2-tert-butylcyclohexyl ethyl carbonate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992-02-20 to 1992-04-30

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

This study was performed according to DIN 38.412 Part II Guideline with GLP statement. However no info on solubility of test item in test media, no range finding test, 20 Daphnids per treatment divided in 2 groups instead of 4, DOC analysis instead of specific measurem using DOCent, decline in exposure concentration (> 20% of initial) at medium and higher concentration, while under static conditions, but several concentration analysed.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: DIN 38.412 Part II

Deviations:

not specified

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

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:

- Physical state: Colourless liquid
- Purity: see confidential data
- Lot/batch No.: see confidential data
- Expiration date of the lot/batch:see confidential data

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

no sampling for monitoring

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: the test substance was mixed 30 min with uIltraturraxto reach a 100 mg/L suspension

- Controls:
negative

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna


ACCLIMATION
no data on Daphnia acclimation

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

no data

Test conditions

Hardness:

no data

Test temperature:

20°C - 21 °C

pH:

7.6-7.9

Dissolved oxygen:

94-98%

Salinity:

not relevant

Nominal and measured concentrations:

final test: 8, 11, 16, 22, 32, 45, 64, 90, 130 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: no data
- Material, size, headspace, fill volume: 20 mL
- No. of vessels per concentration (replicates): 2


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobility

TEST CONCENTRATIONS

- Test concentrations:final test: 8, 11, 16, 22, 32, 45, 64, 90, 130 mg/L

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

9.8 mg/L

Nominal / measured:

meas. (initial)

Details on results:

None

Results with reference substance (positive control):

no data

Reported statistics and error estimates:

No data

Any other information on results incl. tables

see attached table.

Applicant's summary and conclusion

Validity criteria fulfilled:

no

Conclusions:

Under the conditions of the test, The 48h-EC50 of the test substance was determined to be 9.8 mg/L based on the geometric mean of the 0 and 100% immobilisation nominal concentrations.

Executive summary:

The 48-hr acute toxicity of the test substance to Daphnia magna was studied under static conditions. Daphnids were exposed to test chemical at nominal concentrations of 8, 11, 16, 22, 32, 45, 64, 90, 130 mg/L as well as to a control for 48 hr. Immobilization effects were observed. Certain but not all oncentrations were measured using DOC as a surrogate for specific analysis,

The authors took 100 mg/L of test substance and mixed it for 10 minutes with an ultrathurax then serial diluted. However, as the substance is only soluble at 11 mg/L it is therefore not possible to know how much was really in the test vessels. A DOC measurement found 6.9 mg/L at 48 h at a nominal of 32 mg/L. This would convert to 9.8 mg/L as TS (TS/C x concentration= 226/156 x 6.8). Earlier concentrations measured (T0 and T24 were higher) so this nominal of 32 mg/L is probably close to or above saturation in the study. 30 to 40% "mortality" was found at 48 h at this concentration so it can be assumed that the true toxicity approaches or exceeds the limit of solubility of 11 mg/L.

The reported 48-hour EC50 was 23 mg/L based on the geometric means of the 0 and 100% nominal concentrations however as this exceeds the limit of solubility it should not be used for risk assessment. A value of 9.8 mg/L will be used as a conservative estimate of the 48 h EC50. Various other issues were noted for this test, such as the use of 20 Daphnids per treatment divided in 2 groups instead of 4, decline in exposure concentration (> 20% loss compared to initial) at medium and higher concentration, while under static conditions. Therefore the study must be used with caution

Results Synopsis

Test Type : Static

48h-EC50: 9.8 mg/L

Endpoint(s) Effected: mobility