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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
From August 02, 1990 to September 03, 1990
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Refer to the Quaternary ammonium salts (QAS) category or section 13 of IUCLID for details on the category justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
yes
Remarks:
Instead of using 3,5-dichlorophenol as reference (acc. to OECD 209) potassium dichromate was used in a concentration to inhibit respiration of 50%.
GLP compliance:
no
Analytical monitoring:
no
Details on sampling:
Not applicable as nominal test concentrations are evaluated
Vehicle:
no
Details on test solutions:
No further details available
Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Laboratory culture: activated sludge from municipal waste water treatment plant Hildesheim
- Method of cultivation:
- Preparation of inoculum for exposure: washed twice with dechlorinated, autoclaved tap water
- Pretreatment: none
- Initial biomass concentration: 1.251 g/L dry weight
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Post exposure observation period:
Not applicable
Hardness:
Not specified
Test temperature:
22°C
pH:
Not specified
Dissolved oxygen:
Not specified
Salinity:
Not specified
Nominal and measured concentrations:
Nominal: 10 - 18 - 32 - 58 - 100 - 180 mg/L
Details on test conditions:
TEST SYSTEM

- Test vessel:500 mL Erlenmeyer flasks
- Type (delete if not applicable): not specified
- Material, size, headspace, fill volume: 500mL
- Aeration: yes, permanently
- Type of flow-through (e.g. peristaltic or proportional diluter): not specified
- Renewal rate of test solution (frequency/flow rate):not specified
- No. of organisms per vessel:not specified
- No. of vessels per concentration (replicates):1
- No. of vessels per control (replicates):1


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic water acc. to OECD 209

OTHER TEST CONDITIONS
- Adjustment of pH: not specified
- Photoperiod: not specified
- Light intensity: not specified
Reference substance (positive control):
yes
Remarks:
kaliumdichromat
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
9.5 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.:
16 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
Respiration rate
Key result
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
43 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: EC80
Effect conc.:
120 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
Respiration rate
Details on results:
No further details available
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: 32 - 58 - 100 mg/ L

No further details available

Validity criteria fulfilled:
yes
Conclusions:
Under the study conditions, the 3 h EC 10 and EC50 (in activated sludge) of the test substance was determined to be 9.5 and 43 mg/L, respectively.
Executive summary:

A study was conducted to determine the toxicity of the read across substance, C20-22 TMAC (active content not specified), to microorganisms according to OECD Guideline 209 (Activated Sludge Respiration Inhibition Test). Approximately 1.251 g/L dry weight of activated sludge (domestic) was exposed to the test substance at nominal concentrations of 10, 18, 32, 58, 100 and 180 mg/L for 3 h. A positive control group (Potassium dichromate) was included in the experiment and gave values within the expected range. Under the study conditions, the 3 h EC10 and EC50 (in activated sludge) of the test substance was determined to be 9.5 and 43 mg/L (nominal), respectively (Hildesheim, 1990). Based on the results of the read across study, similar EC50 values can be expected for the test substance, C18-22 TMAC.

Description of key information

Based on the results of the read across study, the 3 h EC10 and EC50 (in activated sludge) of the test substance, C18-22 TMAC, is considered to be 9.5 and 43 mg/L, respectively (nominal).

Key value for chemical safety assessment

EC50 for microorganisms:
43 mg/L
EC10 or NOEC for microorganisms:
9.5 mg/L

Additional information

A study was conducted to determine the toxicity of the read across substance, C20-22 TMAC (active content not specified), to microorganisms according to OECD Guideline 209 (Activated Sludge Respiration Inhibition Test). Approximately 1.251 g/L dry weight of activated sludge (domestic) was exposed to the test substance at nominal concentrations of 10, 18, 32, 58, 100 and 180 mg/L for 3 h. A positive control group (Potassium dichromate) was included in the experiment and gave values within the expected range. Under the study conditions, the 3 h EC10 and EC50 (in activated sludge) of the test substance was determined to be 9.5 and 43 mg/L (nominal), respectively (Hildesheim, 1990). Based on the results of the read across study, similar EC50 values can be expected for the test substance, C18-22 TMAC, for toxicity to microorganisms.