| Chemical Abstract Number (CAS #) |
11141165
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| Synonyms | PCB-1232 |
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Aroclor 1232 |
| Analytical Methods |
EPA Method 505 |
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EPA Method 508 |
EPA Method 608 |
EPA Method 617 |
EPA Method 625 |
EPA Method 8080A |
EPA Method 8081 |
EPA Method 8250A |
| Molecular Formula | UVCB |
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| Use | Aroclor was formerly used as hydraulic fluids, rubber plasticizer, and adhesives.
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| Apparent Color | CLEAR OIL; Colorless mobile oil
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| Boiling Point | 290-325 DEG C
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| Molecular Weight | Average mol wt: 221
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| Density | EPA 440/5-80-068] 1.270-1.280/15.5 deg C
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| Sensitivity Data | Irritating to skin and eyes. Polychlorinated biphenyls
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| 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.
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| 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.
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| 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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