Public Health Statement for Atrazine
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for Atrazine. 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.
This public health statement tells you
about atrazine 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.
Atrazine has been found in at least 20 of the 1,636 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 atrazine is 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
If you are exposed to atrazine, 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/them. You must also consider
the other chemicals you're exposed to and your age, sex, diet,
family traits, lifestyle, and state of health.
What is atrazine?
Atrazine is the common name for an herbicide
that is widely used to kill weeds. It is used mostly on farms.
Pure atrazine-an odorless, white powder-is not very volatile,
reactive, or flammable. It will dissolve in water. Atrazine
is made in the laboratory and does not occur naturally.
Atrazine is used on crops such as sugarcane,
corn, pineapples, sorghum, and macadamia nuts, and on evergreen
tree farms and for evergreen forest regrowth. It has also
been used to keep weeds from growing on both highway and railroad
rights-of-way. Atrazine can be sprayed on croplands before
crops start growing and after they have emerged from the soil.
Some of the trade names of atrazine are Aatrex®, Aatram®,
Atratol®, and Gesaprim®. The scientific name for atrazine
Atrazine is a Restricted Use Pesticide (RUP), which means
that only certified herbicide users may purchase or use atrazine.
Certification for the use of atrazine is obtained through
the appropriate state office where the herbicide user is licensed.
Certified herbicide workers (see Section
1.7) may spread atrazine on crops or croplands as a powder,
liquid, or in a granular form. Atrazine is usually used in
the spring and summer months. For it to be active, atrazine
needs to dissolve in water and enter the plants through their
roots. It then acts in the shoots and leaves of the weed to
stop photosynthesis. Atrazine is taken up by all plants, but
in plants not affected by atrazine, it is broken down before
it can have an effect on photosynthesis. The application of
atrazine to crops as an herbicide accounts for almost all
of the atrazine that enters the environment, but some may
be released from manufacture, formulation, transport, and
More complete information about the sources,
properties, and uses of atrazine can be found in Chapters
4 and 5 of this profile.
What happens to atrazine when it enters the environment?
Atrazine is applied to agricultural fields
or to crops to kill weeds. It is also used near highways and
railroads for the same purposes. Some atrazine may enter the
air after it is applied to the soil. Some atrazine may also
be washed from the soil by rainfall and enter surrounding
areas, including streams, lakes, or other waterways. Some
atrazine may migrate from the upper soil surface to deeper
soil layers and enter the groundwater.
After atrazine is applied to soils, it
will remain there for several days to several months; in rare
situations, it may remain in soils for a few years. However,
in most cases, atrazine will be broken down in the soil over
a period of one growing season. In addition to being removed
from soil, atrazine is also taken up by the plants that grow
there, and this uptake is the first step in killing weeds.
Any atrazine that is washed from the
soil into streams and other bodies of water will stay there
for a long time, because breakdown of the chemical is slow
in rivers and lakes. It will also persist for a long time
in groundwater. This is one reason why atrazine is commonly
found in the water collected from drinking water wells in
some agricultural regions.
If atrazine enters the air, it can be
broken down by reactions with other reactive chemicals in
the air. However, sometimes atrazine is on particles such
as dust. When this happens, breakdown is not expected to occur.
Atrazine is removed from air mainly by rainfall. When atrazine
is on dust particles, the wind can blow it long distances
from the nearest application area. For example, atrazine has
been found in rainwater more than 180 miles (300 kilometers)
from the nearest application area.
Atrazine does not tend to accumulate
in living organisms such as algae, bacteria, clams, or fish,
and, therefore, does not tend to build up in the food chain.
More complete information about the environmental
fate of atrazine can be found in Chapter 6 of this profile.
How might I be exposed to atrazine?
Most people are not exposed to atrazine
on a regular basis. People living near areas where atrazine
was applied to crops may be exposed through contaminated drinking
water. Atrazine has been found at about 20 Superfund sites
in the United States. People living near those sites may be
exposed to higher levels of atrazine. If you are a factory
worker who works with atrazine, you may be exposed to higher
amounts of atrazine. The government has estimated that approximately
1,000 people may be exposed to atrazine in this way.
