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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was conducted in conformance to GLP and on the basis of EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test), Cited as Directive 88/302/EEC, C.11
Qualifier:
according to guideline
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Version / remarks:
Cited as Directive 88/302/EEC, C.11
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
no
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Laboratory culture:
- Pretreatment: Aeration, daily feed with synthetic medium; pH 7.6
Test type:
static
Water media type:
freshwater
Total exposure duration:
3 h
Remarks on exposure duration:
16.5 h was the stirring period of test item before the start of incubation
Test temperature:
20 +/- 2 °C (concerning the highest concentration of 10000 mg/l)
pH:
8.2 (concerning the highest concentration of 10000 mg/l)
Dissolved oxygen:
O2-start 5.1; O2-end 3.3 (concerning the highest concentration of 10000 mg/l)
Nominal and measured concentrations:
100, 1000 and 1000 mg/l
Details on test conditions:

TEST MEDIUM
Test concentration of the activated sludge: 480 mg/l suspended solids


OTHER TEST CONDITIONS
- Adjustment of pH: 8.2

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : respiration rate

TEST CONCENTRATIONS: 3 (100, 1000, 10000 mg/l)
Reference substance (positive control):
yes
Remarks:
3,5-Dichlorphenol (5, 10, 20 mg/l)
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
> 10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate

Propylidynetrimethanol, propoxylated showed 2.7% respiration inhibition of activated sludge at a test item concentration of 10000 mg/l, hence the EC10 > 10000 mg/l.

Conclusions:
Propylidynetrimethanol, propoxylated showed 2.7% respiration inhibition of activated sludge at a test item concentration of 10000 mg/l, hence the E10 > 10000 mg/l.

Description of key information

3 hr (domestic sludge respiration rate inhibition) EC10 is >10'000 mgl/l . No inhibition of respiration was observed.

Key value for chemical safety assessment

Additional information

Toxicity to microorganisms has been tested with a sample of activated sludge from a domestic waste water treatment plant over a 3 hr period at nominal concentrations from 100 to 10'000 mgl/l. No effects were observed and the EC10 value is >10'000 mgl/l.