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)

Chemistry and Behavior

Halogenated Alkanes

Methanes

Dibromochloromethane

DibromochloromethaneDibromochloromethane (DBCM, CAS No. 124-48-1) is a heavy, nonflammable, colorless to pale-yellow liquid with a nonirritating odor. DBCM belongs to a group of chemicals known as trihalomethanes. DBCM is slightly soluble in water (2,700 mg/L at 20oC), has a vapor pressure of 76 mm Hg at 20oC, and a specific gravity of 2.451 at 20oC. The compound has a log Koc of 1.92, a log Kowof 2.16, and a Henry's constant of 9.9 x e-4 atm-m3/mol (ATSDR 2005). The Agency for Toxic Substances and Disease Registry has developed a toxicological profile for this chemical that contains a useful summary table of its physical properties.

DBCM is a slightly volatile liquid and tends to exist primarily as a vapor in the atmosphere (ATSDR 2005). Because of its slight solubility in water, the compound in the environment could be removed from the air by dissolution into clouds or raindrops.

As indicated by its log Koc, the chemical has a minor affinity for soil particles. It tends to be mobile in soil particles with low organic content. Because of its log Kow value, DBCM is expected to have low bioaccumulation potential (HSDB).

The theoretical half life of DBCM in a model river is 2.6 hours and 6 days in a model lake (HSDB). Hydrolysis is not expected to be an important fate for the compound (ATSDR 2005). Vapor-phase DBCM is expected to degrade in the atmosphere by reaction with photochemically produced hydroxyl radicals (HSDB). DBCM undergoes aerobic biodegradation slowly, if at all, but readily degrades under anaerobic conditions (HSDB and ATSDR 2005).

References

Dibromochloromethane (CASRN 124-48-1)
U.S. EPA, Integrated Risk Information System (IRIS).

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

Chlorodibromomethane, CASRN: 124-48-1
Hazardous Substances Data Bank (HSDB)
TOXNET, National Library of Medicine Web site.