1.1 What is chloroform? |
1.2 What happens to chloroform when it
enters the environment? |
1.3 How might I be exposed to chloroform? |
1.4 How can chloroform enter and leave
my body? |
1.5 How can chloroform affect my health? |
1.6 Is there a medical test to determine
whether I have been exposed to chloroform? |
1.7 What recommendations has the federal
government made to protect human health? |
1.8 Where can I get more information? |
References |
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September 1997 |
Public Health Statement |
for |
Chloroform |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for chloroform. 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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This public health statement tells you
about chloroform and the effects of exposure.
The Environmental Protection Agency (EPA)
identifies the most serious hazardous waste sites in the nation.
These sites make up the National Priorities List (NPL) and
the sites are targeted for long-term federal cleanup.
Chloroform has been found in at least 717 of the 1,430 current
or former NPL sites, including 6 in Puerto Rico and 1 in the
Virgin Islands. However, it's unknown how many NPL sites
have been evaluated for this substance. As more sites
are evaluated, the sites with chloroform may increase.
This is important because exposure to this substance may harm
you and because these sites may be sources of exposure.
When a substance is released from a large
area, such as an industrial plant, or from a container, such
as a drum or bottle, it enters the environment. This
release does not always lead to exposure. You are exposed
to a substance only when you come in contact with it.
You may be exposed by breathing, eating, or drinking the substance,
or by skin contact.
If you are exposed to chloroform, many
factors determine whether you'll be harmed. These factors
include the dose (how much), the duration (how long), and
how you come in contact with it. You must also consider
the other chemicals you're exposed to and your age, sex, diet,
family traits, lifestyle, and state of health.
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1.1
What is chloroform? |
Chloroform is also known as trichloromethane
or methyltrichloride. It is a colorless liquid with
a pleasant, nonirritating odor and a slightly sweet taste.
Most of the chloroform found in the environment comes from
industry. It will only burn when it reaches very high
temperatures. Chloroform was one of the first inhaled
anesthetics to be used during surgery, but it is not used
for anesthesia today. Nearly all the chloroform made
in the United States today is used to make other chemicals,
but some is sold or traded to other countries. We also
import chloroform.
Chloroform enters the environment from
chemical companies and paper mills. It is also found
in waste water from sewage treatment plants and drinking water
to which chlorine has been added. Chlorine is added
to most drinking water and many waste waters to destroy bacteria.
Small amounts of chloroform are formed as an unwanted product
during the process of adding chlorine to water. Chloroform
can enter the air directly from factories that make or use
it and by evaporating from water and soil that contain it.
It can enter water and soil when waste water that contains
chlorine is released into water or soil. It may enter
water and soil from spills and by leaks from storage and waste
sites. There are many ways for chloroform to enter the
environment, so small amounts of it are likely to be found
almost everywhere.
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1.2
What happens to chloroform when it enters the environment? |
Chloroform evaporates very quickly when
exposed to air. Chloroform also dissolves easily in
water, but does not stick to the soil very well. This
means that it can travel down through soil to groundwater
where it can enter a water supply. Chloroform lasts
for a long time in both the air and in groundwater.
Most chloroform in the air eventually breaks down, but this
process is slow. The breakdown products in air include
phosgene, which is more toxic than chloroform, and hydrogen
chloride, which is also toxic. Some chloroform may break
down in soil. Chloroform does not appear to build up
in great amounts in plants and animals, but we may find some
small amounts of chloroform in foods.
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1.3
How might I be exposed to chloroform? |
You are probably exposed to small amounts
of chloroform in your drinking water and in beverages (such
as soft drinks) made using water that contains chloroform.
