1.1 What is tetrachloroethylene? |
1.2 What happens to tetrachloroethylene
when it enters the environment? |
1.3 How might I be exposed to tetrachloroethylene? |
1.4 How can tetrachloroethylene enter
and leave my body? |
1.5 How can tetrachloroethylene affect
my health? |
1.6 Is there a medical test to determine
whether I have been exposed to tetrachloroethylene? |
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 |
Tetrachloroethylene |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for tetrachloroethylene. 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 tetrachloroethylene 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
are the sites targeted for long-term federal cleanup.
Tetrachloroethylene has been found in at least 771 of the
1,430 current or former NPL sites. However, it's unknown
how many NPL sites have been evaluated for this substance.
As more sites are evaluated, the sites with tetrachloroethylene
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 tetrachloroethylene,
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 tetrachloroethylene? |
Tetrachloroethylene is a synthetic chemical
that is widely used for dry cleaning of fabrics and for metal-degreasing
operations. It is also used as a starting material (building
block) for making other chemicals and is used in some consumer
products. Other names for tetrachloroethylene include
perchloroethylene, PCE, perc, tetrachloroethene, perclene,
and perchlor. It is a nonflammable liquid at room temperature.
It evaporates easily into the air and has a sharp, sweet odor.
Most people can smell tetrachloroethylene when it is present
in the air at a level of 1 part in 1 million parts of air
(ppm) or more. In an experiment, some people could smell
tetrachloroethylene in water at a level of 0.3 ppm.
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1.2
What happens to tetrachloroethylene when it enters the environment? |
Tetrachloroethylene enters the environment mostly by evaporating
into the air during use. It can also get into water
supplies and the soil during disposal of sewage sludge and
factory waste and when leaking from underground storage tanks.
Tetrachloroethylene may also get into the air, soil, or water
by leaking or evaporating from storage and waste sites.
It can stay in the air for several months before it is broken
down into other chemicals or is brought back down to the soil
and water by rain.
Much of the tetrachloroethylene that gets into water and
soil will evaporate into the air. However, because tetrachloroethylene
can travel through soils quite easily, it can get into underground
drinking water supplies. If it gets into underground water,
it may stay there for many months without being broken down.
If conditions are right, bacteria will break down some of
it and some of the chemicals formed may also be harmful.
Under some conditions, tetrachloroethylene may stick to the
soil and stay there. It does not seem to build up in
animals that live in water, such as fish, clams, and oysters.
We do not know if it builds up in plants grown on land.
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1.3
How might I be exposed to tetrachloroethylene? |
People can be exposed to tetrachloroethylene from environmental
and occupational sources and from consumer products.
Common environmental levels of tetrachloroethylene (called
background levels) are several thousand times lower than levels
found in some workplaces. Background levels are found
in the air we breathe, in the water we drink, and in the food
we eat. The chemical is found most frequently in air
and, less often, in water. Tetrachloroethylene gets
into air by evaporation from industrial or dry cleaning operations.
It is also released from areas where chemical wastes containing
it are stored. It is frequently found in water.
For example, tetrachloroethylene was found in 38% of 9,232
surface water sampling sites throughout the United States.
There is no similar information on how often the chemical
is found in air samples, but we know it is widespread.
We do not know how often it is found in soil, but in one study,
it was found in 5% of 359 sediment samples.
In general, tetrachloroethylene levels in air are higher
in cities or industrial areas where it is in use more than
in more rural or remote areas. You can smell it at levels
of 1 ppm in air. However, the background level of tetrachloroethylene
in air is usually less than 1 part in 1 billion parts of air
(ppb). The air close to dry cleaning shops and chemical
waste sites has levels of tetrachloroethylene higher than
background levels. These levels are usually less than
1 ppm, the level at which you can smell it. Water, both
above and below ground, may contain tetrachloroethylene.
Levels in water are also usually less than 1 ppb. Levels
in contaminated water near disposal sites are higher than
levels in water far away from those sites. Water polluted
with this chemical may have levels greater than 1 ppm.
In soil, background levels are probably 100–1,000 times lower
than 1 ppm.
You can also be exposed to tetrachloroethylene by using certain
consumer products. Products that may contain it include
water repellents, silicone lubricants, fabric finishers, spot
removers, adhesives, and wood cleaners. Although uncommon,
small amounts of tetrachloroethylene have been found in food,
especially food prepared near a dry cleaning shop. When
you bring clothes home from the dry cleaners, the clothes
may release small amounts of tetrachloroethylene into the
air. The full significance to human health of these
exposures to small amounts of tetrachloroethylene is unknown,
but to date, they appear to be relatively harmless.
Tetrachloroethylene can also be found in the breast milk of
mothers who have been exposed to the chemical.
The people with the greatest chance of exposure to tetrachloroethylene
are those who work with it. According to estimates from
a survey conducted by the National Institute for Occupational
Safety and Health (NIOSH), more than 650,000 U.S. workers
may be exposed.
For the general population, the estimated amount that a person
might breathe per day ranges from 0.08 to 0.2 milligrams.
The estimated amount that most people might drink in water
ranges from 0.0001 to 0.002 milligrams per day. These
are very small amounts.
