L-Glutamine, L-alanyl-

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-09-21 to 2009-09-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

23 March 2006

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

24 August 2009

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all test concentrations after 0, 24, 48 and 72 h

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution was prepared with a nominal substance concentration of 1 g/L. The test solutions were prepared separately by dilution of the stock solution.
- Eluate: no
- Differential loading: no
- Controls: yes, test medium control

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: 86.81
- Source (laboratory, culture collection): obatined from "Sammlung von Algenkulturen", Göttingen (SAG), (Collection of Algae Cultures, Institute for Plant physiology), University of Göttingen, Germany.
- Method of cultivation: cultured at 25 ± 1 °C and 8000 ± 1000 Lux

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24.8 - 25.1 °C

pH:

7.52 - 816 after 0 h
8.45 - 9.98 after 72 h

Nominal and measured concentrations:

Nominal test substance concentrations: control, 6.25, 12.5, 25, 50 and 100 mg/L
Recovery rates based on DOC were > 90%

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks (300 mL), autoclaved for 15 min at 121 °C
- Type (delete if not applicable): closed with cotton-wool plugs
- Material, fill volume, headspace: glass, 100 mL, 200 mL
- Initial cells density: 5000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH after 0 and 72, Temperature at 0, 24, 48 and 72 h

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: continous illumination
- Light intensity and quality: 8000 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations: photometrically (spectrophotometer) after 0, 24, 48 and 72 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: no

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

41.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- Observation of abnormalities: After 48 h exposure the samples with algae, but not the blind values, showed turbidity at the concentrations 50 and 100 mg/L. After 72 h exposure blind values and the samples were turbid at 50 and 100 mg/L. Pre-test showed that the the turbidity did not conceal a potential inhibition of algal growth in the photometric measurement.

Results with reference substance (positive control):

Latest experiment with reference substance was 2009-04-17 to 2009-04-23. Test result: ErC50 (72 h): 0.9 mg/L

Reported statistics and error estimates:

ECx, NOEC and LOEC were calculated using ToxRat® Professional

Validity criteria fulfilled:

yes

Conclusions:

For the parameter yield the EyC50 value was > 100 mg/L and the EyC10 value was 41.4 mg/L after 72 h of exposure, based on nominal concentrations.
For the parameter growth rate the ErC10 and ErC50 values were > 100 mg/L after 72 h of exposure, based on nominal concentrations.

Description of key information

ErC10/50 (72 h) > 100 mg/L (nominal, OECD 201)

Additional information

One study investigating the toxicity of the substance to aquatic algae is available. The study was conducted according to OECD guideline 201 (GLP). Green algae of the species Desmodesmus subspicatus were exposed to nominal test substance concentrations of 6.25, 12.5, 25, 50, 100 mg/L incl. a control for 72 hours. The test substance concentrations were analytically verified by DOC analysis. The recovery rate was >90% of nominal. An inhibition of algal growth was not observed based on growth rate. An ErC10/50 (72 h) of > 100 mg/L was determined based on nominal concentrations.