Isotridecyl isononanoate

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:

09 - 29 January 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

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:

Isotridecyl isononanoate

EC Number:

255-673-5

EC Name:

Isotridecyl isononanoate

Cas Number:

42131-27-1

Molecular formula:

C22H44O2

IUPAC Name:

Isotridecyl isononanoate

Specific details on test material used for the study:

Test substance name Isotridecyl isononanoate
Scymaris reference number 1014TS074
Physical state Liquid
Lot/batch number 0001067681
Certificate of Analysis Re-test date 19 April 2018
Sample storage Room temperature

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples taken at the start of the study (0 hours) were taken from excess solutions. 100 mL sample was added to a 200 mL volumetric flask and 2 mL 0.5 mg/L D10-Phenanthrene in hexane is added. The contents were mixed for 2 minutes, made up to 200 mL with water and an aliquot taken from the hexane layer for analysis. This constituted a 50:1 extraction ratio.
Samples taken at 72 hours were prepared from test vessels, where 100 mL (whole contents of test vessel) was poured into a 200 mL volumetric flask, and 2 mL 0.5 mg/L D10-Phenanthrene in hexane was added. The contents were mixed for 2 minutes, made up to 200 mL with water and an aliquot taken from the hexane layer for analysis. This constituted a 50:1 extraction ratio.

Test solutions

Vehicle:

yes

Details on test solutions:

Test 1
The first test was run with a dilution water control, solvent control and nominal exposure concentrations of 0.0156, 0.0313, 0.0625, 0.125 and 0.25 mg/L.
A primary stock concentrate of Isotridecyl isononanoate, with a nominal concentration of 2.5 g/L, was prepared by weighing a nominal 0.025 g (actual weight: 0.02492 g) of test substance directly into a 10 mL volumetric flask and made up to volume with tetrahydrofuran (THF). The stock was then manually shaken to mix. The resultant stock was observed to be clear and colourless.
Test solutions were prepared by the direct addition of the appropriate amount of concentrate to dilution water via a microliter syringe into a stirring solution in a volumetric flask. The solvent control was prepared in the same way using solvent only. The control consisted of culture medium only.


Control : 0µL stock, 0 µL additional THF, made up to 1000mL with dilution water
Solvent Control : 0 µL stock, 100 µL additional THF, made up to 1000 mL with dilution water
0.0156 mg/L : 6.24 µL stock (2.5 g/L), 94 µL additional THF, made up to 1000 mL with dilution water
0.0313 mgl/L : 25 µL stock (2.5 g/L), 175 µL additional THF, made up to 2000 mL with dilution water
0.0625 mgl/L : 25 µL stock (2.5 g/L), 75 µL additional THF, made up to 1000 mL with dilution water
0.125 mgl/L : 50 µL stock (2.5 g/L), 50 µL additional THF, made up to 1000 mL with dilution water
0.25 mgl/L : 100 µL stock (2.5 g/L), 0 µL additional THF, made up to 1000 mL with dilution water

The test solutions were all stirred for approximately 10 minutes. Due to the low solubility of the test substance observed in the solubility trial and range finding test, the test solutions were dispensed to test replicates from vigorously stirring solutions with re-stirring or vigorous shaking between each pouring to ensure homogeneity of the dispensed solutions. All test solutions were observed as clear and colourless upon dispensing.

Test 2
A second test with an additional range of concentrations was run with a dilution water control, solvent control and nominal exposure concentrations of 0.25, 0.5, 1.0 and 2.0 mg/L.
Primary stock concentrates of Isotridecyl isononanoate with nominal concentrations of 2.5, 10 and 20 g/L were prepared by weighing a nominal 0.025, 0.1 and 0.2 g of test substance (actual weights: 0.02495, 0.09985 and 0.20011 respectively) directly into separate 10 mL volumetric flasks and were made up to volume with THF. The stocks were all observed to be clear and colourless solutions.
Test solutions were prepared by the direct addition of the appropriate amount of concentrate to dilution water via a microliter syringe into a stirring solution in a volumetric flask. The solvent control was prepared in the same way using solvent only. The control consisted of culture medium only.
The test solutions were all stirred for approximately 10 minutes. The dilution water control, solvent control, 0.25 and 0.5 mg/L nominal test concentrations were observed as clear and colourless. The 1.0 and 2.0 mg/L were observed as colourless with fine particles visible in a homogenous dispersion.

