Registration Dossier
Registration Dossier
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EC number: 207-096-5 | CAS number: 434-03-7
Toxicity to aquatic algae and cyanobacteria
Administrative data
- Endpoint:
- toxicity to aquatic algae and cyanobacteria
- Type of information:
- experimental study
- Adequacy of study:
- other information
- Study period:
- Aug 2010
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: well documented GLP study
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 010
- Report date:
- 2010
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 substance name:
- Ethisterone
- EC Number:
- 207-096-5
- EC Name:
- Ethisterone
- Cas Number:
- 434-03-7
- Molecular formula:
- C21H28O2
- IUPAC Name:
- (1R,3aS,3bR,9aR,9bS,11aS)-1-ethynyl-1-hydroxy-9a,11a-dimethyl-1H,2H,3H,3aH,3bH,4H,5H,7H,8H,9H,9aH,9bH,10H,11H,11aH-cyclopenta[a]phenanthren-7-one
Constituent 1
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
Results and discussion
Effect concentrationsopen allclose all
- Duration:
- 72 h
- Dose descriptor:
- EC50
- Effect conc.:
- 0.5 mg/L
- Nominal / measured:
- estimated
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 72 h
- Dose descriptor:
- NOEC
- Effect conc.:
- 0.003 mg/L
- Nominal / measured:
- estimated
- Conc. based on:
- test mat.
- Basis for effect:
- cell number
- Duration:
- 72 h
- Dose descriptor:
- LOEC
- Effect conc.:
- 0.03 mg/L
- Nominal / measured:
- estimated
- Conc. based on:
- test mat.
- Basis for effect:
- cell number
Any other information on results incl. tables
The EC50 (growth rate) was slightly higher than the highest concentration tested.
Applicant's summary and conclusion
- Validity criteria fulfilled:
- yes
- Conclusions:
- The EC50 for ethisterone (ZK4957) is below 1 mg/L. The NOEC is 0.003, the LOEC 0.03 mg/L.
- Executive summary:
The test substance ethisterone (ZK 4957) was incubated in an aqueous solution including nutrients with an algae population of Desmodesmus subspicatus for a test duration of approximately 72 hours. The test solutions were a saturated solution and a 1:10 and 1:100 dilution. The concentrations of the test solutions were extrapolated from a solubility test which gave a maximum solubility of 0.2 mg/L.
The growth of Desmodemus subspicatus was inhibited at the two highest concentrations. The EC50 was estimated with 0.5 mg/L, the NOEC was 0.003, the LOEC 0.03 mg/L.
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