Dense Nonaqueous Phase Liquids (DNAPLs)Chromium VI
Dense Nonaqueous Phase Liquids (DNAPLs)
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Environmental Occurrence
Halogenated Alkenes
1,1-Dichloroethene
1,1-Dichloroethene (1,1-DCE) is used as a co-monomer and intermediate in the manufacture of synthetic fibers, adhesives, and food coverings, such as Saran wrap™ (Montgomery and Welkom 1991 and Toxnet). The EPA Toxics Release Inventory contains information from 29 facilities that reported the release of 78,077 pounds of 1,1-DCE, of which 77,932 pounds were released through air emissions in 2005.
Most of the 1,1-DCE found in the environment is due either to it having been disposed as a waste product or to the anaerobic biodegradation of tetrachloroethene (PCE) and trichloroethene (TCE) and the hydrolysis of 1,1,1-trichloroethane. These latter chemicals are among the most commonly reported organic compounds at Superfund sites. As such, 1,1-DCE is widely distributed in the environment. In addition to the above mechanisms, 1,1-DCE can be produced by cometabolic degradation of TCE and is sometimes observed with PCE and TCE in reducing conditions where hydrogen sulfide is present. Zhang et al. (2006) were able to produce conditions where a microcosm from the groundwater at a landfill at Dover Air Force Base was made to preferentially degrade TCE to 1,1-DCE instead of the normal 1,2-DCE. They speculated that the 1,1-DCE degrader did not generally compete well with the 1,2-DCE degraders except under very specific conditions. The industrial release of large amounts of 1,1-DCE in air emissions is less of a concern because the half life of 1,1-DCE in clean air is 11 hours and less than two hours in polluted air.
Zorgorski et al. (2006) found that 1,1-DCE is the fourth most commonly detected chemical above health risk levels in both public and private drinking water wells. Only tetrachloroethene, dibromochloropropane, and trichloroethene are detected more often.
The U.S. Geological Survey produces reports on the occurrence of contaminants like 1,1-DCE in localities throughout the United States, including large water basins, as part of the National Water Quality Assessment Program.
Zhang, J., A. Joslyn, and P. Chiu. 2006. 1,1-Dichloroethene as a predominant intermediate of microbial trichloroethene reduction. Environ. Sci. Tecnol. 2006, Vol 40, No. 6, pp 1830-1836.
For Further Information
The 2005 Toxics Release Inventory (TRI) Public Data Release Report
U.S. EPA
Certain classes of businesses report on their releases of pollution to EPA, which compiles the data in the TRI.
Groundwater Chemicals Desk Reference
Montgomery, J. and L. Welkom.
Lewis Publishers, Chelsea, MI, 1991, 640 pp
This book provides a summary of physical and chemical properties of a variety of chemicals, including 1,1-DCE.
TOXNET
The National Library of Medicine
National Institutes of Health
TOXNET is a comprehensive compendium of information on a variety of chemicals, but it is often dated.
The 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, 1112 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.
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Last updated on Monday, November 10, 2008