N-L-alanyl-L-tyrosine

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Desmodesmus subspicatus (Chodat) Hegewald et Schmidt
- Strain: Strain No. 86.81 SAG
- Source (laboratory, culture collection): The algae were originally supplied by the „Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzen-wissenschaften, Universität Göttingen", 37073 Göttingen, Germany

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

0.24 mmol/L (= 24 mg/L) as CaCO3

Test temperature:

21.2 to 21.6 °C

pH:

7.6 - 8.4

Nominal and measured concentrations:

Nominal: 114.3, 36.2, 11.4, 3.62, 1.15, 0.363 and 0.115 mg test item/L and a control (spacing factor 3.16)
Nominal, adjusted to water content: 100, 31.6, 10.0, 3.17, 1.00, 0.317 and 0.100 mg a.i./L and a control (spacing factor 3.16)
Geometric mean measured concentrations of the test item: 124, 31.9, 10.7, 3.32, 0.946, 0.277 and 0.0740 mg test item/L and a control.

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml Erlenmeyer flasks
- Initial cells density: 5000 (nominal)
- No. of vessels per concentration (replicates):3
- No. of vessels per control (replicates):6

GROWTH MEDIUM
- Standard medium used: yes => OECD Medium

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: Continuous illumination
- Light intensity and quality: Mean light intensity => 6965 lux (range: 6710 to 7250 lux)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.16
- Range finding study: yes
- Results used to determine the conditions for the definitive study: yes

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 114.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 114.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 108.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 108.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 124 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 124 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Validity criteria fulfilled:

yes

Conclusions:

The influence of L-Alanyl-L-Tyrosine Dihydrate on the growth of the freshwater green algae Desmodesmus subspicatus was assessed in a static concentration-response test. The 72-hour EC50 for yield and growth rate was determined to be >124 mg test item/L.

Description of key information

ErC50 (72 h) > 100 mg/L (nominal, OECD 201)