Reaction mass of N,N-dimethyldodecanamide and N,N-dimethyltetradecanamide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-02-16 - 2015-09-17

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Test substance concentration not high enought to determine LC50-value.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test substance: N,N Dimethyldodecane-1-amide
- Test substance No.: 13/0555-1
- Batch-Identification: 0009565072
- CAS No.: 3007-53-2
- Purity: N,N-Dimethyldodecanamide: 95.9 area-%; dodecanoic acid (lauric acid): 2.26 area-%
- Homogeneity: Homogeneous
- Storage stability: The stability of the test substance under storage conditions over the test period was guaranteed by the sponsor, and the sponsor holds this responsibility.
- Date of production: 15-03-2013
- Expiry date: 15-03-2016
- Physical state/ Appearance: liquid/colorless, clear
- Density: 0.864 g/mL
- Water solubility: 28.02 mg/L at 20°C
- Storage conditions: The test substance was stored at ambient temperature.

Analytical monitoring:

yes

Details on sampling:

- Sample preparation: The test samples were delivered as aliquots of 20 mL in sealed vials. After addition of a spatula tip of NaCI and 2 mL of ISTD solution, the vials were re-sealed and shaken for 120 min for extraction. After phase separation, the organic layer was removed for analysis.
- Sampling method: The samples were measured after 0, 48 and 96 hours.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance is sparingly water soluble, therefore a stock solution was prepared using a slow-stir liquid-liquid saturator technique according to the following procedure: 20 L of test media (and a magnetic stir bar) was added into a glass aspirator bottle (approx. 20 L) with a bottom side-outlet attached to a stopcock. Prior to use the test substance container was shaken to ensure homogeneity. Then 46.3 µL (2 mg/L, considering density = 0.864 g/cm3) of the test substance was pipetted carefully on the water surface. The bottle was closed and the solution was stirred on a magnetic plate for about 1 day. The stirring was slow (approx. 100 rpm) so that no vortex formed. The required volume (approx. 12 L) of the stock solution was removed from the bottom of the bottle and visually inspected for the presence of any undissolved test substance.
The test substance may adsorb to test vessel walls, therefore the test vessels were conditioned with the corresponding test solution for 3 days before the start of exposure.
- Controls: The control water was prepared similarly but without test substance and in 10 L aquaria.
- Evidence of undissolved material: No undissolved test substance was observed after 24 hours stirring.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebrafish (Danio rerio)
- Source: The fish were hatched at the testing facility (BASF SE, Ludwigshafen, Germany)
- Age at study initiation: Approx. 8 months
- Length at study initiation (mean and range): 2.9 cm (2.8 cm – 3.1 cm)
- Weight at study initiation (mean and range): 0.18 g (0.14 g – 0.21 g)
- Feeding during test: None

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions: The fish were acclimatized to the testing conditions including test water, temperature and light regime.
- Housing: Prior to testing, the batch of fish are housed in an glass tank (approx. 45 L) receiving a continuous supply of fresh test water.
- Photoperiod: 16 hours light, 8 hours dark
- Water quality: The water used for housing and test purposes is non-chlorinated charcoal filtered drinking water (Frankenthal, Germany) mixed with deionized water and aerated to achieve the following water characteristics. The mixed test water is sanitized by UV treatment prior to entering the aquaria.
- Total hardness: Approx. 1 mmol/L = 100 mg/L CaCO3
- Conductivity: Approx. 250 µS/cm (at 25°C)
- Ca content: Approx. 40 mg/L
- Mg content: Approx. 5 mg/L
- Acid capacity: Approx. 2.5 mmol/L
- pH-value: 7.5 – 8.5
- Oxygen content: > 80 % saturation
- TOC: Generally < 2 mg/L
- Temperature: 23 ± 1°C
- Feeding frequency: Inicio ad libitum (additionally generally on workdays)
- Type and amount of food: Commercial fish diet ”Tetramin“ (manufacturer Tetra-Werke, Melle, Germany) daily ad libitum, additionally generally on workdays live juvenile brine shrimp (Artemia nauplii)
- Withdrawal of feed: No feeding from approximately 24 hours before start of exposure
- Medical treatment: None during acclimatization
- Mortality during the last week before start of exposure: 0 %

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

Not performed

Hardness:

Approx. 1 mmol/L = 100 CaCO3 mg/L

Test temperature:

22 °C

pH:

7.5 - 8.5

Dissolved oxygen:

> 60 % (5.3 mg/L)

Salinity:

