| Chemical Abstract Number (CAS #) |
95501
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| Synonyms | 1,2-Dichlorobenzene |
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Benzene, 1,2-dichloro- | o-Dichlorobenzene |
| Analytical Methods |
EPA Method 502.2 |
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EPA Method 503.1 |
EPA Method 524.1 |
EPA Method 524.2 |
EPA Method 601 |
EPA Method 602 |
EPA Method 612 |
EPA Method 624 |
EPA Method 625 |
EPA Method 8010B |
EPA Method 8020A |
EPA Method 8021A |
EPA Method 8120A |
EPA Method 8250A |
EPA Method 8260A |
| Molecular Formula | C6H4Cl2 |
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| Use | SOLVENT FOR WAXES, GUMS, RESINS, TARS, RUBBERS, OILS, ASPHALTS,
INSECTICIDE FOR TERMITES & LOCUST BORERS
REMOVING SULFUR FROM ILLUMINATING GAS; AS INTERMED IN MFR OF DYES;
AS HEAT TRANSFER MEDIUM
AS DEGREASING AGENT FOR METALS, LEATHER, WOOL; AS INGREDIENT OF
METAL POLISHES
INDUST ODOR CONTROL
Herbicide, insecticide, and soil fumigant
AS SOLVENT MIXT USED TO REMOVE LEAD & CARBONACEOUS DEPOSITS FROM
ENGINE PARTS; AS COMPONENT OF RUST-PROOFING MIXT
AS A MAGNETIC COIL COOLANT; IN WOOD-PRESERVING CMPD
CHEM INTERMED FOR MAKING AGRIC CHEM; EMULSIFIABLE FORM
RECOMMENDED FOR DEODORIZING GARBAGE & SEWAGE
ORG SYNTH ESP OF PESTICIDES & SOLVENT IN CHEM PROCESSES
Used as a process solvent in the manufacture of toluene diisocyanate.
Ortho-dichlorobenzene is used as a solvent in the following applications: motor-oil additive
formulations; paints; formulations for removing paints; firearm cleaners; dissolution of pitch on
papermaking felts; a carrier for wood preservatives and repellents; and upper cylinder lubricants
Hydrolysis of 1,2-dichlorobenzene with KOH and NaOH gives ortho-chlorophenol an
intermediate for dyestuffs and initiator for higher chlorinated phenols
Manufacture of 3,4-dichloroaniline, solvent for oxides of non-ferrous metals
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| Consumption Patterns | 53% FOR ORGANIC SYNTHESIS (CHIEFLY FOR PESTICIDES); 20% FOR
SOLVENT IN TOLUENE DI-ISOCYANATE PROCESS; 15% FOR MISC SOLVENT USES;
8% FOR DYESTUFFS MFR, 4% FOR MISC USES (1973)
Organic synthesis (mainly for production of 3,4-dichloroaniline), 70%; solvents for toluene
diisocyanate production, 15%; miscellaneous solvent usage, 8%; dye manufacture 4%; and other
application, 3% (1978)
CHEMICAL PROFILE: o-Dichlorobenzene. Organic synthesis (mainly for 3,-dichloroaniline
herbicides, via 3,4-dichloronitrobenzene), 90%; toluene diisocyanate processing solvent, 5%;
solvent and miscellaneous uses, 5%.
CHEMICAL PROFILE: o-Dichlorobenzene. Demand: 1986: 45 million lb; 1987: 45 million lb;
1991 projected/: 43 million lb.
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| Apparent Color | COLORLESS LIQUID
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| Odor | PLEASANT AROMATIC ODOR
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| Boiling Point | 180.5 DEG C @ 760 MM HG
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| Melting Point | -17.0 DEG C
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| Molecular Weight | 147.01
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| Density | 1.3048 g/ml @ 20 DEG C/4 DEG C
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| Odor Threshold Concentration | ODOR OF O-DICHLOROBENZENE IS DETECTABLE BY AVG PERSON AT 50
PPM IN AIR. ODOR BECOMES STRONG & IRRITATION NOTICEABLE AT CONCN
AROUND 100 PPM. IT HAS FAIR WARNING PROPERTIES AT THIS LEVEL BUT
POSSIBILITY OF ADAPTATION SHOULD BE RECOGNIZED.
Odor threshold low= 12.0 mg/cu-m, Odor threshold high= 300.0 mg/cu-m, Irritating
concentration= 150.0 mg/cu-m (From table).
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| Sensitivity Data | Intense erythema and edema appeared promptly when the cmpd is applied locally.
