N,N'-[(methylimino)bis(trimethylene)]bis(stearamide)

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:

2018-07-04 to 2018-07-06

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)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

At the start of the exposure and at the renewal (0 and 24 hours), samples of the fresh media were taken after preparation of the limit concentration, diluted with Tetrahydrofuran containing 0.2% formic acid (dilution factor 2) and analyzed.
At the renewal and at the end of the exposure (24 and 48 hours), samples of the 24-hours old media were taken directly from the test vessels, diluted with Tetrahydrofuran containing 0.2% formic acid (dilution factor 2) and analyzed.
All samples were stored at room temperature until the start of analysis, if necessary. Prepared samples were stored at room temperature until analysis.

Vehicle:

yes

Remarks:

Tetrahydrofuran + 0.1% formic acid

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: For the preparation of the limit concentration of the test item N,N’-[(methylimino)bis(trimethylene)]bis(stearamide) a stock solution of 1 g test item/L was prepared in the solvent Tetrahydrofuran containing 0.1% formic acid (THF+FA).
The stock solution was treated with ultrasound for 60 minutes at room temperature.
The limit test item concentration was prepared by adding 0.1 mL/L of the appropriate stock solution to the dilution water.
The solution was mixed by manual agitation and used for testing.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone: STRAUS
- Source: continuous laboratory cultures. (Origin: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu), 14195 Berlin, Germany
- Feeding during test: The daphnids were not fed during the study.


ACCLIMATION
- Acclimation period: Acclimatization was not necessary, because the composition of the dilution water was equivalent to the culture medium.
- Type and amount of food: Mix of unicellular green algae, e.g. Pseudokirchneriella subcapitata and Desmodesmus subspicatus.
- Feeding frequency: The daphnids were fed at least 5 times per week ad libitum

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

245 - 270 mg CaCO3/L

Test temperature:

19.1 - 19.2 °C

pH:

7.75 - 8.08

Dissolved oxygen:

8.84 - 8.99 mg/L

Conductivity:

611 -615 µS/cm

Nominal and measured concentrations:

0.100 mg/L nominal (0.103 mg/L measured geometric mean)

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (4 (ID) x 7 (H) cm), 50 mL capacity, loosely covered with watch glasses
- Aeration: no
- Renewal rate of test solution: The test solutions were renewed after 24 hours.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Ca/mg ratio: (245 - 270 mg CaCo3/L)
- Conductivity: 611 - 615 µS/cm


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16/8 hours light/dark cycle
- Light intensity: max. 1500 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilization was determined in all groups after 24 and 48 hours.

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
Testing of different solvents (data not shown) revealed the maximum possible concentration was 1 g/L in the solvent THF. Following the test guideline OECD 201, the maximum solvent use is 0.1 mL/L. Any modifications allowing for possible higher recoveries of the test item would contradict the conditions given in the guideline (i.e. temperature) or compromise the biological system (i.e. higher solvent doses). Inside the conditions of the test guideline and the necessary conditions for the biological system, a higher concentration than 0.1 mg test item/L cannot be achieved.
Therefore, the test item concentration of 0.1 mg/L is considered to represent the maximum solubility in test medium under test conditions.

Reference substance (positive control):

not required

Remarks:

Results of the most recent of the monthly performed reference tests (potassium dichromate)

Key result

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

> 0.108 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.108 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 0.108 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

act. ingr. (dissolved fraction)

Basis for effect:

mobility

Results with reference substance (positive control):

potassium dichromate
EC 50 = 2.03 mg/L (study performed: 2018 06-20 to 2018-06-21) (95 % conifidence limits 1.00 - 4.00 mg/L)

The study was performed according to OECD Guideline 202 (2004). The validity criteria were fulfilled:

·        In the control group, no daphnids were immobilized or showed any signs of disease or stress, e.g. discoloration or unusual behavior such as trapping on the surface of the water, during the 48-hour test

period (required: not more than 10% of the daphnids in the control).

·        The dissolved O₂concentration in the 24-hours old media was≥8.22 mg/L (required: > 3 mg/L in the 24-hours old media) in the limit concentration, in the solvent control and in the control.

Validity criteria fulfilled:

yes

Conclusions:

The test item N,N’ [(methylimino)bis(trimethylene)]bis(stearamide) caused no effect to Daphnia magna up to the limit of solubility in the test medium.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test item N,N’‑[(methylimino)bis(trimethylene)]bis(stearamide) were determined according to OECD 202 (2004).

