Isooctadecanoic acid, monoester with propane-1,2-diol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 - 19 Jan 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

Adopted 13 April 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The department of health of the government of the United Kingdom, Brixham, UK

Analytical monitoring:

yes

Remarks:

LC-MS/MS

Details on sampling:

- Concentrations: dilution water control, solvent control and exposure concentrations of 0.0625, 0.125, 0.25, 0.50 and 1.0 mg/L
- Sampling method: At study start, samples were taken from excess test solutions and at study end from the test vessels of the dilution water control, solvent control and each test concentration. At 0-h, an aliquot was removed from each of the excess dosing solutions (three aliquots for 0.125 mg/L) and an equivalent volume of THF was added. If required, the sample was further diluted with Daphnia media/THF (1:1, v/v). The sample was mixed and an aliquot transferred to an LC/MS vial for analysis. At 48 h, an aliquot was removed from a single test vessel for each concentration (three test vessels for 0.125 mg/L) and an equivalent volume of THF was added. If required, the sample was further diluted with Daphnia media/THF (1:1, v/v). The sample was mixed and an aliquot transferred to an LCMS vial for analysis.

Vehicle:

yes

Remarks:

Dimethylformamide (DMF)

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A primary stock concentrate of 10 g/L, was prepared by adding a nominal 0.100 g of test substance and making up to 10 mL with the solvent. The stock was shaken to mix and observed to be clear and colourless. The stock was used to prepare the test solutions by direct addition of the appropriate amount. The solvent control was prepared in the same way using solvent only.
- Differential loading: yes
- Controls: dilution water control and solvent control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Dimethylformamide (DMF)
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): 0.1 mL/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): The stock was observed to be clear and colourless. All test solutions were clear and colourless prior to use.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: laboratory culture (holding conditions same as test conditions, feeding during holding: Chlorella vulgaris, strain CCAP 211/12 and Pseudokirchneriella subcapitata, strain CCAP 278/4. Fed daily in a ratio depending on the age and density of the culture)
- Age of parental stock (mean and range, SD): D. magna <24 h old, obtained from a single culture vessel, were used for testing. The parent animals were 15 ± 1 days old and had been maintained with a twice weekly renewal of reconstituted water medium since birth. The test organisms and the culture from which they were obtained showed no evidence of disease before the test period.
- Feeding during test: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

236.7 mg/L as CaCO3

Test temperature:

18.8 - 20.1 °C

pH:

8.02 - 8.11

Dissolved oxygen:

8.69 - 9.44 mg/L

Conductivity:

623 µS/cm

Nominal and measured concentrations:

Nominal: dilution water control, solvent control and exposure concentrations of 0.0625, 0.125, 0.25, 0.50 and 1.0 mg/L
Measured: < LOQ, < LOQ, 0.043, 0.066, 0.12, 0.28, 0.57 mg/L (arithm. mean meas.)

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL glass beakers
- Type: beakers were covered with loose fitting glass lids
- Fill volume: 200 mL
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt's M4 medium according to guideline
- Total organic carbon: <0.7 mg/L
- Pesticides: <0.01 µg/L
- Alkalinity: 39.2 mg/L as CaCO3
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH and dissolved oxygen concentrations were measured for the control, solvent control and each exposure concentration at the beginning and at the end of the test. Temperature values were continually recorded.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light: 8 h dark, with 20 min dusk and dawn transition periods

EFFECT PARAMETERS MEASURED: An assessment of the mobility of the D. magna was made 24 and 48 h. Any overt symptoms of toxicity were also recorded.

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: dilution water control, solvent control and nominal test concentrations of 0.0625, 0.125, 0.25, 0.50 and 1.0 mg/L (without analytical confirmation of the concentrations)
- Results used to determine the conditions for the definitive study: 10% immobilization at 0.25 mg/L, 10% immobilization at 0.5 mg/L and 60% immobilization at 1 mg/L.

