Glossary - Perchloroethylene
Perchloroethylene (a.k.a., PERC) is a colourless, nonflammable liquid. It does not occur naturally and is produced in large quantities (310 million pounds in 1991) by three companies in the United States. U.S. demand for PERC declined by approximately 35% from 1989 to 1991, and is likely to continue to fall due mainly to evolving solvent recycling practices and reduced demand for chlorofluorocarbons.
The largest U.S. user of PERC is the dry cleaning industry -- it accounts for 80% to 85% of all dry cleaning fluid used. Textile mills, chlorofluorocarbon producers, vapour degreasing and metal cleaning operations, and makers of rubber coatings also use PERC. It can be added to aerosol formulations, solvent soaps, printing inks, adhesives, sealants, polishes, lubricants, and silicones. Typewriter correction fluid and shoe polish are among the consumer products that can contain PERC.
Exposure to perchloroethylene can occur in the workplace or in the environment following releases to air, water, land, or groundwater. Exposure can also occur when people:
PERC enters the body when breathed in with contaminated air or when consumed with contaminated food or water (it is less likely to be absorbed through skin contact). Once in the body, PERC can remain stored in fat tissue.
What happens to perchloroethylene in the environment?
Perchloroethylene evaporates when exposed to air. It dissolves only slightly when mixed with water. Most direct releases of PERC to the environment are to air. It also evaporates from water and soil exposed to air. Once in air, PERC breaks down to other chemicals over several weeks. Because it is a liquid that does not bind well to soil, PERC that makes its way into the ground can move through the ground and enter groundwater. Plants and animals living in environments contaminated with PERC can store small amounts of the chemical.
How does perchloroethylene affect human health and the environment?
Effects of perchloroethylene on human health and the environment depend on the amount of PERC present and the length and frequency of exposure. Effects also depend on the health of a person or the condition of the environment when exposure occurs.
Breathing PERC for short periods of time can adversely affect the human nervous system. Effects range from dizziness, fatigue, headaches and sweating to incoordination and unconsciousness. Contact with PERC liquid or vapour irritates the skin, the eyes, the nose, and the throat. These effects are not likely to occur at levels of PERC that are normally found in the environment.
Breathing perchloroethylene over longer periods of time can cause liver and kidney damage in humans. Workers exposed repeatedly to large amounts of PERC in air can also experience memory loss and confusion.
Laboratory studies show that PERC causes kidney and liver damage and cancer in animals exposed repeatedly by inhalation and by mouth. Repeat exposure to large amounts of PERC in air may likewise cause cancer in humans.
Perchloroethylene by itself is not likely to cause environmental harm at levels normally found in the environment. PERC can contribute to the formation of photochemical smog when it reacts with other volatile organic carbon substances in air. These reactions tend to eliminate PERC before it reaches the upper atmosphere in amounts sufficient to damage the ozone layer.
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