Octanoic acid, compound with dicyclohexylamine (1:1)

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1990-03-08

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Deviations:

not specified

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge

Details on inoculum:

Concentration of activated sludge: 6 g/l

Test type:

static

Water media type:

not specified

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20.0 - 20.2 °C

pH:

7.9 - 8.5

Nominal and measured concentrations:

Nominal:
100, 1000, 10000 mg/l

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

other: EC05

Effect conc.:

210 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

275 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

712 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

other: EC95

Effect conc.:

2 414 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Validity criteria fulfilled:

yes

Conclusions:

Toxicity to microorganisms of dicyclohexylamine has been investigated in a respiration inhibition test conducted similar to OECD test methods.The EC50 was estimated as 712 mg/L.

Executive summary:

Toxicity to microorganisms of dicyclohexylamine has been investigated in a respiration inhibition test conducted similar to OECD test methods.The EC50 was estimated as  712 mg/L.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

other: CLH Report

Adequacy of study:

key study

Study period:

2013-06-06

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

Deviations:

not specified

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

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

Test organisms (species):

activated sludge

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Nominal and measured concentrations:

Nominal:
10, 32, 100, 320 and 1000 mg/L

Reference substance (positive control):

no

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

>= 837 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: results given for octanoic acid on equimolar basis

Validity criteria fulfilled:

yes

Conclusions:

Toxicity to microorganisms of the read across substance decanoic acid has been investigated in a respiration inhibition test conducted according to OECD Guideline 209.The NOEC was estimated as > 1000 mg/L. The NOEC for octanoic acid can therefore be calculated as ≥ 873 mg/l.

Executive summary:

Toxicity to microorganisms of the read across substance decanoic acid has been investigated in a respiration inhibition test conducted according to OECD Guideline 209.The NOEC was estimated as  > 1000 mg/L. The NOEC for octanoic acid can therefore be calculated as ≥ 873 mg/l.

Description of key information

Since the substance to be registered is Octanoic acid, compound with dicyclohexylamine (1:1) which will dissociate to 1 mol octanoic acid and 1 mol dicyclohexylamine and the EC50 for DCHA and the NOEC for octanoic acid are of the same order of magnitude, the LC50 of 712 mg/l for DCHA is used for the entire substance.

Therefore the LC50 for toxicity to microorganism for Octanoic acid, compound with dicyclohexylamine (1:1) is 712 mg/ml.

DCHA:

Toxicity to microorganisms of dicyclohexylamine has been investigated in a respiration inhibition test conducted similar to OECD test methods.The EC50 was estimated as  712 mg/L.

Octanoic acid:

Toxicity to microorganisms of the read across substance decanoic acid has been investigated in a respiration inhibition test conducted according to OECD Guideline 209.The NOEC was estimated as  > 1000 mg/L. The NOEC for octanoic acid can therefore be calculated as ≥ 873 mg/l.

Key value for chemical safety assessment

EC50 for microorganisms:

712 mg/L

Additional information

Read Across justification:

In aqueous systems Octanoic acid, compound with dicyclohexylamine (1:1) is hydrolytically very unstable so that in aqueous solution a rapid decomposition to the educts can be observed. The substance will rapidly dissociate to octanoic acid and dicyclohexylamine. Therefore Octanoic acid, compound with dicyclohexylamine (1:1) is not stable at “standard” testing conditions representative for human and environmental exposure. Hence, it is fully justified to apply the read-across methodology by use of the respective data from the breakdown/decomposition products to describe the (eco)toxicological behaviour of the substance to be registered.