You can also get chloroform in your body by eating food, by
breathing air, and by skin contact with water that contains
it. You are most likely to be exposed to chloroform
by drinking water and breathing indoor or outdoor air containing
it. The amount of chloroform normally expected to be
in the air ranges from 0.02 to 0.05 parts of chloroform per
billion parts (ppb) of air and from 2 to 44 ppb in treated
drinking water. However, in some places, chloroform
concentrations may be higher than 44 ppb. It is estimated
that the concentration of chloroform in surface water is 0.1
ppb, the concentration in untreated groundwater is 0.1 ppb,
and the amount in soil is 0.1 ppb. As much as 610 ppb
was found in air at a municipal landfill and up to 88 ppb
was found in treated municipal drinking water. Drinking
water derived from well water near a hazardous waste site
contained 1,900 ppb, and groundwater taken near a hazardous
waste site also contained 1,900 ppb. Surface water containing
394 ppb has also been found near a hazardous waste site; however,
no more than 0.13 ppb has been found in soil at hazardous
waste sites. Chloroform has been found in the air from
all areas of the United States and in nearly all of the public
drinking water supplies. We do not know how many areas
have surface water, groundwater, or soil that contains chloroform.
The average amount of chloroform that
you might be exposed to on a typical day by breathing air
in various places ranges from 2 to 5 micrograms per day (µg/day)
in rural areas, 6 to 200 µg/day in cities, and 80 to
2,200 µg/day in areas near major sources of the chemical.
The estimated amount of chloroform you probably are exposed
to in drinking water ranges from 4 to 88 µg/day.
We cannot estimate the amounts that you may be exposed to
by eating food and by coming into contact with water that
has chloroform in it. People who swim in swimming pools
absorbed chloroform through their skin. People who work
at or near chemical plants and factories that make or use
chloroform can be exposed to higher-than-normal amounts of
chloroform. Higher exposures might occur in workers
at drinking-water treatment plants, waste water treatment
plants, and paper and pulp mills. People who operate
waste-burning equipment may also be exposed to higher than
normal levels. The National Institute for Occupational
Safety and Health (NIOSH) estimated that 95,778 persons in
the United States have occupational exposure to chloroform.
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1.4
How can chloroform enter and leave my body? |
Chloroform can enter your body if you
breathe air, eat food, or drink water that contains chloroform.
Chloroform easily enters your body through the skin.
Therefore, chloroform may also enter your body if you take
a bath or shower in water containing chloroform. In
addition, you can breathe in chloroform if the shower water
is hot enough for chloroform to evaporate. Studies in
people and in animals show that after you breathe air or eat
food that has chloroform in it, the chloroform can quickly
enter your bloodstream from your lungs or intestines.
Inside your body, chloroform is carried by the blood to all
parts of your body, such as the fat, liver, and kidneys.
Chloroform usually collects in body fat; however, its volatility
ensures that it will eventually be removed once the exposure
has been removed. Some of the chloroform that enters
your body leaves unchanged in the air that you breathe out,
and some chloroform in your body is broken down into other
chemicals. These chemicals are known as breakdown products
or metabolites, and some of them can attach to other chemicals
inside the cells of your body and may cause harmful effects
if they collect in high enough amounts in your body.
Some of the metabolites also leave the body in the air you
breathe out. Only a small amount of the breakdown products
leaves the body in the urine and stool.
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1.5
How can chloroform affect my health? |
To protect the public from the harmful
effects of toxic chemicals and to find ways to treat people
who have been harmed, scientists use many tests.
One way to see if a chemical will hurt
people is to learn how the chemical is absorbed, used, and
released by the body; for some chemicals, animal testing may
be necessary. Animal testing may also be used to identify
health effects such as cancer or birth defects. Without
laboratory animals, scientists would lose a basic method to
get information needed to make wise decisions to protect public
health. Scientists have the responsibility to treat
research animals with care and compassion. Laws today
protect the welfare of research animals, and scientists must
comply with strict animal care guidelines.
In humans, chloroform affects the central
nervous system (brain), liver, and kidneys after a person
breathes air or drinks liquids that contain large amounts
of chloroform. Chloroform was used as an anesthetic
during surgery for many years before its harmful effects on
the liver and kidneys were recognized. Breathing about
900 parts of chloroform in a million parts of air (900 ppm
or 900,000 ppb) for a short time causes fatigue, dizziness,
and headache. If you breathe air, eat food, or drink
water containing elevated levels of chloroform, over a long
period, the chloroform may damage your liver and kidneys.
