Reaction mass of ethyl 2-ethyl-6,6-dimethylcyclohex-2-enecarboxylate and ethyl 2,3,6,6-tetramethylcyclohex-2-enecarboxylate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 July to 25 November 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl 2-ethyl-6,6-dimethylcyclohex-2-ene-1-carboxylate

EC Number:

261-020-5

EC Name:

Ethyl 2-ethyl-6,6-dimethylcyclohex-2-ene-1-carboxylate

Cas Number:

57934-97-1

Molecular formula:

C13H22O2

IUPAC Name:

ethyl 2-ethyl-6,6-dimethylcyclohex-2-ene-1-carboxylate

Constituent 2

Reference substance name:

Ethyl 2,3,6,6-tetramethylcyclohex-2-ene-1-carboxylate

EC Number:

278-776-7

EC Name:

Ethyl 2,3,6,6-tetramethylcyclohex-2-ene-1-carboxylate

Cas Number:

77851-07-1

Molecular formula:

C13H22O2

IUPAC Name:

ethyl 2,3,6,6-tetramethylcyclohex-2-ene-1-carboxylate

Specific details on test material used for the study:

Test material name (as stated in report): Givescone
Batch No. VE00409039
Appearance: Colourless to pale yellow liquid
Expiration date: January 21, 2018

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Sample preparation and Extraction: Liquid -liquid partitioning with toluene

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

The test system used in this study was the freshwater algae Pseudokirchneriella subcapitata (SAG 86.81).
The organisms were originally supplied by Sammlung von Algenkulturen, Albrecht-von- Haller-Institut, Universität Göttingen, Germany.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21-24 °C, controlled at ±2 °C

pH:

8.1

Nominal and measured concentrations:

Nominal 1.00, 3.16, 10.0, 31.6 and 100% of a saturated solution at a loading rate of 100 mg/L, and a control

Details on test conditions:

Test organism:Pseudokirchneriella subcapitata
Test medium: OECD-Medium (modified)
Endpoints: ECx, (e.g. EC50, EC20, EC10), NOEC/LOEC
Biological parameters: Inhibition of growth in relation to control (growth rate & yield)
Test duration: 72 hours
Temperature (target): 21-24 °C, controlled at ±2 °C
Light regime: Permanent illumination
Light intensity (target):60-120 microEm-2s-1, within ±15% over the incubation area
Test units:60 mL glass vials, air-tightly closed by a screwcap with PTFE lining
Test concentrations (nominal): 1.00, 3.16, 10.0, 31.6 and 100% of a saturated solution at a loading rate of 100 mg/L, and a control
No. of replicates in the control: 6
No. of replicates per test concentration:3
Renewal of test solution during exposure: None (static system)
Chemical analysis of test concentrations: At start (0 hours) and at the end of exposure (72 hours)
Data evaluation:Shapiro-Wilk's Test on Normal Distribution; Levene's Test on Variance Homogeneity; Williams Multiple Sequential t-test for homogeneous variances; Student Test, Weibull analysis

Reference substance (positive control):

yes

Remarks:

potassium dichromate (K2Cr207)

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

15.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.43 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

6.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.51 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.33 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.84 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Any other information on results incl. tables

Samples from the test solutions were analysed to determine actual levels of the test item at start of the exposure period (time 0) and following 72 hours of exposure. At time 0 hours the measured concentrations range between 80-100% of the expected concentrations following dilution of the water saturated solution. After 72 hours exposure, the test concentrations remained stable at between 88-102% of the time 0 hours starting concentration. Therefore, the test item concentration based on initial measured concentration remained stable within ±20% throughout the exposure period.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The ErC50 (72 hours) has been determined to be 15.4 mg/L and NOErC 1.43 mg/l under these test conditions.

Executive summary:

An OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test) test was conducted for the substance Givescone in a static conditions. The ErC50 (72 hours) has been determined to be 15.4 mg/L and the NOErC, 1.43 mg/L under these test conditions.