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

Carbon Tetrachloride

Carbon Tetrachloride Carbon Tetrachloride (CT, CAS #56-23-5) is a clear, nonflammable liquid that does not occur naturally. It is slightly soluble in water (800 mg/L at 20oC), has a vapor pressure of 90 mm Hg at 25oC, and a specific gravity of 1.594 at 25oC. The Henry's Law Constant is 2.94 e-2 atm-m3/mole at 25oC, the log Kow is reported as 2.64, and the log Koc value is reported as 2.04 (ASTDR 2005). A summary tableAdobe PDF Logo of chemical and physical properties can be found in the CT toxicological profile developed by the Agency for Toxic Substances and Disease Registry.

Because of its high vapor pressure, CT is expected to evaporate at a rapid rate from soil. Due to its low soil adsorption coefficient, the compound is expected to absorb slightly to sediment but mostly to be mobile in the soil and migrate into groundwater (ATSDR 2005). Evaporation is a significant source of CT removal from water. The half life of CT in a model river is estimated to be 1.3 hours, and about 5 days in a model lake (HSDB).

Most of the CT in the environment is released to the air as a gas during its production and use. In the atmosphere, CT is very stable and can reside there as long as 30 to 100 years (ATSDR 2005).

CT is not expected to bioaccumulate in animals and fish (ATSDR 2005). Under anaerobic conditions, degradation of CT can occur under both reductive and cometabolic dechlorination. The cometabolic mechanism can be either reductive dechlorination or denitrification (ITRC 2002). CT is recalcitrant or does not degrade at all under aerobic conditions (ITRC 2002, Guang and Englande 1997)

References

Biodegradation Kinetics of Carbon Tetrachloride by Pseudomonas cepacia under Varying Oxidation-Reduction Potential Conditions
Guang, J. and A. Englande Jr.
Water Environment Research 69(6):1094-1099(1997)
View abstract

Carbon Tetrachloride, CASRN: 56-23-5
Hazardous Substances Data Bank (HSDB)
TOXNET, National Library of Medicine Web site.

A Systematic Approach to In Situ Bioremediation in Groundwater, Including Decision Trees for In Situ Bioremediation of Nitrates, Carbon Tetrachloride, and PerchlorateAdobe PDF Logo
Interstate Technology and Regulatory Council (ITRC), ISB-8, 158 pp, 2002

Toxicological Profile for Carbon Tetrachloride
Agency for Toxic Substances and Disease Registry (ATSDR), 361 pp, 2005

For Further Information

Evidence of Biodegradation of Atmospheric Carbon Tetrachloride in Soils: Field and Microcosm Studies
Liu, Xue-Feng, Ph.D. dissertation, Columbia University, 2006

To provide evidence of CT degradation by soils, a 2-year soil air samples monitoring program was initiated in New York and New Jersey. Greenhouse gases (CFC-11, CFC-12, CFC-113, and CHCl3) were monitored with CT. Soil air depth profiles showed that degradation of atmospheric CT occurred in all tested soils and was affected by soil properties such as TOM and pH. Degradation rate constants at Sparkill, NY, were estimated as 0.6/d, 0.2/d, and 0.05/d for soil depth segments of 0, 1 to 2, and 2 to 3 meters, respectively. A time series of CT concentrations at Sparkill showed a seasonal cycle with enhanced degradation in spring. Results suggested that indigenous soil microorganisms were responsible for the degradation. Field soil air profiles of chloroform indicated that it was formed rather than degraded in soils. It is speculated that abiotic mechanisms contributed to the formation of chloroform along with biotic processes. Field soil air profiles of CFCs indicated that CFCs could be considered stable enough with soil depth. In contrast, the microcosm study showed that when native microorganisms were stimulated with appropriate substrates they could transform CFC-11 by both aerobic and anaerobic attack and CFC-12 under anaerobic conditions. A variety of processes investigated contributed to the transformation of CT, chloroform, CFC-11, and CFC-12 in soil. View longer abstract

Toxicological Review for Carbon Tetrachloride (CAS No. 56-23-5) in Support of Summary Information on the Integrated Risk Information System (IRIS)
U.S. EPA, Washington, DC. EPA 635-R-08-005F, 473 pp, 2010