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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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
Justification for type of information:
Please refer to the Category Approach Justification provided in Section 13
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
The concentration of the test item was analysed in all test solutions sampled at the beginning of the exposure period prior to the addition of the algae and in samples of the algae cultures taken from replicates pooled per test concentration at the end of the exposure period.
Duplicate samples of 750 µL were taken from the pooled replicates, given in 2 mL glas vials and analysed immediately. The retain samples has been stored at -20 °C.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The highest test concentration (100 mg pure substance/L) was prepared by solving 136.43 mg of the test item (purity 73.3 %) in 1000 mL growth medium and stirring for 2 hours at room temperature. To obtain the other required test concentrations the highest test concentration was serially diluted with growth medium.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: green algae
- Source (laboratory, culture collection): SAG, Culture Collection of Algae at Pflanzenphysiologisches Institut of the University at Göttingen, Albrecht von Haller Institut, Untere Klarspüle 2, 37073 Göttingen, Germany
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
23.0 °C
pH:
7.9 - 9.4
Nominal and measured concentrations:
Nominal test concentrations: control, 0.95, 3.05, 9.77, 31.25, 100 mg/L
Mean measured test concentrations (study initiation): < LOQ, 0.9, 2.79, 9.01, 30.3, 100 mg/L
Mean measured test concentrations (study end): Recovery rates: 84.7 - 100%

Limit of Quantification (LOQ): 0.1 µg/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size: glass conical flasks with air-permeable silicone-sponge caps, 250 ml
- Initial cells density: 10 000 cells/ml
- Control end cells density: 329.1E+4
- No. of vessels per concentration (replicates): 8
- No. of vessels per control (replicates): 4

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: sterilised synthetic OECD medium prepared with purified water

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuously illuminated
- Light intensity and quality: 4440 - 8880 lux

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: cell number of each test vessel was recorded after 24, 48 and 72

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: 0.75, 3.0, 18 mg/L
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
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:
NOEC
Effect conc.:
31.3 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:
other: yield
Results with reference substance (positive control):
ErC50 = 2.42 mg/L

Description of key information

ErC50 (72 h) > 100 mg a.i./L (nominal) and NOEC (72 h) = 31.3 mg a.i./L (nominal) for Pseudokirchneriella subcapitata.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:
31.3 mg/L

Additional information

For aquatic algae no studies on toxic effects of effects AES (C9 -11, 1 -2.5EO) Na (CAS 160901 -28 -0) are available. Therefore, a read-across approach from the structural comparable AES (C8 -10, 1 -2.5EO) NH4 (CAS 68891 -29 -2) mixture was applied.

For AES (C8 -10, 1 -2.5EO) NH4 a GLP-study was performed according to OECD guideline 201. Based on growth rate an EC50 (72 h) > 100 mg a.i./L (nominal) for Pseudokirchneriella subcapitata was determined. The corresponding NOEC (72 h) was 31.3 mg a.i./L (nominal) (BASF, 2013b).