Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1990-10-10 to 1991-02-01
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline-conform study under GLP without deviations.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 1, 3.2, 10, 32, 50, and 100 mg/l
- Sampling method: After 180 minutes of aeration at 22.5 °C, the first sample was taken for oxygen measurement over a period of up to 10 minutes. Thereafter, in 15 minutes intervals, the rest of the samples were submitted to measurement of oxygen concentration. Sampling was started with the negative control 1. Thereafter, the measurements were continued with the positive controls and the test article samples. Finally, the oxygen consumption of negative control 2 was determined.
- Sample storage conditions before analysis: All samples were worked-up and analyzed on the day of sampling.

Test solutions

Vehicle:
no

Test organisms

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

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Post exposure observation period:
not applicable

Test conditions

Hardness:
14.2 - 15.0 dH°
Test temperature:
19.3 - 20.4 °C
pH:
The initial pH of the systems was, on average, 7.9 for untreated, 7.8 and 7.9 for the treated samples. A t the end of the exposure period, the pH for the respective concentrations were 8.4, 8.5 and 8.4.
Dissolved oxygen:
8.2 - 9.4 mg/l O2
Salinity:
Not being reported as such, however the detailed mineral composition of the test medium is given in the original study report.
Nominal and measured concentrations:
Measured concentration vary between 79.6 - 108.6 mg/l of nominal concentrations.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Duration:
3 h
Dose descriptor:
IC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
3 h
Dose descriptor:
IC10
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
- Results with reference substance valid? yes, IC50 of positive reference substance was found within the expected concentration range
- Relevant effect levels: IC50 = 7.3 mg/l
- Other:
Reported statistics and error estimates:
no statistics applied

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
positive control substance data valid
Conclusions:
The IC50 was determined to be >l00 mg/l. In conclusion, the registered substance was found to be non-toxic to waste-water bacteria.