Large amounts of chloroform can cause sores when the chloroform
touches your skin.
We do not know whether chloroform causes
harmful reproductive effects or birth defects in people.
Miscarriages occurred in rats and mice that breathed air containing
elevated levels (30 to 300 ppm) of chloroform during pregnancy
and in rats that ate chloroform during pregnancy. Abnormal
sperm were found in mice that breathed air containing elevated
levels (400 ppm) of chloroform for a few days. Offspring
of rats and mice that breathed chloroform during pregnancy
had birth defects.
Results of studies of people who drank
chlorinated water showed a possible link between the chloroform
in chlorinated water and the occurrence of cancer of the colon
and urinary bladder. Cancer of the liver and kidneys
developed in rats and mice that ate food or drank water that
had large amounts of chloroform in it for a long time.
We do not know whether liver and kidney cancer would develop
in people after long-term exposure to chloroform in drinking
water. Based on animal studies, the Department of Health
and Human Services (DHHS) has determined that chloroform may
reasonably be anticipated to be a carcinogen (a substance
that causes cancer). The International Agency for Research
on Cancer (IARC) has determined that chloroform is possibly
carcinogenic to humans (2B). The EPA has determined
that chloroform is a probable human carcinogen.
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1.6
Is there a medical test to determine whether I have been
exposed to chloroform? |
Although we can measure the amount of
chloroform in the air that you breathe out, and in blood,
urine, and body tissues, we have no reliable test to determine
how much chloroform you have been exposed to or whether you
will experience any harmful health effects. The measurement
of chloroform in body fluids and tissues may help to determine
if you have come into contact with large amounts of chloroform.
However, these tests are useful only a short time after you
are exposed to chloroform because it leaves the body quickly.
Because it is a breakdown product of other chemicals (chlorinated
hydrocarbons), chloroform in your body might also indicate
that you have come into contact with those other chemicals.
Therefore, small amounts of chloroform in the body may indicate
exposure to these other chemicals and may not indicate low
chloroform levels in the environment. From blood tests
to determine the amount of liver enzymes, we can tell whether
the liver has been damaged, but we cannot tell whether the
liver damage was caused by chloroform.
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1.7
What recommendations has the federal government made to protect
human health? |
The federal government develops regulations
and recommendations to protect public health. Regulations
can be enforced by law. Federal agencies that develop
regulations for toxic substances include EPA, the Occupational
Safety and Health Administration (OSHA), and the Food and
Drug Administration (FDA). Recommendations provide valuable
guidelines to protect public health but cannot be enforced
by law. Federal organizations that develop recommendations
for toxic substances include the Agency for Toxic Substances
and Disease Registry (ATSDR) and the National Institute for
Occupational Safety and Health (NIOSH).
Regulations and recommendations can be
expressed in not-to-exceed levels in air, water, soil, or
food that are usually based on levels that affect animals;
then they are adjusted to help protect people. Sometimes
these not-to-exceed levels differ among federal organizations
because of different exposure times (an 8-hour workday or
a 24-hour day), the use of different animal studies, or other
factors.
Recommendations and regulations are also
periodically updated as more information becomes available.
For the most current information, check with the federal agency
or organization that provides it. Some regulations and
recommendations for chloroform include the following:
The EPA sets rules for the amount of
chloroform allowed in water. The EPA limit for total
trihalomethanes, a class of chemicals that includes chloroform,
in drinking water is 100 micrograms per liter (µg/L,
1 µg/L = 1 ppb in water). Furthermore, EPA requires
that spills of 10 pounds or more of chloroform into the environment
be reported to the National Response Center.
OSHA sets the levels of chloroform allowed
in workplace air in the United States. A permissible
occupational exposure limit is 50 ppm or 240 mg/m³
(ceiling value) in air during an 8-hour workday, 40-hour workweek.
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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). 1997. Toxicological profile
for chloroform. Atlanta, GA: U.S. Department of Health
and Human Services, Public Health Service.
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