlical removal of Aroclor 1221 frohm the d dry deposition, although wet deposition will be more important then dry deposition. The major Aroclor 1221 exposure routes 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 1221, 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. Screening tests have shown that Aroclor 1221 is readily biodegradable. Since no other degradation mechanisms have been shown to be important in soil systems, biodegradation may be the ultimate degradation process in soil. Experimentally determined Koc values have shown that the PCB congeners present in Aroclor 1221 will be tightly adsorbed in soil with adsorption generally increasing as the degree of chlorination of the individual congeners increase although the most water soluble PCBs will be leached preferentially. Aroclor 1221 should not leach significantly in most aqueous soil systems. 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 1221 indicate that significant volatilization of Aroclor 1221 may occur from soil surfaces(2,SRC). AQUATIC FATE: PCBs, such as Aroclor 1221, are mixtures of different congeners of chlorobiphenyl and the relative importance of the environmental fate mechanism generally depends on the degree of chlorination . In general, the persistence of PCBs increases with an increase in the degree of chlorination. Screening tests have shown that Aroclor 1221 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 of Aroclor 1221(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 1221 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 1221 is an important aquatic process. A study conducted on Lake Michigan has indicated that volatilization may be the major removal mechanism 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 1221 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 1221. Aroclor 1221 has been shown to bioconcentrate significantly in aquatic organisms. ATMOSPHERIC FATE: The vapor pressures of the PCB congeners present in Aroclor 1221 indicate that they will exist primarily in the vapor phase in the ambient atmosphere with enrichment of PCBs with the highest vapor pressures (low Cl) and with only minor partitioning to the particulate-phase(1,2). Physical removal of PCB's in the atmosphere is accomplished by wet and dry deposition processes ; dry deposition will be important only for the PCB congeners associated with the particulate-phase. The vapor-phase reaction of Aroclor 1221 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 to 27.8 days with the half-life increasing as the degree of chlorination increases.
Drinking Water Impact DRINKING WATER: PCB congeners of Aroclor 1221 have been detected in tap water from Fort Edward, NY which is located near a heavily polluted section of the Hudson River . Raw tap water in Waterford, NY treatment plant has PCB levels 0.05-0.24 ppb . SURFACE WATER: An assessment of the USEPA STORET Database found Aroclor 1221 detected in 0.09% of 974 observation stations . PCB congeners of Aroclor 1221 have been found at levels of 0.5-145 ng/L at various locations in the Hudson River during July and August 1983 . Aroclor 1221 has been detected in river water from the Nile River in Egypt . RAIN/SNOW: Levels up to 158 ug/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 the USEPA STORET Database found Aroclor 1221 detected in 1.1% of 703 observation stations . Aroclor 1221, in combination with Aroclors 1242 and 1254, was detected at a mean concn of 20 ppb in 14 of 24 raw wastewaters collected from the aluminum forming industries .

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