| Chemical Abstract Number (CAS #) |
124481
|
|---|
| Synonyms | Dibromochloromethane |
|---|
Chlorodibromomethane | Methane, dibromochloro- |
| Analytical Methods |
EPA Method 502.2 |
|---|
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 | CHBr2Cl |
|---|
| Use | LAB CHEM
ORGANIC SYNTHESIS
Dibromochloromethane is used as a chemical intermediate in the manufacture of fire
extinguishing agents, aerosol propellants, refrigerants, and pesticides.
|
|---|
| Apparent Color | COLORLESS TO PALE YELLOW LIQUID
|
|---|
| Boiling Point | 119-120 DEG C @ 748 MM HG
|
|---|
| Melting Point | BELOW -20 DEG C (FP)
|
|---|
| Molecular Weight | 208.28
|
|---|
| Density | Specific Gravity: 2.451 @ 20 DEG C/4 DEG C
|
|---|
| Environmental Impact | The predominant anthropogenic source of chlorodibromomethane 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 43 min to 16.6
days with a typical half-life being 46 hours. In aquatic media where volatilization is not viable (e.g.
groundwater), 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. Chlorodibromomethane 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 which has an estimated half-life of 8.4
months. This relatively persistent half-life indicates that long-range global transport is possible.
The general population is exposed to chlorodibromomethane 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.
|
|---|
| 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 chlorodibromomethane . Chlorodibromomethane 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 chlorodibromomethane is the dominant removal mechanism
from environmental surface waters. The volatilization half-life from rivers and streams has been
estimated to range from 43 min to 16.6 days with a typical half-life being 46 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. Aquatic hydrolysis, oxidation, direct photolysis, adsorption, and
bioconcentration are not environmentally important.
ATMOSPHERIC FATE: Due to its high vapor pressure, chlorodibromomethane should exist
entirely in the vapor-phase in the ambient atmosphere. The only identifiable transformation
process in the troposphere is reaction with hydroxyl radicals which has an estimated half-life of
8.4 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
chlorodibromomethane present in air may eventually diffuse to the stratosphere where it will be
destroyed by photolysis. In addition, long-range global transport is possible. The detection of
chlorodibromomethane in rainwater indicates that atmospheric removal via washout can occur;
however, any chlorodibromomethane which is removed by rainfall is likely to revolatilize into the
atmosphere.
|
|---|
| Drinking Water Impact | DRINKING WATER: In NW England tap water (1974): < 0.01 to 3 ppb
DRINKING WATER: Detected in finished drinking water, in drinking water supplies, and in
wastewater effluents.
DRINKING WATER: 100 UG/L WAS HIGHEST CONCN FOUND IN FINISHED
DRINKING WATER & 1.4 UG/L WAS HIGHEST CONCN FOUND IN RAW DRINKING
WATER WITH NO AVAIL INFORMATION ON CHRONIC TOXICITY. FROM TABLE/
DRINKING WATER: As part of the USEPA Groundwater Supply Survey,
chlorodibromomethane was positively detected in 405 of 945 USA finished water supplies that
use groundwater sources at a median level of about 3.3 ppb . Median levels of 7.5-17 ppb were
detected in the water supplies of over 40% 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 chlorodibromomethane 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), chlorodibromomethane was found in 7 of the 12 waters at levels ranging from
1.1-13 ppb . Positive detections were made in 30 of 40 Michigan drinking water supplies at a
median concn of 2.2 ppb . Drinking water samples collected from Los Angeles and Contra
Coast, CA in 1984 contained mean concns of 8-28 ug/L .
GROUNDWATER: Chlorodibromomethane 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
chlorodibromomethane had been positively detected in 8.0% of 8515 water observation stations
at a median concn below 0.1 ug/l . Chlorodibromomethane was positively detected in 9.8% of
4972 samples collected from 11 stations on the Ohio River during 1980-1 with most concn
between 0.1-1.0 ppb . Concentrations ranging from a trace-15 ng/l and not detected-630 ng/l
were reported for 16 stations on the Niagara River and 95 stations on Lake Ontario, respectively,
for 1981 monitoring .
SEAWATER: Chlorodibromomethane concentrations of 0.1-2.2 ng/l have been detected in the
North Atlantic while a concn of 0.12 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 chlorodibromomethane concn of 2 ppb was detected in stormwater runoff
from Eugene, OR as part of the USEPA Nationwide Urban Runoff Program .
Chlorodibromomethane has been detected in swimming pool water at levels of 6-10 ppb .
EFFL: An analysis of the USEPA STORET Data Base found that chlorodibromomethane had
been positively detected in 6.5% of 1298 effluent observation stations at a median concn below
2.4 ug/l . Chlorodibromomethane was detected in 8 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 25 ppb in 1982 . Not detected
in septic tank effluent in a Regina Saskatachewan study (detection limit not specified) .
|
|---|
