Sodium 2-sulphonatoethyl laurate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

calculation (if not (Q)SAR)

Remarks:

estimated by calculation

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study reports the output from a Toxic Unit approach calculation for lauric acid, 2-sulfoethyl ester, sodium salt.

Reason / purpose for cross-reference:

reference to other study

Guideline:

other: REACH guidance on QSARs R.6 May 2008

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

ca. 1.1 mg/L

Nominal / measured:

estimated

Conc. based on:

act. ingr.

Basis for effect:

reproduction

The results in Table 5 indicate that the soluble concentrations of C12 chain length contribute only 5.4% of the observed toxicity of the mixture. The C14, C16 and C18 chain lengths are estimated to account for 94% of the observed toxicity of the mixture. The results of the study ECD080250 should, therefore, be considered to be an overly conservative estimate for the chronic toxicity to Daphnia to sodium lauroyl isethionate.

Table 5. Calculation of Toxic Unit contribution for sodium lauryl isethionateinDaphniachronic study ECD080250

Chainlength	MW	Concentration at NOEC[1](mg/L)	Concentration at NOEC (mol/L)	Log Kow[2]	Log predicted toxicity (mol/L)	Predicted toxicity (mol/L)	TU[3]	Contribution to toxicity of mixture (%)[4]	TU as a relative contribution to total TU of mixture from each chain length[5]	Predicted NOEC (mol/l)[6]	Predicted NOEC (mg/l)
8	251	0.010164	4.05E-08	-1.56	-1.916	0.01212	0.0000033	0.068	0.00068	5.9E-5	15
10	279	0.014322	5.13E-08	-0.48	-2.521	0.00301	0.0000170	0.348	0.0035	1.5E-5	4.1
12	307	0.060522	1.97E-07	0.6	-3.126	0.00075	0.00026	5.4	0.054	3.7E-6	1.1
14	335	0.02079	6.21E-08	1.68	-3.731	0.00019	0.00033	6.8	0.068	9.1E-7	0.30
16	363	0.02387	6.58E-08	2.76	-4.336	0.00005	0.0014	29	0.29	2.3E-7	0.08
18	391	0.012782	3.27E-08	3.84	-4.940	0.00001	0.0028	58	0.58	5.6E-8	0.022

[1]Concentration at NOEC (mg/L)–dissolved concentration of each chain length at the exposure concentration determined to be the NOEC i.e. % average chain length expected to be in solution x % dissolved chainlength (based on values from ECD080250) x 0.154 mg/L (% dissolved from study ECD090250: C8 = 6.6%, C10= 9.3%, C12= 39.3%, C14= 13.5%, C16= 15.5%, C18=8.3 %)

[2]Log K_ow– C8 based on measured value, subsequent chain lengths calculated by the addition of 0.54 per additional CH₂unit which equates to the fragment value (inc bond contribution)[11].

[3]TU – toxic unit contribution of each chain length i.e. Concentration at NOEC (mol/L)/predicted toxicity (mol/L)

[4]Calculated as a relative TU of each chainlength/ total TU

[5]Total TU = 1 for all chainlengths at NOEC of the mixture since all act by same MoA

[6]Calculated by rearranging Equation 1 to give: NOEC_i= C_i/TU_i(e.g. Predicted NOEC(mol/L) for C12 = 1.97E-7/0.054 = 3.7E-6)

 

Validity criteria fulfilled:

not applicable

Conclusions:

The results in Table 5 indicate that the soluble concentrations of C12 chain length contribute only 5.4% of the observed toxicity of the mixture. The C14, C16 and C18 chain lengths are estimated to account for 96% of the observed toxicity of the mixture. The results of the study ECD080250 should, therefore, be considered to be an overly conservative estimate for the chronic toxicity to Daphnia to sodium lauroyl isethionate.

Executive summary:

The toxicity of a mixture comprising mainly of a distribution of homologues can be predicted from an applicable QSAR, the inclusion level of each homologue and the assumption of concentration addition (given that the homologues all have the same MoA). For a defined class of surfactanttoxicity normally increases logarithmically with increase in chain length of the hydrophobic tail [16]. The measured toxicity of a commercial surfactant, therefore, may be driven predominately by a limited number of the more hydrophobic homologues i.e. those that have toxicity orders of magnitude greater than the shorter chain length homologues.

