Docosyl docosanoate

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

Study period:

30 Jan - 01 Feb 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: WAF of 100 mg test substance/L; WAF of 100 mg test substance/L + 10 mg/L TAGAT CH 60 (emulsifier)

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution of 100 mg/L in M4-medium was prepared. It was stirred for about 24 h. After a settling time of about 2 h the solution was siphoned by a pipette and filtered via 0.2 µm membrane filter (WAF, filtered). This test solution was split up in two parts. To one of them the emulsifier TAGAT CH 60 was added at a concentration of 10 mg/L.
- Controls: A control with M4-medium and a solvent control with M4-medium and the emulsifier was conducted
- Chemical name of vehicle: TAGAT CH 60
- Concentration of vehicle in test medium: 10 mg/L

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: Ephippia were obtained from Creasel, 98000 Deinze, Belgium (Batch: DM / M 270999)
- Method of breeding: Ephippia were hatched in M4-medium at approx. 4800 lux and 20 °C. The incubation of neonates was performed in M4-medium according to Elendt at 20 °C and approx. 900 lux (16 h light and 8 h dark). Neonates were fed with green algae (Scenedesmus subspicatus).

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

20 °C

pH:

8.0 (48 h)

Dissolved oxygen:

98% (48 h)

Nominal and measured concentrations:

Nominal: 0, 100 mg/L
Measured (WAF of 100 mg/L): 0.2 mg/L (0 h), 0.1 mg/L (24 h), < 0.1 mg/L (48 h)
Measured (WAF, filtered + 10 mg/L TAGAT CH 60): 0.1 mg/L (0 h), < 0.1 mg/L (24 h), 0.1 mg/L (48 h)

Details on test conditions:

TEST SYSTEM
- Test vessel: beakers
- Type: covered with glass plates
- Material, size, fill volume, headspace: glass, 100 mL, Fill volume: 50 mL, Headspace: 50 mL
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2 (WAF), 2 (WAF + emulsifier)
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2

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

EFFECT PARAMETERS MEASURED: immobilization was noted every 24 h

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accommodated Fraction (WAF)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accommodated Fraction (WAF) + Emulsifier

Basis for effect:

mobility

Details on results:

- Mortality of control: 0%

Results with reference substance (positive control):

- EC50 (24 h): 0.98 mg/L which is in the range of 0.9 and 1.9 mg/L proposed for validity of the test.

Table 1: Immobilization of test species after 24 h and 48 h.

sample name	replicate	immobilised test species [%]
		24 h	48 h
control	1	0	0
	2	0	0
Solvent control	1	0	0
	2	0	0
WAF, filt. (100 mg/L)	1	0	0
	2	0	0
WAF (100 mg/L) + TAGAT	1	0	0
	2	0	0

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Please refer to analogue justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accomodated Fraction (WAF)

Basis for effect:

mobility

Remarks on result:

other: Source: key, source, RA-A, CAS 95912-87-1, BASF, 2001, D. magna

Description of key information

No effects up to the limit of water solubility based on available data (EU Method C.2).

Additional information

Since no studies investigating the short-term toxicity to aquatic invertebrates of docosyl docosanoate (CAS 17671-27-1) are available for this endpoint, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read across to the structurally related read-across substance fatty acids, C16-18, C12-18-alkyl esters (CAS 95912-87-1) was conducted. The smaller alcohol and fatty acid chain length increases the water solubility and therefore the bioavailability in the water. Water solubility is negatively correlated with the C-chain length of the fatty alcohol and fatty acid (Lide, 2005). Therefore, it is possible to extrapolate from a source substance with higher water solubility since it has an increased bioavailability in the water phase (ECHA, 2017). This read-across is justified in detail in the overall summary (IUCLID section 6.1) and within the analogue justification in IUCLID Section 13. In this case of read-across, the best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substance was used for the assessment. Nevertheless, as it can be seen in the data matrix of the analogue justification in IUCLID section 13 and the overall summary, all reliable data support the hazard assessment by showing a consistent pattern of results.

The study with the read-across substance fatty acids, C16-18, C12-18-alkyl esters was conducted according to EU Method C.2 (GLP) under static conditions with the water flea Daphnia magna (Wierich, 2001). A Water Accommodated Fraction of nominal 100 mg/L was tested in this study. Measured concentrations were in the range of 0.1 - 0.2 mg/L or even below the detection limit (GC analysis). After 48 h no effects on the test organisms were observed resulting in an EL50 > 100 mg/L (nominal).

Based on the result from one structurally related read-across substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which is characterized by a similar ecotoxicological profile and comparable structure, it can be concluded that docosyl docosanoate (CAS 17671-27-1) will not exhibit short-term effects to aquatic invertebrates up to the limit of water solubility.