Entry into the marine environment
The principal use of 4-chloro-3-methyl is as a
general biocide to prevent micro-organisms degrading
organic material. More than 50% of the production
volume of 4-chloro-3-methyl phenol is used in metal
working fluids. These fluids, used to lubricate
and cool during metal grinding or in plant machinery,
are rich in proteins which provide a source of nutrition
for bacterial growth. The other major use is as
a pharmaceutical preservative. For example, hand
and body creams containing organic compounds in
an aqueous phase may contain 4-chloro-3-methyl to
prevent micro-organisms degrading the ingredients
(Dixon et al 1997).
4-chloro-3-methyl phenol is authorised for use
(according to Article 4 of Directive 91/414/EEC
on the placing of plant protection products on the
market, CEC (1991)) as fungicide in plant protection
products in Ireland. However, its use as an agricultural
fungicide has not been reported in the UK .
Other minor uses reported are as a disinfectant,
in external germicides, as a preservative for cosmetics,
medications, glues, gums, paints, inks, textile
and leather goods. In medicine and veterinary medicine,
use of 4-chloro-3-methyl phenol has been reported
as a topical antiseptic (HSDB 1996).
Environmental release of 3-methyl-4-chloro phenol
may occur from product formulation waste waters
and by the use and disposal of products containing
4-chloro-3-methyl phenol, such as metal working
fluids and pharmaceutical products.
Recorded levels in the marine
Dixon et al (1997) provided data from the
Environment Agency on concentrations of 4-chloro-3-methyl
phenol in UK marine waters from the North-West.
The average for 1995 in marine and estuarine waters
was 0.3 µg l-1 (a
high of 0.6 µg l-1) (it
should be noted that these annual average concentrations
may be artificially low due to the treatment of
<LOD results as zero, particularly when the LOD
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. However, 4-chloro-3-methyl phenol was
not monitored in either survey.
Available monitoring data are very limited and
can be considered insufficient for a comparison
to be made with expected environmental concentrations
and toxicity data or environmental standards.
Fate and behaviour in the marine
In water, 4-chloro-3-methyl phenol will not hydrolyse
to any significant degree. However, as the pH of
the water becomes more alkaline, the phenolic group
will dissociate increasingly. Photolysis is an important
fate process for this compound in water, half-lives
of 3.3 hours under a mercury vapour lamp to
46 hours under sunlight have been reported.
Although biodegradation is not as important a fate
mechanism in water as it is in soil, it is still
significant with reported half-lives ranging from
days to weeks. Sorption to suspended or bed sediments
is likely to be limited (log Koc and Kow of 1.7
and 3.1 respectively) and high water solubility
of the compound (4,000 mg l-1 at
25oC) (Dixon et al 1997).
Effects on the marine environment
Toxicity to marine organisms
An exhaustive literature review on the toxicity
of 4-chloro-3-methyl 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 (Dixon et al
1997). The most sensitive groups of organisms have
Dixon et al (1997) were unable to find any
reliable data on the toxicity of 4-chloro-3-methyl
phenol to saltwater organisms. Until further data
become available, it must be assumed they have broadly
similar sensitivities as freshwater organisms.
In freshwaters, acute and chronic EC/LC50s of >=1 mg l-1
have been reported for algae, crustacea and fish.
No data could be located for sediment-dwelling organisms.
Dixon et al (1997) concluded that bioaccumulation
was unlikely to occur.
Potential effects on interest
features of European marine sites
Potential effects include:
- toxicity to algae, invertebrates and fish at
concentrations above the EQS of 40 µg
l-1 (annual average) and 200 µg
l-1 (maximum allowable concentration)
in the water column.