- Conductivity: Approx. 250 µS/cm (at 25 °C)
- Ca content: Approx. 40 mg/L
- Mg content: Approx. 5 mg/L
- Acid capacity: Approx. 2.5 mmol/L

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 0.046, 0.10, 0.22, 0.46, 1.0 mg/L (nominal concentrations based on test substance density without a correction for purity)
- Measured concentrations: 0 (control), 0.04, 0.08, 0.19, 0.36, 0.88 mg/L (mean initial measured concentrations)

Details on test conditions:

TEST SYSTEM
- Test vessel: Approx. 10 L stainless steel aquaria (29 x 21 x 22 cm)
- Test volume: 10 L
- Aeration: yes
- Route of exposure: Semi-static exposure via test water
- Renewal rate of test solution: The renewal period was 48 hours.
- 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): 0
- Biomass loading rate: 7 fish/ test vessel, max. 0.13 g fish/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: charcoal-filtered drinking water from the municipal water works of the city of Frankenthal (Germany) mixed with deionised water.
- Hardness: ca. 100 CaCO3 mg/L
- Ca/mg ratio: 40 / 5
- Conductivity: Approx. 250 µS/cm (at 25°C)
- Culture medium different from test medium: no
- Intervals of water quality measurement: Temperature, pH and dissolved oxygen were measure after 0, 1, 2 3 and 4 days.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16h light, 8h dark
- Light intensity: Approx. 80 – 328 Lux (The light intensity was determined in regular intervals at the surface of the aquaria.)

EFFECT PARAMETERS MEASURED: Mortality and toxic signs after 1, 6, 24, 48, 72 and 96 hours.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: ≤ 2.2
- Range finding study: In a preliminary semi-static range finding test (experimental conduct in accordance with GLP, without a GLP status) the 48 hour EC50 was estimated between 0.1 and 0.3 mg/L.
- Test concentrations:
Nominal concentrations: 0 (control), 0.046, 0.10, 0.22, 0.46, 1.0 mg/L (nominal concentrations based on test substance density without a correction for purity)
Measured concentrations: 0 (control), 0.04, 0.08, 0.19, 0.36, 0.88 mg/L (mean initial measured concentrations)

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

> 0.88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 0.88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

There were no toxic effects observed in any treatment group during this test. The median lethal concentration (LC50) after 1, 6, 24, 48, 72 and 96 hours were based on the nominal concentrations and based on the mean of the initial analytically determined concentrations.The 96h-LC50 and 96h-NOEC were determined to be greater than 1 mg/L based on the nominal concentrations and greater than 0.88 mg/L based on the initial mean measured concentrations.

Results with reference substance (positive control):

Not performed

Reported statistics and error estimates:

No statistical analysis was carried out since no lethality was observed up to the highest tested concentration.

Validity criteria fulfilled:

yes

Conclusions:

In the semi-static short-term toxicity to fish test according to OECD 203 (1992), the 96-hour LC50 of the test substance for Zebrafish (Danio rerio) was determined to be greater than 0.88 mg test item/L (value based on mean initial measured concentration).

Executive summary:

The acute toxicity of the test substance to fish Zebrafish (Danio rerio) was determined according to OECD 203 (1992) and EU Council Regulation No. 440/2008/C.1 (2008) under GLP conditions. This study encompassed one treatment group for the dose rates of the test item and one replicate for the control. Each group contained 7 individuals. The acute toxicity to unfed juvenile Zebrafish (Danio rerio) was determined in an aerated, semi-static, 96-hour test under 48 hours renewal conditions. The test fish were observed after 1, 6, 24, 48, 72 and 96 hours test duration for sublethal effects and mortality. Dead fish were removed at least once daily and discarded. The samples of the test medium were analysed via capillary gas chromatography - mass spectrometry (GC-MS) at start of the test and after 48 and 96 hours.

The nominal test concentrations based on the test substance density without a correction for purity were 0 (control), 0.046, 0.10, 0.22, 0.46, 1.0 mg/L and the mean initial measured concentrations were determined to be 0 (control), 0.04, 0.08, 0.19, 0.36, 0.88 mg/L. The concentrations declined over the 48-h renewal interval to undetectable levels. Consequently, a reliable mean measured concentration could not be calculated from the analytical measurements. The initial measured concentrations were consistent between the two renewal intervals and all individual values were within ± 20 % of the mean. Test concentrations did not remain within ± 20 % of the nominal or mean measured values over the test period and this validity criterion identified by the test guideline was not met. All other test validity criteria required by the test guideline were met. Reasonable efforts were taken to maintain stable test concentrations, including preconditioning the test vessels and using a semi-static exposure. Excessive test substance loss was not observed in other aquatic studies (acute Daphnia and algae growth) with this substance. The test substance loss in this fish test may be due to rapid biodegradation from flora introduced with the test fish. The water pH, temperature and dissolved oxygen were within acceptable guideline specifications.

