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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
toxicity to microorganisms
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Experimental test result performed according to the guideline
Qualifier:
according to guideline
Guideline:
other: EEC L 133, p. 118-122 (30. May 1988)
Deviations:
yes
Remarks:
Instead a centrifuged sludge a settled sludge was used. Due to the poor solubility of the test substance at test concentrations, no stock solution was prepared. The test substance was given directly into the medium.
GLP compliance:
yes
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
other: Activated sludge from a sewage treatment plant.
Details on inoculum:
Test System : Activated sludge collected from the sewage treatment plant of CH-4106 Therwil on 16/10/89. The preparation was carried out according to the method described in the guideline. The sludge was separated from the aqueous layer by settling instead of centrifugation.
Test type:
not specified
Water media type:
not specified
Total exposure duration:
3 h
Test temperature:
20 ± 2°C
Nominal and measured concentrations:
Reference substance : 32, 10 and 3.2 mg/L
Test substance : 108.7; 36.05; 14.65; 5 and 1.25 mg/L
21.74, 7.21, 2.93, 1 and 0.25 mg of the test substance were weighed and added to the test medium. The volume was adjusted to 200 ml with water and aerated for 3 hours.
The sludge concentration in the test bottles was 1.6 g/L.
Details on test conditions:
Test system : Activated sludge from a sewage treatment plant.
Duration : 3 hours
Temperature : 20 ± 2°C
Vessels : 250 ml BOD flasks with gas inlet
Water : Dechlorinated drinking water
Nutrient solution : 16 g Peptone
11 g Meat extract
3.0 g Urea
0.7 g Nacl
0.4 g CaClz∙2 H2O
0.2 g MgSO4∙7 H2O
2.8 g K2HPO4
per liter dechlorinated drinking water
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorophenol
Key result
Duration:
3 h
Dose descriptor:
IC50
Effect conc.:
87 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Key result
Duration:
3 h
Dose descriptor:
other: IC20
Effect conc.:
5 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Key result
Duration:
3 h
Dose descriptor:
other: IC80
Effect conc.:
> 100 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Details on results:
Graphically determined for the test substance:
IC50 = 87 mg/L
IC20 = 5 mg/L
IC80 = > 100 mg/L
Results with reference substance (positive control):
Graphically determined for the reference substance: IC50 = 14 mg/L
Reported statistics and error estimates:
Measurements : Oxygen consumption per hour in mg/liter with a ORION - Electrode Type 97-08, ORION Microprocessor Ionalizer 901 and plotted on a recorder.
Validity criteria fulfilled:
not specified
Conclusions:
Inhibitory concentrations for respiration of the bacteria were graphically determined based on nominal concentrations and values were found as below:
IC50 = 87 mg/L
IC20 = 5 mg/L
IC80 = > 100 mg/L
Executive summary:

Toxicity of test chemical was studied on microorganisms. The study was performed according to EEC method. Activated sludge collected from the sewage treatment plant of CH-4106 Therwil on 16/10/89 was used as a test bacteria. The preparation was carried out according to the method described in the guideline. The sludge was separated from the aqueous layer by settling instead of centrifugation. The sludge concentration in the test bottles was 1.6 g/L. 21.74, 7.21, 2.93, 1 and 0.25 mg of the test substance were weighed and added to the test medium. The volume was adjusted to 200 ml with water and aerated for 3 hours. Study was carried out in a 250 ml BOD flasks with gas inlet at a temperature of 20 ± 2°C for 3 hrs. 3,5-Dichlorophenol was used as a reference substance. The effectes were observed on the respiration of aerobic waste water bacteria for 3 hours. Graphically determined IC50 value for the reference substance was evaluated to be 14 mg/l. Inhibitory concentrations for respiration of the bacteria were graphically determined based on nominal concentrations. Thus, the IC20, IC50 and IC80 value was determined to be 5, 87 and > 100 mg/l, respectively.

Description of key information

Toxicity of test chemical was studied on microorganisms (Experimental study report, 1989). The study was performed according to EEC method. Activated sludge collected from the sewage treatment plant of CH-4106 Therwil on 16/10/89 was used as a test bacteria. The preparation was carried out according to the method described in the guideline. The sludge was separated from the aqueous layer by settling instead of centrifugation. The sludge concentration in the test bottles was 1.6 g/L. 21.74, 7.21, 2.93, 1 and 0.25 mg of the test substance were weighed and added to the test medium. The volume was adjusted to 200 ml with water and aerated for 3 hours. Study was carried out in a 250 ml BOD flasks with gas inlet at a temperature of 20 ± 2°C for 3 hrs. 3,5-Dichlorophenol was used as a reference substance. The effects were observed on the respiration of aerobic waste water bacteria for 3 hours. Graphically determined IC50 value for the reference substance was evaluated to be 14 mg/l. Inhibitory concentrations for respiration of the bacteria were graphically determined based on nominal concentrations. Thus, the IC20, IC50 and IC80 value was determined to be 5, 87 and > 100 mg/l, respectively.

Key value for chemical safety assessment

EC50 for microorganisms:
87 mg/L

Additional information

Toxicity of test chemical was studied on microorganisms (Experimental study report, 1989). The study was performed according to EEC method. Activated sludge collected from the sewage treatment plant of CH-4106 Therwil on 16/10/89 was used as a test bacteria. The preparation was carried out according to the method described in the guideline. The sludge was separated from the aqueous layer by settling instead of centrifugation. The sludge concentration in the test bottles was 1.6 g/L. 21.74, 7.21, 2.93, 1 and 0.25 mg of the test substance were weighed and added to the test medium. The volume was adjusted to 200 ml with water and aerated for 3 hours. Study was carried out in a 250 ml BOD flasks with gas inlet at a temperature of 20 ± 2°C for 3 hrs. 3,5-Dichlorophenol was used as a reference substance. The effects were observed on the respiration of aerobic waste water bacteria for 3 hours. Graphically determined IC50 value for the reference substance was evaluated to be 14 mg/l. Inhibitory concentrations for respiration of the bacteria were graphically determined based on nominal concentrations. Thus, the IC20, IC50 and IC80 value was determined to be 5, 87 and > 100 mg/l, respectively.