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Reference
Endpoint:
activated sludge respiration inhibition testing
Remarks:
IC50
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11 February 1987
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
yes
Remarks:
Sludge from a Husman laboratory apparatus
Qualifier:
equivalent or similar to guideline
Guideline:
ETAD Fermentation Tube Method
GLP compliance:
yes
Specific details on test material used for the study:
Batch No.: Op. 1/86., Vers. 10/86
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
no data
Test organisms (species):
other: mixed culture of bacteria (sludge of a Husman apparatus)
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Test temperature:
20 ± 2 °C
Nominal and measured concentrations:
nominal concentrations: 0, 1, 3.2, 10, 32 and 100 mg/L
Details on test conditions:
O2 consumption, measured with an Oxygen-sensitive electrode system: OXI DIGI 550.
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorophenol
Duration:
3 h
Dose descriptor:
IC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Details on results:
No inhibition was observed except at 10 mg/L. There is no dose-response curve and there are no indications that the effects observed can be related to exposure to the testsubstance
Results with reference substance (positive control):
The IC50 of the reference substance 3,5-Dichlorophenol is: 21 mg/L (criterium: 10 - 25 mg/L)

IC50:

Calculate the respiration rate of each test concentration as a percentage of the mean of the two control respiration rates. Plot the results on a log (concentration)/normal (% inhibition) graph and derive an IC50 value.

 

3 h

Test Substance (mg/1)

O2 -Consumption/(mg/l/min)

Inhibition %

100

1.82

2.1

32

2.13

0.0

10

1.66

10.7

3.2

2.89

0.0

1

1.87

0.0

Validity criteria fulfilled:
yes
Conclusions:
The IC50 of FAT 40224/C is >100 mg/L.
Executive summary:

A bacteria growth inhibition test was performed under GLP following the OECD 209 guideline. The test concentration used in the study were 0, 1, 3.2, 10, 32 and 100 mg/L. No inhibition was observed except at 10 mg/L. There is no dose-response curve and there are no indications that the effects observed can be related to exposure to the test substance. No inhibition was observed except for a single inhibition point. However, this could not be related to the substance. Therefore, the IC50 was determined to be >100 m/L while the IC50 of the reference substance 3,5-Dichlorophenol is 21 mg/L (criterium: 10 - 25 mg/L).

Description of key information

The IC50 of the test substance was determined in a respiration inhibition test performed according to OECD guideline 209. In this study, a mixed culture of bacteria (sludge of a Husman apparatus) was exposed to 0, 1, 3.2, 10, 32 and 100 mg/L test substance for 3 hours. The test concentration used in the study were 0, 1, 3.2, 10, 32 and 100 mg/L. No effects on algal respiration were observed. The IC50 was determined >100 mg/L. There is no dose-response curve and there are no indications that the effects observed can be related to exposure to the test substance. No inhibition was observed except for a single inhibition point. However, this could not be related to the substance. Therefore, the IC50 was determined to be >100 m/L while the IC50 of the reference substance 3,5-Dichlorophenol is 21 mg/L (criterium: 10 - 25 mg/L).

Key value for chemical safety assessment

EC50 for microorganisms:
100 mg/L

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