1.1 What is chlordane? |
1.2 What happens to chlordane when it
enters the environment? |
1.3 How might I be exposed to chlordane? |
1.4 How can chlordane enter and leave
my body? |
1.5 How can chlordane affect my health? |
1.6 Is there a medical test to determine
whether I have been exposed to chlordane? |
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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May 1994 |
Public Health Statement |
for |
Chlordane |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for chlordane. 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 Statement was prepared to give you information about
chlordane and to emphasize the human health effects that may
result from exposure to it. The Environmental Protection Agency
(EPA) has identified 1,350 hazardous waste sites as the most
serious in the nation. These sites comprise the "National
Priorities List" (NPL): Those sites which are targeted for
long-term federal cleanup activities. Chlordane has been found
in at least 176 of the sites on the NPL. However, the number
of NPL sites evaluated for chlordane is not known. As EPA
evaluates more sites, the number of sites at which chlordane
is found may increase. This information is important because
exposure to chlordane may cause harmful health effects and
because these sites are potential or actual sources of human
exposure to chlordane.
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 can be exposed to a substance only when you
come in contact with it. You can be exposed by breathing,
eating, drinking, or through skin contact with substances
containing chlordane.
If you are exposed to a substance such as chlordane, many
factors will determine whether harmful health effects will
occur and what the type and severity of those health effects
will be. These factors include the dose (how much), the duration
(how long), the route or pathway by which you are exposed
(breathing, eating, drinking, or skin contact), the other
chemicals to which you are exposed, and your individual characteristics
such as age, gender, nutritional status, family traits, life-style,
and state of health.
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1.1
What is chlordane? |
Chlordane is a man-made chemical that was used as a pesticide
in the United States from 1948 to 1988. It is sometimes referred
to by the trade names Octachlor® and Velsicol 1068®.
It is a thick liquid whose color ranges from colorless to
amber, depending on its purity. It may have no smell or a
mild, irritating smell. We do not know what it tastes like.
Chlordane is not a single chemical, but is a mixture of many
related chemicals, of which about 10 are major components.
Some of the major components are trans-chlordane, cis-chlordane,
beta-chlordene, heptachlor, and trans-nonachlor. Chlordane
does not dissolve in water. Therefore, before it can be used
as a spray, it must be placed in water with emulsifiers (soap-like
substances), which results in a milky-looking mixture.
From 1983 until 1988, chlordane's only approved use was to
control termites in homes. The pesticide was applied underground
around the foundation of homes. When chlordane is used in
the soil around a house, it kills termites that come into
contact with it.
Before 1978, chlordane was also used as a pesticide on agricultural
crops, lawns, and gardens and as a fumigating agent. Because
of concerns over cancer risk, evidence of human exposure and
build up in body fat, persistence in the environment, and
danger to wildlife, the EPA canceled the use of chlordane
on food crops and phased out other above-ground uses over
the next 5 years. In 1988, when the EPA canceled chlordane's
use for controlling termites, all approved use of chlordane
in the United States stopped. Manufacture for export continues.
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1.2
What happens to chlordane when it enters the environment? |
When used as a pesticide on crops, on
lawns and gardens, and to control termites in houses, chlordane
enters the environment. Although it is no longer used in the
United States, it may be used in other countries. In soil,
it attaches strongly to particles in the upper layers of soil
and is unlikely to enter into groundwater. It is not known
whether chlordane breaks down in most soils. If breakdown
occurs, it is very slow. Chlordane is known to remain in some
soils for over 20 years. Persistence is greater in heavy,
clayey or organic soil than in sandy soil. Most chlordane
is lost from soil by evaporation. Evaporation is more rapid
from light, sandy soils than from heavy soils. Half of the
chlordane applied to the soil surface may evaporate in 2 to
3 days. Evaporation is much slower after chlordane penetrates
into the soil. In water, some chlordane attaches strongly
to sediment and particles in the water column and some is
lost by evaporation. It is not known whether much breakdown
of chlordane occurs in water or in sediment. Chlordane breaks
down in the atmosphere by reacting with light and with some
chemicals in the atmosphere. However, it is sufficiently long
lived that it may travel long distances and be deposited on
land or in water far from its source. Chlordane or the chemicals
that chlordane changes into accumulate in fish, birds, and
mammals. Chlordane stays in the environment for many years
and is still found in food, air, water, and soil. Chlordane
is still commonly found in some form in the fat of fish, birds,
mammals, and almost all humans.
