1,2-Dichloroethene is also called 1,2-dichloroethylene. It is a highly flammable, colorless liquid with a sharp, harsh odor. You can smell very small amounts of 1,2-dichloroethene in air (beginning at a level of about 17 parts per million or ppm). There are two forms of 1,2-dichloroethene; one form is called cis-1,2-dichloroethene and the other is called trans-1,2-dichloroethene. Sometimes both forms are present as a mixture. 1,2-Dichloroethene is used most often to produce solvents and in chemical mixtures.
1,2-Dichloroethene enters the environment through industrial activity of people. This chemical has been found in air, water, and soil. 1,2-Dichloroethene is released to the environment from chemical factories that make or use this chemical, from landfills and hazardous waste sites containing this chemical, from chemical spills, from burning of objects made of vinyl, and from breakdown of other chlorinated chemicals.
Pathways for 1,2-dichloroethenein the environment
1,2-Dichloroethene evaporates rapidly. When released to moist soil surfaces or to lakes, rivers, and other bodies of water, most of it evaporates into the air. Once in the air, it usually takes about 5-12 days for half of any amount of it to break down (half-life in air). 1,2-Dichloroethene that is below soil surfaces in landfills or hazardous waste sites may dissolve in water, seep deeper into the soil, and possibly contaminate groundwater. Some 1,2-dichloroethene may escape as a vapor. Once in groundwater, it takes about 13-48 weeks for half of a given amount to break down (half-life in water). There is a slight chance that small amounts of the 1,2-dichloroethene found in landfills will eventually break down into vinyl chloride, which is believed to be a more hazardous chemical.
Exposure to 1,2-dichloroethene
You might be exposed to 1,2-dichloroethene by breathing contaminated air or by drinking contaminated tap water. If the tap water in your home is contaminated, you could also be breathing 1,2-dichloroethene vapors while cooking, bathing, or washing dishes. There are no known products you can buy that contain 1,2-dichloroethene. People who are most likely to be exposed live near landfills and hazardous waste sites that contain this chemical, work at factories where this chemical is made or used, work at 1,2-dichloroethene contaminated landfills, or work as firefighters. Job-related exposure results from breathing in 1,2-dichloroethene from workplace air or from touching contaminated chemicals or materials. According to a survey conducted between 1981 and 1983 by the National Institute for Occupational Safety and Health (NIOSH), an estimated 215 people in the United States may have been exposed to 1,2-dichloroethene while working.
People who live in cities or suburbs are more likely to be exposed than people living in rural areas. Most people who are exposed to 1,2-dichloroethene through air or water are exposed to very low levels, in the range of parts per million (ppm) to parts per billion (ppb).
Pathways for 1,2-dichloroethene in the body
1,2-Dichloroethene can enter the body through your lungs when you breathe air contaminated with it, through your stomach and intestines when you eat food or drinking water contaminated with it, or through your skin upon contact with the chemical.
When 1,2-dichloroethene enters the body, the blood and other tissues absorb it. It is broken down to other compounds in the liver. Animal studies have looked at how quickly the compound enters and leaves the body and what may happen to it in the body. These animal studies describe effects at levels far greater than those levels at which most people would be exposed. No studies show specifically how 1,2-dichloroethene enters a person's body and how it is changed or removed by the body.
Health effects of 1,2-dichloroethene
Breathing high levels of trans-1,2-dichloroethene can make you feel nauseous, drowsy, and tired. Breathing very high levels of its vapor can kill you. When animals breathed high levels of trans-1,2-dichloroethene for short or longer periods of time, their livers and lungs were damaged. The effects were more severe with longer exposure times. Animals that breathed very high levels of trans-1,2-dichloroethene had damaged hearts. Animals given extremely high doses of cis- or trans-1,2-dichloroethene by mouth died. Lower oral doses of cis-1,2-dichloroethene caused effects in the blood, such as decreased numbers of red blood cells, and effects on the liver.
The long-term human health effects after exposure to low concentrations of 1,2-dichloroethene are not known. Results of a recent animal study suggest that an exposed fetus may not grow as quickly as one that is not exposed. No studies have been done to see whether cancer in people or animals is caused by exposure to 1,2-dichloroethene; exposure has not been shown to affect fertility in people or animals.
Medical tests for exposure to 1,2-dichloroethene
Methods are available to measure concentrations of 1,2-dichloroethene in blood, urine, and tissues. However, these methods are not routinely used to determine whether a person has been exposed to this compound, because the expected breakdown products resulting from exposure to 1,2-dichloroethene may also result from exposure to other chemicals.
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