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 Alkanes

Dibromochloromethane

Dibromochloromethane (DBCM) is no longer produced commercially in the United States (ATSDR 2005).

According to ATSDR (2005), DBCM has been identified in at least 174 of the 1,662 hazardous waste sites proposed for EPA's National Priorities List.

Dibromochloromethane, bromoform, dichlorobromomethane, and chloroform belong to a group of chemicals referred to as trihalomethanes (THMs). THMs are formed when raw source water is processed with chlorine-containing disinfectants that react with natural organic or carbon-containing matter in the water to form disinfection byproducts. The principal source of human exposure to THMs is chlorinated water in public water supplies, usually in the low mg/L range. Normal household use of water containing these chemicals can result in exposure by the ingestion, inhalation, and dermal routes (ATSDR 2005).

According to Zogorski et al. (2006), DBCM is the twelfth most frequently detected volatile organic compound in the aquifers tested in a U.S. Geological Survey assessment of groundwater and drinking water quality in wells in the United States. The chemical occurred in over one percent of the samples and was found in about 4.4 percent of public supply wells and about one percent of private wells (Zogorski et al. 2006). An extensive discussion of DBCM in drinking water wells is available in Chapter 6: Potential for Human Exposure, of the Agency for Toxic Substances and Disease Registry's toxicological profile for bromoform and chlorodibromomethane (ATSDR 2005).

References

The Quality of Our Nation's Waters: Volatile Organic Compounds in the Nation's Ground Water and Drinking-Water Supply WellsAdobe PDF Logo
Zogorski, J., J.M. Carter, T. Ivahnenko, W.W. Lapham, M.J. Moran, B.L. Rowe, P.J. Squillace, and P.L. Toccalino.
U.S. Geological Survey Circular 1292, 112 pp, 2006

Toxicological Profile for Bromoform and Chlorodibromomethane
Agency for Toxic Substances and Disease Registry (ATSDR), 273 pp, 2005

For Further Information

Occurrence of Trihalomethanes in the Nation's Ground Water and Drinking-Water Supply Wells, 1985-2002
Schaap, B.D., and J.S. Zogorski.
U.S. Geological Survey Scientific Investigations Report 2006-5068, 65 pp, 2006