1.1 What are chlorophenols? |
1.2 What happens to chlorophenols when
they enter the environment? |
1.3 How might I be exposed to chlorophenols? |
1.4 How can chlorophenols enter and leave
my body? |
1.5 How can chlorophenols affect my health? |
1.6 How can chlorophenols affect children? |
1.7 How can families reduce the risk of
exposure to chlorophenols? |
1.8 Is there a medical test to determine
whether I have been exposed to chlorophenols? |
1.9 What recommendations has the federal
government made to protect human health? |
1.10 Where can I get more information? |
References |
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July 1999 |
Public Health Statement |
for |
Chlorophenols |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for chlorophenols. 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 chlorophenols 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 activities.
Chlorophenols has been found in at least 116 of the 1,467
current or former NPL sites. However, the total number
of NPL sites evaluated for this substance is not known.
As more sites are evaluated, the sites at which chlorophenols
are found may increase. This information 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 chlorophenols,
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 are chlorophenols? |
Chlorophenols are a group of chemicals
in which chlorines (between one and five) have been added
to phenol. Phenol is an aromatic compound derived from
benzene, the simplest aromatic hydrocarbon, by adding a hydroxy
group to a carbon to replace a hydrogen. There
are five basic types of chlorophenols: mono[one]chlorophenols,
di[two]chlorophenols, tri[three]chlorophenols, tetra[four]chlorophenols,
and penta[five]chlorophenols. In all, there are 19 different
chlorophenols. Eight are discussed in this document:
2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol,
2,4,6-trichlorophenol, 2,3,4,5-tetrachlorophenol, 2,3,4,6-tetrachlorophenol,
and 2,3,5,6-tetrachlorophenol. Pentachlorophenol is
discussed in another document.
Except for 2-chlorophenol, which is a
liquid at room temperature, all of the chlorophenols are solids.
The chlorophenols have a strong medicinal taste and odor;
small amounts (at parts per billion [ppb] to parts per million
[ppm] concentrations) can be tasted in water. Very small
amounts of chlorophenols can also make fish taste bad.
All the compounds discussed are or were produced commercially.
Chlorophenols with at least two chlorines
either have been used directly as pesticides or converted
into pesticides. Also, chlorophenols, especially 4-chlorophenol,
have been used as antiseptics. In addition to being
produced commercially, small amounts of some chlorophenols,
especially the mono- and dichlorophenols, may be produced
when waste water or drinking water is disinfected with chlorine,
if certain contaminants are present in the raw water.
They are also produced during the bleaching of wood pulp with
chlorine when paper is being produced.
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1.2
What happens to chlorophenols when they enter the environment? |
Chlorophenols can enter the environment
while they are being made or used as pesticides. Most
of the chlorophenols released into the environment go into
water, with very little entering the air. The compounds
that are most likely to go into the air are the mono- and
dichlorophenols because they are the most volatile (that is,
have the greatest tendency to form vapors or gases).
Once in the air, sunlight helps destroy these compounds and
rain washes them out of the air. Chlorophenols stick
to soil and to sediments at the bottom of lakes, rivers, or
streams. However, low levels of chlorophenols in water,
soil, or sediment are broken down by microorganisms and are
removed from the environment within a few days or weeks.
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1.3
How might I be exposed to chlorophenols? |
Most people are exposed to very low levels
of chlorophenols in drinking water that has been disinfected
with chlorine (chlorinated drinking water). Chlorophenols
have been measured in chlorinated drinking water at parts
per trillion (ppt) concentrations (that is, the amount [weight]
of chlorophenols per trillion parts [volume] of water).
In lakes, rivers, and streams, chlorophenols were found in
less than 1 percent of the water that was tested. Chlorophenols
have been measured in city air at concentrations of less than
a part per trillion (the amount of chlorophenols [volume]
per trillion parts [volume] of air).
It has been estimated during the National
Occupational Exposure Survey (NOES) from 1981–1983 that about
5,000 people in the United States are exposed to 4-chlorophenol,
2,4,5-trichlorophenol, or 2,4,6-trichlorophenol at work (NOES
1990). It has not been estimated how many people are
exposed at work to the other chlorophenols. People who
make chlorophenols or use them as pesticides are most likely
to have high exposure to these chemicals. For example,
mixtures of tetrachlorophenols are used at sawmills as wood
preservatives. Skin contact while treating wood with
the tetrachlorophenols is the most likely route of exposure.