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1.4
How can tetrachloroethylene enter and leave my body? |
Tetrachloroethylene can enter your body when you breathe
air containing it. How much enters your body in this
way depends on how much of the chemical is in the air, how
fast and deeply you are breathing, and how long you are exposed
to it. Tetrachloroethylene may also enter your body
when you drink water or eat food containing the chemical.
How much enters your body in this way depends on how much
of the chemical you drink or eat. These two exposure
routes are the most likely ways people will take in tetrachloroethylene.
These are also the most likely ways that people living near
areas polluted with the chemical, such as hazardous waste
sites, might be exposed to it. If tetrachloroethylene
is trapped against your skin, a small amount of it can pass
through into your body. Very little tetrachloroethylene
in the air can pass through your skin into your body.
Most tetrachloroethylene leaves your body from your lungs
when you breathe out. This is true whether you take
in the chemical by breathing, drinking, eating, or touching
it. A small amount of the tetrachloroethylene is changed
by your body (especially your liver) into other chemicals
that are removed from your body in urine. Most of the
changed tetrachloroethylene leaves your body in a few days.
Some of it that you take in is found in your blood and other
tissues, especially body fat. Part of the tetrachloroethylene
that is stored in fat may stay in your body for several days
or weeks before it is eliminated.
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1.5
How can tetrachloroethylene 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.
Tetrachloroethylene has been used safely as a general anesthetic
agent, so at high concentrations, it is known to produce loss
of consciousness. When concentrations in air are high—particularly
in closed, poorly ventilated areas—single exposures can cause
dizziness, headache, sleepiness, confusion, nausea, difficulty
in speaking and walking, unconsciousness, and death.
Irritation may result from repeated or extended skin contact
with the chemical. As you might expect, these symptoms
occur almost entirely in work (or hobby) environments when
individuals have been accidentally exposed to high concentrations
or have intentionally abused tetrachloroethylene to get a
"high." In industry, most workers are exposed to levels
lower than those causing dizziness, sleepiness, and other
nervous system effects. The health effects of breathing
in air or drinking water with low levels of tetrachloroethylene
are not definitely known. However, at levels found in
the ambient air or drinking water, risk of adverse health
effects is minimal. The effects of exposing babies to
tetrachloroethylene through breast milk are unknown.
Results from some studies suggest that women who work in dry
cleaning industries where exposures to tetrachloroethylene
can be quite high may have more menstrual problems and spontaneous
abortions than women who are not exposed. However, it
is not known for sure if tetrachloroethylene was responsible
for these problems because other possible causes were not
considered.
Results of animal studies, conducted with amounts much higher
than those that most people are exposed to, show that tetrachloroethylene
can cause liver and kidney damage and liver and kidney cancers
even though the relevance to people is unclear. Although
it has not been shown to cause cancer in people, the U.S.
Department of Health and Human Services has determined that
tetrachloroethylene may reasonably be anticipated to be a
human carcinogen. The International Agency for Research
on Cancer (IARC) has determined that tetrachloroethylene is
probably carcinogenic to humans. Exposure to very high
levels of tetrachloroethylene can be toxic to the unborn pups
of pregnant rats and mice. Changes in behavior were
observed in the offspring of rats that breathed high levels
of the chemical while they were pregnant. Rats that
were given oral doses of tetrachloroethylene when they were
very young, when their brains were still developing, were
hyperactive when they became adults. How tetrachloroethylene
may affect the developing brain in human babies is not known.
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1.6
Is there a medical test to determine whether I have been exposed
to tetrachloroethylene? |
One way of testing for tetrachloroethylene
exposure is to measure the amount of the chemical in the breath,
much the same way breath alcohol measurements are used to
determine the amount of alcohol in the blood. This test
has been used to measure levels of the chemical in people
living in areas where the air is contaminated with tetrachloroethylene
or those exposed to the chemical through their work.
Because it is stored in the body's fat and is slowly released
into the bloodstream, it can be detected in the breath for
weeks following a heavy exposure. Tetrachloroethylene
can be detected in the blood. Also, breakdown products
of the chemical can be detected in the blood and urine of
people exposed to tetrachloroethylene. Trichloroacetic
acid (TCA), a breakdown product of tetrachloroethylene can
be detected for several days after exposure. These tests
are relatively simple to perform. The breath, blood,
or urine must be collected in special containers and then
sent to a laboratory for testing. Because exposure to
other chemicals can produce the same breakdown products in
the urine and blood, the tests for breakdown products cannot
determine if you have been exposed only to tetrachloroethylene.
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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 the 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 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 tetrachloroethylene include the following:
The EPA maximum contaminant level for the amount of tetrachloroethylene
that can be in drinking water is 0.005 milligrams tetrachloroethylene
per liter of water (mg/L) (0.005 ppm).
EPA has established regulations and procedures for dealing
with tetrachloroethylene, which it considers a hazardous waste.
Many regulations govern its disposal. If amounts greater
than 100 pounds are released to the environment, the National
Response Center of the federal government must be told immediately.
OSHA limits the amount of tetrachloroethylene that can be
present in workroom air. This amount is limited to 100
ppm for an 8-hour workday over a 40-hour workweek. NIOSH
recommends that tetrachloroethylene be handled as a chemical
that might potentially cause cancer and states that levels
of the chemical in workplace air should be as low as possible.
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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 tetrachloroethylene. Atlanta, GA: U.S. Department
of Health and Human Services, Public Health Service.
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