Sodium 2-sulphonatoethyl laurate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study reports the output from a QSAR prediction model for lauric acid, 2-sulfoethyl ester, sodium salt.

Justification for type of information:

QSAR prediction

Reason / purpose for cross-reference:

reference to other study

Guideline:

other: REACH guidance on QSARs R.6 May 2008

Analytical monitoring:

not required

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 229.7 mg/L

Nominal / measured:

estimated

Conc. based on:

act. ingr.

Basis for effect:

mobility

Table 3. Predicted toxicity of a series of alkyl isethionates usingEU TGD QSAR forDaphnia magna

Chain length	Measured & extrapolated Log Kow
	logEC50 (mol/L)*	Predicted EC50 (mg/L)
8	-1.9164	3042.8
10	-2.5212	840.2
12	-3.126	229.7
14	-3.7308	62.3
16	-4.3356	16.8
18	-4.9404	4.5

*using equation : logEC50 = -0.56logKow – 2.79    (n= 37   r²= 0.77)

Validation of the prediction is shown in Figure 3 (attached)

Validity criteria fulfilled:

yes

Conclusions:

Scientific validity and applicability: A weight of evidence approach considering an extrapolation method combining a measured logKow value for the C8 homologue with commercialised predictive software (CLOGP), indicates that a logKow value of 0.6 is appropriate for the C12 homologue. Due to low water solubility in test medium, it was possible only to conduct reliable toxicity studies for the shorter homologues in standard acute toxicity studies. These toxicity values correlate well with predicted toxicity values using the extrapolate logKow values for the respective homologues with the accepted EU TGD QSAR for acute toxicity to Daphnia magna.This correlation suggests that the extrapolation approach for generating the logKow value is valid in this case. Based on this conclusion the acute toxicity of the sodium lauroyl isethionate can be predicted with a high degree of confidence.

Regulatory relevance: Short term toxicity testing on invertebrates (preferred species Daphnia) is a requirement of REACH Annex VII 9.1.1

Executive summary:

Scientific validity and appplicability: A weight of evidence approach considering an extrapolation method combining a measured logKow value for the C8 homologue with commercialised predictive software (CLOGP), indicates that a logKow value of 0.6 is appropriate for the C12 homologue. Due to low water solubility in test medium, it was possible only to conduct reliable toxicity studies for the shorter homologues in standard acute toxicity studies. These toxicity values correlate well with predicted toxicity values using the extrapolate logKow values for the respective homologues with the accepted EU TGD QSAR for acute toxicity to Daphnia magna.This correlation suggests that the extrapolation approach for generating the logKow value is valid in this case. Based on this conclusion the acute toxicity of the sodium lauroyl isethionate can be predicted with a high degree of confidence. Regulatory relevance: Short term toxicity testing on invertebrates (preferred species Daphnia) is a requireement of REACH Annex VII 9.1.1

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study start date 25 Feburary 2003, study end date 13 March 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP compliant and conducted under OECD Guideline 202. Concentrations are not measured. 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 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

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

Analytical monitoring:

no

Details on sampling:

- Concentrations: test concentrations were based on nominal measurements

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Hardness:

235mg/l as CaCO3 (+/- 8)

Test temperature:

19.3 degrees Centigrade (+/- 0.3 SD)

pH:

8.1 (+/- 0.4 SD)

Dissolved oxygen:

7 mgl (+/-0.3 SD)

Nominal and measured concentrations:

Nominal

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

Not applicable

Conclusions:

The 24 hour EC50 based on nominal concentrations was greater than 32 mg/l.

The 48 hour EC50 based on nominal concentrations was greater than 32 mg/l.

The 48 hr NOEC was 32 mg/l based on nominal concentrations.

No immobility was observed at any of the test concentrations.

In the rangefinder 100 % immobility was observed at 100 mg/l due to Daphnia becoming caught

up in precipitation.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007-07-18 to 2008-03-03

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted according to GLP and OECD (202) (Guidelines for Testing of Chemicals. Section 2. Guideline 202 "Daphnia sp. Acute Immobilisation Test" (2004)). The analytical chemistry supporting this study was performed to GLP and confirms the identity of the test item but, the separate chemistry report has not been audited at the current time (04 November 2010). 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 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

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:

- Nominal Concentrations: 0, 18, 32, 56, 100, 180 mg/L
- Sampling method: Test item concetrations (Nominal 18, 32, 56, 100 and 180 mg/L) were determined at 0, 24 and 48 hrs. The stock solution and test media were removed and renewed after 24 hours and concentrations determined using LC/MS.
- Sample storage conditions before analysis: No data provided.

