Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

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:
other: Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Report date:
2009

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
25 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
41.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
25 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
After 48 h exposure the samples with algae, but not the blind values, showed turbidity at the concentrations 50 and 100 mg/L. After 72 h exposure blind values and the samples were turbid at 50 and 100 mg/L.
To elucidate the impact of the recorded turbidity on the photometric measurement of algal growth in this study, a NON-GLP experiment with cell counting was performed and revealed similar cell numbers for the control preparation and the 50 mg/L and 100 mg/L test substance concentrations for up to 72 h of exposure as compared to the calculated cell numbers determined by extinction. The results showed that the turbidity did not affect the outcome of the photometric measurements considerably.

Recovery of DOC in the test substance concentration (6.25; 25; 100 mg/L) showed no relevant loss of test substance after 72 h. The recovery rate was between 85 % and 148 % during the 72 h exposure period. The EC values given in this report are based on the nominal concentration.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
For the parameter yield the EyC50 value was > 100 mg/L and the NOEC value was 25 mg/L after 72 h of exposure, based on nominal concentrations.
For the parameter growth rate the ErC50 value was > 100 mg/L and the NOEC value was 25 mg/L after 72 h of exposure, based on nominal concentrations.