POLYCYCLIC AROMATIC HYDROCARBONS (PAHs)
This pamphlet provides answers to basic
questions about polycyclic aromatic hydrocarbons. It will explain what
polycyclic aromatic hydrocarbons are, where they are found, how they can affect
your health, and what you can do to prevent or reduce exposure to them.
Polycyclic aromatic hydrocarbons (PAHs) are
made whenever substances are burned. PAHs are also found at former
coal-gasification sites. Breathing smoke or coming into contact with
contaminated soil exposes people to PAHs. Some PAHs may cause cancer and may
affect the eyes, kidneys, and liver.
WHAT ARE POLYCYCLIC AROMATIC
Polycyclic aromatic hydrocarbons are a group of
chemicals that occur naturally in coal, crude oil, and gasoline. PAHs are also
present in products made from fossil fuels, such as coal-tar pitch, creosote,
and asphalt. When coal is converted to natural gas, PAHs can be released.
Therefore, some coal-gasification sites may have elevated levels of PAHs. PAHs
also can be released into the air during the burning of fossil fuels, garbage,
or other organic substances. The less efficient the burning process, the more
PAHs are given off. Forest fires and volcanoes produce PAHs naturally.
PAHs are found throughout the environment in
the air, water, and soil, and can persist in the environment for months or
years. Although hundreds of PAHs exist, some of the more common are listed
HOW CAN I BE EXPOSED TO PAHs?
Air can be contaminated by PAHs. Levels of PAHs
in urban air may be 10 times greater than those found in rural areas. You may
be exposed to PAHs in soil near hazardous waste sites or near areas where coal,
wood, gasoline or other products have been burned. Low levels of PAHs have been
found in some drinking water supplies in the United States.
In the home, PAHs are present in tobacco smoke,
smoke from wood burning stoves and fireplaces, creosote-treated wood products,
and some foods. Barbecuing, smoking, or charring food over a fire greatly
increases the amount of PAHs in the food. Other foods that may contain low
levels of PAHs include roasted coffee, roasted peanuts, refined vegetable oil,
grains, vegetables, and fruits. A variety of cosmetics and shampoos are made
with coal tar and therefore contain PAHs. The PAH compound naphthalene is
present in some mothballs.
HOW CAN PAHs AFFECT MY HEALTH?
The health effects that can be caused by
exposure to PAHs depend on --
- how much has entered the body,
- how long you have been exposed to PAHs, and
- how the body responds to PAHs.
These effects may be either short-term or
Short-term health effects
It is not clear that PAHs cause short-term
health effects. Other compounds commonly found with PAHs may be the cause of
short-term symptoms such as eye irritation, nausea, vomiting, diarrhea, and
Long-term health effects
Long-term health effects of exposure to PAHs
may include cataracts, kidney and liver damage, and jaundice. Repeated skin
contact to the PAH naphthalene can result in redness and inflammation of the
skin. Breathing or swallowing large amounts of naphthalene can cause the
breakdown of red blood cells.
Long-term exposure to low levels of some PAHs
have caused cancer in laboratory animals. Benzo(a)pyrene is the most common PAH
to cause cancer in animals. Studies of workers exposed to mixtures of PAHs and
other compounds have noted an increased risk of skin, lung, bladder, and
gastrointestinal cancers. The information provided by these studies is limited
because the workers were exposed to other potential cancer-causing chemicals
besides PAHs. Although animal studies have shown adverse reproductive and
developmental effects from PAH exposure, these effects have generally not been
seen in humans.
HOW CAN I REDUCE MY EXPOSURE TO
One of the greatest sources of exposure to PAHs
is breathing these compounds in tobacco smoke. Smokers can lower their own
exposure and the exposure of their families by stopping smoking. People could
also reduce their use of wood burning stoves and fireplaces. Additional steps
to lower exposure to PAHs include --
- decreasing consumption of smoked and
- decreasing the use of coal-tar-based
cosmetics and shampoos;
- substituting cedar shavings or aromatic herbs
for mothballs, moth flakes, and deodorant cakes;
- avoiding skin contact by wearing protective
clothing, such as long-sleeve shirts, long pants, and gloves, if you are
handling creosote-treated wood products;
- avoiding exposure to dust and fumes by
wearing an appropriate respirator when working with products containing PAHs.
ARE THERE ANY REGULATIONS FOR PAHs THAT
PROTECT HUMAN HEALTH?
The U.S. Environmental Protection Agency
(USEPA) has established maximum contaminant levels (MCLs) for public water
supplies to reduce the chances of adverse health effects from drinking
contaminated water. MCLs are enforceable limits that public water supplies must
meet. These standards are much lower than levels at which health effects have
been observed. USEPA has not established MCLs for individual PAHs, but has set
an MCL for total PAHs of 0.2 parts per billion. There are currently no
standards for regulating levels of these chemicals in private wells. USEPA
requires the reporting of any releases of PAHs into the environment that exceed
one pound. There are no regulations for the PAH content of foods.
WHAT CAN MEDICAL TESTS TELL ME ABOUT MY
EXPOSURE TO PAHs?
There are tests available to measure the
presence of PAHs in blood or urine. These tests cannot be used to predict
potential health effects, but can only confirm that you have been exposed to
PAHs. These tests are not routinely available at a doctor's office because they
require special equipment. Some hospitals can provide this testing. If you
suspect you are ill from exposure to PAHs, contact your physician.
WHERE CAN I GET MORE INFORMATION?
Illinois Department of Public Health
Division of Environmental Health
525 W. Jefferson St.
Springfield, IL 62761
TTY (hearing impaired use only) 800-547-0466
This pamphlet was supported in part by funds
from the Comprehensive Environmental Response, Compensation, and Liability Act
trust fund through a cooperative agreement with the Agency for Toxic Substances
and Disease Registry, Public Health Service, U.S. Department of Health and