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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 20, 1999
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:
no
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Deviations:
no
Qualifier:
according to
Guideline:
ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Test organisms (species):
activated sludge
Details on inoculum:
- Source of inoculum: Activated sIudge from Iaboratory wastewater plants treating municipal sewage- Preparation of inoculum for exposure: Inoculum was washed, brought to a concentration of 5 g/L dry substance and aerated for about 24 hours. 50 mL were added to a total volume of 250 mL to obtain a concentration of 1 g/L dry substance in the test.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
30 min
Test temperature:
20 ± 2 °C
pH:
7.2-7.5
Dissolved oxygen:
> 6.5 mg/L
Nominal and measured concentrations:
1,000 mg/L
Details on test conditions:
TEST SYSTEM- Test vessel: - Type: Erlenmeyer-vessel (nominal volume 250 mL)- No. of vessels per control (replicates): Triplicate- No. of vessels per blank control (replicates): Triplicate
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Key result
Duration:
30 min
Dose descriptor:
other: EC20
Effect conc.:
> 1 000 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:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
30 min
Dose descriptor:
other: EC80
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Details on results:
Effective concentrations after 30 min incubation time:- EC20; EC50 and EC80 > 1,000 mg/L (nominal)
Results with reference substance (positive control):
Effective concentrations after 30 min incubation time:- EC20 = 3.3 mg/L; EC50 = 23 mg/L; EC80 = 82 mg/L (nominal)
Validity criteria fulfilled:
yes
Remarks:
Deviation of blank controls < 15 %; EC50 of 3,5-dichlorophenol was 5-30 mg/L.
Conclusions:
Under the test conditions, the EC20, EC50 and EC80 (30 min) values of the test substance were determined to be > 1,000 mg/L.
Executive summary:

A study was performed to assess the inhibitory effect of amine synergist on the oxygen consumption rate of aerobic microorganisms (activated sludge) according to OECD Guideline 209, EU Method C.11 and ISO 8192.

Activated sIudge from municipal sewage was exposed to the test substance (1,000 mg/L) for 30 min and analysed for oxygen consumption rate. 3,5-dichlorophenol was used as reference material. The EC50 (30 min) of the reference material was estimated to be within 5-30 mg/L.

Under the test conditions, the EC20, EC50 and EC80 (30 min) values of the test substance were determined to be > 1,000 mg/L.

Description of key information

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L
EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

A study was performed to assess the inhibitory effect of amine synergist on the oxygen consumption rate of aerobic microorganisms (activated sludge) according to OECD Guideline 209, EU Method C.11 and ISO 8192. The EC20, EC50 and EC80 (30 min) values of the substance were > 1,000 mg/L (nominal) (Werner, 1999).