Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage

Study design

Test type:
flow-through
Limit test:
yes
Total exposure duration:
3 h

Test conditions

Test temperature:
20 2°C
pH:
7 - 8
Details on test conditions:
Type: aquatic

Results and discussion

Effect concentrationsopen allclose all
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
not specified
Conc. based on:
not specified
Basis for effect:
not specified
Key result
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
> 28.9 mg/L
Nominal / measured:
not specified
Conc. based on:
not specified
Basis for effect:
not specified
Details on results:
Piperonyl Butoxide had no significant inhibitory effects on the respiration rate of activated sludge (representing combined carbonaceous and nitrogenous oxidation processes) up to and including the highest test concentration of 1000 mg a.s./L. Taking into that this concentration exceeded the water solubility of Piperonyl Butoxide (28.9 mg/L at 20.4⁰C and pH 7.01), the NOEC for STP microorganisms was set equal to the water solubility value of 28.9 mg/L.

Any other information on results incl. tables

The toxic reference substance (DCP) resulted in inhibition rates of 30, 72 and 91 % in the 5, 15, and 45 mg/L treated vessels, respectively, indicating the suitability of the applied test procedure. No inhibitory effects by Piperonyl Butoxide of more than 15 % were observed

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Piperonyl Butoxide had no significant inhibitory effects on the respiration rate of activated sludge (representing combined carbonaceous and nitrogenous oxidation processes) up to and including the highest test concentration of 1000 mg a.s./L. Taking into that this concentration exceeded the water solubility of Piperonyl Butoxide (28.9 mg/L at 20.4⁰C and pH 7.01), the NOEC for STP microorganisms was set equal to the water solubility value of 28.9 mg/L.