Ethylcyclohexane

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2005-09-16 - 2006-01-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

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)

Analytical monitoring:

yes

Details on sampling:

The test substance concentration was measured at the beginning of exposure and before and after water exchange (except after water exchange after 96 hours) For the exposure levels where all the individuals died, it was measured when all the individuals' deaths were confirmed. At the beginning of the exposure and after the water exchange, the separately collected test solution was measured, and before the water exchange, the sample collected from the middle layer of the test container was measured. The test substance concentration was analyzed by gas chromatography (GC).

Vehicle:

no

Details on test solutions:

The test sample was added to 5.0 L Erlenmeyer flasks (x2) filled with test water to a concentration of about 50 μL/L using a push-button micropipette. After the addition, the mixture was sealed tightly so as not to generate a gas phase immediately, and stirred with a magnetic stirrer at room temperature for about 24 hours to prepare a saturated solution. Thereafter, it was allowed to stand at 24 ± 1°C for about 1 hour, and the middle layer was collected and used as the test stock solution. A necessary amount of test stock solution and test water were mixed and stirred in a preparation container to prepare a test solution. The test container was sealed so as not to generate a gas phase.

Test organisms (species):

Oryzias latipes

Details on test organisms:

Test organism
(1) species
Japanese Medaka (Oryzias latipes)
(2) Reason for selection of species
It is the type recommended in the test guidelines.
(3) Size
Total length: 2.3 ± 1.2 cm
(4) Source
Produced in-house at CERI Kurume.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

120 h

Remarks on exposure duration:

Although the duration in the test method is up to 96 hours, due to poor water solubility of the test substance, the exposure duration was extended to 120 hours

Test temperature:

24 ± 1°C

pH:

7.3 - 7.8

Dissolved oxygen:

7.2 - 8.7 mg/L

Nominal and measured concentrations:

Measured:
0.338, 0.487, 0.622, 0.944, 1.56 mg/l

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.746 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

1.56 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

0.338 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Validity criteria fulfilled:

yes

Conclusions:

In a 120-h acute toxicity study according to OECD Guideline 203, Japanese rice fish (Oryzias latipes) were exposed under semi-static conditions to analytically measured test concentrations of ethylcyclohexane.The 96h-EC50 was 0.746 mg/l based on the geometric mean value of the measured concentrations (95% confidence interval between 0.606–0.971 mg/L).

Executive summary:

In a 120-h acute toxicity study according to OECD Guideline 203, Japanese rice fish (Oryzias latipes) were exposed under semi-static conditions to analytically measured test concentrations of ethylcyclohexane.The 96h-EC50 was 0.746 mg/l based on the geometric mean value of the measured concentrations (95% confidence interval between 0.606–0.971 mg/L).

Description of key information

Japanese rice fish:

In a 120-h acute toxicity study according to OECD Guideline 203, Japanese rice fish (Oryzias latipes) were exposed under semi-static conditions to analytically measured test concentrations of ethylcyclohexane.

The 96h-EC50 was 0.746 mg/l based on the geometric mean value of the measured concentrations (95% confidence interval between 0.606–0.971 mg/L).

Striped bass:

The acute toxicity of ethylcyclohexane towards striped bass was estimated in a static 96-hour test. The 96-hour LC50 was 8.8 mg/l.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.746 mg/L