| Chemical Abstract Number (CAS #) |
75274
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| Synonyms | Bromodichloromethane |
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Methane, bromodichloro- | Dichlorobromomethane |
| Analytical Methods |
EPA Method 502.2 |
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EPA Method 524.1 |
EPA Method 524.2 |
EPA Method 601 |
EPA Method 624 |
EPA Method 8010B |
EPA Method 8021A |
EPA Method 8240B |
EPA Method 8260A |
| Molecular Formula | CHBrCl2 |
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| Use | Fire retardant, solvent, intermediate in synthesis of other compounds
Fire-extinguisher fluid ingredient, heavy liquid for mineral and salt separations; laboratory use
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| Apparent Color | Liquid
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| Boiling Point | 90.1 DEG C @ 760 MM HG
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| Melting Point | -57.1 DEG C
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| Molecular Weight | 163.83
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| Density | SPECIFIC GRAVITY: 1.980 @ 20 DEG C/4 DEG C
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| Odor Threshold Concentration | Odor threshold low: 1680 mg/cu m odor high 1680 mg/cu m. Bromochloromethane/
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| Environmental Impact | The predominant anthropogenic source of bromodichloromethane release to the
environment is its inadvertent formation during chlorination treatment processes of water. In
addition to anthropogenic sources, it is biosynthesized and emitted to the environment by various
species of marine macroalgae which are abundant in various locations of the world's oceans. If
released to surface water, volatilization will be the dominant environmental fate process. The
volatilization half-life from rivers and streams has been estimated to range from 33 min to 12 days
with a typical half-life being 35 hours. In aquatic regions where volatilization is not viable,
anaerobic biodegradation may be the major removal process. Aquatic hydrolysis, oxidation, direct
photolysis, adsorption, and bioconcentration are not environmentally important. If released to soil,
volatilization is again likely to be the dominant removal process where exposure to air is possible.
Bromodichloromethane is moderately to highly mobile in soil and can therefore leach into
groundwaters. If released to air, the only identifiable transformation process in the troposphere is
reaction with hydroxyl radicals. The loss of bromodichloromethane through this transformation
has an estimated half-life of 6.65 months. This relatively persistent half-life indicates that
long-range global transport is possible. The general population is exposed to
bromodichloroemethane through consumption of contaminated drinking water, beverages, and
food products, through inhalation of contaminated ambient air, and through dermal exposure to
chlorinated swimming pool water.
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| Environmental Fate | TERRESTRIAL FATE: In soils where exposure to the atmosphere can occur,
volatilization is likely to be the dominant environmental fate process due to the high vapor
pressure of bromodichloromethane . Bromodichloromethane is moderately to highly mobile in
soil and can therefore leach into groundwater and subsurface regions. Laboratory studies have
indicated that significant biodegradation can occur under anaerobic conditions; therefore, in soil
regions where volatilization is not viable, biodegradation may be the major removal
process.
AQUATIC FATE: Volatilization of bromodichloromethane is the dominant removal mechanism
from environmental surface waters. The volatilization half-life from rivers and streams has been
estimated to range from 33 min to 12 days with a typical half-life being 35 hours . Laboratory
studies have indicated that significant biodegradation can occur under anaerobic conditions;
therefore, in aquatic regions where volatilization is not viable, biodegradation may be the major
removal process. Hydrolysis, oxidation, direct photolysis, adsorption, and bioconcentration are
not environmentally important aquatic fate processes.
ATMOSPHERIC FATE: Due to its high vapor pressure, bromodichloromethane should exist
entirely in the vapor-phase in the ambient atmosphere. The only identifiable transformation
process in the troposphere is reaction with hydroxyl radicals. The loss of bromodichloromethane
through this transformation has an estimated half-life of 6.65 months in typical air . Direct
photolysis does not occur below the ozone layer. This relatively persistent tropospheric half-life
suggests that a small percentage of the bromodichloromethane present in air will eventually
diffuse to the stratosphere where it will be destroyed by photolysis. In addition, long-range global
transport is possible. The detection of bromodichloromethane in rainwater indicates that
atmospheric removal via washout can occur; however, any bromodichloromethane which is
removed by rainfall is likely to revolatilize into the atmosphere.
Monitoring studies of groundwater and surface water at chemical waste sites indicate that
BDCM is a relatively infrequent contaminant. BDCM was detected at only 4 of 818 sites of the
National Priority List (NPL), and at 7% of a number of other sites being investigated under
Superfund (CLPSD 1988). The average concentration of BDCM in ground water at these sites
was 30 ug/l.