Reference substance (positive control):

not specified

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.57 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: slow moving daphnids towards the bottom of the test vessels in the nominal 1.0 mg/L concentration after 24 h. Slow, irregular moving daphnids on the bottom of the test vessels in the nominal 0.25, 0.50 and 1.0 mg/L test solutions after 48 h.
- Mortality of control: no (no immobility observed in the dilution water control or the solvent control)
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: The stock was observed to be clear and colourless. All test solutions were clear and colourless prior to use.
- Effect concentrations exceeding solubility of substance in test medium: yes, since solvent was used

ANALYTICAL RESULTS:

The measured concentration at the start of the study for the test solutions ranged 97 - 138% of nominal. The measured concentration at the end of the study ranged <LOQ - 11% of nominal.

Table 1: Analytical results.

Nominal concentration (mg/L)	Measured concentration				Mean measured concentration (mg/L)	Mean measured concentration (%)
	0 h		48 h
	(mg/L)	% of nominal	(mg/L)	% of nominal
Control	<LOQ	-	<LOQ	-	0	-
Solvent Control	<LOQ	-	<LOQ	-	0	-
0.0625	0.086	138	<LOQ	-	0.043	69
0.125	0.13a	106	<LOQb	-	0.066	53
0.25	0.24	97	<LOQ	-	0.12	48
0.5	0.53	106	0.041	8	0.28	57
1	1.03	103	0.11	11	0.57	57

Arithmetic means are used

a Triplicate analyses: 0.13, 0.14, 0.13 mg/L

b Triplicate analyses: <LOQ, <LOQ, <LOQ mg/L

Where measured concentrations were less than the LOQ, zero values were used to calculate the mean

BIOLOGICAL RESULTS:

Table 2: Daphnia magna response.

Time (h)	Nominal concentration (mg/L)	Mean measured concentration (mg/L)	Number immobilised per replicate				% immobilised
			A	B	C	D
24	Control	0	0	0	0	0	0
	Solvent Control	0	0	0	0	0	0
	0.0625	0.043	0	0	0	0	0
	0.125	0.066	0	0	0	0	0
	0.25	0.12	0	0	0	0	0
	0.5	0.28	0	0	0	0	0
	1	0.57	0	0	0	0	0
48	Control	0	0	0	0	0	0
	Solvent Control	0	0	0	0	0	0
	0.0625	0.043	0	0	0	0	0
	0.125	0.066	0	0	0	0	0
	0.25	0.12	0	1	0	1	10
	0.5	0.28	1	1	1	0	15
	1	0.57	2	1	1	2	30

Further effect concentrations reported in the study:

- NOEC (48 h) = 0.28 mg/L

- LOEC (48 h) = 0.57 mg/L

VALIDITY CRITERIA:

Table 3: Validity criteria for OECD 202.

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.	No immobility or other signs of stress were observed in the control.	yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	Dissolved oxygen concentrations ranged from 8.69 to 9.44 mg/L.	yes

Validity criteria fulfilled:

yes

Remarks:

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

Description of key information

EC50 (48 h) > 0.57 mg/L (meas.) for Daphnia magna (OECD 202)

Additional information

One study is available testing the toxicity of the substance on aquatic invertebrates. The study (2018) was conducted according to the OECD guideline 202 and under GLP standards. Daphnia magna was exposed for 48 h in a static testing regime to the nominal test item concentrations of 0.0625, 0.125, 0.25, 0.50 and 1.0 mg/L (nominal). Since the substance is poorly soluble in water a non-GLP solubility trial was performed prior to test start with different preparation methods of the stock solution. On this basis, dimethylformamide (DMF) was used as a solvent in a final concentration of 0.1 mL/L for the preparation of the test solutions. Therefore, a dilution water and a solvent control were included in the test. All solutions were clear and colourless at test start. An analytical monitoring took place and all tested concentrations including the control and the solvent control were measured via LC-MS/MS at the beginning and at the end of the test.

 

The measured concentration ranged between 97 and 138% of nominal at the start of the study and <LOQ - 11% of nominal after 48 h. Therefore results were expressed in arithmetic mean measured concentrations. The study showed slight effects on the mobility and behavior of Daphnia magna at concentrations between 0.12 and 0.57 mg/L (arithm. mean meas.). These concentrations are assumed to exceed the solubility of the substance in water under environmental conditions, since a solvent was used in the study. However no 50% immobility was recorded resulting in an EC50 (48 h) > 0.57 mg/L (arithm. mean meas.). No immobility was recorded in the controls and all validity criteria given by the guideline were fulfilled.