December 1989 |
Public Health Statement |
for |
Bromodichloromethane |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for bromodichloromethane. It is one in a series
of Public Health Statements about hazardous substances and
their health effects. A shorter version, the ToxFAQs™,
is also available. This information is important because this
substance may harm you. The effects of exposure to any hazardous
substance depend on the dose, the duration, how you are exposed,
personal traits and habits, and whether other chemicals are
present. For more information, call the ATSDR Information
Center at 1-888-422-8737.
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1.1
What is bromodichloromethane? |
Bromodichloromethane (BDCM) is a colorless,
heavy, nonburnable liquid. BDCM does not usually exist as
a liquid in the environment. Rather, it usually is found evaporated
in air or dissolved in water.
Most BDCM in the environment is formed
as a by-product when chlorine is added to drinking water to
kill disease-causing organisms. Small amounts of BDCM are
also made in chemical plants for use in laboratories or in
making other chemicals. A very small amount (less than 1%
of the amount coming from human activities) is formed by algae
in the ocean.
BDCM evaporates quite easily, so most
BDCM that escapes into the environment from chemical facilities,
waste sites, or drinking water enters the atmosphere as a
gas. BDCM is slowly broken down (about 90% in a year) by chemical
reactions in the air. Any BDCM that remains in water or soil
may also be broken down slowly by bacteria.
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1.2
How might I be exposed to bromodichloromethane? |
For most people, the most likely means
of exposure to BDCM is by drinking chlorinated water. Usually
the levels in drinking water are between 1 and 10 ppb (parts
per billion). BDCM is also found in some foods and beverages
such as ice cream or soft-drinks that are made using chlorinated
water, but this is probably not a major source of exposure.
BDCM has been found in chlorinated swimming pools, where exposure
might occur by breathing the vapors or through the skin. Exposure
to BDCM might also occur by breathing BDCM in the air in or
near a laboratory or factory that made or used BDCM.
However, BDCM is not widely used in this
country, so this is not likely for most people. Average levels
of BDCM in air are usually quite low (less than 0.2 ppb).
Another place where human exposure might occur is near a waste
site where BDCM has been allowed to leak into water or soil.
In this situation, people could be exposed by drinking the
water or by getting the soil on their skin. BDCM has been
found in water and soil at some waste sites (about 1% to 10%
of those tested), usually at levels of 1 to 50 ppb.
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1.3
How can bromodichloromethane enter and leave my body? |
Studies in animals show that almost all
BDCM swallowed in water or food will enter the body by moving
from the stomach or intestines into the blood. It is likely
that BDCM would also move from the lungs into the blood if
it were breathed in and would cross the skin if skin contact
occurred, but this has not been studied. Bromodichloromethane
leaves the body mostly by being breathed out through the lungs.
Smaller amounts leave in the urine and feces. BDCM removal
is fairly rapid and complete (about 95% in 8 hours), so it
does not usually build up in the body.
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1.4
How can bromodichloromethane affect my health? |
The effects of BDCM depend on how much
is taken into the body. In animals, the main effect of eating
or drinking large amounts of BDCM is injury to the liver and
kidneys. These effects can occur within a short time after
exposure. High levels can also cause effects on the brain,
leading to incoordination and sleepiness. There is some evidence
that BDCM can be toxic to developing fetuses, but this has
not been well-studied. Studies in animals show that intake
of BDCM for several years in food or water can lead to cancer
of the liver, kidney and intestines. Although effects of BDCM
have not been reported in humans, effects would probably occur
if enough BDCM were taken into the body.
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1.5
Is there a medical test to determine whether I have been exposed
to bromodichloromethane? |
Methods are available to measure low
levels of BDCM in human blood, breath, urine and fat, but
not enough information is available to use such tests to predict
if any health effects might result. Because special equipment
is needed, these tests are not usually done in doctors' offices.
Because BDCM leaves the body fairly quickly, these methods
are best suited to detecting recent exposures.
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1.6
What levels of exposure have resulted in harmful health effects? |
It is not known at what levels BDCM causes
harmful health effects in people. Liver and kidney damage
have occurred when animals ate food with BDCM at levels of
190 parts per million (ppm) and greater. Impaired fetal development
was seen at levels of 1,000 ppm in rats.
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1.7
What recommendations has the federal government made to protect
human health? |
The EPA has set a Maximum Contaminant
Level (MCL) of 0.1 parts per million (ppm) for the combination
of bromodichloromethane and a group of similar compounds (called
trihalomethanes) that occur in chlorinated water. The EPA
recommends that levels of halomethanes in lakes and streams
should be limited to 0.19 ppm to prevent possible health effects
from drinking water or eating fish contaminated with this
group of chemicals.
Any release to the environment greater
than 5,000 pounds of bromodichloromethane must be reported
to the EPA.
The federal recommendations have been
updated as of July 1999.
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1.8 Where can I get more information? |
If you have any more questions or concerns, please contact
your community or state health or environmental quality department or:
Agency for Toxic Substances and Disease Registry
Division of Toxicology
1600 Clifton Road NE, Mailstop F-32
Atlanta, GA 30333
Information line and technical assistance:
Phone: 888-422-8737
FAX: (770)-488-4178
ATSDR can also tell you the location of occupational and environmental health
clinics. These clinics specialize in recognizing, evaluating, and treating illnesses
resulting from exposure to hazardous substances.
To order toxicological profiles, contact:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Phone: 800-553-6847 or 703-605-6000
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References |
Agency for Toxic Substances and Disease
Registry (ATSDR). 1989. Toxicological
profile for bromodichloromethane. Atlanta, GA: U.S. Department
of Health and Human Services, Public Health Service.
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