Octanoic acid, compound with dicyclohexylamine (1:1)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-01-27 - 1993-03-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

not specified

GLP compliance:

no

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Test concentrations: 0.008, 0.016, 0.031, 0.063, 0.125, 0.25, 0.5, 1 mg/l

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

pH:

10.3 - 10.4

Nominal and measured concentrations:

Nominal test concentrations: 0.008, 0.016, 0.031, 0.063, 0.125, 0.25, 0.5, 1 mg/l

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.016 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.031 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Conclusions:

The toxicity towards aquatic algae of dicyclohexylamine was evaluated according to EU method C.3. The NOEC for inhibition of specific growth rate after 72 hours was 0.016 mg/l. The EC50 was estimated as > 1mg/l.

Executive summary:

The toxicity towards aquatic algae of dicyclohexylamine was evaluated according to EU method C.3. The NOEC for inhibition of specific growth rate after 72 hours was 0.016 mg/l. The EC50 was estimated as > 1mg/l.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

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 201 (Alga, Growth Inhibition Test)

Deviations:

not specified

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

not specified

Test organisms (species):

Scenedesmus sp.

Test type:

static

Water media type:

not specified

Limit test:

no

Total exposure duration:

72 h

Hardness:

not specified

Test temperature:

not specified

pH:

not specified

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

not specified

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.67 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: results given for octanoic acid on equimolar basis

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.47 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: results given for octanoic acid on equimolar basis

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of the read across substance decanoic acid towards Scenedesmus subspicatus was determined according to OECD 201. The calculated ErC50 was 2 mg/L (results given in Octanoic acid on equimolare basis: 1.67 mg/L Octanoic acid).

Executive summary:

The toxicity of the read across substance decanoic acid towards Scenedesmus subspicatus was determined according to OECD 201. The calculated ErC50 was 2 mg/L ( result given in Octanoic acid on equimolare basis: 1.67 mg/L Octanoic acid).

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, the lowest EC50 of 1 mg/l and the lowest NOEC of 0.016 mg/l for DCHA acid is calculated for the entire substance considering the molar mass of 325.5 g/mol (55.7% DCHA).

Therefore the EC50 for aquatic algae for Octanoic acid, compound with dicyclohexylamine (1:1) is 1.8 mg/ml and the NOEC is 0.029 mg/l respectively.

DCHA:

The toxicity towards aquatic algae of dicyclohexylamine was evaluated according to EU method C.3. The NOEC for inhibition of specific growth rate after 72 hours was 0.016 mg/l. The EC50 was estimated as > 1mg/l.

Octanoic acid:

The toxicity of the read across substance decanoic acid towards Scenedesmus subspicatus was determined according to OECD 201. The calculated ErC50 was 2 mg/L (corresponding to 1.67 mg/L Octanoic acid).

Key value for chemical safety assessment

EC50 for freshwater algae:

1.8 mg/L

EC10 or NOEC for freshwater algae:

0.029 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.