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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
Study period:
week 43-45 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
The actual exposure concentration of the test product were determined by the analytical laboratory. Duplicate samples of the specially prepared test flasks at each sampling time (24h; 48h and 72H) were stored at -20°C±2.0°C until analyses.
Vehicle:
no
Details on test solutions:
A stock solution of 125 mg/l were prepared by weighing 125 mg of the test product and dissolve it in 1000 ml of algal test medium. The test solution were prepared by diluting the stock solution in algal test medium.
Details on test organisms:
Pseudokirchnerella subcapitata is cultured at DHI. Algae from this culture were used in the study.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Nominal and measured concentrations:
The analytically determined test item concentrations are analyzed in the test media samples. Testconcentrations were 10, 20, 50,100 mg/l at the start of the test. The values found at the end of the test ranged from 85 to 94 % of the initially measured values. Under the test conditions the test item was stable during the test period of 72 hours.
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
20.8 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.:
1.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EC20
Effect conc.:
3.6 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.:
1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Validity criteria fulfilled:
yes
Conclusions:
The test item had a statistically significant inhibitory effect on the growth rate of Pseudokirchnerella subcapitata.
After 72 h EC50 was determined to 20.8 mg/l. NOEC was determinated to 1.0 mg/l. The validation of the test concentrations by chemicals analyses showed a deviation from the nominel concentration throughout the test lower than 20 per cent. Therefore results are based on the nominel concentration.

Description of key information

Hazardous to the aquatioc environment. Chronic Category 3

Key value for chemical safety assessment

EC50 for freshwater algae:
20.8 mg/L
EC10 or NOEC for freshwater algae:
1 mg/L

Additional information