[No public or meaningful name is available]

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

effects on growth of green algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 19 April 2021 to 22 April 2021

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:

28th July, 2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch/Lot number: 381890
Purity: 99.8%

Analytical monitoring:

yes

Details on sampling:

samples were taken and analyzed at the beginning and at the end of the experiment.

Vehicle:

yes

Details on test solutions:

Reconstituted algal growth medium (OECD medium, according to OECD 201) was used as dilution
water for both the range finding and definitive tests.
A stock solution with a concentration of 100.0 mg/L (nominal) was prepared with direct addition of the
test item, mixed into the algal growth medium (OECD Medium), then distributed into the appropriate t
est flasks. As a Limit test was carried out, further dilution of stock solution was not performed.
The test solution was prepared just before introduction of the algae (start of the experiment).

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: 61.81 SAG
- Source (laboratory, culture collection): The algae were supplied by the SAG: Collection of Algal
Cultures, Inst. Plant Physiology, University of Göttingen, GERMANY
- Age of inoculum (at test initiation):
- Method of cultivation:

ACCLIMATION
- Acclimation period: three days
- Culturing media and conditions (same as test or not): same as test
- Any deformed or abnormal cells observed: no

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

22.1-22.3°C

pH:

7.79–8.88

Nominal and measured concentrations:

Nominal concentration: 100 mg/L
Measured concentration: 98.4 mg/L at the start and 95.2 mg/L at the end

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL Erlenmeyer flasks
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 100 mL algal suspension
- Aeration: yes
- Renewal rate of test solution (frequency/flow rate): no
- Initial cells density: 1E+04 algal cells per mL test medium
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH: no
- Photoperiod:
- Light intensity and quality: 7863 lux (equivalent to ~106 uE/m2/s), which was ensured with flu
orescent lamps (with a spectral range of 400-700 nm)
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: The cell concentrations were determined at 24, 48 and 72 h
ours after starting the test by microscopic method.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit 100 mg/L
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations: 0.01, 0.1, 1, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: no toxic effect was observed
during the preliminary range-finding test

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:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Details on results:

There were no any observed morphological deviations during the experiment.

Results with reference substance (positive control):

The 72h-ErC50 is 0.89 mg/L, 72h-EyC50 is 0.53 mg/L.
These results are within the acceptable range (ErC50-value: 0.60 mg/L to 1.03 mg/L, EbC50-value:
0.20 mg/L to 0.75 mg/L according to the ISO Guideline No. 8692) hence this reference study shows
that the acute immobilisation test on Raphidocelis subcapitata is valid in this laboratory.

Validity criteria fulfilled:

yes

Conclusions:

The ErC50 and EyC50 values of the test item were determined as > 100 mg/L; the NOEC for growth
rate and yield were 100 mg/L.

Executive summary:

The effect of test item was assessed on algal growth using the unicellular green alga Raphidocelis
subcapitata, over an exposure period of 72 hours, according to OECD Guideline 201 under GLP.
The ErC50 and EyC50 values of the test item were determined as > 100 mg/L; the NOEC for growth
rate and yield were 100 mg/L.

Description of key information

The effect of test item was assessed on algal growth using the unicellular green alga Raphidocelis
subcapitata, over an exposure period of 72 hours, according to OECD Guideline 201 under GLP.
The ErC50 and EyC50 values of the test item were determined as > 100 mg/L; the NOEC for growth
rate and yield were 100 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L