VAPORS AND SPRAYS ARE IRRITATING TO EYES, NOSE AND THROAT
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| Environmental Impact | Chemical waste dump leachates and direct manufacturing effluents are reported to be the
major source of pollution of the chlorobenzenes (including the dichlorobenzenes) to Lake
Ontario. The major source of 1,2-dichlorobenzene emission to the atmosphere has been reported
to be solvent applications which may emit 25% of annual production to the atmosphere. If
released to soil, 1,2-dichlorobenzene can be moderately to tightly adsorbed. Leaching from
hazardous waste disposal areas has occurred and the detection of 1,2-dichlorobenzene in various
groundwaters indicates that leaching can occur. Volatilization from soil surfaces may be an
important transport mechanism. It is possible that 1,2-dichlorobenzene will be slowly biodegraded
in soil under aerobic conditions. Chemical transformation by hydrolysis, oxidation or direct
photolysis are not expected to occur in soil. If released to water, adsorption to sediment will be a
major environmental fate process based upon extensive monitoring data in the Great Lakes area
and Koc values. Analysis of Lake Ontario sediment cores has indicated the presence and
persistence of 1,2-dichlorobenzene since before 1940. 1,2-Dichlorobenzene is volatile from the
water column with an estimated half-life of 4.4 hours from a model river one meter deep flowing
1 m/sec with a wind velocity of 3 m/sec at 20 deg C; adsorption to sediment will attenuate
volatilization. Aerobic biodegradation in water may be possible, however, anaerobic
biodegradation is not expected to occur. Experimental BCF values of 66-560 have been reported
and 1,2-dichlorobenzene has been detected in trout from Lake Ontario. Aquatic hydrolysis,
oxidation and direct photolysis are not expected to be important. If released to air,
1,2-dichlorobenzene will exist predominantly in the vapor-phase and will react with
photochemically produced hydroxyl radicals at an estimated half-life rate of 24 days in a typical
atmosphere. Direct photolysis in the troposphere is not expected to be important. The detection
of 1,2-dichlorobenzene in rainwater suggests that atmospheric removal via wash-out is possible.
General population exposure to 1,2-dichlorobenzene may occur through oral consumption of
contaminated drinking water and food (particularly fish) and through inhalation of contaminated
air since 1,2-dichlorobenzene has been detected in widespread ambient air.
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| Environmental Fate | Aquatic fate: Since 1,2-dichlorobenzene (1,2-DCB) has a high affinity for lipophilic
materials and is reported to have a relatively low vapor pressure and low aqueous solubility at
ambient temperatures, sorption, bioaccumulation, and volatilization are expected to be
competing proceses. The rate at which each of these competing processes occur will determine
which fate is predominant for 1,2-DCB in the aquatic environment. Should volatilization occur at
a more rapid rate then sorption or bioaccumulation then atmospheric proceses would be expected
to regulate the fate of 1,2-DCB. On the other hand should sorption and bioaccumulation occur
more rapidly than volatilization, biodegradation of 1,2-DCB by aquatic microorganisms would be
anticipated to regulate the fate of this compound.
TERRESTRIAL FATE: Based on experimental adsorption data, 1,2-dichlorobenzene can be
moderately to tightly adsorbed in soil. Leaching from hazardous waste disposal areas in Niagara
Falls to adjacent surface waters has been reported and the detection of 1,2-dichlorobenzene in
various groundwaters indicates that leaching can occur. Volatilization from soil surfaces may be
an important transport mechanism; however, volatilization may be attenuated by tight adsorption
to soil particles or by leaching. It is possible that 1,2-dichlorobenzene will be slowly biodegraded
in soil under aerobic conditions. Chemical transformation processes such as hydrolysis, oxidation
or direct photolysis (on soil surfaces) are not expected to occur.
AQUATIC FATE: Based on suspended solid monitored Koc values of about 39800 and extensive
sediment monitoring data in the Great Lakes area, adsorption to sediment is a major
environmental fate process for 1,2-dichlorobenzene. Its detection in Lake Ontario sediment cores
indicates that 1,2-dichlorobenzene has persisted in these sediments since before 1940 .
