4-tert-pentylcyclohexanone

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: read-across from a guideline study

Justification for type of information:

The acute fish toxicity of Orivone is based on read-across from p-tert-butylcyclohexanon. The documentation is presented in the Endpoint summary of Aquatic toxicity.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

4 mg/L

Basis for effect:

mortality (fish)

Remarks on result:

other: The LC50 was determined as geometric mean from the LC0 and LC50 value (mean meausured concentrations)

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 Sep 2002 to 13 Sep 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

This information is used for read across to Orivone.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Sampling of the control and test concentrations occurred every 24 hours, from both the old and the freshly prepared medium.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution (10 mg/L) was prepared daily to give the desired series of test concentrations. To achieve this the test substance was pulverized, then added to 10 litres of dilution water and treated for 1 h in an ultrasonic bath.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebra fish
- Source: Aqua KloeGer
- Date supplied: July 29, 2002
- Length at study initiation: 2.95 cm (SD = 0.29 cm; n=60)

ACCLIMATION
- Acclimation period: stock held since 29 Jul 2002 and acclimatised to the test conditions since then (43 days)
- Acclimation conditions: same as test, although under flow-through conditions (temperature 20 - 24 °C, dissolved oxygen > 5 mg/L)
- Type and amount of food during acclimation: commerical fish feed
- Feeding frequency during acclimation: daily, discontinued 24h prior to test
- Mortality: < 2% during acclimation period
- Medication: none

FEEDING DURING TEST
Animals were not fed during the exposure period

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

201.7 mg/L (as CaCO3)

Test temperature:

21.5 - 22.9 °C

pH:

7.7 - 8.1

Dissolved oxygen:

7.9 - 8.7 mg/L

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 0.63, 1.25, 2.5, 5 and 10 mg/L
- Measured concentrations: < 0.1 mg/L (control); test concentrations ranged from 79.4 - 104.2% of nominal values in the freshly prepared medium and from 41.3 - 79.8% of nominal values after 24 hours of exposure.

Details on test conditions:

TEST SYSTEM
- Test vessel: glass aquaria
- Fill volume: glass, 5 litres
- Aeration: yes, gentle via narrow glass tubes
- Renewal rate of test solution: daily
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.79 g body weight (wet weight) per litre
- Method if initiation: animals were placed in prepared media

TEST MEDIUM / WATER PARAMETERS
- Preparation of dilution water: Reconstituted water prepared according to the recommendations of ISO 7346. This freshly prepared standard dilution water is used for both, the maintenance of the test animals under flow-through conditions and the preparation of stock and test solutions of the test substance.
- Culture medium different from test medium: no
- Intervals of water quality measurement: Before and after daily refresh

OTHER TEST CONDITIONS
- Photoperiod: 16 h light : 8 h dark

EFFECT PARAMETERS MEASURED:
- Mortality and sub-lethal effects (type and incidence) were determined at 2, 24, 48, 72 and 96 hours after the start of the exposure
- pH and oxygen values are measured at the beginning of the test and every 24 hours thereafter.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: no

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Geometric mean of the LC0 and LC100

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

1.86 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

8.61 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No mortality or behavioral abnormalities were observed over the entire exposure period up to a concentration of 5 mg/L. At 5 mg/L, 5 fish had died after 48 hours, which increased to a total of 7 fish after 72 hours (up to the end of the exposure). At 10 mg/L, all fish had died after 24 hours. See ‘Any other information on results incl. tables’ for additional information on mortality and an overview on behavioral abnormalities observed at the two highest test concentrations.

Results with reference substance (positive control):

No positive control was used.

