Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
a off-white powdery solid, without irritating odor

Study design

Test type:
not specified
Water media type:
other: tap water
Limit test:
no
Total exposure duration:
3 h

Test conditions

Test temperature:
20.4 – 21.2 °C
pH:
7.0
Details on test conditions:
Duration 3 hours
Replicates 1 replicate/concentration (positive control, test item lower concentrations)
5 replicates for test item treatment 1000 mg/L
Blank Control 2 replicates before and 2 after measuring positive control and test item, respectively
Water tap water, see annex 2, page 22
Aeration purified air, using Pasteur pipettes
Feeding nutrient solution, 16 mL/vessel
Temperature 20.4 – 21.2 °C
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol (CAS-No. 591-35-5)

Results and discussion

Effect concentrations
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Details on results:
One experiment was performed.
The test item was tested using 4 concentrations ranging from 1000 to 1 mg/L nominal concentration. For the treatment 1000 mg/L, 5 replicates were used; for the other treatments, 1 replicate each.
Because no significant inhibition was observed, no additional experiment had to be per-formed.
All validity criteria were met. For the estimation of the EC50 of the positive control, the fits showed good statistical correspondence of the data with the dose-response-equation. The positive control gave an EC50 of 7.4 mg/L (95 % confidence interval not determinable) which lies within the recommended range of 2 – 25 mg/L. The coefficient of variation of oxygen uptake rate in control replicates was below 30% at the end of the test. The oxygen uptake rate of the blank controls was above 20 mg O2 per gram activated sludge in 1 hour.
No observations were made which might cause doubts concerning the validity of the study outcome.
The result of the test can be considered valid.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes