Sodium 2-stearoyllactate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 Sep - 24 Oct 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Klimaschutz, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Sodium 2-stearoyllactate

EC Number:

246-929-7

EC Name:

Sodium 2-stearoyllactate

Cas Number:

25383-99-7

Molecular formula:

This reference substance is a UVCB of the NCS type. It is a complex mixture of compounds and therefore molecular formula, molecular weight, SMILES, InChI and structural formula cannot be given.

IUPAC Name:

sodium 2-hydroxy-2-methyl-3-oxoicosanoate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Control and highest test item concentration (samples were taken from all test item concentrations but analytical measurements were performed only with the highest test item concentration)
- Sampling method: Duplicate samples from test media of all test concentrations and the controls were taken at test start and at the end of the test from all aged test media and the control of the actual test by pooling the contents of the beakers of all replicates for each treatment. Analytical measurements were performed for the highest test item concentration only, since no effects were observed up to the highest test item concentration.
- Sample storage conditions before analysis: All samples were stored in a freezer (≤ -20 °C), protected from light until analysis was performed. Afterwards the samples were again stored deep frozen and will be kept stored up to the date of the final report.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The highest loading rate of 100 mg test item/L was prepared by mixing 94.7 and 94.2 mg test item into 947 and 942 mL test water. For the loading rate of 40 mg test item/L, 39.0 and 37.0 mg test item were mixed into 975 and 925 mL test water, for the loading rate of 16 mg test item/L, 15.9 and 15.8 mg were mixed into 994 and 988 mL test water. The loading rate of 6.4 mg test item/L was prepared by mixing 6.3 and 6.1 mg into 984 and 953 mL test water, for 2.56 mg test item/L 5.26 and 5.08 mg were mixed into 2055 and 1984 mL test water and for the loading rate of 1.02 mg test item/L 2.09 and 2.14 mg were mixed into 2049 and 2098 mL test water. Each preparation was ultrasonicated for 15 min after 10 to 30 min stirring, total stirring time was 70 min. Non-dissolved fractions of the test item were separated from the test medium by membrane filtration (0.45 µm cellulose acetate filter).
The test media were prepared just before introduction of the daphnids (= start of the test) and the test medium renewal on Day 1.

- Controls: Medium without test item

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Strain/clone: Daphnia magna (Straus), clone 5
- Age at study initiation (mean and range, SD): From 2.25 to 24.0 h old
- Method of breeding: The daphnids were bred in the laboratories of ibacon under similar temperature and light conditions as used in the test. The cultivation of the parental daphnids was performed in Elendt M4 medium. The test organisms were not first brood progeny.
- Source: The daphnids introduced in the test were taken from ibacon's in house laboratory culture
- Feeding during test : No
- Food type: The daphnids in the stock culture were with green algae (Desmodesmus subspicatus) freshly grown in the test facility.
- Frequency: Fed at least on all working days

ACCLIMATION : not necessary, since the test was performed in the same medium as the culturing.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

2.5 mmol/L (= 250 mg/L) as CaCO3

Test temperature:

20.1 to 21.6 °C (Control)
20.2 to 21.2 °C (Test item concentrations)

pH:

7.9 to 8.0 (Control)
7.4 to 8.0 (Test item concentrations)

Dissolved oxygen:

8.5 to 8.9 mg/L (Control)
5.9 to 8.7 mg/L (Test item concentrations)

Nominal and measured concentrations:

100, 40, 16, 6.4, 2.56 and 1.02 mg/L (nominal concentrations)
0.483, 0.475, n.a., n.a., n.a., n.a. (based on the time weighted average measured concentration)

Details on test conditions:

TEST SYSTEM
Test vessel:
- Type: open
- Material, size, headspace, fill volume: 100 mL glass beakers; fill volume: 60 mL; headspace: 40 mL; covered with a lid to reduce evaporation
- Volume of solution: 60 mL
- Renewal rate of test solution: A semi-static test system with a test medium renewal on Day 1
- No. of organisms per vessel: 5 animals per test vessel
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt "M4" and analytical grade salts and additives were added:
Main components: CaCl2·2 H2O: 293.80 mg/L; MgSO4·7 H2O: 123.30 mg/L; KCl: 5.80 mg/L; NaHCO3: 64.80 mg/L; Na2SiO3·9 H2O: 10.00 mg/L; NaNO3: 0.27 mg/L; KH2PO4: 0.14 mg/L; K2HPO4: 0.18 mg/L
- Alkalinity: 0.9 mmol/L
- Culture medium different from test medium: No, medium was the same
- Intervals of water quality measurement: Daily and at every renewal of the test solution

OTHER TEST CONDITIONS
- Photoperiod: 16 h light : 8 h dark
- Light intensity: 420 to 880 lux (measured once during the test)

EFFECT PARAMETERS MEASURED: The mobility of the daphnids was determined by visual observation after 24 and 48 h. Those animals that are not able to swim within 15 sec after gentle agitation of the test beaker were considered to be immobile (even if they could still move their antennae).

RANGE-FINDING STUDY
- Test concentrations: performed under non-GLP, not reported
- Results used to determine the conditions for the definitive study: Based on the results of a non-GLP range-finding test the following test item concentrations for the main test were tested: 100, 40, 16, 6.4, 2.56 and 1.02 mg/L (spacing factor 2.5)

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.483 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: No behavioural abnormalities were observed in any treatment group.
- Mortality of control: No mortality or immobility was observed.
- Other adverse effects control: No
- Immobilisation of control: No

Results with reference substance (positive control):

For the evaluation of the quality of the Daphnia clone and the consistency of the experimental conditions, the reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions (EC50 (24 h): 0.6 - 2.1 mg potassium dichromate/L).