The results in Table 5 indicate that the soluble concentrations of C12 chain length contribute only 5.4% of the observed toxicity of the mixture. The C14, C16 and C18 chain lengths are estimated to account for 96% of the observed toxicity of the mixture. The results of the study ECD080250 should, therefore, be considered to be an overly conservative estimate for the chronic toxicity to Daphnia to sodium lauroyl isethionate.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 July 2008 – 14 October 2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study has been conducted according to OECD Guideline 211. No claim for GLP compliance is made for this study. However, the study was carried out in the spirit of GLP. Read-across is based upon a commonality of functional groups, constituents, breakdown products and metabolic pathways. A detailed justification is appended in Section 13.

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

no

GLP compliance:

yes

Remarks:

conducted according to the principles of GLP

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Nominal: 0, 560, 1000, 1800, 3200, 5600 (ug/L); Measured total: <0.5, 103, 192, 289, 752, 1307 ug/L
- Sampling method: Test item concentrations were determined by LC/MS
- Sample storage conditions before analysis: no data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A 200 mg/L stock solution was prepared daily by adding 50 mg of S2849001 in 250 mL of purified water. The resulting dispersion was heated to approx 40 - 50 oC with stirring until completely dissolved.
- Eluate: no data
- Differential loading: no data
- Controls: yes
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not applicable (water)
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: daphnia magna
- Strain/clone: not stated
- Justification for species other than prescribed by test guideline: not applicable (prescribed by guideline)
- Source: In-house cultures
- Age of parental stock (mean and range, SD): no data
- Feeding during test: yes
- Food type: chlorella vulgaris & microfeast PZ20 supplement
- Amount: chlorella vulgaris: 3.4 x 10^5 cells/mL/day; microfeast: 1.4mL of a 1g/L solution per day
- Frequency: Daily

ACCLIMATION
- Acclimation period: no

QUARANTINE (wild caught)
- not applicable

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: not applicable

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Post exposure observation period:

No

Hardness:

average of 224mg/L as CaCO3
SD 9.5
(highest concentration and controls measured at various time points; n=39)

Test temperature:

average of 19.6 degrees C
SD 0.31
(measured in 6 vessels daily)

pH:

average 8.42
SD 0.44
(measured in all concentrations on 11 different days)

Dissolved oxygen:

average 9.34 mg/L
SD 0.94
(measured in all concetrations on 11 different days)

Salinity:

not measured

Nominal and measured concentrations:

see tables 1 & 2 below

Details on test conditions:

TEST SYSTEM
- Test vessel: 120mL glass bottle
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: ~100mL
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): semi-static
- Renewal rate of test solution (frequency/flow rate): daily
- No. of organisms per vessel: 1/vessel
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- No. of vessels per vehicle control (replicates): not applicable
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M7 Media
Made up following OECD Guideline 211; no other measurements taken
- Culture medium different from test medium: no
- Intervals of water quality measurement: every 2-3 days

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light/8 hours dark
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : time to first brood, size of first brood, number of offspring per surviving adult, mortality

VEHICLE CONTROL PERFORMED: not applicable

RANGE-FINDING STUDY
- Test concentrations: no data
- Results used to determine the conditions for the definitive study: used to determine test concentrations & analytical method

Reference substance (positive control):

no

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 154 µg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

dissolved

Basis for effect:

reproduction

Remarks on result:

other: no data

Details on results:

- Mortality of parent animals: no data
- No. of offspring produced per day per female: no data
- Body length and weight of parent animals: no data
- Type and number of morphological abnormalities: no data
- Type and number of behavioural abnormalities: no data
- Time to first brood release or time to hatch: 8.7 days (controls), 9.4 (560ug/L), 9.4 (1000ug/L), 9.6 (1800ug/L), 9.8 (3200ug/L), 11 (5600ug/L)
- Egg development time: no data
- Brood size: First brood only: 9.1 (control); 11.5 (560ug/L), 10.5 (1000ug/L), 10.2 (1800ug/L); 10.9 (3200ug/L); 9.2 (5600ug/L)
- Time to sexual maturity: no data
- Type and magnitude of biochemical changes: no data
- Other biological observations: no data
- Effect concentrations exceeding solubility of substance in test medium: not applicable

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

The data were analysed using an analysis of variance followed by Dunnett’s test to obtain the 21 day NOEC for mean juvenile production, time to release of first brood and size of first brood.

