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EC number: 939-408-7
CAS number: 85049-86-1
The category consists of alkyl sulfates with a predominantly linear
alkyl chain length of C8-C18. Most chemicals of this category are not
defined substances, but mixtures of homologues with different alkyl
chain lengths (UVCBs). The most important common structural feature of
the category members is the presence of a predominantly linear aliphatic
hydrocarbon chain with a polar sulfate group, neutralized with a counter
ion (i.e., Na+, K+, NH4+, or an alkanolamine cation). The hydrophobic
hydrocarbon chain (with a length between C8 and C18) and the polar
sulfate group confer surfactant properties and enable the commercial use
of these substances as anionic surfactants. Common physical and
biological pathways result in structurally similar breakdown products,
and are, together with the surfactant properties, responsible for
similar environmental behavior and essentially identical hazard profiles
with regard to human health. The counter ion will not influence chemical
reactivity and classification for the purpose of this assessment is not
expected to be affected by the difference in counter ion (ref. OECD SIDS
2007, HERA Report 2002, Koennecker et al. 2011).
In aqueous environments the salts will dissociate, so that the counter
ions will not fundamentally alter pathways of tissue disposition,
metabolism, excretion, or target organs of toxicity. Accordingly no
major differences were found in most of the endpoints between the
compounds with different counter ions (ref. OECD SIDS 2007, HERA Report
2002, Koennecker et al. 2011). Moreover, several of the counter-ions
have also been assessed in the OECD HPV Program and/or according to
REACH Regulation (EC) No 1907/2006: triethanolamine (CAS 102-71-6), the
ammonia category (CAS 7664-41-7; 1336-21-6; 7783-18-8; 12593-60-1) and
ammonium salts, like ammonium sulfate (CAS 7783-20-2), chloride (CAS
12125-02-9) and bicarbonate (CAS 1066-33-7).
In accordance with Article 13 (1) of Regulation (EC) No 1907/2006,
"information on intrinsic properties of substances may be generated by
means other than tests, provided that the conditions set out in Annex XI
are met. In particular for environmental fate and eco-toxicity,
information shall be generated whenever possible including the use of
information from structurally related substances. In this particular
case the similarity of the alkyl sulfates category members is justified,
in accordance with the specifications listed in Regulation (EC) No.
1907/2006 Annex XI, 1.5 Grouping of substances and read-across, is based
on the scope of overlapping of composition, similar molecular structure,
physico-chemical properties, toxicological, ecotoxicological profiles
and supported by various QSAR methods.
Physico-chemical properties relevant for environmental toxicity of alkyl
Physico-chemical characteristics of the substances in the category are
similar, or follow regular patterns. The most important parameter
influencing PC-properties is the varying length of the alkyl chain.
- Vapour pressure - as ionic substances, category members are
characterized by low vapour pressures.
- Partition coefficient - as surfactants concentrate at
hydrophilic/hydrophobic boundaries and do not equilibrate between
phases, Pow is not a good descriptor of surfactant hydrophobicity and
only of a limited predictive value for the partitioning of these
compounds in the environment. Nevertheless, experimental Pow values have
been obtained, usually as quotients of solubilities in octanol and in
water. Partition coefficients are low (mostly negative values of log
Pow) and they increase with the alkyl chain range.
- Water solubility - the solubility in water of the category members is
high, in the range of 100-1000 g/L. Particular values decrease with the
alkyl chain range.
Environmental fate and pathways of alkyl sulfates:
- The substances are readily biodegradable. Abiotic degradation (e.g.
hydrolysis) is not a relevant for environmental pathway due to the
chemical structure of the substances. All the substances in this
category are essentially non-volatile, which implies that atmospheric
photodegradation is irrelevant. As the log Pow-value is below 3, a
potential for bioaccumulation can be excluded. Due to the low to
moderate log Koc-value, it can be predicted that the sorption to sludge,
sediments and soils will be relatively low. Alkyl sulfates are unlikely
to persist in the aquatic environment.
