2-tert-butylcyclohexyl ethyl carbonate

Bioaccumulation: aquatic / sediment

Administrative data

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 13th January 2006 to 22nd March 2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The test was done according to OECD Guideline for Testing of Chemicals 305E and certified by GLP. However, the use of solvents and dispersants is not recommended in the Guideline but both were used here.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 (Bioconcentration: Flow-through Fish Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-tert-butylcyclohexyl ethyl carbonate

EC Number:

267-184-4

EC Name:

2-tert-butylcyclohexyl ethyl carbonate

Cas Number:

67801-64-3

Molecular formula:

C13H24O3

IUPAC Name:

2-tert-butylcyclohexyl ethyl carbonate

Test material form:

liquid

Details on test material:

- Name of test material (as cited in study report): 2-tert-butylcyclohexyl ethyl carbonate
- Physical state: Colorless transparent liquid

Specific details on test material used for the study:

- Storage condition of test material: Cool and dark condition

Radiolabelling:

no

Sampling and analysis

Details on sampling:

- Sampling intervals/frequency for test organisms: Five occasions during the uptake phase to the exposed group and on two occasions at start and end of the test to the control group.
- Sampling intervals/frequency for test medium samples: Before feeding and at the same time as the fish sampling to the exposed group.

Test solutions

Vehicle:

yes

Details on preparation of test solutions, spiked fish food or sediment:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Chemical name of vehicle: Dimethyl sulfoxide
- Dispersants: 10 times volume of HCO-40

Test organisms

Test organisms (species):

Cyprinus carpio

Study design

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

28 d

Test conditions

Test temperature:

First concentration group: 24.8 - 25.0°C
Second concentration group: 24.7 - 24.8°C
Control group: 24.5°C

pH:

First concentration group: 7.7
Second concentration group: 7.8
Control group: 7.9

Dissolved oxygen:

First concentration group: 7.1 - 7.4 mg/L
Second concentration group: 7.1 - 7.5 mg/L
Control group: 7.5 - 7.7 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 70L glass vessel
- Renewal rate of test solution: 2000 mL/min.
- No. of organisms per vessel: First and second concentration groups: 37, Control group: 12
- No. of vessels per concentration: 1
- No. of vessels per control / vehicle control: 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Ground water
- pH: 8.0
- Total hardness (Ca, Mg): 13.2 mg/L
- Conductivity: 264μS/cm

OTHER TEST CONDITIONS
- Photoperiod: 14 hours light and 10 hours dark

RANGE-FINDING / PRELIMINARY STUDY
- Test concentrations: 10.0 mg/L, 5.00 mg/L, 2.50 mg/L, 1.25 mg/L and control
- Results used to determine the conditions for the definitive study: LC50 = 3.86 mg/L (after 96 hours)

Nominal and measured concentrations:

Nominal concentrations:
First concentration group: 10 μg/L, Second concentration group: 1 μg/L,
Mesured concentrations at steady state:
Peak1 at first concentration group: 9.33 μg/L, Peak 1 at second concentration group: 0.958 μg/L
Peak2 at first concentration group: 9.06 μg/L, Peak 2 at second concentration group: 0.939 μg/L

Results and discussion

Lipid content

Lipid content 1

Lipid content:

3.29 %

Time point:

start of exposure

Lipid content 2

Lipid content:

3.9 %

Time point:

end of exposure

Bioaccumulation factor

Bioaccumulation factor 1

Key result

Conc. / dose:

10 µg/L

Temp.:

24.8 - 25 °C

pH:

7.3

Type:

BCF

Value:

120 L/kg

Basis:

normalised lipid fraction

Time of plateau:

28 d

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:Peak1 at first concentration group

Bioaccumulation factor 2

Key result

Conc. / dose:

1 µg/L

Temp.:

24.7 - 24.8 °C

pH:

7.3

Type:

BCF

Value:

120 L/kg

Basis:

normalised lipid fraction

Time of plateau:

28 d

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:Peak1 at second concentration group

Bioaccumulation factor 3

Conc. / dose:

10 µg/L

Temp.:

24.8 - 25 °C

pH:

7.3

Type:

BCF

Value:

110 L/kg

Basis:

normalised lipid fraction

Time of plateau:

28 d

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:Peak2 at first concentration group

Bioaccumulation factor 4

Conc. / dose:

1 µg/L

Temp.:

24.7 - 24.8 °C

pH:

7.3

Type:

BCF

Value:

130 L/kg

Basis:

normalised lipid fraction

Time of plateau:

28 d

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:Peak2 at second concentration group

Details on results:

- Mortality of test organisms: No
- Behavioural abnormalities: No

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Bioconcentration factor (BCF) of the test substance at steady state showed from 110 to 130.

Executive summary:

The study was performed to assess the bioaccumulation in fish of the test substance according to the OECD 305. The test was done by flow-through fish test using Cyprinus carpio for 28 days. Concentrations of the test group were set at 10 μg/L (first concentration group) and 1 μg/L (second concentration group) in a vehicle mixture of HCO-40 and dimethyl sulfoxide. The analysis of the test substance was done by GC-MS and we could find 2 peaks for the test substance. Bioconcentration factor (BCF) of the test substance at steady state are below,

Peak 1 (first concentration group, 10 μg/L nominal) : 120

Peak 1 (second concentration group, 1 μg/L nominal) : 120

Peak 2 (first concentration group, 10 μg/L nominal) : 110

Peak 2 (second concentration group, 1 μg/L nominal) : 130

Despite the use of vehicle the results are consistent between the two concentration levels and the study is considered suitable for use in risk assessment.