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EC number: 701-368-1
CAS number: 1962138-75-5
the present registration, the various tested LAS mixtures were first
normalized to C11.6 LAS by use of conventional Quantitative
Structure-Activity Relationships, as has been previously described in
the peer reviewed literature and in OECD and USEPA HPV (High
Production Volume) assessments. Similar normalization processes for
environmental risk assessment have also been performed for alcohol
sulfates, alcohol ethoxysulfates, alcohol ethoxylates and long chain
alcohols. The normalization procedures followed the process first
described by van de Plaasche et al. (1999) and replicated for HPV
structure-activity relationships for acute toxicity to fish (and other
species) based on studies of pure chain length materials supports read
across to all members of the distribution of LAS homologues present in
the MEA-LAS substance (Belanger et al., 2016). Four robust and highly
localized (Q)SARs have been developed for LAS normalization, including
a model for invertebrates (separate models built from Daphnia magna
and Ceriodaphnia dubia; Belanger et al., 2016), algae (Desmodesmus
subspicatus; Verge and Moreno, 1996) and fish (Pimephales promelas;
Belanger et al., 2016). These models have been built from high quality
toxicity data using pure LAS chain lengths (C10-C14). Further external
validation was performed using LAS mixtures with different average
alkyl chain lengths. Detailed QSAR Model Reporting Format (QMRF)
documents describing data quality, model development and performance
have been developed for each model and are available in the respective
Robust Study Summaries (RSS) of the IUCLID dataset.
Sensitivity Distribution (SSD)
Species Sensitivity Distribution (SSD) analysis was performed based
upon a robust dataset of chronic aquatic toxicity values available
from tests with various LAS homolog mixtures. The dataset of 19
chronic ecotoxicity studies included 4 species of algae, 2 aquatic
macrophytes, 8 invertebrates and 5 fish. Photosynthetic organisms span
blue-green and green algae as well as two floating aquatic
macrophytes. Molluscs, water fleas, rotifers and insects are
representative invertebrates. Fish include members of the salmonid,
centrarchid and cyprinid families and cover warm and cold-water
species. Effects of LAS are based on well accepted chronic endpoints
such as growth, survival and reproduction.
the data in this summary are from studies judged to be “Reliable
without restriction” (KL1) or “Reliable with restrictions’
(KL2). Thirteen of the 19 studies have appeared in peer-reviewed
literature and the remaining studies are well documented industry and
contract laboratory reports.
quality of the input data used to generate the SSD was evaluated by
criteria discussed in the REACH Guidance (R.10.3.1.3: Calculation of
PNEC for freshwater using statistical extrapolation techniques). These
criteria enable consideration of the potential appropriateness of
additional application factors (AF) in extrapolating the HC5 to a PNEC
(Predicted No Effect Concentration for the ecosystem). According to
these criteria, the data used as input to the SSD satisfied the
appropriateness of using the SSD statistical extrapolation technique
for PNEC derivation with an AF of 2.
chronic toxicity data were normalized to C11.6 LAS using the methods
and LAS-specific QSARs outlined
above. Normalized chronic toxicity values ranged from 0.23 mg/L for
rainbow trout to 16.15 mg/L for the algae Pseudokirchneriella
are presented in Table 1 of the document entitled ‘LAS
Species Sensitivity Distribution Technical Summary 02.06.2020’
attached to Section 13 of the IUCLID dataset).
and analysis of the SSD followed ECHA procedures described in the
REACH Technical Guidance Document R.10.3.1.3 (Calculation of PNEC for
freshwater using statistical extrapolation techniques), supplemented
with additional statistical evidence reflecting the state of the
science. The SSD was estimated by maximum likelihood assuming a
log-logistic distribution of data values, i.e. fitting a logistic
distribution to the log-transformed data values. Confidence intervals
were computed by the methods of Aldenberg and Slob (1993). The
interval on the HC5 is intended to ensure that there is a high
probability (95%) that the true HC5 is within the limits of the
interval, based upon the model fitted to the data.
