N-[3-({[2,2-dimethyl-3-(morpholin-4-yl)propylidene]amino}methyl)-3,5,5-trimethylcyclohexyl]-2,2-dimethyl-3-(morpholin-4-yl)propan-1-imine

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

Study period:

from 2014-05-12 to 2014-05-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

2010-07-22

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2008-05-30

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)

Version / remarks:

1996

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

In this study no analytical measurements were performed. Because of the directly added test item the obtained results were referred to the nominal test item concentration.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: test item directly added

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Laboratory culture: The activated sludge was not used on the day of the collection but continuously aerated (2 L/min) activated sludge, fed once with 50 mL synthetic sewage/L activated sludge.
- Preparation of inoculum for exposure: The pH of the activated sludge inoculum was checked just before use: 7.87. pH adjustment of the inoculum was considered as not necessary

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Hardness:

no data

Test temperature:

20 ± 2 °C

pH:

inoculum: 7.87 before use

Dissolved oxygen:

no data

Salinity:

no data

Nominal and measured concentrations:

limit concentration: 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer bottles of approximately 300 mL volume
- Aeration: with compressed air (0.5 L/min)

OTHER TEST CONDITIONS
- Adjustment of pH: not necessary prior to inoculum addition

TEST CONCENTRATIONS
- Range finding study: 3 cocnentrations tested: 10, 100 and 1000 mg/L
- Test concentrations: limit conc.: 1000 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Key result

Duration:

3 h

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

Key result

Duration:

3 h

Dose descriptor:

EC10

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:

3 h

Dose descriptor:

NOEC

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: EC50 = 15.51 mg/L (95 % confidence limits: 12.28 - 19.58 mg/L)

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the performed Activated Sludge Respiration Inhibition Test, the EC10 and EC50 values of test item were determined as higher than 1000 mg/L. Based on the statistical evaluation in this test the NOEC was ≥ 1000 mg/L.

Executive summary:

The purpose of the 3-hour test was to evaluate the influence of the test item Sika Hardener MI (Sika Härter MI) on the activity of the activated sludge by measuring the respiration rate under defined conditions. The respiration rates (total, heterotrophic and nitrification oxygen uptake rates) of samples of activated sludge fed with synthetic sewage were measured in an enclosed cell containing an oxygen electrode after a contact time of 3 hours. Based on the preliminary information about the test item caused effect on the activated sludge inoculum, the test item Sika Hardener MI (Sika Härter MI) was investigated at the concentration of 1000 mg/L as a limit concentration, only. Defined amounts of the test item were added directly into the test vessels. In parallel with the test item treatments 3,5-Dichlorophenol as positive reference control in a concentrations of 2, 7 and 24.5 mg/L; furthermore blank (inoculum) control and nitrification controls were investigated. The main test was performed without abiotic controls, based on the results of the preliminary test where abiotic controls were tested at the test item concentration of 1000 mg/L and no remarkable abiotic oxygen consumption was noticed. The test was performed without pH adjustment. All validity criteria of the study were met. The test item was investigated at one (limit) concentration level of 1000 mg/L. The observed oxygen consumption rates consequently the specific respiration rates were in the range of the blank controls, no inhibitory effect of the test item was observed. Based on measured oxygen consumption values and calculated specific respiration rates it can be stated that the 3-hour EC10 and EC50 values of the test item are higher than 1000 mg/L. The specific respiration rates were compared with the blank control values using 2 Sample t-Test (a=0.05). No statistical significant differences were observed in the comparison with the blank control values, consequently based on the results of this study the NOEC can be statistically and biologically determined as ≥ 1000 mg/L.

Description of key information

In an activated sludge respiration inhibition test the EC50 and EC10 value of SIKA Hardener MI were determined to be >1000 mg/L. The NOEC was determined to be ≥ 1000 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

The purpose of the 3-hour test was to evaluate the influence of the test item Sika Hardener MI (Sika Härter MI) on the activity of the activated sludge by measuring the respiration rate under defined conditions. The respiration rates (total, heterotrophic and nitrification oxygen uptake rates) of samples of activated sludge fed with synthetic sewage were measured in an enclosed cell containing an oxygen electrode after a contact time of 3 hours. Based on the preliminary information about the test item caused effect on the activated sludge inoculum, the test item Sika Hardener MI (Sika Härter MI) was investigated at the concentration of 1000 mg/L as a limit concentration, only. Defined amounts of the test item were added directly into the test vessels. In parallel with the test item treatments 3,5-Dichlorophenol as positive reference control in a concentrations of 2, 7 and 24.5 mg/L; furthermore blank (inoculum) control and nitrification controls were investigated. The main test was performed without abiotic controls, based on the results of the preliminary test where abiotic controls were tested at the test item concentration of 1000 mg/L and no remarkable abiotic oxygen consumption was noticed. The test was performed without pH adjustment. All validity criteria of the study were met. The test item was investigated at one (limit) concentration level of 1000 mg/L. The observed oxygen consumption rates consequently the specific respiration rates were in the range of the blank controls, no inhibitory effect of the test item was observed. Based on measured oxygen consumption values and calculated specific respiration rates it can be stated that the 3-hour EC10 and EC50 values of the test item are higher than 1000 mg/L. The specific respiration rates were compared with the blank control values using 2 Sample t-Test (a=0.05). No statistical significant differences were observed in the comparison with the blank control values, consequently based on the results of this study the NOEC can be statistically and biologically determined as ≥ 1000 mg/L.