Acrolein is a clear or yellow liquid with a burnt, sweet, pungent odor. Most people begin to smell acrolein in air at concentrations of 0.25 parts acrolein per million parts of air (ppm). It ignites and burns easily in air. Acrolein changes into a vapor much faster than water does at normal temperatures. The change of acrolein from a liquid to a vapor becomes faster as temperature increases. Acrolein might be found in the air, water, or soil near hazardous waste sites if it was not properly stored. Although acrolein may be found in surface water and soil, it can quickly evaporate or can be rapidly inactivated by binding to materials in soil; as such, it is not likely to last a long time in the environment.
Acrolein is primarily used to make other chemicals and may also be found in some livestock feed. Acrolein is itself a pesticide and is added to irrigation canals and the water supplies of some industrial plants to control underwater plant, algae, and slime growth. At much higher concentrations, it is used to make chemical weapons.
Small amounts of acrolein can be formed and can enter the air when organic matter such as trees and other plants (including tobacco) are burned and also when fuels such as gasoline and oil are burned. Acrolein is also formed in building fires at concentrations that can be deadly for occupants.
Pathways of acrolein in the environment
Acrolein can enter the environment as a result of burning wood, tobacco, vehicle fuels; overheating or burning of cooking oils; and accidental release from chemical plants or release from a hazardous waste site. Acrolein that enters the air as a vapor changes into other chemicals within days. When acrolein is introduced into water, it dissolves easily. Some of the acrolein in water changes into a vapor and enters the air. The acrolein left in the water is changed into other chemicals, which are rapidly broken down, or it may be removed by binding to substances in water.
Acrolein that enters the soil can change into vapor and enter the air, be washed out with water, or may bind to soils in such a way as to make it non-toxic.
Exposure to acrolein
If you live near a hazardous waste site in which acrolein is not stored properly, you could be exposed to acrolein from breathing air or drinking water that contains acrolein. Since acrolein easily changes into a vapor, you are more likely to be exposed to it from breathing air than from drinking water. A child playing in this hazardous waste site could be exposed to acrolein by drinking surface water, eating soil, or having skin contact with soil that contains acrolein. However, unless a large amount of acrolein was released at the site, it is unlikely that children would be exposed to acrolein in soil given that the acrolein vaporizes from the surface of the soil or is changed by binding with soil.
Acrolein is formed by the breakdown of many pollutants found in outdoor air. Burning tobacco and other plants forms acrolein. You breathe in acrolein when you smoke tobacco or when you are near someone who is smoking (secondhand smoke). You also breathe in acrolein when you are near automobiles, because burning gasoline forms acrolein which enters the air. However, the amount of acrolein in automobile exhaust tends to be very low. Your own body can produce very small amounts of acrolein when certain fatty molecules or amino acids are broken down. If you live near an oil or coal power plant, you breathe in small amounts of acrolein. You could breathe in acrolein if you work in an industry that uses acrolein to make other chemicals.
Acrolein is formed when fats are overheated. Small amounts of acrolein may also be found in foods such as fried foods, cooking oils, and roasted coffee. Although we know acrolein is in certain foods, the amount that is in the foods that you eat is not known.
The levels of acrolein are usually low in outside air, averaging around 0.20 parts acrolein in one billion parts air (0.2 ppb) in urban air and 0.12 ppb in rural air. However, in several large cities acrolein has been measured at levels of 5.6 ppb. The levels of acrolein within the air of a typical home range between less than 0.02 and 12 ppb but can be higher if you smoke tobacco in your home.
Acrolein has not been found in drinking water, and it is not commonly found in surface waters such as lakes and streams. The background levels of acrolein in these waters or in soil are not known.
Pathways of acrolein in the body
If you breathed in acrolein, most of it would enter your body's tissues within seconds. If you swallowed acrolein or spilled it on your skin, some of it would rapidly enter your body's tissues, but we do not know how much. Once in your body tissues, acrolein changes into other chemicals called metabolites. This probably occurs within minutes or hours. Some of these metabolites leave your body in your urine. It is not known how long this takes.