Aquatic toxicity of alkyl sulfates:
For the alkyl sulfate category many mono-species tests are available on
the acute, sub-chronic and long-term toxicity to fish, invertebrates,
and algae, conducted with single-chain homologues as well as with
technical mixtures. The results demonstrate that invertebrates are the
most sensitive trophic level, followed by fish and algae. The most
important influencing parameter for fish and invertebrate toxicity
within the alkyl sulfates category is the chain length of the alkyl
Short-term toxicity to fish is well studied for the category of alkyl
sulfates and includes the tests with substances ranging from C8 to C18
covering a variety of both freshwater and marine species. Alkyl sulfates
of chain lengths from C8 to C12 seem to have low to moderate toxicity.
Homologues from C13 to C15 are more toxic than C8 to C12. Toxicity of
the chain lengths from C16 and higher is inconsistent, but in general
these substances are less toxic than C13 to C15. This most probably can
be explained by variable bioavailability as a consequence of reduced
The influence of the chain length of alkyl sulfates on the acute
toxicity fish is comparable to invertebrate toxicity (OECD SIDS, 2007).
Also in this case a clear correlation can be shown since the available
database includes the studies for the alkyl sulfates ranging from C8 to
C18. Short-term toxicity to aquatic invertebrates increases with
increasing length of the hydrocarbon chain up to C16 and then decreases.
Available long-term tests on fish with alkyl sulfates show that the
toxicity depends again on the substance chain length. The same pattern
as in the acute tests was observed - homologues C12 and C18 are less
toxic than the chain lengths C14-C15 (OECD SIDS, 2007).
Available information on the long-term toxic effects of alkyl sulfates
to Ceriodaphnia dubia includes the substances with a carbon chain length
from C10 to C18. A clear response curve was observed - toxicity increase
with chain length from C12 to C14 and then decreased up to C18. Since
C18-AS is insoluble in calcium-containing water (i.e., Ceriodaphnia test
waters), the effects are due to physical interactions, not the classic
uptake into the organism and then elicit toxicity. Chronic toxicity
testing with Daphnia magna using the technical product C14 -15 proved
that these are the most toxic chain lengths for aquatic invertebrates
(OECD SIDS, 2007).
Several reliable experimental studies with algae are available for alkyl
sulfates. It seems that algae react less sensitive to alkyl sulfate
exposure than fish and invertebrates. The results do not allow the clear
prediction of a chain length dependency of algal toxicity because most
of the studies were conducted with technical products. Nevertheless, it
seems that the most toxic chain lengths are C10 and also C14 - C15 (OECD
Activated sludge respiration inhibition tests and Pseudomonas putida
tests are available for the alkyl sulfates of chain lengths from C12 to
C18. In Pseudomonas putida testing a tendency of increasing toxic
effects with increasing carbon chain length could be observed (OECD
Acute toxicity key values of 10-12AS Na (CAS 85049-86-1):
- For fish: 48h LC50 (Cyprinus carpio, pre-larvae mortality) = 13 mg/L
(freshwater, nominal concentration, Japanese Industrial Standard JIS
K0102, read-across from CAS 142-87-0); 96h LC50 (Cyprinodon variegatus,
mortality) = 4.1 mg/L (marine water, measured concentration, ASTM E-35
(1980), read-across from CAS 151-21-3)
- For invertebrates: 48h EC50 (Daphnia magna, immobilization) ≥ 5.5 mg/L
(freshwater, nominal concentration, read-across from CAS 151-21-3); 48h
EC50 (Artemia salina, mortality) ≥ 3.15 mg/L (marine water, nominal
concentrations, read-across from CAS 151-21-3)
- For algae: 72h EC50 (growth rate) = 11.5 mg/L (read-across from CAS
142-87-0 and CAS 151-21-3)
Chronic toxicity key values of 10-12AS Na (CAS 85049-86-1):
- For fish: 42d NOEC (Pimephales promelas; mortality and growth) ≥ 1.357
mg/L (measured concentration, read-across from CAS 151-21-3)
- For invertebrates 21d NOEC (Daphnia magna, reproduction) = 1.2 mg/L
(measured concentration, read-across from CAS 142-87-0 and CAS 151-21-3)
- For algae: 72h EC10 (growth rate) = 1.3 mg/L (read-across from CAS
142-87-0 and CAS 151-21-3)
- For microorganisms 3h EC50 (activated sludge respiration inhibition) =
135 mg/L (nominal concentration, similar to OECD 209, read-across from
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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