Fact sheet: Chloroform

From: Public Services and Procurement Canada

Discover a list of a contaminant's important chemical properties, how it will react in the environment, main sources of contamination related, and a brief overview of health and safety issues.

On this page

General information

CAS number

67-66-3

Molecular formula

CHCl3

Formula weight

119.4 g/mol

Family

Chlorinated aliphatic hydrocarbons (CAH)

Properties (at room temperature where applicable)

Compound properties list
ParameterValueComment
Melting/boiling point -137 °C / 12 °CLiquid
Relative density1.48 g/cm3Sinks in water
Vapour pressure170 mm HgVery volatile
Vapour density4.1Denser than air
Solubility in water7,000 mg/LModerately soluble
Henry's law constant3 x 10-3 atm·m3/molRapid volatilization when dissolved
log Koc (Depending on soil or sediment characteristics)1.5 - 2.0*Moderate adsorption to organic matter

Environmental behaviour

At 20 0C, chloroform is a liquid denser than water and very volatile. Characterized by moderate solubility, it will volatilize rapidly once dissolved and adsorbs moderately to organic matter. During a spill, the majority of the compound evaporates but may also enter into the soil or migrate into a waterway. Once it encounters water (surface or subsurface), the chloroform will dissolve or sink until it reaches an impermeable surface. The liquid chloroform that accumulates in a saturated zone will gradually dissolve before volatilization occurs. The adsorbed chloroform in the vadose and saturated zones will rapidly disappear, liberating contamination in either the gaseous or dissolved state. The resulting plumes (gaseous or dissolved) will be relatively large in size.

Health and safety

Chloroform should be handled with care as it is toxic.

Principal resources

Chloroform is produced industrially by either the chlorination of methane or the chlorination of chloromethane. Canada has not produced chloroform since 1976, but continues to import chloroform. Nearly all the chloroform produced is used to make other chemicals, primarily chlorodifluoromethane (HFC-22) (HFC-22) (hydrochlorofluorocarbon-22), which is used as a refrigerant, and in the production of fluoropolymers. HCFC-22 is one of the few fluorocarbons not restricted by the Montreal Protocol on ozone depleting chemicals. Other miscellaneous uses include aerosol propellant, solvent and degreasing agent, spot remover in dry cleaning, solvent for the industrial, pharmaceutical and analytical chemistry, heat transfer medium in fire extinguishers, and intermediate in the preparation of dyes and pesticides.

Chloroform enters the environment from chemical companies and paper mills. It is also found in wastewater from sewage treatment plants and drinking water to which chlorine has been added. Chlorine is added to most drinking water and many wastewaters to destroy bacteria. Small amounts of chloroform are formed as an unwanted product during water chlorination.

References

Agency for Toxic Substances and Disease Registry (ATSDR). 1997. Toxicological Profile for Chloroform. U.S. Department of Health and Human Services, Public Health Service, Georgia, USA. (Viewed March 2010)

Canadian Council of Ministers of the Environment, 1999. Canadian Water Quality Guidelines for the Protection of Aquatic Life: Halogenated Methanes, Trichloromethane (Chloroform). In: Canadian Environmental Quality Guidelines. Canadian Council of Ministers of the Environment, Manitoba, Canada. (Viewed March 2010)

Montgomery, John H. 2007. Groundwater Chemicals, Desk Reference, Fourth Edition, CRC Press, Taylor and Francis Group, Florida, USA.

Version:
1.2.1