1.1 What is diisopropyl methylphosphonate? |
1.2 What happens to diisopropyl methylphosphonate
when it enters the environment? |
1.3 How might I be exposed to diisopropyl
methylphosphonate? |
1.4 How can diisopropyl methylphosphonate
enter and leave my body? |
1.5 How can diisopropyl methylphosphonate
affect my health? |
1.6 Is there a medical test to determine
whether I have been exposed to diisopropyl methylphosphonate? |
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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August 1998 |
Public Health Statement |
for |
Diisopropyl Methylphosphonate |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for diisopropyl methylphosphonate. 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 diisopropyl methylphosphonate 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 clean-up.
Diisopropyl methylphosphonate has been found in at least 2
of the 1,416 current or former NPL sites. However, it's
unknown how many NPL sites have been evaluated for this substance.
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 diisopropyl methylphosphonate,
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 diisopropyl methylphosphonate? |
Diisopropyl methylphosphonate is a colorless
liquid at normal temperatures. It is also known as methyl-,bis-(1-methyl-ethyl)ester,
phosphonic acid, and methyl-diisopropyl ester.
Diisopropyl methylphosphonate, or DIMP,
is a chemical by-product resulting from the manufacture and
detoxification of GB (also called Sarin), a nerve gas that
the Army produced from 1953 to 1957. A chemical by-product
is a chemical that is formed while making another substance.
You might find diisopropyl methylphosphonate in places where
GB has been produced, stored, or used, for example, the Rocky
Mountain Arsenal (RMA) outside of Denver, Colorado.
The RMA is where GB was produced for loading into chemical
warfare munitions. Production of GB was discontinued
in 1957, and it is not likely that GB, or diisopropyl methylphosphonate,
will be produced in the United States in the future because
of signing of a chemical treaty that bans not only the use
but also the production and stockpiling of poison gases.
Diisopropyl methylphosphonate is a colorless liquid.
A small amount (0.1%, or 1g of DIMP in 1,000 mL of water)
of it dissolves in water, but some scientists have found it
to be more soluble (8%). Once it is dissolved, little,
if any, evaporates into the air.
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1.2
What happens to diisopropyl methylphosphonate when it enters
the environment? |
Diisopropyl methylphosphonate was released
into the environment at the RMA between 1953 and 1957.
While most discharged diisopropyl methylphosphonate entered
the groundwater at the RMA, some also entered the surface
water and soils. It is unlikely that diisopropyl methylphosphonate
escaped to the air because it does not evaporate easily.
Diisopropyl methylphosphonate does not break down in the environment
very quickly and can remain in water and soil for years.
The flow of water during irrigation can carry diisopropyl
methylphosphonate through the soil. Plants can take
up diisopropyl methylphosphonate and store or accumulate it
in leaves and DIMP may enter the food chain when animals eat
these plants. However, because DIMP is rapidly changed
to isopropyl methylphosphonic acid (IMPA) by animals that
eat it, it is unlikely that DIMP will be present further up
the food chain. Human exposure may also occur by consumption
of home-grown fruits and vegetables irrigated by DIMP-contaminated
water.
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1.3
How might I be exposed to diisopropyl methylphosphonate? |
Exposure of the general population to
diisopropyl methylphosphonate is expected to be rare and even
then in small amounts. Only people living near a site
where DIMP is found (such as RMA) may be exposed to this substance.
Drinking or showering with water containing
diisopropyl methylphosphonate, or eating vegetables irrigated
with it are the most likely ways that a person can be exposed
to it. Water contaminated with DIMP has been found only
at or near the RMA. In 1974 diisopropyl methylphosphonate
was first measured in the groundwater at RMA. The reported
amounts ranged from 0.5 parts per billion (ppb) to 44,000
ppb (1 ppb is equivalent to one part by weight of diisopropyl
methylphosphonate in a billion parts by volume of water or
soil). In 1989, soil samples from some areas in the
RMA were reported to contain approximately 50 ppb to 240 ppb
of diisopropyl methylphosphonate. During the most recent
comprehensive groundwater sampling at RMA in 1995, diisopropyl
methylphosphonate concentrations in groundwater were reported
to range from less than 0.110 ppb to 965 ppb. It is
possible that exposure to diisopropyl methylphosphonate might
occur by eating plants that absorbed it from water or soil.
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1.4
How can diisopropyl methylphosphonate enter and leave my body? |
Diisopropyl methylphosphonate may enter
your body after drinking water contaminated with it or it
may enter through your skin. You could be exposed to
diisopropyl methylphosphonate if you drink water that contains
the chemical near the RMA. Exposure of the general population
to diisopropyl methylphosphonate is not likely to occur.
Studies in animals show that diisopropyl methylphosphonate
enters the bloodstream relatively quickly following oral exposure.
Animal studies also show that once diisopropyl methylphosphonate
is inside the body, it is changed almost completely into isopropyl
methylphosphonic acid (IMPA) and leaves the body in the urine.
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1.5
How can diisopropyl methylphosphonate affect my health? |
Scientists use many tests to protect
the public from the harmful effects of toxic chemicals and
to find ways to treat people who have been harmed.
One way to see if a chemical will hurt
people is to learn how the chemical is absorbed, changed,
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.
Little is known about the human health
effects of diisopropyl methylphosphonate. Skin rashes
and other signs of irritation have been reported in some people
who handled dead animals near a pond containing diisopropyl
methylphosphonate and other chemicals, but it is not known
which substances caused these effects.
Drinking large amounts of diisopropyl
methylphosphonate kills animals. The amount needed to
cause death in humans is not known for sure. Animal
studies have shown no evidence that drinking or eating diisopropyl
methylphosphonate causes fertility problems or birth defects.
Animal studies have shown that eating diisopropyl methylphosphonate
can affect some liver enzymes (indicating a response by the
liver). However, test animals showed no liver disease.
While most animal studies have shown only minimal toxic effects
below a certain level of exposure, there is some evidence
that diisopropyl methylphosphonate can cause effects on the
blood and nervous systems at high levels. Overall, however,
it is not a very toxic chemical.
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1.6
Is there a medical test to determine whether I have been exposed
to diisopropyl methylphosphonate? |
Once inside the body, diisopropyl methylphosphonate
is rapidly converted to isopropyl methylphosphonic acid (IMPA),
which is rapidly cleared from the blood. Laboratory
tests can determine the amount of IMPA in the blood or urine.
However, because IMPA leaves the body rapidly, these tests
are useful only for recent exposure. It is helpful for
your doctor to know whether there are other chemicals to which
you have been exposed.
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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 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 diisopropyl methylphosphonate include
the following:
The EPA has issued guidelines concerning
recommendations for levels of diisopropyl methylphosphonate
that may be in drinking water, including Health Advisories.
It has concluded that a lifetime of exposure to drinking water
containing 0.6 mg/L (1 mg/L = 1 milligram of diisopropyl methylphosphonate
in 1 liter of water) of diisopropyl methylphosphonate would
not result in any noncancer harmful health effects.
This amount, 0.6 mg/L, is the same as 600 parts per billion
parts of water. The EPA has determined that diisopropyl
methylphosphonate is unclassifiable as to its ability to cause
cancer in humans, that is, there are not enough data to classify
the ability of diisopropyl methylphosphonate to cause cancer
in humans.
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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). 1998. Toxicological
profile for diisopropyl methylphosphonate. Atlanta, GA:
U.S. Department of Health and Human Services, Public Health
Service.
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