Control : 0µL stock, 0 µL additional THF, made up to 1000mL with dilution water
Solvent Control : 0µL stock, 100 µL additional THF, made up to 1000mL with dilution water
0.25 mg/L : 100 µL stock (2.5 g/L), 0 µL additional THF, made up to 1000 mL with dilution water
0.5 mgl/L : 100 µL stock (10 g/L), 100 µL additional THF, made up to 2000 mL with dilution water
1.0 mgl/L : 100 µL stock (10 g/L), 0 µL additional THF, made up to 1000 mL with dilution water
2.0 mgl/L : 100µL stock (20 g/L), 50 µL additional THF, made up to 1000 mL with dilution water

A solvent was used in this study to assist in dosing the test compound due to its apparent low solubility in test media, the concentration of solvent used in all exposure solutions in both tests with the exception of the control was 100 µL/L.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The test organism was the freshwater crustacean, Daphnia magna, obtained from continuous laboratory cultures held at Scymaris.
The stock cultures of D. magna were maintained in a reconstituted water medium, the same as the test dilution water, at a temperature of 20 ± 2°C. The cultures were maintained in 2 L glass vessels with a working volume of 1.6 L. A photoperiod of 16 hours’ light:8 hours dark, with 20-minute transition periods was provided.
The D. magna cultures were fed on a mixed algae diet of Chlorella vulgaris, strain CCAP 211/12 and Pseudokirchneriella subcapitata, strain CCAP 278/4. The D. magna cultures were fed daily ad libitum depending on age and density of the culture. Culture conditions were such that the D. magna reproduction was by diploid parthenogenesis.
D. magna <24 hours old, obtained from a single culture vessel, were used for testing. The parent animals for the first test were 28 ± 1 days old and for the second test were 18 ± 1 days old. The cultures had been maintained with a twice weekly renewal of reconstituted water medium since birth. The test organisms and the cultures from which they were obtained showed no evidence of disease before the test period.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

236.7-248.7 mg/L CaCO3

Test temperature:

19.8-20.5

pH:

7.78-8.18

Dissolved oxygen:

9.06-9.26 mg/L

Conductivity:

616-623 µS/cm

Nominal and measured concentrations:

nominal 0.0156 mg/L : measured 0.014 mg/L
nominal 0.0313 mgl/L : measured 0.029 mg/L
nominal 0.0625 mgl/L : measured 0.051 mg/L
nominal 0.125 mgl/L : measured 0.11 mg/L
nominal 0.25 mgl/L : measured 0.29 mg/L

nominal 0.25 mg/L : measured 0.18 mg/L
nominal 0.5 mgl/L : measured 0.47 mg/L
nominal 1.0 mgl/L : measured 0.95 mg/L
nominal 2.0 mgl/L : measured 2.0 mg/L

Details on test conditions:

Glass beakers of 250 mL nominal capacity were used as test vessels, with four replicates per test concentration. Each vessel contained 200 mL of test solution providing a depth of approximately 60 mm. The beakers were covered with loose fitting glass lids. The positions of the treatments were randomly allocated within the test area.
Both tests were initiated by the addition of 5 impartially selected D. magna, in <2.0 mL of dilution water, to each test vessel. Each treatment contained a total of 20 D. magna.
The nominal test solution temperature was 20 ± 1°C, and a photoperiod of 16 hours light: 8 hours dark, with 20 minute dusk and dawn transition periods, was provided.
The test solutions were not aerated and the D. magna were not fed during the course of the study.

