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CAS No.: 67-66-3
Registry name: Chloroform
Chemical name: Trichloromethane
Synonyms, Trade names: Methyl trichloride, methane trichloride, formyl trichloride, Haloform, R20
Chemical name (German): Chloroform, Trichlormethan
Chemical name (French): Chloroforme
Appearance: clear, colourless, highly refractive liquid with sweet odour
BASIC CHEMICAL AND PHYSICAL DATA
|Empirical formula:||CHCl 3|
|Rel. molecular mass:||119.4 g|
|Relative gas density:||4.12|
|Vapour pressure:||21 x 103 Pa|
|Solvolysis/solubility:||in water: 8.1 g/l
miscible with solvents such as benzene, pentane, hexane, ethanol and diethyl ether
|Conversion factors:||1 ppm = 4.96 mg/m3
1 mg/m3 = 0.20 ppm
ORIGIN AND USE
Most of the total production of chloroform is used to produce monochlorodifluoromethane (CFC22) which is used as a refrigerant but also as an intermediate in the manufacture of tetrafluoroethene which then may be polymerised (PTFE). Chloroform is also used in the production of dyes, pharmaceuticals and pesticides. Its use as a solvent and application in anaesthesia is rapidly on the decline.
90 - 95 % of chloroform is produced either by the hydrochlorination of methanol or by the chlorination of methane. 5 - 10 % is of natural origin and found in seawater (reaction of methyl iodide with inorganic chlorine). Chlorine bleaching of cellulose produces large quantities of chloroform. Considerable amounts likewise result from water chlorination. Commercially available chloroform contains, amongst other substances, bromochloromethane, bromodichloromethane, methylene chloride, tetrachloromethane, 1,2-dichloroethane, trichloroethylene and tetrachloroethane as contaminants.
|Worldwide 1973:||245,000 - 300,000 t||acc. KOCH, 1989|
|D 1982:||35,500 t||acc. UBA, 1986|
The production and application-related emissions amount to some 10,000 t; this is supplemented by annual impacting of surface and groundwater with a further 10,000 t/a (acc. KOCH, 1989).
|Humans:||5,000 mg/m3 after 7 min. dizziness, head congestion||acc. BUA, 1985|
|20,000 mg/m3 feeling faint||acc. BUA, 1985|
|69,440 mg/m3 deep full anaesthesia||acc. BUA, 1985|
|> 79,360 mg/m3 apnoea, death||acc. BUA, 1985|
|LDLo 10 ppm, inhalation (1 a)||acc. KOCH, 1989|
|Rat:||LD50 1,194 mg/kg, oral||acc. DVGW, 1988|
|LCLo 8,000 ppm, inhalation (4 h)||acc. BUA, 1985|
|Mouse:||LD50 80 mg/kg, oral||acc. BUA, 1985|
|LD50 28,000 mg/kg, inhalation||acc. BUA, 1985|
|Dog:||LD50 1,100 mg/kg, oral||acc. DVGW, 1988|
|Rabbit:||LDLo 500 mg/kg, oral||acc. BUA, 1985|
|Guinea pig:||LCLo 20,000 ppm, inhalation (2 h)||acc. BUA, 1985|
|Golden orfe:||LC50 162-191 mg/l (48 h)||acc. UBA, 1986|
|Rainbow trout:||LC50 18-66.8 mg/l (96 h)||acc. UBA, 1986|
|Blue perch:||LC50 18-115 mg/l (96 h)||acc. UBA, 1986|
|Water flea:||LC50 28.9 mg/l (48 h)||acc. UBA, 1986|
Humans/mammals: Intake is most frequently by inhalation with some of the substance being resorbed in the lungs and the remainder being exhaled. Oral application likewise results in the majority being exhaled or discharged by the kidneys.
Chloroform damages the liver and the kidneys, the central nervous system and the heart. Large doses have a narcotic effect.
Chloroform has proved to be carcinogenic in animal experiments. Mutagenic or teratogenic effects have not been established to date.
The degradation of chloroform in water is extremely slow (water hazard class 3). The high volatility results in degasification over surface water. Bioaccumulation is minimal despite the high fat solubility of chloroform (bioconcentration factor in fish: 6; UBA, 1986).
Chloroform ingresses into the atmosphere because of its high volatility and is accumulated there in small quantities. The substance is decomposed by photolysis.
There is no adsorption on particles thus precluding the possibility of accumulation in soil or sediment.
Degradation, decomposition products:
Biological degradation under anaerobic conditions results in carbon dioxide, chloride and methane; degradation in the organism produces carbon dioxide, chloride and phosgene. The presence of oxidising agents causes chloroform to decompose with phosgene and hydrochloric acid being formed (DVGW, 1988).
Chloroform is ubiquitous and thus may also be found in foodstuffs. Drinking water sometimes contains high chloroform concentrations caused by water chlorination. The daily chloroform absorption is estimated at an average of 10 m g/person with one quarter each resulting from drinking water and foodstuffs and the other half from the atmosphere (DVGW, 1988).
|Medium/ acceptor||Sector||Country/ organ.||
|1 mg/l||IAWR||For natural treatment||acc. DVGW, 1988|
|5 mg/l||IAWR||For phys.-chem. treatment||acc. DVGW, 1988|
|350 µg/l||1978||acc. DVGW, 1988|
|25 µg/l||1)||acc. DVGW, 1988|
|25 µg/l||BGA commission1)||acc. DVGW, 1988|
|100 µg/l||Sum of trihalomethanes||acc. DVGW, 1988|
|30 µg/l||acc. DVGW, 1988|
|20 mg/m3||mass flow > 100 g/h||acc. TA Luft, 1986|
|25 µg/l||Table, mineral water||acc. DVGW, 1988|
1) Sum of chloroform, bromoform, bromodichloromethane, dibromochloromethane
2) Substance with a suspected carcinogenic potential
The use of chloroform in cosmetics, medicines and pesticides is banned in Germany
|Rhine (Wiesbaden, 1986)||D||0.35-2.1 µg/l||acc. DVGW, 1988|
|Rhine (Lobith, 1985)||D||0.5-4 µg/l||acc. DVGW, 1988|
|Main (Sindlingen, 1983)||D||21 µg/l||acc. DVGW, 1988|
|Moselle (1983)||D||0.5-0.7 µg/l||acc. DVGW, 1988|
|Elbe (1983)||D||0.6-9.8 µg/l||acc. DVGW, 1988|
|North Sea coast (Emden)||D||0.56-3.8 µg/l||acc. UBA, 1986|
|Baltic coast||D||0.06-0.17 µg/l||acc. UBA, 1986|
|Ruhr (1972-1981)||D||1-3 mg/kg||acc. DVGW, 1988|
|Basic atmospheric impact||0.05-0.1 µg/m3||acc. KOCH, 1989|
|Urban areas||up to 74 µg/m3||acc. KOCH, 1989|
On account of its ubiquitous distribution and the considerable quantities emitted into the environment every year, chloroform has to be considered as an environmental hazard. There is no information to date on the effect and concentration in soils and soil organisms and the genotoxic potential likewise remains unclear. In particular, water chlorination should be avoided as far as possible in order to reduce the pollution of groundwater and drinking water without neglecting the necessity of hygienic prevention measures.
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