U.S. EPA Contaminated Site Cleanup Information (CLU-IN)


U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Dense Nonaqueous Phase Liquids (DNAPLs)

Environmental Occurrence

Halogenated Alkenes

The halogenated ethenes consist of five high-production chemical compounds that are widely used for industrial and commercial applications, such as degreasers, solvents, and chemical intermediates. Tetrachloroethene (PCE) and trichloroethene (TCE) are among the most widely detected organic compounds at Superfund National Priority List sites. They are also among the most detected in public and private drinking water wells (Zorgorski et al. 2006). cis 1,2-dichloroethene and trans 1,2-dichloroethene, which are produced commercially, are also byproducts of the degradation TCE and PCE. Therefore, they are often found with TCE and PCE in soil and ground water. Both cis and trans 1,2-dichloroethene were considered potential drinking water problems in a nationwide study of volatile organic compounds in aquifers (Zorgorski et al. 2006).

Some manufacturing and commercial facilities release over a million pounds of TCE and PCE to the air each year, and while TCE degrades relatively rapidly in air, PCE does not.

The two isomers of 1,3-dichloropropene are large-quantity soil fumigant pesticides. Zorgorki et al. (2006) did not detect them in public or private drinking water wells. However, there is sufficient concern about their mobility to restrict their use to non-sandy soil and fields with ground water deeper than 50 feet. Although they degrade naturally in the environment, their volatilization from fields shortly after application can expose individuals living near those fields.

For Further Information

Adobe PDF LogoOccurrence and Implications of Selected Chlorinated Solvents in Ground Water and Source Water in the United States and in Drinking Water in 12 Northeast and Mid-Atlantic States, 1993-2002
U.S. Geological Survey Scientific Investigations Report 2005-5268, 82 pp, 2005

The U.S. Geological Survey compiled occurrence and distribution data on methlyene chloride, 1,1,1-trichloroethane, tetrachloroethene, and trichloroethene in samples of ground water, source water, and drinking water collected during 1993-2002.

Adobe PDF LogoThe Quality of Our Nation's Waters: Volatile Organic Compounds in the Nation's Ground Water and Drinking-Water Supply Wells
Zogorski, John, Janet M. Carter, Tamara Ivahnenko, Wayne W. Lapham, Michael J. Moran, Barbara L. Rowe, Paul J. Squillace, and Patricia L. Toccalino
U.S. Geological Survey, USGS Circular 1292, 2006, 112 pp

This report summarizes the findings of an investigation of aquifers that supply drinking water to the public. The purpose of the investigation was to determine the presence or absence of 55 volatile organic chemicals in the aquifers.