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1.3
How might I be exposed to chlordane? |
Everyone in the United States has been exposed to low levels
of chlordane. A more relevant question is whether or not you
may have been exposed to high levels of chlordane. Before
its ban in 1988, you might have been exposed to high levels
of chlordane if you worked in the manufacture, formulation,
or application of chlordane. Therefore, farmers and lawn-care
workers may have been exposed to chlordane before 1978, and
pest control workers may have been exposed to chlordane before
1988 by skin contact and breathing dust and vapor. A national
survey conducted from 1980 to 1983 estimated that 3,732 workers
were potentially exposed to chlordane in the United States.
This number of potentially exposed workers should have decreased
after chlordane's use was banned in the United States. However,
the ban on chlordane did not eliminate it from your environment,
and some of your opportunities for exposure to chlordane continue.
Today, people receive the highest exposure to chlordane from
living in homes that were treated with chlordane for termites.
Chlordane may be found in the air in these homes for many
years after treatment. Houses in the deep south and southwest
were most commonly treated. However, chlordane use extended
from the lower New England States south and west to California.
Houses built since 1988 have not been treated with chlordane
for termite control. You can determine if your home was treated
with chlordane by examining your records or contacting your
termite treatment service.
Over 50 million persons have lived in chlordane-treated homes.
Indoor air in the living spaces of treated homes have been
found to contain average levels of between 0.00003 and 0.002
milligram (mg) of chlordane in a cubic meter of air (mg/m³).
However, levels as high as 0.06 mg/m³ have been
measured in the living areas of these homes. Even higher levels
are found in basements and crawl spaces.
The most common source of chlordane exposure is from ingesting
chlordane- contaminated food. Chlordane remains in the food
supply because much of the farmland was treated with chlordane
in the 1960s and 1970s, and it remains in some soil for over
20 years. However, since chlordane has been banned, the levels
in soils would be expected to decrease with the passage of
time. Chlordane may also be found in fish and shellfish caught
in chlordane-contaminated waters. If you are in doubt about
whether a lake or river is contaminated, call your local Game
and Fish or Health departments. Chlordane is almost never
detected in drinking water. A survey conducted by the Food
and Drug Administration (FDA) determined daily intake of chlordane
from food to be 0.0013 microgram per kilogram of body weight
(µg/kg) for infants and 0.0005-0.0015 µg/kg for
teenagers and adults (a microgram is one thousandth of a milligram).
The average adult would, therefore, consume about 0.11 µg
of chlordane.
You may come into contact with chlordane while digging in
soil around the foundation of homes where it was applied to
protect the homes against termites. Soil may also be contaminated
with chlordane around certain NPL hazardous waste sites.
Chlordane has been found at 176 of 1,350 hazardous waste sites
on the NPL in the United States. The highest level of chlordane
found in soil near an NPL site was 344 ppm. People may be
exposed to chlordane at these sites by breathing low levels
of chlordane volatilizing from the soil or from touching the
soil. Levels of chlordane found in groundwater near NPL sites
containing chlordane ranged from 0.02 to 830 parts of chlordane
per billion parts of water (ppb).
Finally, some chlordane may be left over from pre-ban days.
Old containers of material thought to contain chlordane should
be disposed of carefully and contact with the skin and breathing
vapors should be avoided.
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1.4
How can chlordane enter and leave my body? |
Chlordane can enter the body through
the skin if skin contact occurs with contaminated soils, through
the lungs if breathed in with contaminated air, and through
the digestive tract if swallowed. Uptake through the skin
and digestive tract increases if chlordane is in an oily mixture,
which might occur at hazardous waste sites. The importance
of each of these ways for chlordane to enter the body depends
on the kind of exposure. For example, people living in houses
that have been treated with chlordane will be exposed mostly
by breathing the vapor in the air. Workers who sprayed chlordane
as a pesticide were exposed mostly by breathing the compound
in the air and by contact with the skin. Other people may
be exposed to small quantities by eating food or drinking
water that contains chlordane. People at or near waste sites
may be exposed by touching chlordane in the soil, by breathing
chlordane that evaporates into the air, by drinking water
that contains chlordane or by eating contaminated fish or
crops. The amount of chlordane that enters the body depends
on the amount in air, food, or water, and the length of time
a person is exposed to it. Most chlordane that enters the
body leaves in a few days, mostly in the feces, and a much
smaller amount leaves in the urine. Chlordane and its breakdown
products may be stored in body fat, where they cause no bad
effects, unless released from body fat in large amounts. It
may take months or years before the chlordane and the breakdown
products that are stored in fat are able to leave the body.
