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

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-02-03 - 2015-10-06

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)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

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.
- Chemical Name: Dodecanamide, N,N-dimethyl-
- 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: At the start of the exposure (0 h) samples from vessels without daphnids and at the end of the exposure (48 h) samples from vessels with daphnids were analyzed.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance is sparingly soluble in water, therefore a stock solution was prepared using a slow-stir liquid-liquid saturator technique according to the following procedure: The stock solution (1 mg/L) was prepared by pipetting 2 mg (2.3 µL based on the density 0.864 g/mL) test substance into 2 L of test medium and stirring for about one day. The test vessels were saturated with test solution for approx. 1 day before the start of exposure. Fresh test solutions were prepared and renewed daily and the test was performed in closed test vessels to maximize the exposure to all soluble components of the test substance. All test solutions were visibly clear over the exposure period.
- Controls: yes. Blank control and positive control.
- Evidence of undissolved material: No undissolved test substance was observed after 1 day stirring. The lower test concentrations were prepared diluting this stock solution. The stock and test solutions appeared colorless-clear.

Test organisms (species):

Daphnia magna

Details on test organisms:

EST ORGANISM
- Common name: Daphnia magna STRAUS
- Source: The clone of Daphnia magna STRAUS 1820 used was supplied by the Institut National de Recherche Chimique Appliquée, France, in 1978. From this date on this clone was cultured and bred continuously in the Ecotoxicology Laboratory of Experimental Toxicology and Ecology, BASF SE, Ludwigshafen Germany.
- Age at study initiation: < 24 hours (at least 3rd brood progeny)
- Method of breeding: Daphnia brood stock are kept in mass cultures consisting of approx. 20–30 parthenogenetically reproducing females for a maximum of 4 weeks. All individuals in each mass culture originate from a single female and are thus genetic clones. After approximately 14 days the adults have produced at least 3 broods and the young can be used in tests. Offspring are removed from the mass cultures at least once daily during the normal work week to ensure that young daphnia are <24-h old (first instar) at test initiation. Only young from healthy cultures without signs of stress are used for testing.
- Feeding during test: No feeding during the exposure period

ACCLIMATION
- Acclimation conditions (same as test or not): The Daphnia are cultured under the identical conditions as the test including test media (Elendt M4), water quality, and temperature (20 ± 1°C).
- Type and amount of food: live unicellular algae (Desmodesmus subspicatus) cultured continuously at the test facility.
- Feeding frequency: continuosly

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

Not performed

Hardness:

- Total hardness: 2.20 – 3.20 mmol/L
- Acid capacity up to pH 4.3: 0.80 – 1.00

Test temperature:

19.7 – 21.8 °C (continuous monitoring)

pH:

7.9 – 8.0

Dissolved oxygen:

8.3 – 8.9 mg/L

Salinity:

Conductivity: 550 - 650 µS/cm

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 0.046, 0.1, 0.22, 0.46, 1.0 mg/L (nominal concentrations based on test substance density without correction for purity)
- Measured concentrations: 0 (control), 0.045, 0.095, 0.205, 0.425, 0.975 mg/L (mean measured concentrations)

Details on test conditions:

TEST SYSTEM
- Test vessel: Sealed glass flasks (nominal volume 50 mL)
- Test volume: ca. 50 mL
- Aeration: To assure optimal dissolved oxygen levels, the M4 medium was aerated for approximately 24 hours prior to use but there was no aeration during the test period.
- Type of system: static-renewal exposure via test water
- Renewal rate of test solution (frequency/flow rate): In order to insure constant exposure conditions this study was conducted as a static-renewal exposure. The renewal period was 24 hours.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 0
- Biomass loading rate: 5 animals / test vessel (0.1 animals/mL)

TEST MEDIUM / WATER PARAMETERS
- Test medium: A synthetic fresh water (Elendt M4) is used as media for culture and test purposes. For the composition of this M4 medium see OECD 202. The general properties of this medium are as follows.
Total hardness: 2.20 – 3.20 mmol/L
Acid capacity up to pH 4.3: 0.80 – 1.00 mmol/L
Molar ratio Ca:Mg: about 4:1
pH value: 7.5 – 8.5
Conductivity: 550 - 650 µS/cm
Total organic carbon: < 2 mg/L
- Culture medium different from test medium: No
- Intervals of water quality measurement: Throughout the test, the appearance of the test solutions and dissolution behavior of the test substance was observed and recorded daily in old and new test solutions. The chemical and physical parameters of the test medium (total hardness, acid capacity, pH, TOC and conductivity) were determined after aeration and prior to use in the test. The pH and dissolved oxygen content of the test solutions was measured after 0h and 24h (new test solutions) and after 24 h and 48h (old test solutions) in replicate 1 of each tested concentration. In addition, temperature was measured continuously during the whole exposure period in a separate vessel filled with water proximal to the test vessels.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light : 8 hours darkness
- Light intensity: About 207 – 743 lux at a wave length of 400 – 750 nm

EFFECT PARAMETERS MEASURED: Immobilization of daphnids after 0, 24 and 48 hours. In addition any abnormal behavior or appearance was documented.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: ≤ 2.2
- Range finding study: Yes
- Results used to determine the conditions for the definitive 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, 0.1, 0.22, 0.46, 1.0 mg/L (nominal concentrations based on test substance density without correction for purity)
- Measured concentrations: 0 (control), 0.045, 0.095, 0.205, 0.425, 0.975 mg/L (mean measured concentrations)

