Aesculin

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:

2018

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)

Version / remarks:

28.07.2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Analytical data are required by the guidelines for verification of test item concentrations as well as the stability of the test item over the entire test period. Analytical samples were taken at 0 hours (initial value) from fresh test solutions and after 24 hours, 48 hours and 72 hours from aged solutions from all test item concentrations and control. For each sampling also a retain sample was taken. Samples were taken and treated as described in Appendix E (Sample Work-Up Procedure).
All samples were stored deep frozen until they were transferred to the analytical laboratory.

Vehicle:

no

Details on test solutions:

Analytical samples were taken at 0 hours (initial value) from fresh test solutions and after 24 hours, 48 hours and 72 hours from aged solutions from all test item concentrations and control. For each sampling also a retain sample was taken. Samples were taken and treated as described in Appendix E (Sample Work-Up Procedure).

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

The test organism Pseudokirchneriella subcapitata Hindák (Sphaeropleales: Selenastraceae), strain: SAG 61.81, was purchased from a commercial supplier, MBM Sciencebridge GmbH, HansAdolf-Krebs-Weg 1, D-37077 Göttingen, Germany.
The algae are grown semi-continuously in sterile cultures in the laboratory. Old medium is periodically replaced by fresh mineral solution in order to keep the algae in an exponential growth state. Stock cultures are ordered regularly from our commercial supplier.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

n.d.

Test temperature:

22.8 - 23.0

pH:

7.66 - 8.20

Dissolved oxygen:

not reported

Salinity:

not applicable

Conductivity:

not applicable

Nominal and measured concentrations:

Following a static non-GLP range-finding test with nominal test item concentrations of 100, 10.0, 1.00, 0.100, 0.0100 mg/L and control a static main test with nominal test item concentrations of 100, 31.3, 9.77, 3.05, 0.954 mg/L and control was performed.

Details on test conditions:

Six replicates were employed for the control and three for each test item concentration. An additional replicate per treatment without algae (blank replicate) was set-up in parallel to assess the background level for fluorescence measurements. The test was performed in 100 mL Erlenmeyer flasks each containing ~ 50 mL test solution. The pH was recorded at test start and test end. Temperature was measured continuously over the whole test period and recorded daily. Light intensity of the continuous illumination was measured at test start.

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

Remarks on result:

not determinable because of methodological limitations

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

Remarks on result:

not determinable

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

not determinable because of methodological limitations

Key result

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

not determinable because of methodological limitations

Validity criteria fulfilled:

yes

Description of key information

Aesculin is not harmfull to algae under conditions of test.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

The objective of this study was to determine the effects of Aesculin on the growth of the single cell green alga Pseudokirchneriella subcapitata, to determine the no observed effect concentration (NOEC), to determine the lowest observed effect concentration (LOEC) and to determine the effect concentration (EC10, 20, 50), where possible.