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
Study period:
2010-01-18 to 2010-01-22
Reliability:
2 (reliable with restrictions)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
The nominal concentration selected was far in excess of the water solubility of the test substance
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
yes
Remarks:
The nominal concentration selected was far in excess of the water solubility of the test substance
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
1-Propanesulfonamide, N-[3-[[5-bromo-1-(2,6-dichlorobenzoyl)-1H-pyrrolo[2,3-b]pyridin-3-yl]carbonyl]-2,4-difluorophenyl]-
EC Number:
806-756-5
Cas Number:
1262985-24-9
Molecular formula:
C24 H16 Br Cl2 F2 N3 O4 S
IUPAC Name:
1-Propanesulfonamide, N-[3-[[5-bromo-1-(2,6-dichlorobenzoyl)-1H-pyrrolo[2,3-b]pyridin-3-yl]carbonyl]-2,4-difluorophenyl]-
Test material form:
other: solid
Details on test material:
Purity: >99%

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Test substance concentrations were measured at the beginning and after 24, 48 and 72 hours of exposure. Effect concentrations (ECx) were based on the time weighted average values.

Test solutions

Vehicle:
no
Details on test solutions:
A stock solution of the test substance was prepared in acetone. An appropriate aliquot of this stock solution was transferred to an empty glass vessel. After complete evaporation of the solvent under a stream of compressed air, the OECD medium was added to give the respective nominal test concentration. The solutions were moderately stirred for 24 h at room temperature. After this incubation time the undissolved material was removed by filtration through a glass fibre filter in a sterile vessel each. The resulting water accommodated fractions was used in the test.
The pH of the OECD medium was not adjusted before the start of the exposure. Blanks of the test medium without test substance served as controls

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Axenic slope culture of Desmodesmus subspicatus 86.81 SAG (Collection of Algal Cultures, Institute of Freshwater Ecology, University of Göttingen, D- 37073 Göttingen, Germany)

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
None

Test conditions

Test temperature:
22 ± 2°C, thermo-controlled room
pH:
8.0 ± 0.2
Nominal and measured concentrations:
Based on the results of three non-GLP range finding tests with 1, 10, and 100 mg/L, a limit test with 100 mg/L nominal concentration was performed as the definitive test.
The measured concentrations are in the table below.
Details on test conditions:
Validity criteria
¿ The biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72 h test period.
¿ The average specific growth rate of the controls must exceed 0.92 day-1.
¿ The coefficient of variation of the average specific growth rates during the whole test period in replicate control cultures must not exceed 7%.
¿ The mean of the section by section (days 0–1, 1–2, and 2–3) specific growth rates must not exceed 35% in the control samples.
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:
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.:
>= 0.01 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Details on results:
No statistically significant growth inhibition with respect to algal growth rates and algal yield (biomass production) compared to the untreated control was observed.
HPLC analyses of the test substance concentrations were conducted at the beginning and after 24 h, 48 h and 72 h of exposure. The test substance was detected in the samples taken at 0, 24 and 48 h. The time weighted average concentration for these measurements was determined to be 0.01 mg/L.

Based on the analytically determined concentrations all effect concentrations were >0.101 mg/L.

Any other information on results incl. tables

No statistically significant growth inhibition with respect to algal growth rates and algal yield (biomass production) compared to the untreated controls was observed. HPLC analyses of the test substance concentrations were conducted at the beginning and after 24 h, 48 h and 72 h of exposure. The test substance was detected in the samples taken at 0, 24 and 48 h. The time weighted average concentration for these measurements was determined to be 0.01 mg/L. Based on the analytically determined concentrations all effect concentrations were >0.101 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The nominal concentration level of 100 mg/L was in vast excess of the water solubility of the test substance (0.57 mg/L) and the achieved test concentration was below the quantification limit of 0.101 mg/L. Therefore no meaningful conclusions can be drawn.
Executive summary:

Method: The effect on growth inhibition, growth rate and the yield (algal biomass production) of the test substance to the green alga Desmodesmus subspicatus were investigated over a period of 72 h. The nominal concentration of the test substance was 100 mg/L, however the achieved test concentration was below the quantification limit of 0.101 mg/L. These test concentration was prepared as water accommodated fraction. HPLC analyses of the test substance concentrations were conducted at the beginning and after 24,48 and 72 h of exposure, respectively.

Results: No statistically significant growth inhibition with respect to algal growth rates and algal yield (biomass production) compared to the untreated controls was observed.

Conclusions: No statistically significant growth inhibition with respect to algal growth rates and algal yield (biomass production) compared to the untreated controls was observed.