SSD is plotted in Figure 1 of the document entitled ‘LAS
Species Sensitivity Distribution Technical Summary 02.06.2020’
attached to Section 13 of the IUCLID dataset. The 5th percentile value
calculated from the SSD, the HC5, was 0.21 mg/L. Hence, the HC5 for
LAS was equal to or lower than any of the predicted chronic toxicity
values for the 19 taxa tested.
evaluations were also conducted to assess the stability and
sensitivity of the C11.6 LAS HC5. The analysis consisted of two
assessment of stability based on a reduced data set where one of the
19 values was theoretically never generated and the HC5 was
data deletion at the lowest end of the distribution (e.g.,
Oncorhynchus mykiss) results in a raise in the estimated HC5
concentration to 0.26 mg/L. Data deletion near the centre and upper
end of the distribution (> 1 mg/L) resulted in lower HC5 values (~0.20
mg/L), indicating that the variance term had increased as a result of
the deletion. Overall the HC5 was stable and would not shift
substantially if selected values were deleted.
influence of adding hypothetical data to the LAS chronic toxicity
dataset on the HC5was evaluated. This
technique allows a determination of the influence of adding additional
data which could measurably impact the HC5. The emphasis in
this analysis is on adding data on the low end of the toxicity
distribution. This can be viewed this as the likelihood of discovering
new and previously unknown ultrasensitive taxa.
order to lower the HC5 by a factor of two (0.11 mg/L), a new chronic
toxicity value of 0.0032 mg/L would have to be derived. The
probability of finding a new taxon with this hazard concentration is 1
order to lower the HC5 by a factor of three (0.07 mg/L), a new chronic
toxicity value of 9.1 x 10-5mg/L would have to be derived.
The probably of finding a new taxon with this hazard concentration is
1 in 4,160,000.
evaluations demonstrated that the chronic toxicity data were highly
ordered and strongly adhered to statistical assumptions. The SSD and
the resulting HC5 were highly stable to either deletion or addition of
cited in Annex 1
T. and Slob, W. 1993. Confidence limits for hazardous concentrations
based on logistically distributed NOEC toxicity data. Ecotoxicology
and Environmental Safety25:48–63.
S.E. et al. 2006.Aquatic
risk assessment of alcohol ethoxylates in North America and Europe.
Ecotoxicology and Environmental Safety 64: 85-99.
S. E. et al. 2009.Assessment
of the environmental risk of long-chain aliphatic alcohols.
Ecotoxicology and Environmental Safety 72:1006-1015.
(Organization for Economic Cooperation and Development). 2005. Linear
Alkylbenzene Sulfonate (LAS). OECD SIDS Initial Assessment Report. 357
de Plassche, E. J. et al. 1999.Predicted
no-effect concentrations for four surfactants: linear alkyl benzene
sulfonate (AES), alcohol ethoxylates (AE), alcohol ethoxylated
sulfates (AES) and soap. Environmental Toxicology and Chemistry
D.C. et al. 2011.Adverse
outcome pathways during early fish development: a conceptual framework
for identification of chemical screening and prioritization
strategies. Toxicological Sciences 123(2):349-58.
for the aquatic environment
model ecosystem study of LAS with a NOEC of 0.268 mg/L was used to
derive the aquatic PNEC values for LAS. ECHA describes the interactive
roles of statistical extrapolation techniques with the deterministic
based PNECs for mesocosms in the REACH Technical Guidance Document
Sections R.10.3.1.2 (Calculation of PNEC for freshwater using
assessment factors) and R.10.3.1.3 (Calculation of PNEC for freshwater
using statistical extrapolation techniques). Stream model ecosystems
are considered the most appropriate for assessing this chemical
(versus ponds) due to the wide dispersive use and route of discharge
to receiving waters via wastewater treatment plants. In the case of
the model ecosystem study summarized by Belanger et al. (2002), the
following considerations support no additional application factor to
be applied to the result when deriving the PNEC water (see ECETOC,
1997; Giddings et al., 2002; OECD, 2006). The most important factors
are knowledge of the biological complexity, sensitivity, study
duration, exposure determination, and relevance to natural systems for
the specific system being assessed. For the model ecosystem study of
The model ecosystem was biologically complex, containing a
highly diverse community with 117 invertebrate genera assessed
(including ~500 insect species). Approximately 150 algal species were
studied, dominated by sensitive diatom flora. Protozoa which were not
studied in this particular investigation historically accounted for an
additional 300 species.
