Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
20.02.2007 to 27.04.2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

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

Test material

Constituent 1
Chemical structure
Reference substance name:
1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluoro-6-iodohexane
EC Number:
206-586-6
EC Name:
1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluoro-6-iodohexane
Cas Number:
355-43-1
Molecular formula:
C6F13I
IUPAC Name:
1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluoro-6-iodohexane
Test material form:
liquid

Test organisms

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

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 h

Test conditions

pH:
The pH of the activated sludge inoculum was adjusted from 8.8 to 7.2 with a diluted sulfuric acid solution.
Nominal and measured concentrations:
1000 mg/L
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrations
Key result
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Results with reference substance (positive control):
The 3-hour EC50 of the reference item 3,5-dichlorophenol (positive control) was calculated to be 17 mg/L with 95% confidence limits from 1 to 241 mg/L. The 3-hour EC50 is within the guideline-recommended range of 5-30 mg/L, confirming the suitability of the activated sludge used.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
NOEC(3h) > 1000 mg/L
Executive summary:

The test item had no significant inhibitory effect (<15%) on the respiration rate of activated sludge after the incubation period of three hours at the limit test concentration of 1000 mg/L.

Thus, the 3-hour NOEC (EC 15) of the substance to activated sludge microorganisms was at least 1000 mg/L. This value might even be higher, but concentrations above 1000 mg/L were not tested. The 3-hour EC20, EC50, and EC80 could not be calculated, but were clearly higher than 1000 mg/L.

The oxygen consumption rates of the two controls (run at the start and at the end of the test) differed by 8% (guideline-recommended maximum variation: 15%).