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Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed according to OECD Guideline 209 and with GLP compliance
Reason / purpose for cross-reference:
reference to same study
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
yes
Remarks:
see below
Qualifier:
according to guideline
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Deviations:
yes
Remarks:
see below
Principles of method if other than guideline:
The temperature for the main study lay in a range of 24.0 to 25.0 °C and therefore higher than stated in the guidelines. As normal growth was observed in the controls, this deviation was stated as uncritical.
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant D-67435 NW-Lachen-Speyerdorf.
Upon arrival in the test facility, the sludge was filtrated, washed with tap water and re-suspended in tap water. The activated sludge was aerated until usage in the test and fed daily with 50 mL/L synthetic sewage feed.
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:
17.7 - 19°C (deviation was stated uncritical, as normal respiration activity of the control could be observed)
pH:
pH = 7.5±0.5 (nutrient solution).
No data on the experiment solution.
Dissolved oxygen:
No data
Salinity:
No data
Details on test conditions:
Nominal concentrations: control - 100 - 320 - 1000 - 3200 and 10000 mg/L
Reference substance (positive control):
yes
Remarks:
3.5-Dichlorophenol
Duration:
3 h
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
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
290 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: Ci 95% [230-350 mg/L]
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
890 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: CI 95% [740-1000 mg/L]
Results with reference substance (positive control):
3h-EC50 = 7.9 mg/L with a 95% Confidence Interval < 11 mg/L (13 Dec 2012).
Validity criteria fulfilled:
yes
Conclusions:
3h-NOEC for respiration, activated sludge = 100 mg/L
3h-EC10 for respiration, activated sludge = 290 mg/L
3h-EC50 for respiration, activated sludge = 890 mg/L
Executive summary:

In a 3-h acute toxicity test, activated domestic sewage sludge were exposed to Aqueous solution of Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid at nominal concentrations of 0 - 100 - 320 - 1000 - 3200 and 10000 mg/L. 3, 5-dichlorophenol was used as reference material. The study was performed according to the OECD Guideline No 209 (1984). The 3h-EC50 value was determined at 890 mg/L (based on nominal concentrations).

This study is classified as acceptable and satisfies the guideline requirements for toxicity to microorganisms study with Activated Sludge.

Results synopsis

Activated sludge

Static conditions

3h-NOEC for respiration, activated sludge = 100 mg/L

3h-EC10 for respiration, activated sludge = 290 mg/L (CI 95% 230 -350 mg/L)

3h-EC50 for respiration, activated sludge = 890 mg/L (CI 95%740 -1000 mg/L)

Endpoint Effected: respiration

Description of key information

3h-NOEC for respiration, activated sludge = 100 mg/L
3h-EC50 for respiration, activated sludge = 890 mg/L (CI 95%740 -1000 mg/L)

Key value for chemical safety assessment

EC50 for microorganisms:
890 mg/L
EC10 or NOEC for microorganisms:
100 mg/L

Additional information

In a 3-h acute toxicity test, activated domestic sewage sludge were exposed toAqueous solution of Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acidat nominal concentrations of 0 - 100 - 320 - 1000 - 3200 and 10000 mg/L. 3, 5-dichlorophenol was used as reference material. The study was performed according to the OECD Guideline No 209 (1984). The 3h-EC50 value was determined at 890 mg/L (based on nominal concentrations of the test material).

This study is classified as acceptable and satisfies the guideline requirements for toxicity to microorganisms study with Activated Sludge.

Results synopsis

Activated sludge

Static conditions

3h-NOEC for respiration, activated sludge = 100 mg/L

3h-EC10 for respiration, activated sludge = 290 mg/L (CI 95% 230 -350 mg/L)

3h-EC50 for respiration, activated sludge = 890 mg/L (CI 95%740 -1000 mg/L)