cis-2-tert-butylcyclohexyl acetate

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:

19 May 1992 to 12 Mar 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Sampling date: 12-12-1992
- Concentrations: all concentrations, inluding the control
- Sampling method: daily sampling, before and after renewal
- Sample storage conditions before analysis: not specified

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Controls: yes
- Substance dissolved in synthetic freshwater according to ISO, by means of Ultra-Turrax (60 sec. at 8000 RPM)

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

- Source: West-Aquarium (Bad Lauterberg)
- Age at study initiation: about 2 months
- Length at study initiation: 2.5 - 3.5 cm
- Mortality during acclimation: < 2%

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

14.2 ºdH

Test temperature:

20.2 - 22.8 ºC

pH:

7.6 - 8.2

Dissolved oxygen:

7.5 - 9.7 mg/L

Nominal and measured concentrations:

- Nominal: 0, 7.8, 11 and 16 mg/L.
- Measured*: 0, 1.0, 1.5 and 2.9 mg/L

* values are calculated as arrythmic means of concentrations measured just before each renewal of test medium (after 24 hours). The limit of quantification (LOQ) of the analytical method was 1 mg/L; values below the LOQ were evaluated as half the LOQ (i.e. 0.5 mg/L).

Details on test conditions:

TEST SYSTEM:
- Test vessel: 300 x 135 x 200 mm
- No. of organisms per vessel: 10
- Aeration: yes
- Renewal rate of test solution: every 24 hours

TEST MEDIUM / WATER PARAMETERS:
- Source/preparation of dilution water: synthetic freshwater according to ISO, 5 L per aquarium
- Intervals of water quality measurement: 24 hours

OTHER TEST CONDITIONS:
- Photoperiod: 16-hour light and 8-hour dark cycle

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

5.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: See discussion section

Details on results:

ABNORMAL RESPONSES:
After 96 hours of exposure to 11 mg/L (nominal concentration), 6 animals showed slow lethargic swimming behaviour and 2 animals showed slow lethargic swimming behaviour and anomalous orientation.

Sublethal observations / clinical signs:

Cumulative mortality data from the toxicity test with Brachydanio rerio.

Nominal concentration (mg/L)	Cumulative mortality (%)
	2h	24h	48h	72h	96h
control	0	0	0	0	0
7.8	0	0	0	0	0
11	0	0	0	20	20
16	0	0	0	100	100

Validity criteria fulfilled:

yes

Conclusions:

The 96-hour LC50 of the test substance to zebrafish (Danio rerio) was 5.6 mg/L.

Executive summary:

Introduction and methods: The acute toxicity of Verdox to fish was determined in a GLP-compliant EU Acute toxicity to fish (C.1). In this semi-static test, groups of 10 zebra fish (Danio rerio) were exposed for 96 hours to nominal test concentrations of 0, 7.8, 11 and 16 mg/L of the test substance in ISO-water. Samples of the test solutions were taken at the start of the test and after each 24-hour renewal and analysed by gas chromatography (GC).

Results: Measured concentrations at t=0 were already much lower than the nominal concentration and at 24 h the test substance decreased to ca 25 to 30% of the initial measured concentration. At initial measured concentration of 6 mg/l (and 2.6 mg/l after 24 h): 20% mortality was seen (at nominal concentration of 11 mg/l at 72h exposure). At these concentrations also lethargic effects were seen in fish. At initial measured concentration of 13 mg/l (and 5 mg/l after 24 h): 100% mortality was seen (at nominal concentration of 16 mg/l and 72h exposure)

At initial measured concentrations up to 6 mg/l no mortality was observed and also not a 2.6 mg/l when measured at 24h (nominal concentration was 11 mg/l). 100% mortality was observed at 13.2 mg/l.

Discussion: The test result can be interpreted such that concentrations of 13 - 5 mg/l cause 100% mortality. These values are around the water solubility of the test substance. Therefore the toxicity may partly due to physical effects, because of the effects seen at the water solubility and the all or nothing effect as well as the lethargic behavior before the fish were dying. The absence of mortality is seen at maximum concentrations of 6 - 2.6 mg/l.

Conclusion: Because no mortality is seen at 6 mg/l initial measured concentration and at 2.6 mg/l finally measured concentrations and 100% mortality at 13 mg/l initial measured and at 5 mg/l finally measured, it seems justified to calculate an LC50 being a geometric mean between 3.9 mg/ (root of 6 x 2.6 mg/l) and 8 mg/l (root of 13x5 mg/l) = 5.6 mg/l. Again this seems to be a worst case value because the physical effects cannot be excluded.

Description of key information

The acute toxicity of Verdox to fish was determined in a GLP-compliant EU Acute toxicity to fish (C.1). In this semi-static test, groups of 10 zebra fish (Danio rerio) were exposed for 96 hours to nominal test concentrations of 0, 7.8, 11 and 16 mg/L of the test substance in ISO-water. Samples of the test solutions were taken at the start of the test and after each 24-hour renewal and analysed by gas chromatography (GC).

Measured concentrations at t=0 were already much lower than the nominal concentration and at 24 h the test substance decreased to ca 25 to 30 % of the initial measured concentration. At initial measured concentration of 6 mg/l (and 2.6 mg/L after 24 h): 20 % mortality was seen (at nominal concentration of 11 mg/L at 72 h exposure). At these concentrations also lethargic effects were seen in fish. At initial measured concentration of 13 mg/L (and 5 mg/L after 24 h): 100 % mortality was seen (at nominal concentration of 16 mg/L and 72 h exposure). At initial measured concentrations up to 6 mg/l no mortality was observed and also not a 2.6 mg/L when measured at 24 h (nominal concentration was 11 mg/L) 100 % mortality was observed at 13.2 mg/L.

The test result can be interpreted such that concentrations of 13 - 5 mg/L (initial and final measured) cause 100 % mortality. These values are around the water solubility of the test substance. Therefore the toxicity may partly due to physical effects, because of the all or nothing effect as well as the lethargic behaviour before the fish were dying. The absence of mortality is seen at maximum concentrations of 6 -2.6 mg/L (initial and final measured). Because no mortality is seen at 6 mg/L initial measured concentration and at 2.6 mg/L finally measured concentrations and 100 % mortality at 13 mg/L initial measured and at 5 mg/L finally measured, it seems justified to calculate an LC50 of 5.6 mg/L, being a geometric mean between 3.9 mg (root of 6 x 2.6 mg/L) and 8 mg/L (root of 13x5 mg/L). Again this seems to be a worst case value because the physical effects cannot be excluded.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

5.6 mg/L