Another likely route of exposure is breathing air contaminated
by mono- and dichlorophenols.
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1.4
How can chlorophenols enter and leave my body? |
When chlorophenols are eaten, almost
all of the compounds quickly enter the body. Chlorophenols
also rapidly enter the body through the skin. Little
is known about how much of the chlorophenols enter the body
if one breathes air containing them. The monochlorophenols
do not stay inside the body very long. They are changed
to less harmful products, and most leave through the urine
within 24 hours. The other chlorophenols (dichlorophenol,
trichlorophenols, tetrachlorophenols), which also leave through
the urine as less harmful chemicals, can stay in the body
for several days.
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1.5
How can chlorophenols 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.
One man who splashed pure 2,4-dichlorophenol
on his arm and leg died shortly after the accident.
Workers who made pesticides from chlorophenols and were exposed
to chlorophenols as well as other chemicals through breathing
and through the skin developed acne and mild injury to their
livers. According to some studies, the risk of cancer
was also slightly higher among workers who had made pesticides
for a long time. These workers were exposed to very
high levels of other chemicals as well as chlorophenols, so
it is not certain whether the effects were caused by the chlorophenols
or the other chemicals.
Animals that were given food or drinking
water containing chlorophenols at high levels developed adverse
or negative health effects. The major effects with exposure
to high levels of chlorophenols were on the liver and the
immune system. Also, the animals that ate or drank chlorophenols
did not gain as much weight as the animals that ate food and
drank water not containing chlorophenols.
Feeding rats and mice high doses of 2,4-dichlorophenol
for a long time did not cause cancer. However, long-term
treatment of rats and mice with high doses of 2,4,6-trichlorophenol
in food caused leukemia in rats and liver cancer in mice,
suggesting that 2,4,6-trichlorophenol may be a carcinogen.
The Department of Health and Human Services has determined
that 2,4,6-trichlorophenol may reasonably be anticipated to
be a carcinogen. The International Agency for Research
on Cancer (IARC) has determined that the chlorophenols as
a group, are possibly carcinogenic to man. The Environmental
Protection Agency (EPA) has determined that 2,4,6-trichlorophenol
is a probable carcinogen.
Putting chlorophenols on the skin or
eyes of animals causes severe injuries. Injury is greatest
with exposure to the mono- and dichlorophenols. The
signs of severe skin injury include redness, swelling, scabbing,
and scar formation. The cornea was damaged when monochlorophenols
were placed directly onto the eyes of rabbits.
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1.6
How can chlorophenols affect children? |
This section discusses potential health
effects from exposures during the period from conception to
maturity at 18 years of age in humans. Potential effects
on children resulting from exposures of the parents are also
considered.
The most likely source from which children
could be exposed to chlorophenols is water that has been disinfected
with chlorine. Children could receive larger doses because
they consume more fluids per bodyweight than adults.
Children may also be exposed in areas where chlorophenols
have been sprayed as pesticides or herbicides. Children
playing outdoors in areas with contaminated soil could be
at risk for exposure because they often put objects or hands
in their mouths. Monochlorophenols are used as household
antiseptics, and 2,4-DCP is used for mothproofing. More
complex chlorophenols are used as biocides. Biocides
are substances used to kill organisms.
We do not know whether chlorophenols
cause birth defects in humans; chlorophenols have not been
shown to cause birth defects in animals, even at high doses.
High levels of chlorophenols given to pregnant female rats
in the drinking water have tended to reduce the number of
their newborn animals and to decrease the weights of the newborn.
In one study animals exposed to chlorophenols showed delayed
hardening of some bones. We do not know whether chlorophenols
can cross the placenta or get into breast milk.
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1.7
How can families reduce the risk of exposure to chlorophenols? |
If your doctor finds that you have been
exposed to significant amounts of chlorophenols, ask if children
may also be exposed. When necessary your doctor may
need to ask your state department of public health to investigate.
