Fatty acids, C18-unsaturated, 2-hexyldecyl ester

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No purity; Limited information on test design

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Qualifier:

according to guideline

Guideline:

other: OECD Environmental Health and Safety Publication. Series on testing and assessment, no. 23

GLP compliance:

no

Remarks:

Non-GLP testing facility.

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test solutions are prepared in accordance with the OECD monography number 23. The preparation consists of 68 hours of gentle agitation by magnetic stirring to obtain a vortex of about 1/3 (or less in some conditions) of the height between the top and the bottom of the flask, followed by 4 hours of phase separation. The aqueous phase, containing the soluble substances (Water Accommodated Fraction) is taken to perform the test. The test solution is identified according to its loading rate (massic proportions of substance to be tested / test medium mass introduced into the diphasic reactor) while operating the ‘WAF’.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Source: Own breed. They are obtained by acyclic parthenogenesis and are minimum of the second generation.
- Feeding during test: None
- Age: < 24 h

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

21 ± 1 °C

pH:

7.8 ± 0.2

Dissolved oxygen:

>7 mg/L

Nominal and measured concentrations:

nominal: 0.104 g/1000 g (loading ratio: massic proportions of substance to be tested / test medium mass introduced into the diphasic reactor) which will be determined as 0.104 g/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL test tubes
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Mineral salts medium according to OECD 202 guideline

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 0.104 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(WAF)

Basis for effect:

mortality

No immobile daphnids were observed after 48 h exposure to a test concentration of 0.104 g/1000 g (loading ratio while operating the 'WAF'). This test concentration is stated as 0.104 g/L.

VALIDITY CRITERIA

Table 1: 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.	The inhibition of mobility level in the control cohort is not above 10%.	Yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	The dissolved oxygen concentration in dilution water is higher than 7 mg/L.	Yes

 

Validity criteria fulfilled:

yes

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

27 Jan - 29 Jan 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

Spacing factor between concentration exceeds 2.2

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 1000 - 3000 mg/L
- Sampling method: samples were taken after 0, 24 and 48 h

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: direct addition of the test substance to the medium. After stirring for approx. 24 h an oily film on the surface and oily droplets on the glass were observed. After that the stock solutions were filtered through a glass fibre filter which was pre-treated with NaOH and rinsed with water (Water-Accomodated Fraction).
- Eluate: no
- Differential loading: yes
- Controls: M4-medium according to EU Method C.2 from 31 Jul 1992 without addition of test substance

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: Ephippia were obtained from BioInternational B.V., NJ Horn Niederlande (delivered on 22 Oct 1997, batch: DM150296/MS 2)
- Age at study initiation: 6 - 24 h
- Method of breeding: Hatching of ephippia was conducted under approx. 4800 lux (continuous illumination) at 20 °C in M4-medium according to Elendt. The incubation of the neonates was performed under approx. 900 lux (16 h light / 8 h dark) at 20 °C in M4-medium according to Elendt. The neonates were fed with green algae (Scenedesmus subspicatus).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20.5 °C

pH:

8.0

Dissolved oxygen:

97% (after 48 h)

Nominal and measured concentrations:

Nominal concentrations: 1000 and 3000 mg/L
Measured concentrations: 1000 mg/L: 1.07 mg/L (0 h), 0.97 mg/L (24 h), 1.00 mg/L (48 h) - 3000 mg/L: 0.17 mg/L (0 h), 0.12 mg/L (24 h), < 0.10 mg/L (48 h)

Details on test conditions:

TEST SYSTEM
- Test vessel: beakers
- Type: slightly closed with glass plates
- Material, size, headspace, fill volume: glass, 100 mL, 50 mL, 50 mL
- No. of organisms per vessel: 10
- No. of vessels per concentration: 2
- No. of vessels per control: 2

OTHER TEST CONDITIONS
- Photoperiod: 16 h light / 8 h dark
- Light intensity: approx. 900 lux

EFFECT PARAMETERS MEASURED: immobilization after 24 and 48 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3
- Justification for using less concentrations than requested by guideline: Due to the low water solubility of the test substance only two test concentrations were chosen.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EL0

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EL100

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 1.034 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: no behavioural abnormalities were observed
- Mortality of control: 10% in replicate 2 after 48 h
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: The test substance floated on top of the water surface after 24 and 48 h in some test vessels.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 1.4 mg/L (24 h)

The highest nominal test concentration (3000 mg/L) was not used for the assessment since the measured concentrations were lower compared to the nominal test concentration of 1000 mg/L. Even the nominal concentration of 1000 mg/L is high above the water solubility and represents the highest amount of test substance soluble in test medium.

Table 1: Immobilised test species after 24 and 48 h.

loading [mg/L]	replicate	immobilised test species [%]
		24 h	48 h
0	1	0	0
	2	0	10
1000	1	0	0
	2	0	0
3000	1	0	10
	2	0	0

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Justification for type of information:

Refer to analogue justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EL0

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EL100

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 1.034 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Executive summary:

No effects up to the limit of water solubility (EU Method C.2, D. magna, 48 h).

Description of key information

No effects up to the limit of water solubility (OECD 202, D. magna)

Additional information

Two studies are available, in which the short-term toxicity of the target substance Fatty acids, C18-unsaturated, 2-hexyldecyl ester to aquatic invertebrates was investigated according to internationally accepted testing guidelines. The key study was conducted with the target substance and the supporting study was conducted with the structurally related source substance fatty acids, C16-18, 2-hexyldecyl esters (CAS 101227-09-2). The source substance is characterized by similar fatty acid and alcohol components and is therefore considered a suitable representative for the assessment of the short-term toxicity of the target substance to aquatic invertebrates. Read-across was conducted in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5 and a detailed justification of the analogue approach is provided in IUCLID section 13.

In the key study, Daphnia magna was exposed to a water accommodated fraction (WAF) with a nominal test item loading rate of 0.104 g/L for 48 h in a static limit test according to OECD guideline 202. After 48 h no immobilization was observed, resulting in an EL50 (48 h) of > 0.104 g/L (nominal).

 

In the supporting GLP-study, D. magna was exposed to two WAFs with nominal test item loading rates of 1000 and 3000 mg/L, respectively, for 48 h in a static test according to EU Method C.2. Test item concentrations were analytically verified by GC after 0, 24 and 48 h.

The measured test item concentrations in the 1000 mg/L WAF were 1.07 mg/L (0 h), 0.97 mg/L (24 h), and 1.00 mg/L (48 h). The measured concentrations in the 3000 mg/L WAF were 0.17 mg/L (0 h), 0.12 mg/L (24 h), and < 0.10 mg/L (48 h). After 48 h, no immobilization was observed resulting in an EL50 (48 h) > 1000 mg/L (nominal) and > 1.034 mg/L (measured). The highest test concentration was omitted from assessment due to the poor solubilisation of the test item (floating particles), which was considered justifiable since both concentrations exceeded the water solubility by a factor of > 1000.

In summary, the available key study showed that the target substance Fatty acids, C18-unsaturated, 2-hexyldecyl ester does not cause any short-term effects on aquatic invertebrates up to the limit of water solubility(< 0.56 mg/L). This finding is confirmed by the supporting study with the source substancefatty acids, C16-18, 2-hexyldecyl esters (CAS 101227-09-2).Based on the structural and chemical similarity of the target and source substances, the target substance is expected to exhibit a similar ecotoxicological profile as the source substance.