There were no toxic effects observed in any treatment group during this test. The 96-hour LC50 was determined to be greater than 1 mg/L based on the nominal concentrations and greater than 0.88 mg/L based on the initial mean measured concentrations.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2015-02-16 - 2015-09-17

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Test substance concentration not high enought to determine LC50-value.

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The chemical characterisation and physico-chemical properties of the source and target substances support read-across between the substance for acute ecotoxicity endpoints.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source: N,N-dimethyldodecanamide [EC 221-117-5; CAS 3007-53-2].
Target: Reaction mass of N,N-dimethyldodecanamide and N,N-dimethyltetradecanamide [EC not assigned; CAS not assigned]. Details of composition provided in section 1.2.
3. ANALOGUE APPROACH JUSTIFICATION
The source substance constitutes 65-80 %w/w of the target substance. The other main constituent (20-35 %w/w) has identical functional groups and an additional two carbons in the alkyl chain. The similarity of the measured water solubility and log Kow for the source substance and the measured water solubility and estimated log Kow for the target substance suggests that both substances will behave similarly in aquatic systems and that data available for the source may be used to read across to the target.
4. DATA MATRIX
Source: Water solubility = 28.08 mg/L (OECD TG 105); Log Kow = 5.2 (OECD TG 117); Readily biodegradable (86% after 28 days; OECD TG 301B);
96-h LC50 > 0.88 mg/L (Danio rerio; OECD TG 203); 48-h EC50 = 0.313 mg/L (Daphnia magna; OECD TG 202); 72-h ErC50 = 0.805 mg/L; 72-h NOErC = 0.351 mg/L (Pseudokirchneriella subcapitata; OECD TG 201), 3-h EC50 = 170 mg/L; EC10 = 20 mg/L (activated sewage sludge; OECD TG 209)
Target: Water solubility = 43.61 mg/L (EU Method A.6); Log Kow >4.6 (estimate from solubility in n-octanol and water)
Ecotoxicological endpoints – no data

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

> 0.88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 0.88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Description of key information

96-hour LC50 > 0.88 mg/L (Danio rerio; N,N-dimethyldodecanamide)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.88 mg/L

Additional information

The acute toxicity of the test substance, N,N-dimethyldodecanamide, to fish Zebrafish (Danio rerio) was determined according to OECD 203 (1992) and EU Council Regulation No. 440/2008/C.1 (2008) under GLP conditions. This study encompassed one treatment group for the dose rates of the test item and one replicate for the control. Each group contained 7 individuals. The acute toxicity to unfed juvenile Zebrafish (Danio rerio) was determined in an aerated, semi-static, 96-hour test under 48 hours renewal conditions. The test fish were observed after 1, 6, 24, 48, 72 and 96 hours test duration for sublethal effects and mortality. Dead fish were removed at least once daily and discarded. The samples of the test medium were analysed via capillary gas chromatography - mass spectrometry (GC-MS) at start of the test and after 48 and 96 hours.

The nominal test concentrations based on the test substance density without a correction for purity were 0 (control), 0.046, 0.10, 0.22, 0.46, 1.0 mg/L and the mean initial measured concentrations were determined to be 0 (control), 0.04, 0.08, 0.19, 0.36, 0.88 mg/L. The concentrations declined over the 48-h renewal interval to undetectable levels. Consequently, a reliable mean measured concentration could not be calculated from the analytical measurements. The initial measured concentrations were consistent between the two renewal intervals and all individual values were within ± 20 % of the mean. Test concentrations did not remain within ± 20 % of the nominal or mean measured values over the test period and this validity criterion identified by the test guideline was not met. All other test validity criteria required by the test guideline were met. Reasonable efforts were taken to maintain stable test concentrations, including preconditioning the test vessels and using a semi-static exposure. Excessive test substance loss was not observed in other aquatic studies (acute Daphnia and algae growth) with this substance. The test substance loss in this fish test may be due to rapid biodegradation from flora introduced with the test fish. The water pH, temperature and dissolved oxygen were within acceptable guideline specifications.

There were no toxic effects observed in any treatment group during this test. The 96-hour LC50 was determined to be greater than 1 mg/L based on the nominal concentrations and greater than 0.88 mg/L based on the initial mean measured concentrations.

The results of this study are read-across to Reaction mass of N,N-dimethyldodecanamide and N,N-dimethyltetradecanamide.