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Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From July 29th, 2002 to July 31st, 2002
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Version / remarks:
1984
Qualifier:
according to guideline
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Version / remarks:
1988
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Reference substance name:
Yellow 6314-PPT
IUPAC Name:
Yellow 6314-PPT
Test material form:
solid

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

Test conditions

Test temperature:
20 °C
pH:
6.7-7.6 test item
6.7-7.7 control
Dissolved oxygen:
7.5-8.6 test item
8.4-8.7 control
Nominal and measured concentrations:
Nominal concentrations: 0, 32, 100, 320 and 1000 mg/l.
Details on test conditions:
Continuous aeration during 3-hours test period.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol at 5, 16, 50 mg/l

Results and discussion

Effect concentrationsopen allclose all
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Details on results:
Up to and includíng the highest concentration of 1000 mg/l the test item had no significant inhibitory effect (<15 %) on the respiration rate of activated sludge after the incubation period of 3 hours. The inhibition of the respiration rates of the activated sludge after the incubation period was in the range of 0.6 to 11.5 % compared to the controls.
All test concentrations were above the water solubility limit of the test item under the present test conditions. Thus, the 3-hour NOEC (EC15) of the test item to activated sludge microorganisms under the present test conditions was at least at the limit of water solubility, or at least 1000 mg/l.
The 3-hour EC20, EC50 and EC80 could not be calculated, but were clearly higher than the water solubility limit of the test item under the present test conditions, or higher than 1000 mg/l.
Results with reference substance (positive control):
The results confirmed the suitability of the activated sludge and the method used.

Applicant's summary and conclusion

Conclusions:
NOEC (3h) = 1000 mg/l (nominal concentration).

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