Sublethal observations / clinical signs:

Table: Incidence of mortality and total mortality during the test (initial population: 10)

Nominal concentration (mg/L)	Cumulative mortality					Total mortality (%)
	2h	24h	48h	72h	96h
0 (control)	0	0	0	0	0	0
0.63	0	0	0	0	0	0
1.25	0	0	0	0	0	0
2.5	0	0	0	0	0	0
5	0	5	7	7	7	70
10	0	10	10	10	10	100

Table: Incidence of abnormalities, observed only at the two highest test concentrations

Nominal concentration (mg/L)	Abnormalities	Exposure period
		2h	24h	48h	72h	96h
5	Abnormal swimming action	2/10	0/5	0/3	0/3	0/3
	Abnormal behaviour	8/10	3/5	1/3	1/3	0/3
10	Abnormal swimming action	4/10	+
	Moribund	3/10	+
	Abnormal behaviour	3/10	+

+ all fish dead

Validity criteria fulfilled:

yes

Conclusions:

The 96-h LC50 value is 4.0 mg/L (geometric mean LC0/LC100) in zebra fish (D. rerio).

Executive summary:

The short-term toxicity to freshwater fish was determined in a study according to OECD TG 203 and in compliance with GLP criteria. In this study, groups of 10 zebra fish (D. rerio) were exposed for 96 hours to nominal test concentrations of 0 (control), 0.63, 1.25, 2.5, 5 and 10 mg/L. The study was semi-static with a 24-hour renewal rate of test media. Test concentrations were analytically verified before and after daily renewals. The measured concentrations ranged from 79.4 - 104.2% of nominal values in the freshly prepared medium and from 41.3 - 79.8% of nominal values after 24 hours of exposure. Therefore, effect values are reported as mean measured concentrations. Incidences of mortality and abnormalities were recorded after 2, 24, 48, 72 and 96 hours exposure.

Abnormalities were observed up to 72 hours exposure in the 5 mg/L group and up to 2 hours exposure in the 10 mg/L group (preceding mortality). Abnormalities consisted of abnormal swimming action, abnormal behaviour and moribund behaviour. No mortality occurred up to a nominal test concentration of 2.5 mg/L. At the test concentration 5 mg/L, 7 fish were dead after 96 hours exposure (70% mortality). At the highest test concentration of 10 mg/L, all fish were dead after 24 hours exposure. Based on these findings, the 96-h LC0 is determined at 1.86 mg/L and the 96-h LC100 at 8.61 mg/L. The 96-h LC50 was calculated as geometric mean of the LC0 and LC100 (mean measured concentrations) to be 4.0 mg/L. In this study all OECD validity criteria were met.

Description of key information

No data is available for Orivone. Therefore read-across is performed to the close structural analogue p-tert-butylcyclohexanone (CAS 98-53-3). Its short-term toxicity to freshwater fish was determined in a study according to OECD TG 203 and in compliance with GLP criteria. In this study, groups of 10 zebra fish (D. rerio) were exposed for 96 hours to nominal test concentrations of 0 (control), 0.63, 1.25, 2.5, 5 and 10 mg/L. The study was semi-static with a 24-hour renewal rate of test media. Test concentrations were analytically verified before and after daily renewals. The measured concentrations ranged from 79.4 - 104.2% of nominal values in the freshly prepared medium and from 41.3 - 79.8% of nominal values after 24 hours of exposure. Therefore, effect values are reported as mean measured concentrations. Incidences of mortality and abnormalities were recorded after 2, 24, 48, 72 and 96 hours exposure. Abnormalities were observed up to 72 hours exposure in the 5 mg/L group and up to 2 hours exposure in the 10 mg/L group (preceding mortality). Abnormalities consisted of abnormal swimming action, abnormal behaviour and moribund behaviour. No mortality occurred up to a nominal test concentration of 2.5 mg/L. At the test concentration 5 mg/L, 7 fish were dead after 96 hours exposure (70% mortality). At the highest test concentration of 10 mg/L, all fish were dead after 24 hours exposure. Based on these findings, the 96-h LC0 is determined at 1.86 mg/L and the 96-h LC100 at 8.61 mg/L. The 96-h LC50 was calculated as geometric mean of the LC0 and LC100 (mean measured concentrations) to be 4.0 mg/L. In this study all OECD validity criteria were met. There is no need to convert the toxicity of the source chemical data towards Orivone, because of the comparable properties of the substances.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

4 mg/L