2-cyclohexylethyl acetate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-cyclohexylethyl acetate

EC Number:

244-543-3

EC Name:

2-cyclohexylethyl acetate

Cas Number:

21722-83-8

Molecular formula:

C10H18O2

IUPAC Name:

2-cyclohexylethyl acetate

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

The stock solution used in the range-finding test was prepared by dissolving 0.025 g of the
test substance in 250 mL with OECD medium, resulting in a concentration of 100 mg.L-1.
The stock solution used in the definitive test was prepared by dissolving 1.0 g of the test
substance in 1000 mL with OECD medium, resulting in a concentration of 1000 mg.L-1.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

The unicellular green alga species Pseudokirchneriella subcapitata used is part of the Chloroficeae group, Chlorococcales order.

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test conditions

Test temperature:

22.1 to 22.2°C

pH:

7.8-8.1

Details on test conditions:

The definitive test was carried out under the conditions described below:
Temperature: 22.1 to 22.2°C
Light: 4716 lux (average)
Photoperiod: continuous light
Shaker velocity: 130 rpm (average)
Test duration: 72 hours

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

other: EyC50

Effect conc.:

ca. 28.44 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

other: yield growth inhibition

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

other: ErC50

Effect conc.:

ca. 126.59 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

growth rate

Details on results:

The 72-hours EyC50 value of test substance, obtained in this study with Pseudokirchneriella subcapit ata, was 28.44 mg.L-1 (95% confidence limits = 23.97 to 33.75 mg.L-1) and the 72-hours ErC50 value was 126.59 mg.L-1 (95% confidence limits = 102.48 to 156.38 mg.L-1). The highest concentration of the test substance in which was not observed any statistically significant adverse effect on algal growth (NOEC) over the test period (72 hours) was 3.2 mg.L-1 and the lowest test substance concentration at which was observed significant reducing effect on growth (LOEC) was 10 mg.L-1.

Results with reference substance (positive control):

The 72-hours EyC50 value of the reference substance potassium dichromate was 0.70 mg.L-1 (confidence limits at 95% = 0.64 to 0.77 mg.L-1), demonstrating that the toxic sensitivity of the algae was within the accepted range (ISO, 1989), which report toxicity ranged between 0.60 and 1.03 mg.L-1.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72-hours EyC50 value for alga Pseudokirchneriella subcapitata exposed to Cyclohexyl Ethyl Acetate was 28.44 mg.L-1 and the 72-hours ErC50 value was 126.59 mg.L-1. The highest test substance concentration with no observed significant adverse effect (NOEC) on algal growth was 3.2 mg.L-1 and the lowest test substance concentration at which was observed significant reducing effect on growth (LOEC) was 10 mg.L-1.