Cyclohexanemethanol, 4-(1-methylethyl)-

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:

October 11, 2011 to October 16, 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Deviations:

yes

Remarks:

Oxygen concentration below 60% saturation in most test vessels due to sealed test vessels as a result of volatile substance. No adverse effects were observed in the control fish, thus, this deviation was considered to not affect the test outcome.

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Inspected on July 19-21, 2011 / Signed on August 31, 2011

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Purity test date: March 21, 2012

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Control, 1.0, 3.2, 5.6, 10
- Sampling method: The test samples plus an amount of sodium chloride and formic acid were extracted directly with a volume of hexane in the bottle. An aliquot of the hexane layer was taken for analysis.
- Sample storage conditions before analysis: -20 °C

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: An amount of test item (1100 mg) was added to 11 liters of dechlorinated tap water and stirred using a propeller stirrer at approximately 1500 rpm for 24 hours to give a 100 mg/L stock solution. Aliquots (200, 360, 640, 1120 and 2000 mL) of this stock solution were each separately added to a final volume of 20 liters of dechlorinated tap water, and stirred using a flat bladed mixer for approximately 1 minute, to give the 1.0, 1.8, 3.2, 5.6 and 10 mg/L test concentrations respectively.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: juvenile rainbow trout
- Source: Brow Well Fisheries Limited, Hebden, near Skipton, Yorkshire, UK
- Age at study initiation (mean and range, SD): juvenile
- Length at study initiation (length definition, mean, range and SD): 4.8 cm
- Weight at study initiation (mean and range, SD): 1.43 g
- Feeding during test: feeding discontinued approximately 24 hours prior to start of test


ACCLIMATION
- Acclimation period: 11 days
- Acclimation conditions (same as test or not): yes
- Type and amount of food: commercial trout pellet
- Health during acclimation (any mortality observed): no mortality in the 7 days prior to the test

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

140 mg/L as CaCO3

Test temperature:

14 °C

pH:

7.2 to 7.7

Dissolved oxygen:

The oxygen concentration in the majority of the test vessels was observed to be below 60% Air Saturation Value in the old media. This was considered to be due to the use of completely filled and sealed test vessels which received no aeration for the duration of the test due to the suspected volatile nature of the test item. As no adverse effects were observed in the control fish throughout the duration of the test this deviation was considered not to have affected the outcome of the test.

Salinity:

freshwater

Nominal and measured concentrations:

Nominal = 0, 1.0, 1.8, 3.2, 5.6, 10
Measured = 0 hours (fresh media):

Details on test conditions:

TEST SYSTEM
- Test vessel: glass exposure vessels
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 20 litre
- Aeration: None
- Renewal rate of test solution (frequency/flow rate): daily renewal of the test preparations
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.50 g bodyweight/litre.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water (dechlorinated by passage through an activated carbon filter (Purite Series 500))
- Total organic carbon: 0.920 mg/L
- Ca/mg ratio: partly softened (Elga Nimbus 1248D Duplex Water Softener) giving water with a total hardness of approximately 140 mg/L as CaCO3
- Culture medium different from test medium: no


OTHER TEST CONDITIONS
- Photoperiod: 16 hours of light

TEST CONCENTRATIONS
- Spacing factor for test concentrations: approximately X1.8
- Range finding study: yes - 1.0, 10, and 100 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Duration:

3 h

Dose descriptor:

LC50

Effect conc.:

7.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL: 5.6-10 Concentrations resulting in 0% and 100% mortalities respectively

Duration:

6 h

Dose descriptor:

LC50

Effect conc.:

7.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL: 5.6 - 10 Concentrations resulting in 0% and 100% mortalities respectively

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

7.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL: 5.6 - 10 Concentrations resulting in 0% and 100% mortalities respectively

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

7.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL: 5.6 - 10 Concentrations resulting in 0% and 100% mortalities respectively

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

4.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL: 3.2 - 5.6 Concentrations resulting in 0% and 100% mortalities respectively

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

4.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL: 3.2 - 5.6 Concentrations resulting in 0% and 100% mortalities respectively

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LOEC

Effect conc.:

5.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Biological observations: Sub-lethal effects of exposure were observed at test concentrations of 5.6 mg/L and above. These responses were increased pigmentation and the presence of moribund fish.
After approximately 1 hour exposure all of the fish at 10 mg/L were observed to be moribund. Due to animal welfare implications (Animals (Scientific Procedures) Act 1986) these fish were sacrificed and classed as mortalities for the following observational time point.
After approximately 48 hours exposure all of the fish at 5.6 mg/L were observed to exhibit prolonged sub-lethal effects. Due to animal welfare implications (Animals (Scientific Procedures) Act 1986) these fish were sacrificed and classed as mortalities for the following observational time point.
- Mortality of control: none
- Other adverse effects control: none

Validity criteria fulfilled:

yes

Conclusions:

The 96 hour LC50 was determined to be 4.2 mg/L (based on nominal concentrations, measured concentrations were >80% to nominal) in Oncorhynchus mykiss

Executive summary:

A study was performed according to OECD Guideline 203 and EU Method C.1 to assess the acute toxicity of the test item to rainbow trout (Oncorhynchus mykiss). Following a preliminary range-finding test, fish were exposed, in groups of seven, to an aqueous solution of the test item over a range of concentrations of 1.0, 1.8, 3.2, 5.6, and 10 mg/L for a period of 96 hours at a temperature of approximately 14 °C under semi-static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours. The 96-Hour LC50 based on nominal test concentrations was 4.2 mg/L with 95% confidence limits of 3.2 – 5.6 mg/L. Analysis of the test preparations at 0, 24 and 96 hours showed measured test concentrations to range from 81% to 97% of nominal and so the results are based on nominal test concentrations only.

Description of key information

The substance was toxic to Oncorhynchus mykiss when tested according to OECD Guidelines for Testing of Chemicals (July 1992) No 203. The LC50 observed after 96 hours was 4.2 mg/L (based on nominal concentrations, measured concentrations were >80% to nominal).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

4.2 mg/L

Additional information

One acute toxicity study was performed to assess the acute toxicity of the substance to the freshwater fish species Oncorhynchus mykiss (Harlan Laboratories, 2012). The study was conducted under GLP and according to OECD Guideline 203. The study was conducted in a semi-static system, and the test substance was replenished every 24 hours.  Fish were exposed to the substance at a range of concentrations from 1 to 10 mg/L in freshwater. The test was performed with 7 fish per vessel and concentration. For each concentration, the percentage of mortality at 24, 48, 72, and 96 hours was recorded. The following OECD 203 validity criteria were met: mortality in the control did not exceed 10% at the end of the test; constant conditions (temperature and pH) were within specified deviations; and the concentration of the substance was at least 80% of the nominal concentration throughout the test.   However, oxygen concentrations below 60% saturation was reported in most test vessels due to sealed test vessels; no adverse effects were observed in the control fish, thus, this deviation was considered to not affect the test outcome.  Under the conditions of the test, the 96 hour LC50 was 4.2 mg/L (based on nominal concentrations, measured concentrations were >80% to nominal).