Table 3: Summary of Effect Data

Nominal concentration (µg/L	Mean Measured Concentration (µg/L)		Mean Number of Neonates at Day 21^#	Percentage Adult Mortality at Day 21	Mean size of first brood	Mean time to release of 1st brood (days)
	Total	Dissolved
0	<5.0	<5.0	70	0	9.1	8.7
560	102	77.7	99.6*	0	11.5	9.4
1000	192	154	104.9*	0	10.5	9.4
1800	289	260	121.3*	0	10.2	9.6*
3200	752	457	112.3*	10	10.9	9.8*
5600	1307	717	102.1*	30	9.2	11*

^{#  including dead neonates}

^{* Significantly different to the control (P<0.05)} 

Validity criteria fulfilled:

yes

Conclusions:

The lowest value determined for an adverse effect was time to first brood. The 21 day NOEC for this endpoint based on dissolved concentrations was 154 μg/L (192 μg/L total concentration)

Executive summary:

The purpose of this study was to determine the effects of SLI (76) stripped on survival and reproduction of Daphnia magna.

SLI (76), provided by Unilever Mannheim was stripped of its fatty acid content via Soxhlet extraction at the Materials Science Laboratory, Trumbull, USA. The resulting material, SLI (76) stripped was used for this study.

Daphnia were exposed to a range of concentrations, nominally 0.0, 560, 1000, 1800, 3200 and 5600 μg/L. Test item analysis was performed to determine total and dissolved concentrations. The dilution medium used was Elendt M7 artificial medium. A 3.4 x 105 cells/mL aliquot of Chlorella vulgaris and 1.4 mL of a 1 g/L Microfeast PZ20 supplement was added to the test media containing the appropriate concentration of SLI(76) stripped. The stock solution and test media were renewed daily.

The data were analysed using an analysis of variance followed by Dunnett’s test to obtain the

21 day NOEC for mean juvenile production, time to release of first brood and size of first

brood.

The lowest value determined for an adverse effect was time to first brood. The 21 day NOEC for this endpoint based on dissolved concentrations was 154 μg/L (192 μg/L total concentration).

There was no statistically significant effect at any concentration on size of first brood therefore the NOEC for this endpoint based on dissolved concentrations can be quoted as >717 μg/L (>1307 μg/L total concentration)

A statistically significant stimulatory effect was observed at all concentrations based on number of neonates per surviving adult. The number of neonates rose steadily up to a dissolved concentration of 260 ug/L (289 μg/L total concentration) after which it then began

to decline. The NOEC for this endpoint cannot therefore be determined with any confidence. The 21 day NOEC for adult mortality is 260 μg/L based on mean measured dissolved concentrations (289 μg/L as total concentration).

Description of key information

A 21 day NOEC for daphnia was calculated for the target substanceusing a polar narcosis QSAR and Toxic unit approach methodology from the results obtained in a study using C12-18 and C18-unsatd., 2-sulfoethyl esters, sodium salts (CAS no 85408-62-4)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.1 mg/L

Additional information

There is nochronic invertebrate toxicity studyavailable for lauric acid 2-sulfoethyl ester, sodium salt (sodium lauroyl isethionate) CAS No 7381-01-3. There is however a study on the source chemicalFatty acids, C12-18 and C18-unsatd., 2-sulfoethyl esters, sodium salts CAS No 85408-62-4, which isKlimisch rated 2and was carried out according to theOECD guideline 211 under GLP,as described in Roberts, 2010.

The results from the Roberts study were used as the starting point for calculating the NOEC for for lauric acid 2-sulfoethyl ester, sodium salt using a Toxic Unit approach.

The toxicity of a mixture comprising mainly of a distribution of homologues can be predicted from an applicable QSAR, the inclusion level of each homologue and the assumption of concentration addition (given that the homologues all have the same MoA). For a defined class of surfactant toxicity normally increases logarithmically with increase in chain length of the hydrophobic tail [16]. The measured toxicity of a commercial surfactant, therefore, may be driven predominately by a limited number of the more hydrophobic homologues i.e. those that have toxicity orders of magnitude greater than the shorter chain length homologues.

The results indicate that the soluble concentrations of C12 chain length contribute only 5.4% of the observed toxicity of the mixture. The C14, C16 and C18 chain lengths are estimated to account for 93% of the observed toxicity of the mixture. The results of the study ECD080250 should, therefore, be considered to be an overly conservative estimate for the chronic toxicity to Daphnia to sodium lauroyl isethionate.

.