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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:
July - August 1992
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:
In deviation from the Guideline settled sludge instead of centrifugated sludge was used.
GLP compliance:
yes
Remarks:
This study has been performed in compliance with GLP in Switzerland, Procedures and Principles, March 1986, issued by the Swiss federal Department of the Interior and the Intercantonal Office for the Control of Medicaments.
Analytical monitoring:
not required
Vehicle:
no
Test organisms (species):
activated sludge
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Key result
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
64.2 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:
other: EC20
Effect conc.:
7.3 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:
EC100
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Validity criteria fulfilled:
yes
Remarks:
The two control respiration rates are within 15 % of each other and the EC50 (3h) of 3,5-Dichlorphenol is in the accepted range 5 to 30 mg/l
Conclusions:
EC50 (3h) = 64.2 mg/L
EC20 (3h) = 7.3 mg/L
EC100 (3h) > 100 mg/L
Executive summary:

The toxicity of CA 1139 A to activated sludge was determined in a 3-hours respiration inhibition test, according to GLP Guideline OECD 209, under aerobic conditions at room temperature (20 +/-2 ºC). The experiment was conducted in compliance with Good Laboratory Practice (GLP) in, Procedures and Principles, March 1986, issued by the Federal Department of the interior and the Intercantonal Office for the Control of Medicaments.

The test substance concentrations tested were 100.3, 32.1, 10.0, 3.2 and 1.0 mg/l. The reference substance 3,5-Dichlorophenol was tested in concentrations of 32, 10 and 3.2 mg/l. 

The test system consisted of activated sludge collected from a communal sewage treatment plant. 1.69 g/l sludge (dry weight) was used.

The respiration rate of the activated sludge fed with a standard amount of synthetic sewage feed was measured (ORION – Electrode Type 97-08, ORION Microprocessor Ionalizer 901) after a contact time of 3 hours with the test substance. The reference substance 3,5-Dichlorophenol and a blank (synthetic sewage feed, inoculum and water) served as controls.

 

The following values have been graphically determined:

EC50 (3h) = 64.2 mg/L

EC20 (3h) =  7.3 mg/L

EC100 (3h) > 100 mg/L

The results are based on nominal concentrations. 

 

Description of key information

The toxicity of CA 1139 A to activated sludge was determined in a 3-hours respiration inhibition test,

according to GLP Guideline OECD 209, under aerobic conditions at room temperature (20 +/-2 ºC). The experiment was conducted in compliance with Good Laboratory Practice (GLP) in, Procedures and Principles, March 1986, issued by the Federal Department of the interior and the Intercantonal Office for the Control of Medicaments.
The test substance concentrations tested were 100.3, 32.1, 10.0, 3.2 and 1.0 mg/l. The reference substance 3,5-Dichlorophenol was tested in concentrations of 32, 10 and 3.2 mg/l.
The test system consisted of activated sludge collected from a communal sewage treatment plant. 1.69 g/l sludge (dry weight) was used.
The respiration rate of the activated sludge fed with a standard amount of synthetic sewage feed was measured (ORION – Electrode Type 97-08, ORION Microprocessor Ionalizer 901) after a contact time of 3 hours with the test substance. The reference substance 3,5-Dichlorophenol and a blank (synthetic sewage feed, inoculum and water) served as controls.
The following values have been graphically determined:
EC50 (3h) = 64.2 mg/L
EC20 (3h) = 7.3 mg/L
EC100 (3h) > 100 mg/L
The results are based on nominal concentrations.

Key value for chemical safety assessment

EC50 for microorganisms:
64.2 mg/L

Additional information

   

Guideline Test Type

Species

Results

Reference

Reliability

OECD 209

activated sludge of a communal sewage treatment plant

EC50(3h) = 64.2 mg/l

EC20(3h) = 7.3 mg/L

EC100(3h) > 100 mg/L

 

Ciba-Geigy Ltd., Baumann, W.; 1992

Reliable without restriction