Octadecyl docosanoate

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:

18 Dec 2017 - 21 Feb 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

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)

Version / remarks:

13 April 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesanstalt für Umwelt, Messungen und Naturschutz Baden-Württemberg, Karlsruhe, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Octadecyl docosanoate

EC Number:

246-115-1

EC Name:

Octadecyl docosanoate

Cas Number:

24271-12-3

Molecular formula:

C40H80O2

IUPAC Name:

octadecyl docosanoate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Analytical samples taken at 0 hours (initial value) and 24 hours from fresh and 24 hours and 48 hours from aged test solutions were analysed from control and the highest test concentration of 100 mg/L.
- Sample storage conditions before analysis: All samples were stored deep frozen until they were transferred to the analytical laboratory.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances):
- Method: The necessary amount of test item for preparing the stock solution was weighed on a weighing scoop and transferred to a volumetric flask. Test medium was added up to the bench mark and the solution was stirred for 24 hours at room temperature in the dark. After the settling of the undissolved test item, the necessary volumes for the test were withdrawn via a Teflon tube from the medium level of the stock solution. Lower test solutions were prepared by dilution of the stock solution with test medium. The preparation procedure was repeated after 24 hours. Approx. 50 mL of the prepared solutions were transferred to each test vessel
- Controls: blank control without the test item
- Eluate: no
- Differential loading: no
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): After stirring, the substance was observed to be at the magnetic stirring bar and at the surface and the substance looked dry.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: Continuously bred in the laboratory and originally purchased in a healthy condition from the Federal Environment Agency in Berlin/Germany.
- Age: Freshly hatched daphnids less than 24 hours old were used for the test.
- Culture conditions: Daphnia magna was bred as single culture (1 daphnid per 100 mL) in Elendt M4 medium. The pH value of the aerated water was within a range of 6.0 – 9.0. The dissolved oxygen was above 60 % saturation and the total hardness 140 - 250 mg/L (as CaCO3), corresponding to 7.8 - 14°dH. The animals were fed with single cell green algae (Desmodesmus subspicatus, formerly Scenedesmus subspicatus) at least three times a week.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

13°dH (232 mg/L as CaCO3)

Test temperature:

19.3 ± 0.4 °C

pH:

7.84 ± 0.10

Dissolved oxygen:

9.3 ± 0.1 mg/L

Nominal and measured concentrations:

nominal: 0.0100, 0.100, 1.00, 10.0 and 100 mg/L, and control
measured: 1.22 mg/L for nominal 100 mg/L; < LOD for control; other test concentration levels were not analysed

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass vessel (100 mL), were filled up with ~ 50 mL test solution. The test units were covered with a glass plate.
- Renewal rate of test solution: The test solutions were freshly prepared at 0 and 24 h.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
Elendt M4 standard medium was used as test medium. At test initiation the pH-value of the control (untreated test medium) was 7.69, the dissolved oxygen concentration was 9.3 mg/L and the total hardness was 13°dH (232 mg/L as CaCO3).
- Intervals of water quality measurement: The test temperature and the pH-value as well as the oxygen concentration of the test solutions were measured at all concentrations and the control at t = 0 h fresh and t = 24 h from fresh test solutions and after t = 24 h and t = 48 h from aged test solutions in one separate replicate per test concentration without test organisms.

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light/8 hours darkness daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Immobility after 24 and 48 h
- Behavioural changes of daphnids were recorded at 24 and 48 hours after starting the test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

>= 1.22 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI could not be determined. Please refer to section "Reported statistics and error estimates".

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI could not be determined. Please refer to section "Reported statistics and error estimates".

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.22 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Mortality of control: 0%
- Behavioural changes: After 24 hours and after 48 hours the mobile daphnids in the test concentration of 10.0 mg/L and 100 mg/L were present at the surface of the test item solutions.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: At 10.0 mg/L and 100 mg/L, flakes of substance were observed at the surface of the test item solutions. This might have caused the immobilised daphnid observed.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50 (24 h) < 1.00 mg/L

Reported statistics and error estimates:

EC50 and NOEC-values of daphnids exposed to the test item were evaluated using nominal and actual concentrations. Due to an inhibition below 50%, the database was weak for probit analysis which was hence not performed.

Any other information on results incl. tables

Table 1: Results of the test, 48 h values

	Nominal test item concentrations [mg/L]
	Control	0.0100	0.100	1.00	10.0	100
	Immobilised daphnids after 48 h
Group 1	0	0	0	1*	1	0
Group 2	0	0	0	0	0	0
Group 3	0	0	0	0	0	0
Group 4	0	0	0	0	0	1
Σ	0	0	0	1	1	1
%	0	0	0	5	5	5

* the daphnia died accidentally

Table 2: Determined concentration of Octadecyl docosanoate

Test item	Octadecyl docosanoate   nominal [mg/L]	Sampling	Octadecyl docosanoate		Geometric mean	Actual concentration
nominal [mg/L]		[h]	[mg/L]	% of nominal	[mg a.i./L]	[mg test item/L]
Control	0	0 fresh	n.d.	-	-	-
		24 aged	n.d.	-
		24 fresh	n.d.	-
		48 aged	n.d.	-
100	92.0	0 fresh	0.615	1	1.12	1.22
		24 aged	0.315	0
		24 fresh	3.01	3
		48 aged	2.66	3

- = not calculated; n.d. = not detectable; LOQ = 0.100 mg/L Octadecyl docosanoate

Table 3: Validity criteria

Criterion from the guideline	Outcome	Validity criterion fulfilled
In the control, including the control containing the solubilising agent, not more than 10% of the daphnids should have been immobilized.	Control: 0%	yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	≥ 9.2 mg/L	yes

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.