1.1 What are total petroleum hydrocarbons
(TPH)? |
1.2 What happens to TPH when it enters
the environment? |
1.3 How might I be exposed to TPH? |
1.4 How can TPH enter and leave my body? |
1.5 How can TPH affect my body? |
1.6 Is there a medical test to determine
whether I have been exposed to TPH? |
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 1999 |
Public Health Statement |
for |
Total Petroleum Hydrocarbons
(TPH) |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for total petroleum hydrocarbons (TPH). 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 total petroleum hydrocarbons (TPH) 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.
TPH, itself, has been reported at 34 of the 1,519 current
or former NPL sites. Many NPL sites are contaminated
with components of TPH, though no estimate has been made of
the number of these sites. This information is important
because exposure to these components 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 TPH, 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 total petroleum hydrocarbons (TPH)? |
Total Petroleum Hydrocarbons (TPH) is
a term used to describe a broad family of several hundred
chemical compounds that originally come from crude oil.
In this sense, TPH is really a mixture of chemicals.
They are called hydrocarbons because almost all of them are
made entirely from hydrogen and carbon. Crude oils can
vary in how much of each chemical they contain, and so can
the petroleum products that are made from crude oils.
Most products that contain TPH will burn. Some are clear
or light-colored liquids that evaporate easily, and others
are thick, dark liquids or semi-solids that do not evaporate.
Many of these products have characteristic gasoline, kerosene,
or oily odors. Because modern society uses so many petroleum-based
products (for example, gasoline, kerosene, fuel oil, mineral
oil, and asphalt), contamination of the environment by them
is potentially widespread. Contamination caused by petroleum
products will contain a variety of these hydrocarbons.
Because there are so many, it is not usually practical to
measure each one individually. However, it is useful
to measure the total amount of all hydrocarbons found together
in a particular sample of soil, water, or air.
The amount of TPH found in a sample is
useful as a general indicator of petroleum contamination at
that site. However, this TPH measurement or number tells
us little about how the particular petroleum hydrocarbons
in the sample may affect people, animals, and plants.
By dividing TPH into groups of petroleum hydrocarbons that
act alike in the soil or water, scientists can better know
what happens to them. These groups are called petroleum
hydrocarbon fractions. Each fraction contains many individual
compounds.
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1.2
What happens to TPH when it enters the environment? |
TPH is released to the environment through
accidents, as releases from industries, or as byproducts from
commercial or private uses. When TPH is released directly
to water through spills or leaks, certain TPH fractions will
float in water and form thin surface films. Other heavier
fractions will accumulate in the sediment at the bottom of
the water, which may affect bottom-feeding fish and organisms.
Some organisms found in the water (primarily bacteria and
fungi) may break down some of the TPH fractions. TPH
released to the soil may move through the soil to the groundwater.
Individual compounds may then separate from the original mixture,
depending on the chemical properties of the compound.
Some of these compounds will evaporate into the air and others
will dissolve into the groundwater and move away from the
release area. Other compounds will attach to particles in
the soil and may stay in the soil for a long period of time,
while others will be broken down by organisms found in the
soil.
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1.3
How might I be exposed to TPH? |
Everyone is exposed to TPH from many
sources, including gasoline fumes at the pump, spilled crankcase
oil on pavement, chemicals used at home or work, or certain
pesticides that contain TPH components as solvents.
A small amount of lighter TPH components are found in the
general air you breathe. Many occupations involve extracting
and refining crude oil, manufacturing petroleum and other
hydrocarbon products, or using these products. If you
work with petroleum products, you may be exposed to higher
levels of TPH through skin contact or by breathing contaminated
air. If TPH has leaked from underground storage tanks
and entered the groundwater, you may drink water from a well
contaminated with TPH. You may breathe in some of the
TPH compounds evaporating from a spill or leak if you are
in the area where an accidental release has occurred.
Children may be exposed by playing in soil contaminated with
TPH.
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1.4
How can TPH enter and leave my body? |
TPH can enter and leave your body when
you breathe it in air; swallow it in water, food, or soil;
or touch it. Most components of TPH will enter your
bloodstream rapidly when you breathe them as a vapor or mist
or when you swallow them. Some TPH compounds are widely
distributed by the blood throughout your body and quickly
break down into less harmful chemicals. Others may break
down into more harmful chemicals. Other TPH compounds
are slowly distributed by the blood to other parts of the
body and do not readily break down. When you touch TPH
compounds, they are absorbed more slowly and to a lesser extent
than when you breathe or swallow them. Most TPH compounds
leave your body through urine or when you exhale air containing
the compounds.
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1.5
How can TPH affect my body? |
Health effects from exposure to TPH depend
on many factors. These include the types of chemical
compounds in the TPH, how long the exposure lasts, and the
amount of the chemicals contacted. Very little is known
about the toxicity of many TPH compounds. Until more
information is available, information about health effects
of TPH must be based on specific compounds or petroleum products
that have been studied.
