N,N-bis(2-ethylhexyl)formamide

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

9 June - 13 Jun 2020

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No analytical measurements of the test substance concentrations were conducted Only 4 test substance concentrations were tested The solvent DMSO was used in concentrations >100 mg/L

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

2019

Deviations:

yes

Remarks:

No analytical monitoring of the test substance concentration was conducted

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N,N-bis(2-ethylhexyl)formamide

EC Number:

860-695-9

Cas Number:

88247-41-0

Molecular formula:

C17H35NO

IUPAC Name:

N,N-bis(2-ethylhexyl)formamide

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

yes

Remarks:

HCO-40 and Dimethyl sulfoxide

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Differential loading: 0 (control), 0.2, 0.5, 1.0, 2.0 mg/L
- Method: The test substance was added to Dimethylsulfoxide, mixed with a 50% (w/v) HCO-40/dimethylsulfoxide solution and again mixed with dimethyl sulfoxide to obtain the stock solution (stock solution concentration 10000 mg/L test substance). This was diluted in dilution water to the final test concentrations.
- Controls: A control including the used vehicles up to and exceeding the highest vehicle concentration in the test substance concentrations was used.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): PEG-40 hydrogenated castor oil; dimeythl sulfoxide
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)):
HCO-40: 4, 10, 20, 40 mg/L (for further details, please refer to Table 1 at "Any other information on results incl. tables")
Dimethyl sulfoxide: 16, 40, 79, 160 ppm (for further details, please refer to Table 1 at "Any other information on results incl. tables")
- Test concentration separation factor: 2
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): non reported

Test organisms

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: Medaka
- Source:Testing laboratory culture
- Length at study initiation (length definition, mean, range and SD): 2 ± 1 cm
- Weight at study initiation: approximately 0.1 g

ACCLIMATION
- Acclimation period: 1 June - 8 June 2020
- Acclimation conditions: Temperature and lighting same as test. Flow-through conditions
- Type and amount of food during acclimation: Tetramin, Tetra Werke; approximately 2% of body weight
- Feeding frequency during acclimation: daily. Feeding was suspended for 24 h before testing
- Health during acclimation: Mortality 1 week before testing < 5%

FEEDING DURING TEST
The medaka were not fed during the test

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Test temperature:

24 ± 1°C

Dissolved oxygen:

≥ 60% of the saturation (≥ 5 mg/L at 24°C)

Nominal and measured concentrations:

Nominal: 0.2, 0.5, 1.0, 2.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Aquarium
- Type: open (covered by plastic plate)
- Fill volume: 3 L
- Aeration: Continuous
- Renewal rate of test solution: 24 h renewal
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1


OTHER TEST CONDITIONS
- Photoperiod: 16 h light/8 h dark
- Light intensity:room light

EFFECT PARAMETERS MEASURED:
Cumulative mortality was measured after 24 h, 48 h, 72 h and 96 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Test concentrations: 0.2 - 0.5 - 1.0 - 2.0 mg/L

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.67 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: test substance concentrations not analytically measured

Details on results:

- Other abnormalities: none reported
- Mortality of control: 0%
- Other adverse effects control: none reported
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none reported

Any other information on results incl. tables

Sublethal observations / clinical signs:

Table 1: Preparation of Test Concentrations

Test substance concentration [mg/L]	HCO-40 concentration [mg/L]	Dimethyl sulfoxide concentration [ppm (v/v)]	Volume of stock solution*		Final Volume [L]
			Control [mL]	Treatment [mL]
0 (control)	40	160	0.6	-	3
0.2	4	16	-	0.06
0.5	10	40	-	0.15
1.0	20	79	-	0.3
2.0	40	158	-	0.6

* Stock solution concentrations = Test substance: 10000 mg/L (only for Treatment); HCO-40: 200000 mg/L

Table 2: Acute Toxicity (96 h)

Nominal concentration [mg/L]	Cumulative mortality [%]
	24 h	48 h	72 h	96 h
0 (Control)	0	0	0	0
0.2	0	0	0	0
0.5	0	0	0	14
1.0	0	43	86	100
2.0	100	100	100	100

Table 3: Validity criteria for OECD 203

Criterion from the guideline	Outcome	Validity criterion fulfilled
The mortality in the control(s) should not exceed 10% (or one fish if less than ten are used) at the end of the test	0%	Yes
The dissolved oxygen concentration must have been at least 60 per cent of the air saturation value throughout the test	≥60% of the saturation	Yes
There must be evidence that the concentration of the substance being tested has been satisfactorily maintained, and preferably it should be at least 80 of the nominal concentration throughout the test. If the deviation from the nominal concentration is greater than 20 per cent, results should be based on the measured concentration.	No analytical measurements of the test substance concentration were performed during the exposure period. No evidence on test substance concentration can be given.	No

Applicant's summary and conclusion

Validity criteria fulfilled:

no

Remarks:

please refer to Table 3 at "Any other information on results incl. tables"