Health effects of acreolein
Scientists use many tests to protect the public from harmful effects of toxic chemicals and to find ways for treating persons who have been harmed.
You should know that one way to learn whether a chemical will harm people is to determine how the body absorbs, uses, and releases the chemical. For some chemicals, animal testing may be necessary. Animal testing may also help identify such health effects as cancer or birth defects. Without laboratory animals, scientists would lose a basic method for getting information needed to make wise decisions that protect public health. Scientists have the responsibility to treat research animals with care and compassion. Scientists must comply with strict animal care guidelines because laws today protect the welfare of research animals.
Additionally, there are vigorous national and international efforts to develop alternatives to animal testing. The efforts focus on both in vitro and in silico approaches and methods. For example, the National Toxicology Program (NTP) at the National Institute of Environmental Health Sciences (NIEHS) created the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) in 1998. The role of NICEATM is to serve the needs of high quality, credible science by facilitating development and validation—and regulatory and public acceptance—of innovative, revised test methods that reduce, refine, and replace the use of animals in testing while strengthening protection of human health, animal health and welfare, and the environment. In Europe, similar efforts at developing alternatives to animal based testing are taking place under the aegis of the European Centre for the Validation of Alternative Methods (ECVAM).
How a chemical affects your health depends on the amont and length of time of exposure. As you are exposed to more acrolein, and for a longer period of time, the effects that you experience are likely to become worse. If you breathed in low levels of acrolein for a short time, your eyes might water and your nose and throat might become sore. These effects disappear within minutes after the exposure stops. However, if you were exposed to higher levels, your lungs might be affected more severely and for a longer time. Breathing in very high levels of acrolein might affect your lungs so severely that you might die.
We do not know if eating food or drinking water containing acrolein affects your health. However, animals that swallowed acrolein had stomach irritation, vomiting, stomach ulcers, and bleeding. No one knows if breathing or eating acrolein or spilling it on your skin causes birth defects, affects your ability to have children, or causes cancer. The Department of Health and Human Services (DHHS) has not classified acrolein as to its carcinogenicity. International Agency for Resarch on Cancer (IARC) has determined that acrolein is not classifiable as to carcinogenicity in humans. The EPA has stated that the potential carcinogenicity of acrolein cannot be determined based on an inadequate database.
Health effects on children
This section discusses potential health effects in humans from exposures during the period from conception to maturity at 18 years of age.
Acrolein is very irritating to the eyes, nose, throat, lungs, stomach, and skin. In general, children are not likely to be affected by acrolein more than adults. However, children who are sensitive to irritants in the air (such as children with asthma) may be more sensitive to lung irritation from acrolein.
In animal studies, ingestion of very large amounts of acrolein during pregnancy caused reduced birth weights and skeletal deformities in newborns. Also, the levels causing these effects were often fatal to the mother.
Reducing risk of exposure to acrolein
If your doctor finds that you have been exposed to substantial amounts of acrolein, ask whether your children might also have been exposed. Your doctor might need to ask your state health department to investigate.
Children are expected to be exposed to acrolein in the same ways that adults are exposed. Like adults, children may be exposed to unknown levels from inhaling second-hand tobacco smoke. Children's exposure from eating or touching contaminated soil is not likely to differ from that of adults, because acrolein evaporates quickly, does not move well in soil, and doesn't last long in the environment. You can reduce your family's exposure to acrolein by reducing their exposure to tobacco smoke, smoke from burning wood products or cooking oils and grease, and exhaust from diesel or gasoline vehicles.
Medical tests for exposure to acrolein
Tests have been developed that can measure acrolein or its breakdown products in blood or urine. These measurements are known as biomonitoring. These tests require specialized laboratory equipment and cannot be performed in a physician's office. These tests also cannot be used to determine whether or not you have been exposed to acrolein in the environment, because acrolein can be produced by the breakdown of other chemicals in the body.
- The Agency for Toxic Substances and Disease Registry
- Interagency Coordinating Committee on the Validation of Alternative Methods
- European Centre for the Validation of Alternative Methods
- Institute for Laboratory Animal Research
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