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.29 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

> 0.29 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Test 1
Based on immobility compared to the control (p <0.05) the 48 hour No Observed Effect Concentration (NOEC) was determined to be 0.29 mg/L and the Lowest Observed Effect Concentration (LOEC) was >0.29 mg/L.
There was no immobility or toxicity observed in the dilution water control or solvent control.

24h observations for 0.11mg/L
90% of daphnids on surface, One daphnid stuck to moult debris, Slower moving than controls

24h observations for 0.29mg/L
100% of daphnids on surface, One daphnid stuck to moult debris, Slower moving than controls

No symptoms of toxicity were observed in the other test concentrations. All daphnids on the solution surface were re-submerged with test solutions dripped with a glass Pasteur pipette.

48h observations for 0.11mg/L
85% of daphnids on surface, Moult debris on surface, Two daphnids stuck together, Slower moving than controls

48h observations for 0.29mg/L
65% of daphnids on surface stuck together and to moult debris, 20% of daphnids only mobile on gentle agitation of test vessel, Slower moving than controls

No symptoms of toxicity were observed in the other test concentrations.
Daphnids stuck together were separated by dripping test solution from glass Pasteur pipette for mobility assessment

Test 2
Based on immobility compared to the control (p <0.05) the 48 hour No Observed Effect Concentration (NOEC) was determined to be 0.18 mg/L and the Lowest Observed Effect Concentration (LOEC) was 0.47 mg/L.
Physical effects had a significant impact on the test results for this test substance. The difference in NOEC and EC50 results between Test 1 and Test 2 was likely due to the physical effects of the test substance which included daphnids that were stuck together or to moult debris and daphnids that had test substance stuck to their appendages. Physical effects such as these significantly affected daphnid mobility. Full details are given in the table below.
There was no immobility or toxicity observed in the dilution water control or solvent control.

24h observations for 0.18mg/L
100% of daphnids on surface, 15% of daphnids stuck together. Moult debris on surface. Less active and slow swimming compared to controls.

24h observations for 0.47mg/L
100% of daphnids stuck together on surface in a raft with moult debris. Mobile daphnids less active and slow swimming compared to controls. All daphnids (mobile and immobile) were observed to be still alive dueto twitching movement.

24h observations for 0.95mg/L
100% of daphnids stuck together on surface in a raft with moult debris. All daphnids were observed to be still alive due to twitching movement. Test substance visible on the surface as droplets.

24h observations for 2.0mg/L
100% of daphnids stuck together on surface in a raft with moult debris. All daphnids were observed to be still alive due to twitching movement. Test substance visible on the surface as droplets


48h observations for 0.18mg/L
100% of daphnids on surface, 60% of daphnids stuck to moult debris or stuck together with moult debris. Mobile daphnids less active and slow swimming compared to controls. Three immobile daphnids observed as still alive due to twitching movement.

48h observations for 0.47mg/L
85% of daphnids on surface stuck together in raft with moult debris.

48h observations for 0.95mg/L
100% of daphnids on surface stuck together with moult debris and test substance. Test substance visible on surface as droplets.

48h observations for 2.0mg/L
100% of daphnids on surface stuck together with moult debris and test substance.
Test substance visible on surface as droplets.

No symptoms of toxicity were observed in the other test concentrations.
Test solution was dripped onto surface-bound daphnids in all test concentrations using a glass Pasteur pipette in order to separate them for mobility assessment.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on immobility compared to the control (p <0.05) the 48 hour No Observed Effect Concentration (NOEC) was determined to be 0.18 mg/L and the Lowest Observed Effect Concentration (LOEC) was 0.47 mg/L.
Physical effects had a significant impact on the test results for this test substance. The difference in NOEC and EC50 results between Test 1 and Test 2 was likely due to the physical effects of the test substance which included daphnids that were stuck together or to moult debris and daphnids that had test substance stuck to their appendages. Physical effects such as these significantly affected daphnid mobility.