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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Nov. 18, 1996 to Dec. 13, 1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
yes
Remarks:
from the guidelines: regards to preparation of the inoculum : higher sludge weight after washing procedure, but sludge concentrations in test according to guidelines.
Qualifier:
according to
Guideline:
other: EEC Directive 87/302, L 133/118 - 122 "Activated Sludge, Respiration Inhibition Test", (Edition: 30.05,1988)
GLP compliance:
yes (incl. certificate)
Remarks:
Swiss GLP
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: WP2/96
- Expiration date of the lot/batch: 11/2004

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Solubility of the test substance in the solvent/vehicle: ca. 50 g/l
Analytical monitoring:
no
Details on sampling:
no data
Vehicle:
no
Details on test solutions:
Stock solutions: 500 mg/l test substance / reference substance in deionized water
Test organisms (species):
activated sludge, domestic
Details on inoculum:
Sludge pretreatment: 3 times washing with tap water and addition of synthetic sewage feed (a day before the main test).
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Post exposure observation period:
no data
Hardness:
no data
Test temperature:
20 ± 2 °C
pH:
no data
Salinity:
no data
Nominal and measured concentrations:
nominal: 320, 100, 32 and 10 mg/l of the test substance
Details on test conditions:
Sludge dry weight: 1.32 g/l
Test volume: 100 ml
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorophenol
Duration:
3 h
Dose descriptor:
IC50
Effect conc.:
> 320 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Details on results:
no data
Results with reference substance (positive control):
The IC50(3 h) of the reference substance 3,5-Dichlorophenol was 12mg/l.
Reported statistics and error estimates:
no data
Validity criteria fulfilled:
yes
Conclusions:
The IC50 (3 h) of FAT 45176/A was > 320 mg/l.
Executive summary:

The toxicity of FAT 45176/A to activated sludge was determined in a 3-h respiration inhibition test according to the EEC Directive 87/302, L 133/118 -122 and OECD 209 guideline.The test substance concentrations tested were 320, 100, 32 and 10 mg/l. The reference substance, 3,5-Dichlorophenol was tested in concentrations of 32,10 and 3.2 mg/l.

The respiration rate of an activated sludge fed with a standard amount of synthetic sewage feed was measured after a contact time of 3 h. The respiration rate of the same activated sludge in the presence of various concentrations of the test substance under otherwise identical conditions was also measured. The inhibitory effect of the test substance at a particular concentration was expressed as a percentage of the mean respiration rates of two controls. An IC50 value was calculated from determinations at different concentrations.

The IC50(3 h) of the test substance FAT 45176/A was > 320 mg/l. The IC50 (3 h) of the reference substance 3,5-Dichlorophenol was12mg/l.

Description of key information

The IC50(3 h) of the test substance Reactive Orange 136 was > 320 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:
320 mg/L

Additional information

In a key study, the toxicity of FAT 45176/A to activated sludge was determined in a 3-h respiration inhibition test according to the EEC Directive 87/302, L 133/118 -122 and OECD 209 guideline.The test substance concentrations tested were 320, 100, 32 and 10 mg/l. The reference substance, 3,5-Dichlorophenol was tested in concentrations of 32,10 and 3.2 mg/l.

The respiration rate of an activated sludge fed with a standard amount of synthetic sewage feed was measured after a contact time of 3 h. The respiration rate of the same activated sludge in the presence of various concentrations of the test substance under otherwise identical conditions was also measured. The inhibitory effect of the test substance at a particular concentration was expressed as a percentage of the mean respiration rates of two controls. An IC50value was calculated from determinations at different concentrations.

The IC50(3 h) of the test substance FAT 45176/A was > 320 mg/l. The IC50(3 h) of the reference substance 3,5-Dichlorophenol was 12mg/l.

In another supporting study, the inhibitory effect of FAT45'176/A on aerobic waste water microorganisms of activated sludge was investigated in a respiration test according to OECD 209 guideline. This study examined nominal test article concentrations in the range from 3.2 mg/l to 100 mg/l. The respiration rate of aerobic waste water microorganisms was practically not inhibited (-3.8 to 4.9 %) when exposed to the test article concentrations in the range from 3.2 to 100 mg/l.

 

Based on the study results, the EC50and EC20(30 minutes) were therefore determined to be >100 mg/l.