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| Drinking Water Impact | DRINKING WATER: BROMODICHLOROMETHANE HAS BEEN
IDENTIFIED AS COMPONENT OF NEW ORLEANS DRINKING WATER. HIGHEST
CONCN IN RAW WATER (SOURCE UNIDENTIFIED) IS REPORTED TO BE 11 UG/L &
IN FINISHED WATER, 116 UG/L.
In a National Organics Reconnaissance Survey of 80 cities: 72 cities had a positive result with
0.0004 mg/l being the minimum concentration, 0.110 mg/l being the maximum concentration and
0.0012 being the median.
USEPA Region Organics Survey of 83 sites: 60% of locations had positive results with 0.015
mg/l the maximum concentration, the median was 0.001 mg/l.
DRINKING WATER: As part of the USEPA Groundwater Supply Survey,
bromodichloromethane was positively detected in 445 of 945 USA finished water supplies that
use groundwater sources at a median level of about 1.8 ppb . Median levels of 9.2-18 ppb were
detected in the water supplies of over 80% of the 113 USA cities monitored during the three
phases (1976-7) of USEPA National Organic Monitoring Survey . A Canadian national survey
of 70 drinking water supplies found bromodichloromethane levels of 0-33 ppb with an overall
median level of 1.4 ppb . In a survey of drinking waters from 12 areas of the world (China,
Taiwan, north and south Philippines, Egypt, Indonesia, Australia, England, Brazil, Nicaragua,
Venezuela, Peru), bromodichloromethane was found in 9 of the 12 waters at levels ranging from
1.7-10 ppb . Positive detections were made in 35 of 40 Michigan drinking water supplies at a
median concn of 2.7 ppb . Median concn of 5.8 and 12.3 ppb were found in samples collected
from Bayonnel Elizabeth, NJ in winter 1981 and spring 1982 ; median concns of 12.5 and 24.3
ppb were found in Los Angeles, CA samples from spring and summer 1984 .
GROUNDWATER: Bromodichloromethane was one of 27 organic compounds identified in
groundwater collected from 315 wells in the area of the Potomac-Raritan-Magothy aquifer system
adjacent to the Delaware River . Levels of 0.3 ppb have been detected in groundwater from the
Netherlands .
SURFACE WATER: An analysis of the USEPA STORET Data Base found that
bromodichloromethane had been positively detected in 14.0% of 8885 water observation stations
at a median concn of 0.1 ug/l . Bromodichloromethane was positively detected in 20.9% of
4972 samples collected from 11 stations on the Ohio River during 1980-1 with most concn
between 0.1-1.0 ppb . Positive identifications were determined at 24 of 204 sites (1-12 ppb) in
14 heavily industrialized river basins in the USA . Concentrations ranging from a trace-25 ng/l
and not detected-20 ng/l were reported for 16 stations on the Niagara River and 95 stations on
Lake Ontario, respectively, for 1981 monitoring . Lake St. Clair - 3 sites > 0.03 ppb; sites
0.10-.03 ppb; 45 sites <0.01 ppb; range 0-0.089 ppb .
SEAWATER: Bromodichloromethane concentrations of 0.1-1 ng/l have been detected in the
North Atlantic while a concn of 0.1 ng/l was detected in the South Atlantic during 1985
monitoring . Qualitative detection has been reported for the Narragansett Bay off RI in
1979-80 .
RAIN/SNOW: A concn of 0.4 ng/l was detected in rain collected in southern Germany in
1985 .
OTHER WATER: A bromodichloromethane concn of 2 ppb was detected in stormwater runoff
from Eugene, OR as part of the USEPA Nationwide Urban Runoff Program .
Bromodichloromethane has been detected in swimming pool water at levels of 6-10 ppb .
EFFL: An analysis of the USEPA STORET Data Base found that bromodichloromethane had
been positively detected in 11.0% of 1375 effluent observation stations at a median concn of 5
ug/l . Bromodichloromethane was detected in 14 of 63 industrial wastewater discharges in the
USA at levels ranging from <10-100 ppb . Three municipal wastewater treatment facilities in
Cincinnati, OH were found to be discharging levels as high as 0.2 ppb in 1982 . % occurrence
in raw wastewater, septic tank effluents, septic tank sludge, septic tank scum, lift station
wastewater & lagoon cell effluents was (%, no. of samples) 100,2; 100,5; 67,3; 100,3; 100,7; and
86,7 in a Regina, Saskatchewan study (detection limit = 0.02 ppb) .
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