Atrazine, one of the most widely used
herbicides in the United States, is intentionally applied
to crops, especially corn, sugarcane, pineapples, and sorghum.
Therefore, people who live near areas where these crops are
grown, especially farm workers and herbicide applicators who
apply atrazine, may be exposed to atrazine because it is used
in agriculture. You may be exposed to atrazine if you are
nearby when crops are treated with atrazine, if you are involved
in the application of atrazine to crops, or if you are near
other places where it is applied. Most of the time, atrazine
is not found in high concentrations in the air, but may be
found in higher concentrations in the air near disposal facilities
or near areas where it is being applied to crops. You may
also be exposed to atrazine by digging in dirt that has atrazine
in it. Your children may be exposed to atrazine by playing
in dirt that contains atrazine. You and your children may
also be exposed to atrazine if you drink water from wells
that are contaminated with the herbicide. While it is used
on many crops, it has not been found in many food samples,
and then only at very low levels. Therefore, it is very unlikely
that you would be exposed to atrazine by eating any foods.
More information regarding exposure to
atrazine can be found in Chapter 6.
How can atrazine enter and leave my body?
Scientists do not know how much or how
quickly atrazine will be absorbed into your body if you breathe
it in. If you inhale atrazine-containing dust, some of the
particles may deposit in your lungs. Larger atrazine particles
may deposit before reaching the lungs and be coughed up and
swallowed. If your skin comes in contact with atrazine-contaminated
soil or water, a small amount of it may pass through your
skin and into your bloodstream. If you swallow food, water,
or soil containing atrazine, most of it will pass through
the lining of your stomach and intestines and enter your bloodstream.
Once atrazine enters your bloodstream
(is absorbed), it is distributed to many parts of your body.
Animal studies indicate that atrazine is changed in your body
into other substances called metabolites. Some atrazine and
its metabolites may enter some of your organs or fat, but
atrazine does not build up or remain in the body. Most of
the metabolites leave your body within 24-48 hours, primarily
in your urine, with a lesser amount in your feces.
More information on how atrazine enters
and leaves your body can be found in Chapter 3.
How can atrazine 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
One of the primary ways that atrazine
can affect your health is by altering the way that the reproductive
system works. Studies of couples living on farms that use
atrazine for weed control found an increase in the risk of
pre-term delivery. These studies are difficult to interpret
because most of the farmers were men who may have been exposed
to several types of pesticides. Atrazine has been shown to
cause changes in blood hormone levels in animals that affected
the ability to reproduce. Some of the specific effects observed
in animals are not likely to occur in occur in humans because
of biological differences between humans and these types of
animals. However, atrazine may affect the reproductive system
in humans by a different mechanism. Atrazine also caused liver,
kidney, and heart damage in animals; it is possible that atrazine
could cause these effects in humans, although this has not
Not enough information is available to
definitely state whether atrazine causes cancer in humans.
Studies of human populations indicate that there may be a
link between atrazine use and some types of cancer, but the
information was not specific enough to make a definitive connection
between atrazine and cancer. An increased risk of developing
mammary tumors was observed in one strain of female rats.
Because of biological differences between rats and humans,
it is not likely that humans would develop this type of cancer
following atrazine exposure. Other studies in animals did
not find atrazine-related increases in cancer. The International
Agency for Research on Cancer (IARC) has determined that atraine
is not classifiable as to its carcinogenicity to humans based
on inadequate evidence in humans and sufficient evidence in
More information on how atrazine can
affect your health can be found in Chapter 3.
How can atrazine affect children?
This section discusses potential health
effects from exposures during the period from conception to
maturity at 18 years of age in humans.
Children are likely to be exposed to
atrazine in the same way as adults, primarily through contact
with dirt that contains atrazine or by drinking water from
wells that are contaminated with the herbicide.
Little information is available regarding
the effects of atrazine in children. Maternal exposure to
atrazine in drinking water has been associated with low fetal
weight and heart, urinary, and limb defects in humans. Atrazine
has been shown to slow down the development of fetuses in
animals, and exposure to high levels of atrazine during pregnancy
caused reduced survival of fetuses. It is unclear whether
or at what level of exposure this might occur in humans.