model ecosystem was sensitive. The system was optimized for
statistical and biological sensitivity. Key endpoints evaluated
possessed Minimum Detectable Differences using inferential statistics
of 5-20% (change needed to be identified as statistically different
from the control). Use of PRC, Principal Response Curve Analysis,
corroborated use of repeated measure ANOVAs on single population
endpoints and coincides with NOECs on the most sensitive taxa and
taxonomic groups. The dominant invertebrate taxa were sensitive
species of the EPT group (mayflies, stoneflies, and caddisflies; a
total of 28 genera were represented). Dominant algae were diatoms,
many known as sensitive species. Functional endpoints were also
investigated including photosynthesis, organic matter processing, in
situ biodegradation, organism drift, insect emergence.
The model ecosystem study was longer than most chronic toxicity
tests(approximately 4 months duration). Colonization of the
streams, leading to stable, consistent and testable communities, was
for 10 weeks with exposure of stream communities to LAS was for 8
weeks. Repeated sampling insured ecological and toxicological shifts
The exposure to LAS was verified weekly and found to be nearly 100%
of nominal. For example, the streams exposed to nominal
concentrations of 0.300 and 3.000 mg/L were measured at 0.293 mg/L and
2.973 mg/L, respectively. A dynamic sorption model based on detailed
weekly investigations of sorption, daily evaluations of suspended
solids, and weekly assessments of DOC, TOC were used to express
exposure based on the free fraction of dissolved LAS.
study is relevant to natural systems. Studies by the sponsor
demonstrated the model ecosystem was nearly indistinguishable from the
source system and representative streams that were relatively
uninfluenced by man. Dyer and Belanger (1999) showed ESF stream
communities were as or more sensitive than >80% of streams in Ohio
surveyed at >1200 locations from the period of 1985-1995. The more
sensitive systems were Appalachian mountain slope, first or second
order systems that never have seen effect or been exposed to human
influences to any degree. Peterson et al. (2001) and Morrall et al.
(2006) demonstrated community function of the test system was similar
to that of low order streams across the globe (including systems
outside of the United States) and that predator-prey relationships in
the ESF were equivalent to the source river used to deliver water to
summary, the NOEC of LAS measured from the ESF model ecosystem study
was equal to 293 µg LAS/L which corresponds to 268 µg LAS/L as free
(dissolved and not associated with organic or particulate matter).
Further, an Application Factor (AF) of 1 is justified, especially when
viewed in concert with the chronic toxicity Single Species Sensitivity
Distribution (SSD) HC5of 0.21 mg/L. Based on this data, the
PNECfreshwater was calculated as the model ecosystem study NOEC/1 or
0.268 mg LAS/L.
calculate the PNECmarine the aquatic NOEC of 0.268 mg/L from the model
ecosystem study was used as a starting point. The AF for the marine
PNEC is generally 10 applied to the PNECaquatic resulting in a
PNECmarine of 0.0268 mg/L. This AF is considered appropriate given the
detailed literature reviews regarding marine and freshwater organism
sensitivity to LAS (Temara et al., 2001). Temara and coworkers
provided conclusions that were similar to observations from van de
Plaasche et al. (1999), but with additional data to derive a chronic
marine SSD to compare with a chronic freshwater SSD. In these
investigations, the sensitivity of marine taxa versus freshwater is
typically 10-fold, consistent with the AF consistent with principals
described in the REACH Technical Guidance Document Sections
R.10.3.2.3 (Calculation of PNEC for marine water).
the PNEC intermittent releases was calculated as normal by using the
lowest acute LC50 value and applying an AF of 100 to get a final PNEC
intermittent releases value of 0.0167 mg/L.
not cited in Annex 1
S.E. et al., 2002.Integration
of aquatic fate and ecological responses to linear alkyl benzene
sulfonate (LAS) in model stream ecosystems. Ecotox. Env. Saf.
