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Ecotoxicological information

Toxicity to microorganisms

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Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Reference:
Composition 0
Composition 0
Qualifier:
according to
Guideline:
ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
Deviations:
yes
Remarks:
see 'Principles of method if other than guideline'
Principles of method if other than guideline:
Comparable to guideline study with acceptable restrictions (Documentation of the older study falls short of today´s requirements, but corresponds to the standards at the time the study was conducted; the quality of the study performance is nevertheless not influenced. Sufficient data suitable for assessment.)
GLP compliance:
no
Test material information:
Composition 1
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Laboratory culture: Municipal activated sludge from laboratory wastewater treatment plant fed with municipal sewage and synthetic wastewater.
- Initial biomass concentration: Concentration of dry substance = 1 g/L
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
30 min
Nominal and measured concentrations:
Nominal: control, 100, 500, 1000 mg/L
Details on test conditions:
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorophenol
Key result
Duration:
30 min
Dose descriptor:
other: EC20
Effect conc.:
900 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Key result
Duration:
30 min
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
EC20 = 3 mg/L
EC50 = 10 mg/L
EC80 = ca. 150 mg/L
Conclusions:
Under the study conditions, the 3 min NOEC established based on inhibition of nitrification rate was 100 mg/L.
Executive summary:

A study was conducted to determine the toxicity of the test substance to microorganisms according to ISO Method 8192. Municipal activated sludge was used as inoculum and initial biomass concentration of dry substance was at 1 g/L. Test substance concentration applied was: 100, 500, 1000 mg/L plus control. Under the study conditions, the 3 min NOEC established based on inhibition of nitrification rate was 100 mg/L (BASF, 1993).

Endpoint:
activated sludge nitrification inhibition testing
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Reference:
Composition 0
Qualifier:
according to
Guideline:
ISO 9509 (Toxicity test for assessing the inhibition of nitrification of activated sludge microorganisms)
Deviations:
not specified
GLP compliance:
not specified
Test material information:
Composition 1
Analytical monitoring:
not specified
Vehicle:
no
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
Activated sludge from a municipal wastewater treatment plant
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
4 h
Test temperature:
20°C
pH:
6.5-7.5
Dissolved oxygen:
5-6 mg/L
Nominal and measured concentrations:
between 0-1.2 mg Zn/L.
Reference substance (positive control):
no
Key result
Duration:
4 h
Dose descriptor:
other: IC20
Effect conc.:
0.16 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
inhibition of nitrification rate
Key result
Duration:
4 h
Dose descriptor:
IC50
Effect conc.:
0.35 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
inhibition of nitrification rate
Key result
Duration:
4 h
Dose descriptor:
NOEC
Effect conc.:
0.1 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
inhibition of nitrification rate
Validity criteria fulfilled:
yes
Conclusions:
Under the study conditions, measured IC50 and NOECs were established based on inhibition of nitrification rate. The 4 h IC50 was determined at 0.35 mg/L and the 4 h NOEC at 0.1 mg/L.
Executive summary:

A study was conducted to determine the toxicity of the test substance to microorganisms according to ISO Method 9509. The experiments were performed in two isothermal, closed and well-mixed reactors, one as a reference of the non-inhibited system, and one with the inhibitor to be tested. Each reactor was filled with 400 mL of activated sludge collected from a municipal wastewater treatment plant at 3–3.5 g/L MLSS, 80 mL of substrate fluid. The concentration range of Zn2 + used was 0.3 to 1.2 mg/L. Under the study conditions, measured IC50 and NOECs were established based on inhibition of nitrification rate. The 4 h IC50 was determined at 0.35 mg/L and the 4 h NOEC at 0.1 mg/L (Juliastuti, 2003).

Description of key information

Key value for chemical safety assessment

EC10, LC10 or NOEC for microorganisms:
0.1 mg/L

Additional information

Zinc sulphate studies

A study was conducted to determine the toxicity of the test substance to microorganisms according to ISO Method 9509. The experiments were performed in two isothermal, closed and well-mixed reactors, one as a reference of the non-inhibited system, and one with the inhibitor to be tested. Each reactor was filled with 400 mL of activated sludge collected from a municipal wastewater treatment plant at 3–3.5 g/L MLSS, 80 mL of substrate fluid. The concentration range of Zn2 + used was 0.3 to 1.2 mg/L. Under the study conditions, measured IC50 and NOECs were established based on inhibition of nitrification rate. The 4 h IC50 was determined at 0.35 mg/L and the 4 h NOEC at 0.1 mg/L (Juliastuti, 2003).

Acrylic acid studies

A study was conducted to determine the toxicity of the test substance to microorganisms according to ISO Method 8192. Municipal activated sludge was used as inoculum and initial biomass concentration of dry substance was at 1 g/L. Test substance concentration applied was: 100, 500, 1000 mg/L plus control. Under the study conditions, the 3 min NOEC established based on inhibition of nitrification rate was 100 mg/L (BASF, 1993).