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EC number: 205-597-3
CAS number: 143-28-2
Alcohols with chain length carbon number >C15 are not expected to be toxic at the limit of solubility (expert judgement).
No reliable measured data are available for long-term toxicity of
(z)-octadec-9-enol to aquatic invertebrates. In an expert statement
based on ecotoxicological information available on the alcohols category
no toxicity is expected at the limit of solubility.
No aquatic toxicity is expected at chain lengths >C15, therefore a study
on long-term toxicity of aquatic invertebrates to pentadecan-1-ol (CAS
629-76-5, C15) has been read across for the purpose of setting
indicative aquatic PNECs for use in assessing risk to the sediment and
terrestrial compartments, using the equilibrium partitioning method.
A 21-d EC10 of 0.012 mg/l has been determined for the effects
of pentadecan-1-ol (CAS 629-76-5, C15) on reproduction of Daphnia
Data are available from 21-day Daphnia magna reproduction tests
conducted generally in accordance with standard test guideline OECD 211
with single carbon chain length alcohols: 1-octanol (Kuhn et al.,
1989), 1-decanol, 1-dodecanol, 1-tetradecanol, 1-pentadecanol (Schäfers,
2005a-d respectively) 1-octadecanol (Guhl 1992), pentadecanol branched
and octadecanol branched (ABC 1999a and 1999c respectively). Some
modifications to the test guideline procedures took place in the
Schäfers studies in order to reduce losses of test substance due to the
extensive and rapid biodegradation of the alcohols. Details of the
modifications to the guideline are provided in the IUCLID dossiers and
in the CSR.
The results of the tests are given in Table 1. Summary statistics for
each test are presented as both NOEC and EC10. The 1-octanol
and 1-octadecanol studies are reliability 2, valid with restrictions;
the other studies are reliability 1.
Table 1. Long-term (21-d)
aquatic toxicity of long chain alcohols to Daphnia magna.
Exposure based on mean measured concentrations in fresh and old media
551,000 at 25°C
1930 at 20°C
191 at 25°C
7.8 and EC10 12
102 at 25°C
0.07 mg/L (estimate)
1.1 at 25°C
0.0056 mg/L (estimate)
is not available
no analytical analysis took place.
The study with C18 determines a NOEC of 0.98 mg/L, corresponding to the
lowest concentration tested. Should a lower exposure concentration have
been tested, it is likely that the NOEC would also be lower.
A pattern of increased toxicity with increasing chain length is apparent
up to C14. The NOEC and EC10 values then increase from C14 to
C15. This is almost certainly the result of the concentration exceeding
the solubility of the substance (Rufli et al. 1998). Based on the
trends observed in these data it is expected that the NOEC for long-term
effects on mortality and reproduction would be above the solubility
limit of linear alcohols with carbon numbers >C15 Schäfers et
This is also discussed in the attached ECOTOXICITY Alcohols C6-24
Discussion of trends in the Category of C6-24 linear and
essentially-linear aliphatic alcohols:
Data of an acceptable quality are available for 21-day
reproduction studies with Daphnia magnafor the single carbon
chain length LCAAs 1-octanol (Kuhn et al., 1989), 1-decanol,
1-dodecanol, 1-tetradecanol, 1-pentadecanol (Schäfers, 2005a-d
respectively), pentadecanol branched (ABC 1999a) and octadecanol
branched (ABC 1999c). The data were obtained generally in accordance
with standard test guideline OECD 211. However some modifications to the
normal guideline procedures were necessary to reduce losses of test
substances due to the extensive and rapid biodegradation of the LCAAs.
The following changes to typical protocols were therefore adopted to
enable the performance of high-quality and meaningful studies:
Vessels were closed, to reduce entry of bacteria from the
Gentle aeration of test vessels was required as degradative losses
of LCAAs resulted in unacceptably low dissolved oxygen concentrations;
Test solution renewals were made daily, with confirmatory analysis
on both renewed and initial test solutions;
Static renewal was determined to be the best exposure regime for
long chain aliphatic alcohols as this reduced the transfer of LCAAs
-degrading or consuming microbes (as compared to flow-through systems,
where it becomes increasingly difficult to discourage acclimation and
bio film formation; see Brixham Environmental Laboratory, AstraZeneca,
Saturated alcohol stock solutions were prepared daily for each
test concentration. This involved a detailed preparatory method to
reduce the possibility of insoluble material being present in the tests
(Schäfers, 2005a, b);
Daphnia magna were carefully rinsed with each
daily transfer to reduce bacterial cross over to fresh exposure
solutions. As Daphnia magna grow in size, this becomes less
Dilution water and test vessels were autoclaved prior to use each
time (Schäfers et al., 2005a, b, c, d).
Algae have been found to metabolize LCAAs and this is an
unavoidable occurrence in long-term studies with Daphnia magna fed
with algae. No modifications could be made to counter this without
conducting further research into an alternative diet.
In spite of the guideline modifications significant losses of test
substance still occurred. It was therefore necessary to report the
results both in terms of the mean of the measured concentrations in the
fresh media and the mean of the measured concentrations in the fresh and
old media. The test substance renewal interval was 24 hours. Survival
and reproduction endpoints have been summarised using standard
statistical techniques. Conclusions for each test are presented as both
NOEC and EC10. The 1-octanol and 1-octadecanol study are
reliability 2, valid with restrictions; the other studies are
The effect of LCAAs on Daphnia magna survival is generally
less sensitive than the effect on reproduction. A pattern of increased
toxicity with increasing chain length is also apparent. In the octanol
study, the most sensitive and only reported effect was on time to first
brood release which occurred at 1000 µg/L (nominal concentration). For
comparison of results across chain lengths and structure activity models
the response for survival and reproduction was assumed to be equal to
the effect on time to first brood.
The data indicates that for survival and reproduction, the NOEC
and EC10 values increase from C14 to C15. This is almost
certainly due to exceeding the limit of water solubility as would be
expected from conventional toxicological theory (Rufli et al.
1998). Under these circumstances a more accurate interpretation of the
results might be obtained by setting the exposure to the solubility of
the substance (i.e. 49 µg/L). This has the effect of lowering the
toxicity values but they are still higher than those for the C14
substance. This pattern is not in keeping with the trend of reducing
short-term toxicity values (i.e. higher toxicity) observed between the
C8 and C14 alcohols. Similarly, the NOEC identified for C18 is a limit
value of >980 µg/L but a lower value would have been obtained if a lower
loading had been tested. A more accurate NOEC would therefore be
obtained by expressing it as greater than the water solubility of the
test substance, which is 10 µg/L. This statement is supported by data on
C15 and C15 branched, where the NOEC was not achieved at the solubility
It must be appreciated that significant uncertainty exists in
identifying the true exposure concentrations in the region of the water
solubility of a substance. The water solubility values of the LCAAs
category decrease with increasing chain length (see section 1.4 for
further details.). In a review of aquatic toxicity testing of sparingly
soluble compounds Rufli et al. (1998) point out that
interpretation of toxicity responses observed above the solubility limit
is aggravated by artefacts and that testing should only occur at or
below the limit. For LCAAs with carbon numbers greater than C15 there
are significant experimental difficulties in producing, maintaining and
quantifying exposures of the test substance due to progressively lower
solubility, while exceptionally rapid biodegradability would remain
unchanged. This explains why there are no data for such substances.
However, based on the trends observed in the available data, it is
expected that for linear LCAAs with carbon numbers ≥C15 the NOEC for
long-term effects on mortality and reproduction would be above the
solubility limit (Schäfers et al. 2009).
No measured data are available for multi-constituent substances of
different carbon chain length LCAAs.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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