Reference substance (positive control):

yes

Remarks:

Sodium chloride (NaCl)

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

0.46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.313 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.22 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

0.425 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.29 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.205 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The water pH, temperature and dissolved oxygen were within acceptable guideline specifications. All measured concentrations deviated less than 20 % from the nominal concentration. Thus, the test substance was stable in solution under test conditions and nominal concentrations are an accurate representation of exposure levels maintained throughout the test period, therefore the effect concentrations are expressed relative to the nominal concentration.
The EC50 value based on mean nominal concentration was determined to be 0.313 mg/L and the NOEC value based on mean nominal concentration was determined to be 0.22 mg/L. The EC50 value based on mean measured concentration was determined to be 0.290 mg/L and the NOEC value based on mean measured concentration was determined to be 0.205 mg/L.
The toxicity results presented here are consistent with the results from preliminary tests. The results in this study are consistent with all validity criteria and the test is valid according to the guidelines of this study. No deviations from test guidelines or other incidents occurred during the course of the reported test which may have influenced the results.

Results with reference substance (positive control):

The EC50 (48h) of the reference substance sodium chloride was determined to be 4.78 g/L after 48 hours.
This result is within the range of 3.88 – 7.22 g/L and indicates that the culture of Daphnia magna used in this study was responding normally to toxic stress.

Reported statistics and error estimates:

For the statistical evaluation of the data and calculation of the EC50 the probit method (Finney, 1971) was used and performed with the commercial software "TOXRAT Professional 2.10" (ToxRat Solutions GmbH, Alsdorf, Germany).

Validity criteria fulfilled:

yes

Conclusions:

In the semi-static immobilization test, young Daphnia magna STRAUSS (< 24 h old) were exposed to the test item for 48 hours according to OECD 202 (2004). The EC50 value was determined to be nominal 0.313 mg test item/L.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test substance with a nominal loading of 0.046, 0.1, 0.22, 0.46 and 1.0 mg test item/L and a control (0 mg test item/L) were determined according to OECD 202 (2004) and Council Regulation (EC) No. 440/2008/C2 (2008) under GLP conditions. The corresponding mean measured concentrations of the test substance were determined to be 0 (control), 0.045, 0.095, 0.205, 0.425, 0.975 mg/L. The study encompassed 4 replicates per concentration and 1 replicate per control. The number of the organisms per vessel was 5. The mobility of the Daphnia was determined in a static-renewal (semi-static) 48-hour test by visual observation after 24 and 48 hours. The renewal period was 24 hours. The samples collected at start and at the end of the test (48 hours) were analyzed via capillary gas chromatography - mass spectrometry (GC-MS). The EC50 of the reference substance (sodium chloride) after 48 hours was determined to be 4.78 g test item/L. This result was within the range of 3.88 – 7.22 g/L and indicates that the culture of Daphnia magna used in this study was responding normally to toxic stress. The water pH, temperature and dissolved oxygen were within acceptable guideline specifications. The toxicity results presented here were consistent with the results from preliminary tests. Immobilization (mortality) and sublethal effects were observed daily. The analytically determined concentrations of the test substance in the test solutions were within ± 20% of the nominal concentrations, therefore the effect concentrations can be expressed relative to the nominal concentration for the evaluation of the test substance. The NOEC was determined to be 0.22 mg test item/L, the Lowest Concentration with 100% immobile was determined to be 0.46 mg test item/L and the EC50 value was determined to be 0.313 mg test item/L. All reported results refer to the nominal concentrations.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Study period:

2015-02-03 - 2015-10-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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 202 (Daphnia sp. Acute Immobilisation Test)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

0.46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.313 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.22 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

0.425 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.29 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.205 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Description of key information

48-h EC50 = 0.313 mg/L (Daphnia magna; N,N-dimethyldodecanamide)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.313 mg/L

Additional information

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test substance, N,N-dimethyldodecanamide, with a nominal loading of 0.046, 0.1, 0.22, 0.46 and 1.0 mg test item/L and a control (0 mg test item/L) were determined according to OECD 202 (2004) and Council Regulation (EC) No. 440/2008/C2 (2008) under GLP conditions. The corresponding mean measured concentrations of the test substance were determined to be 0 (control), 0.045, 0.095, 0.205, 0.425, 0.975 mg/L. The study encompassed 4 replicates per concentration and 1 replicate per control. The number of the organisms per vessel was 5. The mobility of the Daphnia was determined in a static-renewal (semi-static) 48-hour test by visual observation after 24 and 48 hours. The renewal period was 24 hours. The samples collected at start and at the end of the test (48 hours) were analyzed via capillary gas chromatography - mass spectrometry (GC-MS). The EC50 of the reference substance (sodium chloride) after 48 hours was determined to be 4.78 g test item/L. This result was within the range of 3.88 – 7.22 g/L and indicates that the culture of Daphnia magna used in this study was responding normally to toxic stress. The water pH, temperature and dissolved oxygen were within acceptable guideline specifications. The toxicity results presented here were consistent with the results from preliminary tests. Immobilization (mortality) and sublethal effects were observed daily. The analytically determined concentrations of the test substance in the test solutions were within ± 20% of the nominal concentrations, therefore the effect concentrations can be expressed relative to the nominal concentration for the evaluation of the test substance. The NOEC was determined to be 0.22 mg test item/L, the Lowest Concentration with 100% immobile was determined to be 0.46 mg test item/L and the EC50 value was determined to be 0.313 mg test item/L. All reported results refer to the nominal concentrations.

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