The compounds in different TPH fractions
affect the body in different ways. Some of the TPH compounds,
particularly the smaller compounds such as benzene, toluene,
and xylene (which are present in gasoline), can affect the
human central nervous system. If exposures are high
enough, death can occur. Breathing toluene at concentrations
greater than 100 parts per million (100 ppm) for more than
several hours can cause fatigue, headache, nausea, and drowsiness.
When exposure is stopped, the symptoms will go away.
However, if someone is exposed for a long time, permanent
damage to the central nervous system can occur. One
TPH compound (n-hexane) can affect the central nervous system
in a different way, causing a nerve disorder called "peripheral
neuropathy" characterized by numbness in the feet and legs
and, in severe cases, paralysis. This has occurred in workers
exposed to 500–2,500 ppm of n-hexane in the air. Swallowing
some petroleum products such as gasoline and kerosene causes
irritation of the throat and stomach, central nervous system
depression, difficulty breathing, and pneumonia from breathing
liquid into the lungs. The compounds in some TPH fractions
can also affect the blood, immune system, liver, spleen, kidneys,
developing fetus, and lungs. Certain TPH compounds can
be irritating to the skin and eyes. Other TPH compounds,
such as some mineral oils, are not very toxic and are used
in foods.
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. Animal studies
have shown effects on the lungs, central nervous system, liver,
kidney, developing fetus, and reproductive system from exposure
to TPH compounds, generally after breathing or swallowing
the compounds.
One TPH compound (benzene) has been shown
to cause cancer (leukemia) in people. The International
Agency for Research on Cancer (IARC) has determined that benzene
is carcinogenic to humans (Group 1 classification).
Some other TPH compounds or petroleum products, such as benzo(a)pyrene
and gasoline, are considered to be probably and possibly carcinogenic
to humans (IARC Groups 2A and 2B, respectively) based on cancer
studies in people and animals. Most of the other TPH
compounds and products are considered not classifiable (Group
3) by IARC.
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1.6
Is there a medical test to determine whether I have been exposed
to TPH? |
There is no medical test that shows if
you have been exposed to TPH. However, there are methods
to determine if you have been exposed to some TPH compounds,
fractions, or petroleum products. For example, a breakdown
product of n-hexane can be measured in the urine. Benzene
can be measured in exhaled air and a metabolite of benzene,
phenol, can be measured in urine to show exposure to gasoline
or to the TPH fraction containing benzene. Exposure
to kerosene or gasoline can be determined by its smell on
the breath or clothing. Methods also exist to determine
if you have been exposed to other TPH compounds. For
example, ethylbenzene can be measured in the blood, urine,
breath, and some body tissues of exposed people. However,
many of these tests may not be available in your doctor's
office.
If you have TPH compounds in your body,
they could be from exposure to many different products, and
tests cannot determine exactly what you were exposed to.
Tests are useful if you suspect that you were exposed to a
particular product or waste that contains TPH. For information
on tests for exposure to specific TPH compounds, see the ATSDR
toxicological profiles for benzene, toluene, total TPHsylenes,
polycyclic aromatic hydrocarbons, and hexane.
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1.7
What recommendations has the federal government made to protect
human health? |
The federal government develops regulations
and guidelines to protect public health. Regulations
can be enforced by law. Federal agencies that develop
regulations for toxic substances include the EPA, the NRC
(Nuclear Regulatory Commission), 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), Centers for Disease Control and Prevention
(CDC), 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.
Although there are no federal regulations
or guidelines for TPH in general, the government has developed
regulations and guidelines for some of the TPH fractions and
compounds. These are designed to protect the public from the
possible harmful health effects of these chemicals. To protect
workers, the Occupational Safety and Health Administration
(OSHA) has set a legal limit of 500 parts of petroleum distillates
per million parts of air (500 ppm) in the workplace.
EPA regulates certain TPH fractions,
products, or wastes containing TPH, as well as some individual
TPH compounds. For example, there are regulations for
TPH as oil; these regulations address oil pollution prevention
and spill response, stormwater discharge, and underground
injection control. EPA lists certain wastes containing
TPH as hazardous. EPA also requires that the National
Response Center be notified following a discharge or spill
into the environment of 10 pounds or more of hazardous wastes
containing benzene, a component in some TPH mixtures.
Nearly all states have cleanup standards
for TPH or components of TPH (common cleanup standards are
for gasoline, diesel fuel, and waste oil). Analytical
methods are specified, many of which are considered to be
TPH methods.
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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). 1999. Toxicological
profile for total petroleum hydrocarbons (TPH). Atlanta,
GA: U.S. Department of Health and Human Services, Public Health
Service.
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