1,2-Dichlorobenzene is volatile from water with an estimated half-life of 4.4 hours from a river
one meter deep flowing 1 m/sec with a wind velocity of 3 m/sec at 20 deg C; adsorption to
sediment in water will attenuate volatilization 1,2-Dichlorobenzene may biodegrade in aerobic
water after microbial adaptation; however, it is not expected to biodegrade under anaerobic
conditions which may exist in lake sediments or various groundwaters. Experimental BCF values
of 66-560 have been reported; the detection of 1,2-dichlorobenzene in trout from Lake Ontario
has confirmed that bioaccumulation is important. Aquatic hydrolysis, oxidation and direct
photolysis are not expected to be important. The persistence half-life of 1,2-dichlorobenzene in
the water column has been estimated to be 0.3-3 days in rivers, 3-30 days in lakes and 30-300
days in groundwaters(2,SRC).
ATMOSPHERIC FATE: 1,2-Dichlorobenzene will exist predominantly in the vapor- phase in the
atmosphere. The half-life for the vapor-phase reaction of 1,2-dichlorobenzene with
photochemically produced hydroxyl radicals in the atmosphere has been estimated to be 24 days.
Direct photolysis is not expected to be important. The detection of 1,2-dichlorobenzene in
rainwater suggests that atmospheric removal via wash-out is possible.
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| Drinking Water Impact | DRINKING WATER: A mean 1,2-dichlorobenzene concn of 0.003 ppb was detected in
drinking water samples from 3 cities near Lake Ontario in 1980 . Concn of 1 ppb identified in
Miami, FL drinking water and qualitative detections reported for Philadelphia, PA and Cincinnati,
OH . 1,2-Dichlorobenzene was found in 2 of 945 finished water supplies throughout the US
that use groundwater sources at concn of 2.2 and 2.7 ppb . Qualitative detection reported for
Cleveland, OH tap water . Qualitative detection reported for two drinking water supply sources
in the United Kingdom .
GROUNDWATER: 1,2-Dichlorobenzene was positively detected in 20 of 685 groundwaters
analyzed in NJ during 1977-1979 with 6800 ppb the highest concn found .
SURFACE WATERS: 1,2-Dichlorobenzene was detected in 15 of 463 surface waters analyzed in
NJ during 1977-1979 with 8.2 ppb the highest concn found . Mean concentrations of 5 and 6
parts per trillion detected in Lake Ontario and Grand River water, respectively, during 1980 near
Niagara Falls; concn of 0-56 parts per trillion found in the Niagara River . Concn of 3.9-240
parts per trillion (mean concn of 23 parts per trillion) detected in Niagara River at
Niagara-On-The-Lake between 1981 and 1983 . Concn of 5.6-190 parts per trillion (mean
concn of 18 parts per trillion) detected in the Niagara River between 1981 and 1983 . An
average concn of 20 parts per trillion was found in the Niagara River near Niagara-On-The-Lake
between Sept and Oct 1982 . Positive detection of 1,2-dichlorobenzene was reported by 0.6%
of 1077 USEPA STORET stations(6). Qualitative detection reported for the Delaware and
Raritan Canal in NJ(7). Concn below 0.5 ppb detected in the Rhine River between 1978-1982(8).
An average concn of 0.32 ppb found in the Rhine River near Dusseldorf in 1984(9).
SEA WATER: 1,2-Dichlorobenzene was detected in the water column of the Narragansett Bay
near Rhode Island .
RAIN/SNOW: A mean 1,2-dichlorobenzene concn of 0.49 parts per trillion was detected in
Portland, OR rainwater during March-April 1982 ; Concn of not detected to 0.62 parts per
trillion found in Portland, OR rainwater during 1984 .
EFFL: The wastewater effluents from four water treatment plants discharging into the Grand
River and Lake Ontario contained a mean 1,2-dichlorobenzene concn of 13 ppt during 1980
sampling . Positive detection of 1,2-dichlorobenzene was reported by 2.5% of 1311 USEPA
STORET stations . Concn of 0.3-41 ppb were detected in Southern California municipal
wastewater effluents in 1976 . Concn of 10-32 ppb were detected in leachates from municipal
solid waste landfills in Minnesota . Concn of 2.8-13 ppb found in leachate associated
groundwater beneath a municipal landfill in Ontario, Canada . The dichlorobenzene isomers
were qualitatively detected in waters adjacent to hazardous waste disposal areas in Niagara Falls,
NY as a result of leaching(6). Ambient mean air concn of 0.04-0.86 ppb were detected above six
abandoned hazardous waste sites in NJ as a result of volatile emanations(7). Flue gas effluents
from a municipal refuse-fired steam boiler in Virginia contained 4.4 ug/cu m of the
dichlorobenzene isomers(8); flue gas effluents from a refuse-derived-fired power plant in Ohio
contained 7.8 ng/cu m of the dichlorobenzene isomers(8).
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