Ethylcyclohexane

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2005-11-11 - 2006-01-18

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:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Molecular formula
C8H16
Molecular weight
112.21.5
CAS number
1678-91-7
Purity
99.5% (GC)

Details on sampling:

The concentration of the test substance in the test solution was measured at the beginning and the end of the exposure. Separately, the container prepared for the analytical sample was allowed to stand for 1 hour, and then the test liquid for measurement at the start of exposure was collected. After standing for 1 hour after the end of shaking culture, equal amounts of test liquid for measurement at the end of exposure were taken from each of the two test vessels for each test concentration and mixed, respectively. The test substance concentration was analyzed by gas chromatography (GC).

Vehicle:

no

Details on test solutions:

A required amount of test sample was fractionated using pushbutton micropipettes and directly added to the medium contained in the closed type test container. Thereafter, it was prepared by stirring from the day before the start of exposure with a magnetic stirrer at 21°C to 24°C. (fluctuation range of ± 2°C.). The purity (99.5%) of the test solution was not corrected.

Test organisms (species):

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

Details on test organisms:

(1) species
Pseudokirchneriella subcapitata (ATCC22662)
(formerly: Selenastrum capricornutum)
(2) Reason for selection of species
It is the type recommended in the test guidelines.
(3) Supply source
Pseudokirchneriella subcapitata which were obtained from June 30, 1995, from the American Type Culture Collection (12301 Parklawn Drive Rockville, Maryland 20852-1776 U.SA) and subcultured at CERI Kurume was used. EbC50(0-72h) and ErC50(0-3d) of potassium dichromate (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) by the test organisms conducted (from August 29 to September 1, 2005) in order to confirm the reproducibility of the test system were 0.492 and 1.09 mg/L, respectively. [Background data: The mean ± standard deviation of EbC50(0-72h) and ErC50(0-3d) are 0.408 ± 0.079 and 1.12 ± 0.44 mg/L respectively, n = 10 [However, ErC50(0-3d) includes extrapolation value].

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23.8°C to 24.8°C

pH:

7.8 to 7.9 at the beginning of exposure and 8.1 to 10.5 at the end of exposure

Nominal and measured concentrations:

Nominal: 5, 14, 38.8, 108, 300 μl/L
Measured: 0.0424, 0.0639, 0.218, 0.756, 1.89 mg/l

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.633 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.413 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.406 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.218 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.218 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.218 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of ethylcyclohexane to the unicellular freshwater green alga Pseudokirchnerella subcapitata was determined according to the principles of OECD guideline 201.
The 72-hour EC50 value for growth rate reduction (ErC50) was 0.63 mg/L and the NOEC was 0.218 mg/L respectively.

Executive summary:

The toxicity of ethylcyclohexane to the unicellular freshwater green alga Pseudokirchnerella subcapitata was determined according to the principles of OECD guideline 201.

The 72-hour EC50 value for growth rate reduction (ErC50) was 0.63 mg/L and the NOEC was 0.218 mg/L respectively.

Description of key information

The toxicity of ethylcyclohexane to the unicellular freshwater green alga Pseudokirchnerella subcapitata was determined according to the principles of OECD guideline 201.

The 72-hour EC50 value for growth rate reduction (ErC50) was 0.63 mg/L and the NOEC was 0.218 mg/L respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.63 mg/L

EC10 or NOEC for freshwater algae:

0.218 mg/L