Details on test solutions:

A nominal 1800 mg/L stock solution was prepared by adding 1800 mg of SLI (76) stripped to 1000 mL of purified water. The solution was heated to approximately 40-50 degrees C whilst stirring continuously until test item dissolved. Test media were prepared by diluting the warm 1800 mg/L stock solution with Elendt M7 medium to obtain nominal test concentrations of 0, 18, 32, 56, 100 and 180 mg/L. The test solutions were left to stand for 1 hour after preparation to allow for settling of the test item precipitate. The resulting supernatant was decanted and used as the final test media.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Age at study initiation (mean and range, SD):<24 hrs old
- Daphnia were not fed duing the test


ACCLIMATION
- Acclimation period: <24 h
- Acclimation conditions (same as test or not): no data
- Type and amount of food: no food
- Feeding frequency: not applicable
- Health during acclimation (any mortality observed): no data

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

h

Post exposure observation period:

None

Hardness:

Measured in 0 and 180 mg/L nominal test solutions at 0, 24 and 48 hrs. Mean = 276 (SD = 10) mg/L as CaCO3

Test temperature:

The temperature was measured in five random test vessels at 0, 24 and 48 hrs. Mean = 20.0 (SD = 0.6) degrees C

pH:

The pH was measured in all test concentrations at 0, 24 and 48 hrs. Mean = 7.6 (SD = 0.2)

Dissolved oxygen:

The dissolved oxygen concetration was measured in all test concentrations at 0, 24 and 48 hrs. Mean = 8.0 (SD = 1.2) mg/L

Salinity:

No data

Nominal and measured concentrations:

Nominal: 0, 18, 32, 56, 100 and 180 mg/L
Measured concentrations reported as time weighted averages for both total and dissolved:
Total measured concentrations: 15.7, 29.1, 49.8, 101.6 and 169.2 mg/L
Dissolved measured concentrations: 10.8, 19.6, 34.6, 50.1 and 80.6 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 120 mL crytallising dish

- Renewal rate of test solution (frequency/flow rate): every 24 hours
- No. of organisms per vessel: five
- No. of vessels per concentration (replicates): four replicates per concentration
- No. of vessels per control (replicates): four
- No. of vessels per vehicle control (replicates): not applicable
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS
Elendt M7 media. No details provided.

OTHER TEST CONDITIONS
Normal laboratory light intensity with photoperiod of 16 h light and 8 h dark.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Immobility in the Daphnia is due mainly to indirect effects. At 48 hours the Daphnia exposed to 56 mg/L (nominal) SLI(76) stripped were fully mobile however there was evidence of the precipitate adhering to the carapace and antennae. Similarly at 100 mg/L (nominal), the majority of the Daphnia were coated in precipitate around the head, carapace and antennae although they were still considered mobile. At 180 mg/L (nominal), individuals were severely hindered by test precipitate and were considered immobile according to the criteria set by OECD i.e. unable to swim after 15 seconds agitation. It should be noted however that no mortality was observed.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 101.6 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

act. ingr.

Basis for effect:

mobility

Remarks on result:

other: 95% Confidence Interval

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 50 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

dissolved

Basis for effect:

mobility

Remarks on result:

other: 95% confidence interval

Details on results:

None of the concetrations caused 100% immobility.

Immobility in the Daphnia is due mainly to indirect effects. At 48 hours the Daphnia exposed to 56 mg/L (nominal) SLI(76) stripped were fully mobile however there was evidence of the precipitate adhering to the carapace and antennae. Similarly at 100 mg/L (nominal), the majority of the Daphnia were coated in precipitate around the head, carapace and antennae although they were still considered mobile. At 180 mg/L (nominal), individuals were severely hindered by test precipitate and were considered immobile according to the criteria set by OECD i.e. unable to swim after 15 seconds agitation. It should be noted however that no mortality was observed and it is believed that without the precipitation no effects would have been observed.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

95% confidence intervals

TABLE 1. SUMMARY OF SLI (76) STRIPPED CONCENTRATIONS during 48 hour Daphnia magna study

Nominal concentration (mg/L)	Measured concentration (mg/L)								Mean measured concentration (mg/L)*
	0 hours		24 hrs (old)		24 hrs (new)		48 hrs
	Total	Dissolved	Total	Dissolved	Total	Dissolved	Total	Dissolved	Total	Dissolved
18	17.7	10.1	17.4	15.4	18.7	10.3	10.0	7.9	15.7	10.8
32	30.3	15.4	31.4	27.6	31.6	17.3	23.5	19.4	29.1	19.6
56	53.4	39.4	50.1	37.4	54.3	41.0	42.1	22.4	49.8	34.6
100	102.8	54.4	93.9	40.7	103.8	67.8	106.1	40.4	101.6	50.1
180	169.6	100.6	155.9	61.1	168.6	116.9	183.2	54.8	169.2	80.6