It is not known whether atrazine or its
metabolites can be transferred from a pregnant mother to a
developing fetus through the placenta or from a nursing mother
to her offspring through breast milk.
How can families reduce the risk of exposure to atrazine?
If your doctor finds that you have been
exposed to significant amounts of atrazine, ask whether your
children might also be exposed. Your doctor might need to
ask your state health department to investigate.
Only certain people can use atrazine
because it is a Restricted Use Pesticide (RUP), so most people
cannot purchase it freely or use it. Since most people cannot
purchase it for private use, one way you can reduce your risk
of exposure to atrazine is by avoiding areas where it is being
used on crops or for control of weeds. You can also reduce
your risk of exposure by avoiding digging or working in soils
where it has been applied. If you live in an area where atrazine
is used, you may wish to avoid being near the area when it
is being applied. If children play in or near areas where
it atrazine has been applied too soon after it has been applied,
they can be exposed to the herbicide. You should encourage
your children to not play in these areas.
Atrazine has been found in water collected
from many drinking water wells in the Midwestern United States.
Therefore, you may be able to reduce your risk of exposure
to atrazine by ensuring that your water supply is free of
atrazine, or contains no measurable levels of atrazine. Atrazine
has also been found in streams, rivers, and lakes near fields
where it has been applied. Higher amounts have been found
in these waterways in the spring and summer months. Therefore,
you may wish not to swim in, nor drink from, these bodies
of water. Children may be exposed to atrazine if they play
in fields where atrazine has been applied or in streams receiving
runoff from those fields. They should be encouraged not to
play in these fields or bodies of water. Low amounts of atrazine
have also been found in carpet and house dust in homes in
the Midwest. However, very few children living in these homes
have had any atrazine in their bodies. To prevent possible
exposure of yourself or your children to atrazine, you may
wish to vacuum floors and dust surfaces on a frequent basis,
especially during the spring and summer months.
If you are a worker who applies atrazine
to crops or for weed control, you can reduce your exposure
to atrazine by using it according to instructions and wearing
proper clothing and protective gear. Be sure to follow all
instructions and heed any warning statements.
Is there a medical test to determine whether I have been exposed to atrazine?
Specific and sensitive tests have been
developed to detect atrazine in blood, fat, semen, and breast
milk of exposed individuals. Because atrazine is removed from
the body relatively quickly, these tests are only useful in
detecting recent exposures (within 24-48 hours) and are not
useful for detecting past exposures to atrazine. These tests
currently cannot be used to estimate how much atrazine you
have been exposed to or whether adverse health effects will
occur. These tests are not usually performed in a doctor's
office because special equipment is required and samples must
be sent to a laboratory for testing.
More information on tests that detect
atrazine and its metabolites can be found in Chapter 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 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 atrazine include the following:
Atrazine is currently under review for
pesticide re-registration by EPA. Therefore, EPA may be contacted
for more information about atrazine. OSHA has set a limit
of 5 mg atrazine/m3 of workroom air for an 8 hour workday.
NIOSH recommends a standard for occupational exposure of 5
mg atrazine/m3 of workroom air during a 10 hour shift
to protect workers from a concern that atrazine may cause
cancer. The EPA has set a maximum amount of atrazine allowable
in drinking water of 3 µg/L. In addition, atrazine is
designated as a Restricted Use Pesticide, which means that
only certified pesticide applicators can use atrazine. For
more information, please see Chapter 8.
Agency for Toxic Substances and Disease
Registry (ATSDR). 2003. Toxicological
Profile for Atrazine.
Atlanta, GA: U.S. Department of Health and Human Services,
Public Health Service.
Where can I get more information?
If you have questions or concerns, please contact your community or state health or environmental quality department or:
For more information, contact:
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
4770 Buford Highway
Chamblee, GA 30341-3717
Phone: 1-800-CDC-INFO 888-232-6348 (TTY)
Email: Contact CDC-INFO
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.