The chlorophenols presented in this profile
exist in eight different forms, each one having different
properties and uses. Therefore, different routes exist
in which a family may be exposed to chlorophenols. Chlorophenols
are primarily used as antiseptics, disinfectants, herbicides,
pesticides, and wood preservatives. People are at greater
risk of exposure if they live near industrial facilities that
use or manufacture chlorophenols or waste sites that could
be releasing it into the environment. Most released
chlorophenols are found in surface water or have become adsorbed
in soil near the release point. Children should be kept
from coming in contact with water or dirt in an area that
could be contaminated. You should prevent your children
from eating dirt. Make sure they wash their hands frequently
and before eating. Discourage your children from putting
their hands in their mouths or other hand-to-mouth activity.
People who do not live near production
or waste sites can still be exposed to chlorophenols through
other routes. Chlorophenols can be present in drinking
water when chlorine is used to disinfect it. The safe
drinking water standard for 2-chlorophenol is 39 mg/L (monthly
average). At low concentrations, chlorophenols give
water an unpleasant, medicinal taste.
Chlorophenols and other related chemicals
are often used as herbicides and pesticides. 2,4-D and
2,4,5-T, the latter of which has been banned, are herbicides
often used on food crops that can break down to form 2,4-DCP.
Children should be deterred from playing in areas where 2,4-D
or other chlorophenol based herbicides or pesticides have
been sprayed. Children are lower to the ground than
adults and may be exposed because they often get dirt, grass,
and other outdoor material on their skin and in their mouths.
Also, your children may be exposed to chlorophenols if an
unqualified person applies pesticides containing them around
your home. In some cases, the improper use of pesticides
banned for use in homes has turned homes into hazardous waste
sites. Make sure that any person you hire is licensed
and, if appropriate, certified to apply pesticides.
Your state licenses each person who is qualified to apply
pesticides according to EPA standards and further certifies
each person who is qualified to apply "restricted use" pesticides.
Ask to see the license and certification. Also ask for
the brand name of the pesticide, a Material Safety Data Sheet
(MSDS), the name of the product's active ingredient, and the
EPA registration number. Ask whether EPA has designated
the pesticide "for restricted use" and what the approved uses
are. This information is important if you or your family
react to the product.
If you buy over-the-counter pesticide
products to apply yourself, be sure the products are in unopened
pesticide containers that are labeled and contain an EPA registration
number. Carefully follow the instructions on the label.
If you plan to spray inside, make sure the pesticide is intended
for indoor use.
If you feel sick after a pesticide has
been used in your home, consult your doctor or local poison
control center.
Chlorophenols may also be present in
many household products. 2,4-DCP is commonly used for
mothproofing. 4-CP is used as a disinfectant in homes,
farms, hospitals, and as an antiseptic for root canal treatment.
Monochlorophenols have been used as antiseptics, although
they have largely been replaced by other chemicals.
Pesticides and household chemicals should be stored out of
reach of young children to prevent unintentional poisonings.
Always store pesticides and household chemicals in their original
labeled containers. Never store pesticides or household
chemicals in containers children would find attractive to
eat or drink from, such as old soda bottles.
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1.8
Is there a medical test to determine whether I have been exposed
to chlorophenols? |
There is no medical test that is specific
for chlorophenols to determine whether you have been exposed
to these chemicals. Compounds that have been made by
your body from chlorophenols can be measured in the urine.
However, these compounds can also be found in the urine when
you are exposed to other chemicals such as lindane (an insecticide)
or to 2,4-dichlorophenoxyacetic acid (a chemical that kills
weeds).
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1.9 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 Environmental
Protection Agency (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 chlorophenols include the following:
The EPA recommends that drinking water
concentrations of 2-chlorophenol should not be more than 0.04
part per million (ppm), and concentrations of 2,4-dichlorophenol
should not be more than 0.02 ppm; these are levels that can
be tasted. In order for chlorophenols to be lower than
levels that can be tasted, the EPA recommends levels of 0.1
part per billion (ppb; the amount of chlorophenols per billion
parts of water) for monochlorophenols, 0.3 ppb for 2,4-dichlorophenols,
and 1 ppb for 2,4,5-trichlorophenol and 2,3,4,6-tetrachlorophenol.
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1.10 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). 1999. Toxicological
profile for chlorophenols. Atlanta, GA: U.S. Department
of Health and Human Services, Public Health Service.
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