* calculated as time weighted means

Table 2. 24 & 48 hour immobility data

Nominal	% immobility
Conc (mg/L)	at 24 hrs	at 48 hrs
0.0	0	0
18	0	0
32	0	0
56	0	0
100	0	0
180	10	60

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour EC50 of SLI(76) stripped to juvenile (<24 h old) Daphnia magna based on total mean measured concentrations was > 101.6 (95 % confidence intervals). The 48-hour EC50 based on dissolved mean measured concentrations was >50.0 (95 % confidence intervals).

Executive summary:

The 48-hour EC50 of SLI(76) stripped to juvenile (<24 h old) Daphnia magna, under semi-static conditions, based on total mean measured concentrations was > 101.6 (95 % confidence intervals). The 48-hour EC50 based on dissolved mean measured concentrations was >50.0 (95 % confidence intervals). Test concentrations were determined throughout the study by LC/MS. The study was conducted according to GLP and OECD (202) testing guideline.

Description of key information

The acute toxicity of lauric acid 2-sulfoethylester was calculated using a polar narcosis QSAR based upon predicted Log Kow values. As supporting evidence, three acute daphnia tests have been performed to evaluate toxicity of the sodium salt of coco fatty acids 2-sulfoethylester. In addition acute daphnia tests were conducted on shorter chain length isethionates, octanoyl and decanoyl.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

229.7 mg/L

Additional information

Three acute daphnia tests have been performed to evaluate toxicity of the sodium salt of coco fatty acids 2-sulfoethylester. EC50 values ranging from 7.9 to > 48 mg a.i./L were observed. In two studies, the effects observed were addressed to indirect effects of precipitates adhering to the carapac or antennae of the daphnia. In the Key study test solutions of Fatty acids, C12-18 and C18-unsatd., 2-sulfoethyl esters, sodium salts (CAS no 85408-62-4) which is a substance very similar to lauric acid 2-sulfoethyl sodium salt were prepared containing a nominal concentration of 0, 18, 32, 56, 100 and 180 mg/L of test substance.

After preparing the test solutions they were left for 1 hour to allow for settling of precipitate. Measured concentrations using LC-MS are reported as time weighted averages for both total and dissolved: Total measured concentrations: 15.7, 29.1, 49.8, 101.6 and 169.2 mg/L. Dissolved measured concentrations: 10.8, 19.6, 34.6, 50.1 and 80.6 mg/L. An EC50 of >48 mg a.i./L has been derived using the weighted mean of the measured dissolved concentration. None of the concentrations caused 100% immobility. Immobility in the Daphnia is due mainly to indirect effects. Read-across from the source chemical Fatty acids, C12-18 and C18-unsatd., 2-sulfoethyl esters, sodium salts (CAS no 85408-62-4) to the target chemcial lauric acid 2-sulfoethyl sodium salt is considered to be justified as both substance are very similar and the source chemical contains a higher content of longer alkyl chain products which are known to more toxic than the shorter alkyl chain products. The conclusion that the source chemical is more toxic than the target chemical is considered sufficient to select the more toxic derivative as the worst-case representative in the hazard assessment of both substances. For this reason read-across of ecotoxicity results of the source chemical (C12-18 and C18-unsatd) to the target chemical (lauryl) is considered to be justified without the introduction of an additional safety factor. Further refinement of the EC50 value for lauric acid 2-sulfoethyl sodium salt was performed using a polar narcosis QSAR based upon the predicte d logKow values for the target substance:

Scientific validity and appplicability: A weight of evidence approach considering an extrapolation method combining a measured logKow value for the C8 homologue with commercialised predictive software (CLOGP), indicates that a logKow value of 0.6 is appropriate for the C12 homologue. Due to low water solubility in test medium, it was possible only to conduct reliable toxicity studies for the shorter homologues in standard acute toxicity studies. These toxicity values correlate well with predicted toxicity values using the extrapolate logKow values for the respective homologues with the accepted EU TGD QSAR for acute toxicity to Daphnia magna.This correlation suggests that the extrapolation approach for generating the logKow value is valid in this case. Based on this conclusion the acute toxicity of the sodium lauroyl isethionate can be predicted with a high degree of confidence. Regulatory relevance: Short term toxicity testing on invertebrates (preferred species Daphnia) is a requirement of REACH Annex VII 9.1.1