1-Propanaminium, 2-hydroxy-N-(2-hydroxypropyl)-N,N-dimethyl-, esters with C18-unsatd. fatty acids, Me sulfates (salts)

Toxicity to microorganisms

Link to relevant study record(s)

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:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Version / remarks:

31 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material: 1-Propanaminium, 2-hydroxy-N-(2-hydroxypropyl)-N,N-dimethyl-, esters with fatty acids, C18 unsatd., Me-sulfates (salts)
- Physical state: liquid
- Analytical purity: 100%

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The relevant amounts of test substance and reference substance were directly weighed into beakers and 170 mL demineralised water were added. For the final
preparations, 9.6 mL synthetic sewage and 120 mL inoculum suspension were added to each mixture.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Laboratory culture: a fresh sample from the aeration basin of a municipal sewage treatment plant (Moers, Germany) was collected one day before carrying out the test
- Preparation of inoculum for exposure: filtration by means of a water jet pump through a filter paper, sludge was washed twice with mineral medium; 50 mL synthetic sewage were added and the whole mixture was stirred and aerated (0.5 - 1.0 litre per minute) overnight at 20 ± 2°C
- Initial biomass concentration: 4 g/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20±2°C

pH:

7.39

Nominal and measured concentrations:

nominal 0, 10, 32, 100, 320 and 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 1 L beaker
- Aeration: compressed synthetic air (0.5 -1.0 litre per minute) under permanent stirring with a magnetic stirrer
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2

OTHER TEST CONDITIONS
- Adjustment of pH: not necessary; with a measured pH value of 7.39, it was within the required range of 6.0 to 8.0

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- pH at start and end of incubation
- oxygen consumption at end of incubation

Reference substance (positive control):

yes

Remarks:

3,5- dichlorophenol: 3.2, 10 and 32 mg/L

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

323.4 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

The respiration rates of the controls showed a coefficient of variation of 8.3%. The EC50 for the reference substance was calculated to be 10.0 mg/L, thus fulfilling the validation criteria mentioned in the test guidelines.

Validity criteria fulfilled:

yes

Conclusions:

The 3 h EC50 of MDIPA Esterquat C18 unsatd. towards activated sludge microorganisms was >1000 mg/L, the 3 h EC10 was 323.4 mg/L.

Executive summary:

In a 3 h respiration inhibition study, activated sludge from the aeration basin of a municipal sewage treatment plant fed with synthetic sewage was exposed to MDIPA Esterquat C18 unsatd. at nominal concentrations of 0 (control), 10, 32, 100, 320 and 1000 mg/L in accordance with EU method C.11 (31 May 2008). 3,5- dichlorophenol at concentrations of 3.2, 10 and 32 mg/L was used as reference substance.

The 3 h EC50 of MDIPA Esterquat C18 unsatd. was determined to be >1000 mg/L, the 3 h EC10 was 323.4 mg/L.

Description of key information

EC10 =323.4 mg/L, EC50 > 1000 mg/L (EU method C.11 (respiration inhibition test) with activated sludge; GLP)

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

EC10 or NOEC for microorganisms:

323.4 mg/L

Additional information

In a 3 h respiration inhibition study, activated sludge from the aeration basin of a municipal sewage treatment plant fed with synthetic sewage was exposed to MDIPA Esterquat C18 unsatd. at nominal concentrations of 0 (control), 10, 32, 100, 320 and 1000 mg/L in accordance with EU method C.11 (31 May 2008). 3,5- dichlorophenol at concentrations of 3.2, 10 and 32 mg/L was used as reference substance.

The 3 h EC50 of MDIPA Esterquat C18 unsatd. was determined to be >1000 mg/L, the 3 h EC10 was 323.4 mg/L.

Similar results were obtained with the closely related read-across substance MDEA-EsterquatC16-18 and C18 unsatd.:

In a 3-hour toxicity study, activated sludge fed with synthetic sewage was exposed to MDEA-EsterquatC16-18 and C18 unsatd.at nominal concentrations of 0 and 47.4 mg a.i./L in accordance with OECD 209 (Activated Sludge Respiration Inhibition). The NOEC based on respiration rate was >47.4 mg a.i./L.