α,2,2,6-tetramethylcyclohexene-1-butyraldehyde

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:

2015-09-14 to 2015-11-02

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 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

α,2,6,6-tetramethyl-2-cyclohexene-1-butyraldehyde

EC Number:

277-458-5

EC Name:

α,2,6,6-tetramethyl-2-cyclohexene-1-butyraldehyde

Cas Number:

73398-85-3

Molecular formula:

C14H24O

IUPAC Name:

2-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)butanal

Constituent 2

Reference substance name:

α,2,6,6-tetramethylcyclohexene-1-butyraldehyde

EC Number:

282-993-2

EC Name:

α,2,6,6-tetramethylcyclohexene-1-butyraldehyde

Cas Number:

84518-22-9

Molecular formula:

C14H24O

IUPAC Name:

2-methyl-4-(2,6,6-trimethylcyclohex-1-en-1-yl)butanal

Specific details on test material used for the study:

Test material name (as stated in the report): Cetonal
Batch No.:SC00011028
Expiry date: 23 June, 2016

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

At the start of the exposure intervals (0 and 24 hours), sampling was carried out after preparation of the test concentrations.
At the end of the exposure intervals (24 and 48 hours), samples were taken directly from the test vessels.

Test solutions

Vehicle:

yes

Details on test solutions:

The test item was expected to evaporate. To reduce losses of the test item, the study was conducted in a closed system without headspace.
A stock solution of 3.00 mg/L of the test item was prepared one day before the start of each exposure interval (at -24 and 0 hours). For this purpose, 6.75 pL of the test item (density of the test item taken into account) were directly introduced by pipette into a 2 L glass flask, completely filled with the dilution water (approximately 2065 mL of ISO test water as specified below) below the water surface while stirring.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Test system: Daphnia magna STRAUS (Clone 5)
Origin: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu), 14195 Berlin, Germany

20 daphnids, divided into 4 replicates, each with 5 daphnids, were used per concentration level and control.

Age of the Daphnia: 2 to 24 hours old daphnids from a healthy stock were used for the study. Juvenile daphnids were removed from the culture vessels latest 22 hours before the start of the exposure and discarded. The juveniles born within this period of max. 22 hours preceding the exposure were used for the test after an acclimatisation phase in the dilution water of at least 2 hours. No first brood progeny was used for the test.

Acclimatisation: At least 2 hours in dilution water

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

262 to 267 fmg CaCCb/Ll

Test temperature:

20.4 to 20.3 °C

pH:

7.96 to 7.75

Dissolved oxygen:

7.03 to 8.28 [mg/L]

Conductivity:

653 to 648 microS/cml

Nominal and measured concentrations:

5 test item concentrations in a geometric series with a separation factor of 2, prepared by diluting the stock solution of 3.00 mg/L with dilution water, were tested as follows:
0.188 - 0.375 - 0.750 - 1.50 - 3.00 mg/L.
The nominal concentrations mentioned above correspond to the geometric mean measured concentrations of:
0.156 - 0.321 - 0.676 - 1.51 - 2.99 mg/L.

Details on test conditions:

The study was conducted in a closed system (sealed glass flasks) without headspace under semistatic conditions over a period of 48 hours with 5 concentrations in the range of 0.188 to 3.00 mg/L of the test item CETONAL in a geometric series with a separation factor of 2.
The test item CETONAL is a pale yellow liquid with a water solubility of 4.63 mg/L (20 °C, pH 7). The test item was expected to evaporate. To reduce losses of the test item, the study was conducted in a closed system without headspace.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate p.a. (Sigma)

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.739 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The measured concentrations of the test item at the start of the exposure intervals (0 and 24 hours) were in the range of 93 to 124 % of the nominal concentrations. At the end of the exposure intervals (24 and 48 hours), the measured concentrations of the test item were in the range of 65 to 92 % of the nominal concentrations.
Since the measured test item concentrations did not remain within ± 20 % of the nominal concentrations, the effect values given in Table 1 are based on the geometric mean measured concentrations of the test item CETONAL calculated as follows:
0.156 - 0.321 - 0.676 - 1.51 - 2.99 mg/L.

Results with reference substance (positive control):

A reference test is conducted by the laboratory under static conditions with a test duration of 24 hours once per month in order to prove the validity of the test system and test conditions at the test facility. The EC50-value for the most recent of the monthly performed reference tests was 1.61 mg/L (Cl: 1.43 - 1.82 mg/L).
The EC50-value of the reference item potassium dichromate after 24 hours is within the prescribed concentration range of 0.6 - 2.4 mg/L of quality criteria according to AQS P 9/2 (02/2000) for daphnids clone 5 cultured in Elendt M4 medium. The EC50-value of the reference item is also within the recommended range of 0.6 - 2.1 mg/L according to OECD-Guideline 202.

Any other information on results incl. tables

The water quality parameters (i.e. pH-value and dissolved oxygen concentration), measured at the start (0 and 24 hours) and at the end of the exposure intervals (24 and 48 hours), were within the acceptable limits. The validity criteria of the test guideline were fulfilled.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Acccording to the test conditions the EC50(48hours) of the test item CETONAL with 95 % confidence limits has been determined to be 0.739 [mg/L] (Cl: 0.707 - 0.774) based on geometric mean measured test item concentrations.

Executive summary:

In the acute immobilisation test with Daphnia magna (STRAUS), the effects of the test item CETONAL (batch number: SC00011028) were determined according to OECD 202 guideline.

Twenty daphnids were exposed to each concentration level and the control. The concentrations of the test item CETONAL were analytically verified after derivatisation using 2,4-Dinitrophenylhydrazine via LC-MS/MS at the start (0 and 24 hours) and at the end of the exposure intervals (24 and 48 hours) in all concentration levels and the control. The measured concentrations of the test item at the start of the exposure intervals (0 and 24 hours) were in the range of 93 to 124 % of the nominal concentrations. At the end of the exposure intervals (24 and 48 hours), the measured concentrations of the test item were in the range of 65 to 92 % of the nominal concentrations.

Since the measured test item concentrations did not remain within ± 20 % of the nominal concentrations, the effect values given in Table 1 are based on the geometric mean measured concentrations of the test item CETONAL calculated as follows: 0.156 - 0.321 - 0.676 - 1.51 - 2.99 mg/L.

The water quality parameters (i.e. pH-value and dissolved oxygen concentration), measured at the start (0 and 24 hours) and at the end of the exposure intervals (24 and 48 hours), were within the acceptable limits. The validity criteria of the test guideline were fulfilled.

The EC50(48hours) with 95 % confidence limits has been determined to be 0.739 [mg/L] (Cl: 0.707 - 0.774) based on geometric mean measured test item concentrations.