S.D. and Belanger, S.E., 1999. Determination
of the sensitivity of macroinvertebrates in stream mesocosms through
field-derived assessments. Env.
Tox. Chem. 18(12):2903-2907.
(European Center for Toxicology and Ecotoxicology), 1997. The value of
aquatic model ecosystem studies in ecotoxicology. ECETOC
Technical Report No. 73.
J.M. et al.(Eds.). 2002,
Community Level Aquatic Systems Studies Interpretation Criteria. SETAC
Press, Pensacola, FL.
S.W. et al., 2006. Removal and environmental exposure of alcohol
ethoxylates in US sewage treatment. Ecotoxicol. Environ. Saf.
B.J. et al., 2001. Control of nitrogen export from watersheds by
headwater streams. Science 292:86–90.
A. et al., 2001. Marine risk assessment: linear alkylbenzenesulponates
(LAS) in the North Sea. Mar. Pollut. Bull. 42(8):635-42.
de Plassche, E. J. et al., 1999. Predicted no-effect concentrations
for four surfactants: linear alkyl benzene sulfonate (AES), alcohol
ethoxylates (AE), alcohol ethoxylated sulfates (AES) and soap. Env.
Tox. Chem. 18(11):2653-2663.
for the terrestrial environment
review of studies on the toxicity of LAS to soil macro-organisms and
terrestrial plants was conducted in order to determine a PNEC in soil.
Nine invertebrate and 12 plants studies were used to calculate the
PNEC. Full references for all studies used are provided below. In all
the plant experiments, LAS was added as an aqueous solution, and the
most sensitive endpoint, growth, was used in calculated the PNEC. In
cases where a NOEC or an EC10 value was not reported, the original
data or graphical estimations were used to calculate the EC10. This
was considered more appropriate than using an arbitrary extrapolation
factor. Invertebrate data was based on 9 chronic studies. In cases
where there was more than one study on a particular species, a
geometric mean of the data was used. The data for both sets of studies
were merged as the sensitivity of both types of species were similar.
This was confirmed by the Kolmogorov-Smirnov test. The species
sensitivity distribution was then calculated. From this, the
concentration that would exceed the NOEC or EC10 for 5% of species
(HC5) was calculated (HC5).
on this methodology, the HC5 was determined to be 35.3 mg/kg soil dry
weight (dw). The 95% confidence interval was 18.6 -50.0 mg/kg soil dw.
The PNEC for soil is therefore 35 mg/kg soil dw. The data used to
calculate the PNEC is presented below.
approach used to derive the soil PNEC value is detailed in a
publication by Jensen et al. (2007).
used in the determination of a soil PNEC
Gunther and Pestemer, 1992
Krogh et al., 2007
Holmstop and Krogh, 2001
Holmstrup and Krogh, 1996
Holmstrup et al., 2001
Jensen and Sverdrup, 2002
Jensen et al., 2001
Holmstrup and Krogh, 2001
J. et al., 2007. European risk assessment of LAS in agricultural soil
revisited: Species sensitivity distribution and risk estimates.
lowest acute data point for MEA-LAS is a 96 h LC50 value of 2.22 mg/L in Pimephales
and Brill, 2006).
The lowest chronic data point is a 56 d NOEC of 0.268 mg/L from a
mesocosm model ecosystem (Belanger, 1997, 2002 and 2004; Lower, 1996).
Given that MEA-LAS is readily biodegradable, the substance therefore
qualifies for classification as Aquatic Chronic 3 – H412 (Harmful to
aquatic life with long-lasting effects) according to EU CLP
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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