The test item is a yellow solid with a low water solubility of 10 - 500 µg/L. In the definitive test the solvent Tetrahydrofuran containing 0.1% formic acid (THF+FA) was used as it helps dissolving the test item in the test medium at the limit of the water solubility. As observed in the range finding test, the test item is insoluble / instable in the test medium and under test conditions and, therefore, the use of a solvent was necessary to prepare a defined test item concentration at the limit of the water solubility of the test item. A limit concentration of 0.100 mg/L of the test item was tested.

The study was performed over a period of 48 hours under semi-static conditions with a renewal of test solution after 24 hours as a worst case exposure. Twenty daphnids (divided into 4 replicates with 5 daphnids each) were exposed to the limit concentration, the solvent control and the control.

The limit concentration was colorless and visually clear throughout the exposure period.

The concentration of the test item N,N’-[(methylimino)bis(trimethylene)]bis(stearamide) was analytically verified via LC-MS/MS in the fresh media at the start of the exposure (0 hours and 24 hours) and in the corresponding old media and the renewal of the test solutions and at the end of the exposure (24 hours and 48 hours) in the limit concentration, the solvent control and the control.

The measured concentration of the test item in the fresh media (0 and 24 hours) was 64% and 306% of the nominal test item concentration and 101% and 69 % in the corresponding old media (24 and 48 hours). The geometric mean measured concentration is 0.108 mg/L. This concentration is considered to be the maximum solubility level of the test item in test medium under test conditions..

The effect levels given are based on the geometric mean measured concentration of the test item N,N’-[(methylimino)bis(trimethylene)]bis(stearamide):

EC10/ EC50/ EC10024 hours: > 0.108 mg/L

EC10/ EC50/ EC10048 hours: > 0.108 mg/L

The validity criteria of the test guidelines were fulfilled.

The test itemN,N’‑[(methylimino)bis(trimethylene)]bis(stearamide) caused no effect to Daphnia magna up to the limit of solubility in the test medium and under the test conditions.

 

Description of key information

N,N’[(methylimino)bis(trimethylene)]bis(stearamide) caused no effect to Daphnia magna up to the limit of solubility.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.108 mg/L

Additional information

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test item N,N’‑[(methylimino)bis(trimethylene)]bis(stearamide) were determined according to OECD 202 (2004).

The test item is a yellow solid with a low water solubility of 10 - 500 µg/L. In the definitive test the solvent Tetrahydrofuran containing 0.1% formic acid (THF+FA) was used as it helps dissolving the test item in the test medium at the limit of the water solubility. As observed in the range finding test, the test item is insoluble / instable in the test medium and under test conditions and, therefore, the use of a solvent was necessary to prepare a defined test item concentration at the limit of the water solubility of the test item. A limit concentration of 0.100 mg/L of the test item was tested.

The study was performed over a period of 48 hours under semi-static conditions with a renewal of test solution after 24 hours as a worst case exposure. Twenty daphnids (divided into 4 replicates with 5 daphnids each) were exposed to the limit concentration, the solvent control and the control.

The limit concentration was colorless and visually clear throughout the exposure period.

The concentration of the test item N,N’-[(methylimino)bis(trimethylene)]bis(stearamide) was analytically verified via LC-MS/MS in the fresh media at the start of the exposure (0 hours and 24 hours) and in the corresponding old media and the renewal of the test solutions and at the end of the exposure (24 hours and 48 hours) in the limit concentration, the solvent control and the control.

The measured concentration of the test item in the fresh media (0 and 24 hours) was 64% and 306% of the nominal test item concentration and 101% and 69 % in the corresponding old media (24 and 48 hours).

The geometric mean measured concentration is 0.108 mg/L. This concentration is considered to be the maximum solubility level of the test item in test medium under test conditions..

The effect levels given are based on the geometric mean measured concentration of the test item N,N’-[(methylimino)bis(trimethylene)]bis(stearamide):

EC₁₀/ EC₅₀/ EC₁₀₀24 hours: > 0.108 mg/L

EC₁₀/ EC₅₀/ EC₁₀₀48 hours: > 0.108 mg/L

The validity criteria of the test guidelines were fulfilled.

 

The test item N,N’‑[(methylimino)bis(trimethylene)]bis(stearamide)caused no effect to Daphnia magna up to the limit of solubility in the test medium and under the test conditions.