L-Glutamic acid, N-coco acyl derivs., disodium salts

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001-01-15 to 2001-01-31

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with acceptable restrictions. No coefficient of variation was reported for the control for both endpoints (growth rate/biomass).

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Samples of the 7.76, 37.6 and 182 mg/L treatments were taken after 0, 24, 48 and 72 h.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A clear stock solution with a nominal concentration of 2 g product/L deionized water was prepared. Appropriate volumes were taken from the constantlly stirred solution and pipetted into the test vessels. 10 mL of a 10-fold concentrate of the test medium were pipetted to each test vessel and then each test solution was filled up to a final volume of 100 mL with deionized water.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Source: Pflanzenphysiologisches Institut der Universittät Göttingen, delivered on 2000-09-21

ACCLIMATION
- Acclimation period: Preincubation about 3-4 days in test medium
- Culturing media and conditions: same as test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24.5 °C

pH:

after 0 h: 7.8
after 72 h: 7.9 - 8.5

Nominal and measured concentrations:

Nominal concentration: 0, 3.53, 7.76, 17.1, 37.6, 82.6, 182, 400 mg product/L.
The base analysis yielded in 186 mg TOC/g product resulting in 0, 0.66, 1.44, 3.18, 6.99, 15.36, 33.85, 74.4 mg TOC/L. Three of the eight concentrations (1.44, 6.99 and 33.85 mg TOC/L) were determined via TOC-Analysis. Mean measured concentrations were 1.42, 6.5 and 28.4 mg TOC/L with a mean substance recovery of 91.9 %.

Details on test conditions:

TEST SYSTEM
- Test vessel: conical flasks
- Material: glass; Size: 300 mL; Fill volume: 100 mL
- Initial cells density: 10^4 cells/mL
- Control end cells density: 1.1x10^6 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes, according to guideline

TEST MEDIUM / WATER PARAMETERS
- Source of dilution water: deionized water
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH was measured daily and the temperature range was recorded

OTHER TEST CONDITIONS
- Photoperiod: continuous illumination
- Light intensity and quality: daylight spectrum with approximately 2000 lux

EFFECT PARAMETERS MEASURED: Algal cell concentrations were measured after 24, 48 and 72 h test duration.
- Determination of cell concentrations: Coulter-Counter

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.2

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

32.56 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

biomass

Remarks on result:

other: converted to active matter

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

11.25 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

biomass

Remarks on result:

other: converted to active matter

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

38 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

110 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 750 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Reported statistics and error estimates:

Effect concentrations were calculated using probit method. A t-test was performed to obtain to EC0.

After 0, 24, 48 and 72 hours samples were taken from nominal concentrations of 7.76 mg/L, 37.6 mg/ and 182 mg/L (according to the base analysis which yielded in 186 mg TOC/g product: 1.44, 6.99 and 33.85 mg TOC/L, respectively). Mean measured concentrations were 1.42, 6.5 and 28.4 mg TOC/L. The mean substance recovery was 91.9 % of the nominal values, therefore the nominal concentrations were taken into account for the calculation of the EC-values.

Validity criteria fulfilled:

yes

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

32.56 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

biomass

Description of key information

EC50 (72h) = 32.56 mg/L, NOEC (72h) = 11.25 mg/L (nominal, based on active matter) for Scenedesmus subspicatus (OECD 201, read across)

Key value for chemical safety assessment

EC50 for freshwater algae:

32.56 mg/L

EC10 or NOEC for freshwater algae:

11.25 mg/L

Additional information

No studies investigating the toxicity of l-Glutamic acid, N-coco acyl derivs., disodium salts (CAS No. 68187-30-4) to algae are available. Thus, available data for the source substance l-Glutamic acid, N-coco acyl derivs., monosodium salts (CAS No. 68187-32-6) was used in a read across approach. The read across is considered valid as both substances are structurally identical (solely differing in the degree of deprotonation being di- and monosodium salts, respectively), which assume very similar physico-chemical properties resulting in identical environmental behavior and ecotoxicity.

The read across key study was performed according to GLP and OECD guideline 201 using Scenedesmus subspicatus as test organism (Cognis, 2001). A 29.6 % solution of the substance in water was tested. Nominal concentrations between 3.53 and 400 mg/L (based on test material) were tested over a period of 72 h. The 72h-EC50 (based on active matter) is determined to be 32.56 mg/L and the 72h-NOEC is determined to be 11.25 mg/L. Due to the very high structural similarity, this result can also be considered for l-Glutamic acid, N-coco acyl derivs., disodium salts (CAS No. 68187-30-4).