Sodium N-methyl-N-(1-oxotetradecyl)aminoacetate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 Sep 2012 - 08 Mar 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Water samples were taken from the control and each test group (replicates R1 – R4 pooled) at 0 and 48 h for quantitative analysis. Duplicate samples were taken and stored at approximately -20 °C for further analysis if necessary. Samples at the No Observed Effect Concentration and above only were analyzed.
- Sample storage conditions before analysis: The samples were stored at approximately -20 °C prior to analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: An amount of test item (1100 mg) was dispersed in 11 liters of reconstituted water with the aid of a propeller stirrer at a rate of approximately 1500 rpm for a period of 24 hours. After stirring, any undissolved test item was removed via filtration using a 0.2 µm Gelman Acrocap filter (initial approximate 100 mL discarded to pre-condition the filter) to give the 100% v/v saturated solution test concentration. Aliquots (20, 64, 200 and 640 mL) of the 100% v/v saturated solution test concentration were each separately added to a final volume of 2 liters of reconstituted water to give further test concentrations of 1.0, 3.2, 10 and 32% v/v saturated solution. Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
- Eluate: no
- Differential loading: no
- Controls: yes, test medium control

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: in-house laboratory culture
- Age at study initiation (mean and range, SD): < 24 h
- Method of breeding: Adult Daphnia were maintained in 150 mL glass beakers containing Elendt M7 medium in a temperature controlled room at approximately 20 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods. Each culture was fed daily with a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension. Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.
- Feeding during test: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20 - 21 °C

pH:

8.1 - 8.5

Dissolved oxygen:

> 90% air saturation

Nominal and measured concentrations:

nominal: control, 1, 3.2, 10, 32, 100% v/v saturated solution
measured: control: < LOQ; 32% v/v: 1.92 mg/L (0 h) and 1.44 mg/L (48 h); 100% v/v: 5.43 mg/L (0 h) and 4.78 mg/L (48 h)

Details on test conditions:

TEST SYSTEM
Test vessel
- Type (delete if not applicable): covered to reduce evaporation
- Material, size, headspace, fill volume: glass; size: 250 mL; headspace: 0 mL; fill volume: approximately 250 mL
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Photoperiod: 16 h light and 8 h dark
- Light intensity: 509 to 515 lux

EFFECT PARAMETERS MEASURED: Any immobilization or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Range finding study
- Test concentrations: 0.1, 1, 10, 100% v/v saturated solution
- Results used to determine the conditions for the definitive study: No immobilization was observed at the test concentrations of 0.10 and 1.0% v/v saturated solution. However, immobilization was observed at 10 and 100% v/v saturated solution. Chemical analysis of the freshly prepared media at 0 hours for the 1.0, 10 and 100% v/v saturated solution test concentrations showed measured concentrations of 0.077, 0.56 and 5.7 mg/L respectively. Analysis of the old media at 48 hours for the 1.0, 10 and 100% v/v saturated solution test concentrations showed measured concentrations of 0.0072, 0.41 and 6.3 mg/L respectively. Whilst a slight decline in measured concentration was observed for the 1.0% v/v saturated solution, this was not thought to affect the validity of the result as the No Observed Effect Concentration for the definitive test was above this concentration. However, the measured concentrations for the 10 and 100% v/v saturated solution test concentrations indicated that the test item was stable under test conditions.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.7 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

5.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.9 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% Confidence limits: 1.7 - 5.1 mg/L

Details on results:

- Mortality of control: 0%
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: The test preparations were observed to be clear colorless solutions for the duration of the test.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50/LC50: EC50 (48 h): 0.45 mg/L (95% CL: 0.42 - 0.48 mg/L)

Table 1: Cumulative Immobilization data in the definitive test

Nominal concentration [% v/v saturated solution]	Cumulative Immobilized Daphnia (Initial Population: 5 per replicate)
	24 h						48 h
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4	Total	%
Control	0	0	0	0	0	0	0	0	0	0	0	0
1.0	0	0	0	0	0	0	0	0	0	0	0	0
3.2	0	0	0	0	0	0	0	0	0	0	0	0
10	0	0	0	0	0	0	0	0	0	0	0	0
32	0	0	0	0	0	0	0	0	0	0	0	0
100	5	5	5	5	20	100	5	5	5	5	20	100

Test samples at the No Observed Effect Concentration and above only were analyzed. Analysis of the fresh media test preparations at 0 hours for the 32 and 100% v/v saturated solution test concentrations showed measured concentrations of 1.9 and 5.4 mg/L respectively. Analysis of the old media at 48 hours for the 32 and 100% v/v saturated solution test preparations showed measured concentrations of 1.4 and 4.8 mg/L respectively. Given the slight variation in measured test concentrations it was considered justifiable to base the results on the mean measured test concentrations of the test media in order to give a "worst case" analysis of the data.

Validity criteria fulfilled:

yes

Description of key information

EC50 (48 h) = 2.9 mg/L for Daphnia magna (OECD 202)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.9 mg/L

Additional information

Short-term toxicity of Sodium N-methyl-N-(1-oxotetradecyl)aminoacetate (CAS 30364-51-3) towards aquatic invertebrates was investigated in one study according to OECD Guideline 202 and GLP (Harlan, 2013). Daphnia magna was exposed to nominal, filtered test concentrations of 1, 3.2, 10, 32 and 100 % v/v saturated solution for 48 h. Analytical measurements of test concentrations using HPLC-MS resulted in significantly lower measured concentrations (1.7 mg/L and 5.1 mg/L) with respect to nominal concentrations (32 and 100 % v/v saturated solution). Thus, the effect concentrations were based on the arithmetic mean measured concentrations. Effects on daphnids mobility were only observed at the highest concentration (5.1 mg/L, measured), leading to an EC50 (48 h) of 2.9 mg/L (arith. mean measured).