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Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Vehicle:
no
Test organisms (species):
activated sludge of a predominantly domestic sewage
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Key result
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 64 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate

The EC50 of the reference compound 3.5-Dichlorophenol was 8.0 mg/L. Estradiol had no inhibitory effect on the respiration rate of activated sludge.

Validity criteria fulfilled:
yes
Conclusions:
The EC50 of the respiration rate was higher than the tested range (up to 64 mg/L).
Executive summary:

The test substance estradiol was incubated in an aerated activated sludge with microorganisms from a municipal sewage treatment plant including synthetic sewage feed for 3 hours followed by the measurement of the respiration rate by an oxygen probe. Additionaly, a reference substance (3.5-dichlorophenole) in three concentrations (5, 15 and 30 mg/L in test vessel) was prepared. The study was conducted accroding to OECD 209. Results: The EC50 of the reference compound 3.5-Dichlorophenole was 8.0 mg/L fulfilling the OECD validity criteria. Estradiol had no inhibitory effect on the respiration rate of activated sludge. The EC50 was higher than the tested range (up to 64 mg/L).

Description of key information

The test substance estradiol was incubated in an aerated activated sludge with microorganisms from a municipal sewage treatment plant including 
synthetic sewage feed for 3 hours followed by the measurement of the respiration rate by an oxygen probe. Additionaly, a reference substance (3.5-dichlorophenole) in three concentrations (5, 15 and 30 mg/L in test vessel) was prepared. The study was conducted accroding to OECD 209.
Results: The EC50 of the reference compound 3.5-Dichlorophenole was 8.0 mg/L fulfilling the OECD validity criteria.
Estradiol had no inhibitory effect on the respiration rate of activated sludge. The EC50 was higher than the tested range (up to 64 mg/L).

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
64 mg/L

Additional information

The study was performed according to GLP (report A48733)