| Chemical Abstract Number (CAS #) |
12674112
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| Synonyms | PCB-1016 |
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Aroclor 1016 |
| 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 | Although the production and sale was discontinued in late 1977, it is still present in
capacitors now in use.
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| Apparent Color | Colorless mobile oil.
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| Odor | PRACTICALLY ODORLESS
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| Boiling Point | Distillation range: 323-356 deg C at 760 mm
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| Molecular Weight | Aroclor is a variable PCB composition mixture. Polychlorinated biphenyls/
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| Density | 1.33 g/ml at 25 deg C
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| Environmental Impact | Current evidence suggests that the major source of Aroclor 1016 release to the
environment may be an environmental cycling process of Aroclor 1016 previously introduced into
the environment; this cycling process involves volatilization from ground surfaces (water, soil)
into the atmosphere with subsequent removal from the atmosphere via wet/dry deposition and
then revolatilization. PCBs, such as Aroclor 1016, are also currently released to the environment
from landfills containing PCB waste materials and products, incineration of municipal refuse and
sewage sludge, and improper (or illegal) disposal of PCB materials, such as waste transformer
fluid, to open areas. Aroclor 1016 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. Screening studies have shown that Aroclor 1016 is biodegraded slowly.
Although biodegradation of Aroclor 1016 may occur slowly on an environmental basis, no other
degradation mechanisms have been shown to be important in natural water and soil systems;
therefore, biodegradation may be the ultimate degradation process in water and soil. The PCB
composition of the biodegraded aroclor is different from the original aroclor. If released to soil,
the PCB congeners present in Aroclor 1016 will become tightly adsorbed to the soil particles.
Although the volatilization rate of Aroclor 1016 may be low from soil surfaces, the total loss be
volatilization over time may be significant because of the persistence and stability of Aroclor
1016. 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 can immobilize Aroclor 1016 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 1016
volatilizes relatively rapidly from water. However, strong PCB adsorption to significantly
competes with volatilization which may have a half-life of 2-7 years in typical bodies of water.
Although the resulting volatilization rate may be low, the total loss by volatilization over time may
be significant because of the persistence and stability of Aroclor 1016. Aroclor 1016 has been
shown to bioconcentrate significantly in aquatic organisms. If released to the atmosphere, the
PCB congeners in Aroclor 1016 will primarily exist in the vapor-phase with enrichment of the
most volatile PCBs although a relatively small percentage will partition to the particulate 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 27.8 days
to 3.1 months. Physical removal of Aroclor 1016 from the atmosphere, which is important
environmentally due to the chemical stability of Aroclor 1016, is accomplished by wet and dry
deposition. The major Aroclor 1016 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.
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| Environmental Fate | TERRESTRIAL FATE: PCBs, such as Aroclor 1016, 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
1016 is biodegraded slowly. Although biodegradation of Aroclor 1016 may occur slowly on an
environmental basis, no other degradation mechanisms have been shown to be important in soil
systems; therefore, biodegradation may be the ultimate degradation process in soil. Experimentally
determined Koc values have shown that Aroclor 1016 will be tightly adsorbed to soil with
adsorption generally increasing as the degree of chlorination of the individual congeners increase.
Aroclor 1016 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. Although the
volatilization rate of Aroclor 1016 may not be rapid from soil surfaces due to the tight adsorption,
the total loss by volatilization over time may be significant because of the persistence and stability
of Aroclor 1016.
AQUATIC FATE: PCBs, such as Aroclor 1016, 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. Screening tests have shown that Aroclor 1016 is
biodegraded slowly. It has also been shown that the more highly chlorinated congeners in PCBs
are susceptible to a reductive dechlorination by anaerobic microorganisms found in aquatic
sediments . Although biodegradation of Aroclor 1016 may occur slowly on an environmental
basis, no other degradation mechanisms have been shown to be important in environmental
aquatic systems; therefore, biodegradation may be the ultimate degradation process in natural
water. In water, adsorption to sediments and organic matter is a major fate process for Aroclor
1016(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 1016 will sorb less strongly than the higher
chlorinated 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 suggesting that the substantial quantities of PCBs contained in aquatic
sediments can act as an environmental sink for environmental redistribution of PCBs(4,5).
Volatilization of dissolved Aroclor 1016 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 1016 from typical bodies of water has been estimated to be 2-7
years when the effects of adsorption are considered. Although the volatilization rate may be low,
the total loss by volatilization over time may be significant because of the persistence and stability
of the PCBs. Aquatic hydroylsis and oxidation are not important processes with respect to
Aroclor 1016. Arclor 1016 has been shown to bioconcentrate significantly in aquatic
organisms.
ATMOSPHERIC FATE: The vapor pressures of the PCB congeners present in Aroclor 1016
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) although a relatively small
percentage can be expected to partition to atmospheric particulates(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 detection of
Aroclor 1016 in rainwater may be an indication of the importance of wet deposition. The
vapor-phase reaction of Aroclor 1016 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 1016 has been estimated to
range from 27.8 days to 3.1 months with the half-life increasing as the degree of chlorination
increases. The relatively long degradation half-lives in air indicate that physical removal may be
more important than chemical transformation.
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| Drinking Water Impact | DRINKING WATER: Aroclor 1016 levels ranging from not detectable (detection limit
= 12 ng/L) to 130 ng/L (median 85 ng/L in finished water), water found in reservoirs serving Fort
Edward, NY near the Hudson River . Raw tap water in Waterford, NY, treatment plant has
PCB levels of 0.05-0.24 ppb .
SURFACE WATER: An assessment of the USEPA STORET Database found Aroclor 1016
detected in 0.8% of 931 observation stations . Aroclor 1016 has been positively detected in
Lakes Ontario, Erie, Huron, Michigan and Superior . Aroclor 1016 and its congeners have been
detected in the Hudson River .
RAIN/SNOW: Mean Aroclor 1016 levels of 1300 ng/l were were found in rainwater collected at
Fort Edward, NY near the Hudson River . Levels up to 158 ug/L (1975-78) found in Canada,
USA, 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 1016 detected in 0.9%
of 701 observation stations . The concentration of Aroclors 1242 and 1016 found in the
leachate from a hazardous waste landfill was 0.11-1.9 ppm . The concn of Aroclor 1016, in
combination with Aroclors 1242 and 1254, was found to range from 110 ug/l to 1.8 g/l in
leachate form the Kin-Buc I landfill in NJ .
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