Reported statistics and error estimates:

No statistical analysis was performed. The EL50 could not be quantified due to the absence of toxicity of the test item and were determined to be higher than the highest test concentration. The NOEL and the LOEL were determined directly from the raw data.

Any other information on results incl. tables

Biological Results:

Table 1: Biological Results of the test item on the mobility of Daphnia magna and sublethal effects

Loading rate No. of Daphnia tested No. of immobilised Daphnia after % of immobilised Daphnia after Observations [mg test item/L] 24 h 48 h 24 h 48 h 24 h 48 h Control 5 0 0 0 0 0 0 5 0 0 0 0 5 0 0 0 0 5 0 0 0 0 Filtrate of 1.02 5 0 0 0 0 0 0 5 0 0 0 0 5 0 0 0 0 5 0 0 0 0 Filtrate of 2.56 5 0 0 0 0 0 0 5 0 0 0 0 5 0 0 0 0 5 0 0 0 0 Filtrate of 6.4 5 0 0 0 0 0 0 5 0 0 0 0 5 0 0 0 0 5 0 0 0 0 Filtrate of 16 5 0 0 0 0 0 0 5 0 0 0 0 5 0 0 0 0 5 0 0 0 0 Filtrate of 40 5 0 0 0 5 0 0 5 0 0 0 0 5 0 1 0 0 5 0 0 0 0 Filtrate of 100 5 0 0 0 0 0 0 5 0 0 0 0 5 0 0 0 0 5 0 0 0 0

Abbreviations for observations:

0: No abnormalities

Table 2. Summary of Biological Results

Endpoints	Test item concentration [mg/L]
EL50 [mg test item/L]: EC50   [mg test item/L]:	> filtrate of 100   (> 0.483)
95 % CI [mg test item/L]:	n.d.
EL20 [mg test item/L]: EC20   [mg test item/L]:	> filtrate of 100   (> 0.483)
95 % CI [mg test item/L]:	n.d.
EL10 [mg test item/L]: EC10   [mg test item/L]:	> filtrate of 100   (> 0.483)
95 % CI [mg test item/L]:	n.d.
NOEL [mg test item/L]: NOEC   [mg test item/L]:	≥ filtrate of 100  (≥ 0.483)
LOEL [mg test item/L]: LOEC   [mg test item/L]:	> filtrate of 100  (> 0.483)

Values refer to nominal loading rates; the values in brackets refer to time weighted average concentrations
CI: Confidence interval; n.d.: not determinable; NOEC and LOEC were determined directly from the raw data

Analytical Results

Table 3:  Results for the Determination of the Test Item in the Test Samples

Sample Description	Sampling Age		Concentration found	Concentration Calculated	Concentration Nominal	% of nominal	Time weighted average concentration
[mg test item/L]	[day]	[h]	[mg test item/L]	[mg test item/L]	[mg test item/L]		[mg test item/L]
Control (untreated)	0	0	<LOD	n.a.	0.000	n.a.
	1	24	<LOD	n.a.	0.000	n.a.
	1	0	<LOD	n.a.	0.000	n.a.
	2	24	<LOD	n.a.	0.000	n.a.
Control	0		<LOD	n.a.	0.000	n.a.
	0		<LOD	n.a.	0.000	n.a.
	1		<LOD	n.a.	0.000	n.a.
	1		<LOD	n.a.	0.000	n.a.
	1		<LOD	n.a.	0.000	n.a.
	1		<LOD	n.a.	0.000	n.a.
	1		<LOD	n.a.	0.000	n.a.
	2		<LOD	n.a.	0.000	n.a.
	2			n.a.	0.000	n.a.
Filtrate of 40	0	0	0.067	0.671	40.000	2
Filtrate of 40	0	0	0.056	0.562	40.000	1
Filtrate of 40	1	24	0.045	0.454	40.000	1
Filtrate of 40	1	24	0.048	0.482	40.000	1
Filtrate of 40	1	0	0.059	0.587	40.000	1
Filtrate of 40	1	0	0.057	0.566	40.000	1
Filtrate of 40	2	24	0.027	0.266	40.000	1
Filtrate of 40	2	24	0.029	0.239	40.000	1
					Time weighted average (n=8)		0.475
Filtrate of 100	0	0	0.031	0.615	100.00	1
Filtrate of 100	0	0	0.032	0.634	100.00	1
Filtrate of 100	1	24	<LOD	n.a.	0.00	n.a.
Filtrate of 100	1	24	<LOD	n.a.	0.00	n.a.
Filtrate of 100	1	0	0.032	0.633	100.00	1
Filtrate of 100	1	0	0.032	0.633	100.00	1
Filtrate of 100	2	24	0.017	0.332	100.00	0.3
Filtrate of 100	2	24	0.020	0.391	100.00	0.4
					Time weighted average (n=6)		0.483

 

Table 4: Validity criteria

Criterion from the guideline	Outcome	Validity criterion fulfilled
In the control, including the control containing the solubilising agent, not more than 10% of the daphnids should have been immobilized.	0%	Yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	7.8 mg O2/L	Yes

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.