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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:
other information
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:
2010
Report Date:
2010

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes

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.:
72.7 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
5.1 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
51.2 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
growth rate

Any other information on results incl. tables

The EC50 was estimated to be slightly higher than the highest concentration tested. However, the data distribution was not fully in agreement with the parameters required for the model (probit) used for the calculation of the EC50, because only one concentration differed from the control growth.Therefore, this value is only a very rough estimate. The highest concentration showed a reduction in cell numbers which was more than 50% compared to controls.

Applicant's summary and conclusion

Conclusions:
Boldenone (ZK5320) inhibits the growth of the green algae Desmodemus subspicatus. The EC50 was estimated slightly above the solubility limit,
however, cell numbers were >50% reduced at the highest concentration tested (51.2 mg/L). The NOEC was 5.1 mg/L.
Executive summary:

The test substance boldenone ( ZK 5320) was incubated in an aqueous solution including nutrients with an algae population of Desmodesmus subspicatus for a test duration of approximately 72 hours.

The highest concentration was a 1:1.25 dilution of a saturated solution (51.2 mg/L), the further concentrations were obtained by dilutions of 1:10 and 1:100 of the saturated solution. The substance concentration was extrapolated from a measurement of the concentration in the saturated solution and based on the dilution factor.

As a parameter for the growth of the algae population, the number of the algal cells was measured with a cell counter

The EC50 for the growth rate was estimated with 72.7 mg/L, the NOEC was 5.1 mg/L, the LOEC 51.2 mg/L