7-azatridecane-1,13-diamine

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

For details on endpoint specific justification please see read-across report in section 13 or find a link in cross-reference “read-across: supporting information”.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

assessment report

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

179 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

BHT

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 95% CL: 143-231 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The 3-hour EC50 of the test item BHT amine on the activated sludge respiration was found to be 335 mg/L with 95% confidence limits from 267 to 432 mg/L.
The 3-hour EC10 was found to be 12 mg/L with 95% confidence limits from 6.4 to 18 mg/L.
The EC50 of 335 mg/L for the test item BHT amine (with 53.5% BHT) leads to a EC50 of 179 mg BHT/L

Executive summary:

The inhibitory effect of the test item BHT amine on the respiration rate of aerobic wastewater micro-organisms of activated sludge was investigated in a 3-hour respiration inhibition test according to the OECD Guideline for Testing of Chemicals, No. 209, adopted 2010.

Range-finding test

A range-finding test using the following three test item concentrations of 10 mg/L, 100 mg/L and 1000 mg/L and four blank controls was performed. As a positive control, the reference item 3,5-dichlorophenol was tested under identical test conditions at concentrations of 3.2, 10 and 32 mg/L.

The results of the blank and positive control treatments confirmed suitability of the activated sludge and the method used. The validity criteria were fulfilled.

In conformity with the guideline, since in the range-finding test the test item showed inhibitions of the respiration rate of 65, 26 and 6.4% for the test item concentrations of 1000, 100 and 10 mg/L, respectively, a definitive test was performed.

Definitive test

Based on the results of the range-finding test and in agreement with the Sponsor a definitive test with the following nominal test item concentrations was performed: 10, 32, 100, 320 and 1000 mg/L with three replicates per concentration to permit the determination of the EC50.

As a positive control, the reference item 3,5-dichlorophenol was tested under identical test conditions at concentrations of 3.2, 10 and 32 mg/L (all single replicates).

Six blank controls, containing an equal volume of activated sludge and synthetic medium but no test or reference item were included in the definitive test.

The vessels were prepared in the following order: two blank controls, the reference item group (with ascending concentrations), two further blank controls, the test item group (with ascending concentrations) and at last two blank control vessels.

 

The mean inhibition of the respiration rates for the tested concentrations was 8.8% at 10 mg/L, 21% at 32 mg/L, 31% at 100 mg/L, 48% at 320 mg/L and 68% at 1000 mg/L compared to the control, i.e. a clear concentration-effect relationship on the inhibition of the respiration rate was determined.

Based on this the ECX values and their 95% confidence limits were as follows:

EC10 12 mg/L, 95% confidence limits: 6.4 - 18 mg/L

EC20: 37 mg/L, 95% confidence limits: 25 - 51 mg/L

EC50: 335 mg/L, 95% confidence limits: 267 - 432 mg/L

EC80: >1000 mg/L.

The EC50 of 335 mg/L for the test item BHT amine (with 53.5% BHT) leads to a EC50 of 179 mg BHT/L.

The study used as source investigated Reaction mass of 7-azatridecane-1,13-diamine and hexamethylenediamine (EC 907 -605 -7, which contains relevant amounts of the submission substance,

7-azatridecane-1,13-diamine).The study results of the source compound were considered applicable to the target compound. Justification and applicability of the read-across approach (structural analogue) is outlined in the read-across report in section 13 or find a link in cross reference “assessment report”.

Description of key information

The inhibitory effect of the test item BHT amine (reaction mass with BHT as main constituent, at 53.5%) on the respiration rate of aerobic wastewater micro-organisms of activated sludge was investigated in a 3-hour respiration inhibition test according to the OECD Guideline for Testing of Chemicals, No. 209, adopted 2010.

Definitive test

Based on the results of the range-finding test a definitive test with the following nominal test item concentrations was performed: 10, 32, 100, 320 and 1000 mg/L with three replicates per concentration to permit the determination of the EC50. As a positive control, the reference item 3,5-dichlorophenol was tested under identical test conditions at concentrations of 3.2, 10 and 32 mg/L (all single replicates).

Six blank controls, containing an equal volume of activated sludge and synthetic medium but no test or reference item were included in the definitive test.

The vessels were prepared in the following order: two blank controls, the reference item group (with ascending concentrations), two further blank controls, the test item group (with ascending concentrations) and at last two blank control vessels.

 The mean inhibition of the respiration rates for the tested concentrations was 8.8% at 10 mg/L, 21% at 32 mg/L, 31% at 100 mg/L, 48% at 320 mg/L and 68% at 1000 mg/L compared to the control, i.e. a clear concentration-effect relationship on the inhibition of the respiration rate was determined.

Based on this the ECX values and their 95% confidence limits were as follows:

EC10 12 mg/L, 95% confidence limits: 6.4 - 18 mg/L

EC20: 37 mg/L, 95% confidence limits: 25 - 51 mg/L

EC50: 335 mg/L, 95% confidence limits: 267 - 432 mg/L

EC80: >1000 mg/L.

The EC50 of 335 mg/L for the test item BHT amine (with 53.5% BHT) leads to a EC50 of 179 mg BHT/L

Key value for chemical safety assessment

EC50 for microorganisms:

179 mg/L