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1.5
How can chlordane affect my health? |
Most health effects in humans that may be linked to chlordane
exposure are on the nervous system, the digestive system,
and the liver. These effects were seen mostly in people who
swallowed chlordane mixtures. Large amounts of chlordane taken
by mouth can cause convulsions and death. Convulsions occurred
in a man who had long-term skin contact with soil containing
large amounts of chlordane. Swallowing small amounts or breathing
air containing high concentrations of chlordane vapors can
cause a variety of nervous system effects, including headaches,
irritation, confusion, weakness, and vision problems, as well
as upset stomach, vomiting, stomach cramps, diarrhea, and
jaundice.
No harmful effects on health have been confirmed in studies
of workers who made chlordane. One study found minor changes
in liver function in workers in Japan who used chlordane as
a pesticide. There are indications that chlordane may cause
anemia and other changes in the blood cells, but the evidence
is not very strong.
Animals given high levels of chlordane by mouth for short
periods of time died or had convulsions. Long-term exposure
of animals to chlordane in their food caused harmful effects
in the liver. It is not known whether chlordane will cause
cancer in humans after long-term exposure. Studies of workers
who made or used chlordane do not link exposure with cancer,
but the information is not sufficient to know for sure. Mice
fed low levels of chlordane in their food for most of their
lifetimes developed liver cancer. The International Agency
for Research on Cancer (IARC) has determined that chlordane
is not classifiable as to its carcinogenicity to humans. It
is not known whether chlordane will cause reproductive or
birth defects in humans. Studies of workers who made or used
chlordane do not link exposure to the chemical with birth
defects, but there are not enough studies in humans to know
for sure. There is some evidence that animals exposed before
birth or while nursing develop behavioral effects while growing
up.
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1.6
Is there a medical test to determine whether I have been exposed
to chlordane? |
Chlordane and its breakdown products
(metabolites) can be measured in human blood, urine, feces,
and breast milk. Tests have shown that most Americans have
low levels of chlordane metabolites in their body fat. The
breakdown products can stay in body fat for very long periods,
so finding them in body fat or breast milk does not tell how
much or how long ago exposure to chlordane occurred. Not all
of the breakdown products are specific for chlordane. Finding
chlordane and/or breakdown products in your body also cannot
predict what health effects will occur, if any. Levels in
blood and fat can be tested, although the tests are not routinely
available.
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1.7
What recommendations has the federal government made to protect
human health? |
The EPA guidelines for drinking water suggest that no more
than 60 ppb chlordane should be present in drinking water
that children consume for no longer than 10 days. Drinking
water should contain no more than 0.5 ppb for children or
2 ppb for adults if they drink the water for longer periods.
EPA stopped all use of chlordane on food crops, effective
March 1978. Until 1988, EPA permitted chlordane use for termite
control or dipping the roots or tops of nonfood plants. On
April 14, 1988, however, EPA stopped all sales and commercial
use of chlordane.
The Food and Drug Administration has established that the
levels of chlordane and its breakdown products in most fruits
and vegetables should not be greater than 300 ppb and in animal
fat and fish should not be greater than 100 ppb.
Federal regulations limit the amount of chlordane that factories
can release into waste water. The EPA requires industry to
report releases or spills of 1 pound or more. A temporary
guideline of the National Research Council indicated that
0.005 mg/m³ should be the maximum amount allowed in the
air of military housing.
The Occupational Safety and Health Administration (OSHA)
regulates chlordane levels in the workplace. The maximum allowable
level in workplace air is 0.5 mg/m³ for a person who
is exposed for 8 hours per workday and 40 hours per workweek.
The National Institute for Occupational Health and Safety
(NIOSH) also recommends an exposure limit of 5 mg/m³
for a person exposed to chlordane in the workplace for 8 hours
per workday and 40 hours per 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). 1994 Toxicological profile
for chlordane. Atlanta, GA: U.S. Department of Health
and Human Services, Public Health Service.
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