Entry into the marine environment
Carbon tetrachloride is a volatile, clear, colourless,
heavy liquid. This substance is an ozone-depleting
substance and, as a result, its production and use
(except for essential uses) within the European
Community was due to be phased out by 1st January
1995. Carbon tetrachloride production in
the United Kingdom has recently ceased and the major
use for carbon tetrachloride (production of CFC-11
and CFC-12) is now in decline. The majority of the
reported levels of carbon tetrachloride in the environment
were measured before these controls were introduced
and therefore may not accurately reflect the present
A Coopers Lybrand and Deloitte report for the Department
of Trade and Industry (DTI) states that the United
Kingdom consumption of carbon tetrachloride was
40,000-50,000 tonnes per annum in 1990 (DTI, 1990).
Willis et al (1994) estimated that to be
far less in 1994 due to the reduction in the production
of CFC-11 and CFC-12, which was a major use of carbon
Most carbon tetrachloride produced is used in the
manufacture of chlorofluorocarbons (CFCs). Other
recorded uses of carbon tetrachloride include in
fire extinguishers, as a grain fumigant, flammability
suppressant, solvent, metal degreaser and various
roles in the production of paint, plastics, semi-conductors
and petrol additives (CEC, 1986). Carbon tetrachloride
is used as a chemical intermediate in the manufacture
of pharmaceutical and pesticide products. It is
widely used as a reagent in laboratories (RSC, 1981).
Recorded levels in the marine
Carbon tetrachloride is ubiquitous in the global
atmospheric and aquatic environments and numerous
measurements of carbon tetrachloride levels have
been made and reported.
Willis et al (1998) found that carbon tetrachloride
levels in the atmosphere had been measured extensively
(as the atmosphere is acknowledged to be the major
sink for carbon tetrachloride). The authors estimated
the global background level of carbon tetrachloride
to be around 0.7-1.0 µg m-3.
For UK freshwaters, the authors reported concentrations
in the range 0.3-24 µg l-1
(the higher levels generally having been measured
near to source dominated areas). Typical levels
away from sources of carbon tetrachloride were <lµg l-1.
For UK marine waters, Willis et al (1994)
reported levels to be between <0.1 - 44 µg l-1.
Again, higher levels were found in source dominated
areas. Levels measured in the open ocean were generally
much lower, at around 0.5 ng l-1.
Monitoring data from the National Rivers Authority
and the National Monitoring Programme Survey of
the Quality of UK Coastal Waters are presented in
Appendix D. Only one water column concentration
was found to approach the EQS value (see Appendix
D). Monitoring data were not available for sediments
The available data suggest that concentrations
of carbon tetrachloride in UK coastal and estuarine
waters do not, generally exceed relevant quality
standards derived for the protection of saltwater
Fate and behaviour in the marine
Willis et al (1994) reviewed the environmental
fate and behaviour of carbon tetrachloride. The
authors concluded that the major removal process
from water bodies was volatilisation to the atmosphere.
Laboratory tests have suggested a volatilisation
lifetime from water between 29 minutes and a few
hours, depending on the degree of agitation (Dilling
et al, 1975; Versar Inc., 1979). Zoeteman et
al (1980) calculated half-life values for carbon
tetrachloride in rivers and lakes, and groundwaters
of 0.3-3 days and 30-300 days respectively.
Adsorption of carbon tetrachloride onto soil and
sediment may occur to a small extent (Organic carbon-water
partition coefficient (Koc) of 439 (log 2.6) (Eastwood
et al 1991)) have been reported for carbon
tetrachloride, but carbon tetrachloride is likely
to be mobile in such media.
Carbon tetrachloride is highly resistant to photolysis
and photo-oxidation reactions in the troposphere.
The major removal process for carbon tetrachloride
in the troposphere is transfer to the stratosphere.
Once in the stratosphere, carbon tetrachloride is
photodegraded by short wavelength radiation and
contributes to ozone depleting processes. The overall
atmospheric lifetime for carbon tetrachloride is
around 50 years, the lifetime being dominated by
the troposphere to stratosphere turnover time.
Carbon tetrachloride does not appear to biodegrade
under aerobic conditions. Many bacteria have been
shown to dehalogenate carbon tetrachloride under
Effects on the marine environment
Toxicity to marine organisms
An exhaustive literature review on the toxicity
of carbon tetrachloride to marine organisms has
not been carried out for the purposes of this profile.
The information provided in this section is taken
from existing review documents (Willis et al
1994). The most sensitive groups of organisms have
Willis et al (1994) reviewed data on the
aquatic toxicity of carbon tetrachloride. No toxicity
data appear to be available for marine species of
algae. However, for freshwater algae, the lowest
toxic concentration of carbon tetrachloride was
105 mg 1-1 which caused a reduction
in cell multiplication in the freshwater algae Microcystis
For invertebrates, Willis et al (1994) only
found data for the freshwater crustacean Daphnia
magna with the lowest acute LC50 reported being
35 mg l-1.
For marine fish, the lowest acute LC50 found was
50 mg l-1 for dab Limanda limanda.
In comparison, for freshwater species, an LC50 of
1.97 mg l-1 was reported for the embryo-larval
stages of rainbow trout Oncorhynchus mykiss.
However, the results of this test have been criticised
as they are an order of magnitude lower than reported
in other studies.
No data could be located for sediment-dwelling
The log octanol-water partition coefficient of
carbon tetrachloride is 2.64. This indicates a moderate
potential for bioaccumulation under conditions of
constant exposure. However, studies cited in Willis
et al (1994) have shown that the compound's
short tissue lifetime reduces this tendency. Barrows
et al (1980) reported a tissue half-life
of less than 1 day for the bluegill sunfish, and
a bioconcentration factor of 30. A similar tissue
half-life of <l day has been reported for trout
muscle (Niimi, 1987) and a steady state bioconcentration
factor for rainbow trout of 17.7 has been measured
(Neely et al, 1974). No significant bioaccumulation
in marine food chains was found in an extensive
study by Pearson and McConnell (1975).
A slightly higher bioconcentration factor of 300
(on a wet weight basis) has been measured for carbon
tetrachloride in the green alga Chlorella fusco
exposed to 50 µg l-1
of carbon tetrachloride for at least 24 hours (Geyer
et al 1984).
Potential effects on the interest
features of European marine sites
Potential effects include:
- toxicity to algae, invertebrates and fish at
concentrations above the EQS of 12 µg
l-1 (annual average) in the water column.