Docosyl docosanoate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03 Dec - 07 Dec 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study, tested with the source substance dodecyl oleate (CAS 36078-10-1). According to the ECHA guidance document “Practical guide 6: How to report read-across and categories (March 2010)”, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

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

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Samples were taken from the control and the exposure vessel (100 mg/L).
- Sampling method: Sampling at start (0 h) and end (96 h), 4.8 mL were taken from the test and the control aquarium for chemical analysis.
- Sample storage conditions before analysis: Sample storage in 4 mL brown glass vials (filled up to the brim to avoid oxidative processes), maximum storage period of 8 d at 5 °C ± 3 °C before analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Due to sparingly soluble properties of the test item, the study was performed with the water accommodated fraction (WAF) prepared with synthetic fish water according to OECD 203. The test solutions were withdrawn from the middle of the suspension og the beakers after 1 h settling using a glass tube and transferred into the test vessels (aquarium).
Two beakers were prepared like this and stirred for a period of 48 h at 12-22 °C in diffuse light. For stirring an overhead high-grade stainless steel radial impeller was used (about 500 rpm). The impeller was placed about 5 cm above the bottom of the beakers. The depth of the vortex was about 10% of the total height of the liquid. The test item is very mobile and was therefore added by pipetting. According to the density indicated by the sponsor of 0.8529 g/cm3 the amount to be added was converted into volume.
The filtration of the WAF to obtain the water soluble fraction (WSF) was not taken into consideration to avoid unwanted impacts of the filtration process and to have a worst case scenario.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): Slightly whitish oily spots were still floating on the surface of the solutions. The test solutions were withdrawn from the middle of the suspension on the beakers using a glass tube and transferred into the test vessels (aquarium).

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebra fish
- Source: Aquarium Dietzenbach Fischzucht, Dietzenbach, Germany, delivery date: 20 Nov 2012
- Length at study initiation (length definition, mean, range and SD): 2 ± 1 cm
- Feeding during test: none

ACCLIMATION
- Acclimation period: 8 days before the test started.
- Acclimation conditions (same as test or not): same as test
- Feeding frequency: 2 x every working day.
- Health during acclimation (any mortality observed): No mortality, the fish behaved normally.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test temperature:

22.3 - 23.9 °C

pH:

8.0 - 8.1

Dissolved oxygen:

Control: 7.9 - 8.6 mg O2/L
100 mg/L: 7.9 - 8.7 mg O2/L

Nominal and measured concentrations:

Nominal: control, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Size: 8 L aquarium
- Aeration: yes
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 14 h light / 10 h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality every 24 h (and 6 h after study initiation); behavioural abnormalities

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accommodated Fraction (WAF)

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOELR

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accommodated Fraction (WAF)

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no
- Mortality of control: no

Sublethal observations / clinical signs:

No fish died or showed any abnormal behaviour during the 96 h exposure period.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 Mar - 11 Mar 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study with acceptable restrictions (Insoluble test substance was visible during the test).

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

yes

Remarks:

Fish were fed during the main-test

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Samples were taken from 1000 and 10000 mg/L test system after 0 h and 24 h.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was directly weighed into the test vessels and treated with ultraturrax for 10 sec.
- Eluate: no
- Differential loading: yes
- Controls: yes, water control

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebra fish
- Source: Obtained from Fa. Westaquarium, Germany (delivered on 15 Dec 1993)
- Feeding during test
- Food type: Altromin N 1324 spezial 161293 1500 (preliminary study); Altromin N 1324 spezial 140694 0825 (main study)

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

21.5 - 23.1 °C

pH:

8.1 - 8.6

Dissolved oxygen:

67 - 89%

Nominal and measured concentrations:

Nominal: control - 1000 - 3000 - 10000 mg/L
Measured (DOC analysis):
1000 mg/L (=39.2 mg DOC/L): 2.1 mg DOC/L (0 h); 2.0 mg DOC/L (24 h); 1.0 mg DOC/L (0 h); 1.5 mg DOC/L (24 h)
10000 mg/L (=392 mg DOC/L): 2.8 mg DOC/L (0 h); 2.0 mg DOC/L (24 h); 1.2 mg DOC/L (0 h); 1.5 mg DOC/L (24 h)

Details on test conditions:

TEST SYSTEM
- Fill volume: 5 L
- Renewal rate of test solution (frequency): every 24 h
- No. of organisms per vessel: 10

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: drinking water

OTHER TEST CONDITIONS
- Adjustment of pH: no

EFFECT PARAMETERS MEASURED: mortality was checked after 0, 4-6, 24, 48, 72 and 96 h of exposure

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: no behavioural effects were observed
- Mortality of control: 0%
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: The test substance was not completely soluble in water and floated on top of the surface of the test solutions.

Sublethal observations / clinical signs:

Table 1: Percental mortality of fish during the study

Concentration [mg/L]	% mortality after x hours
	0 h	4-6 h	24 h	48 h	72 h	96 h
0	0	0	0	0	0	0
1000	0	0	0	0	0	0
3000	0	0	0	0	0	0
10000	0	0	0	0	0	0

Reference 3

Endpoint:

short-term toxicity to fish

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

Reason / purpose for cross-reference:

read-across source

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: Water Accommodated Fraction (WAF)

Basis for effect:

mortality (fish)

Remarks on result:

other: Source: key, RA-A, CAS 36078-10-1, Dako, 2013, D. rerio

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other:

Remarks:

Source: key, RA-A, CAS 95912-87-1, BASF, 1994, B. rerio

Description of key information

No effects up to the limit of water solubility (EU Method C.1; OECD 203).

Additional information

Since no studies investigating the short-term toxicity of docosyl docosanoate (CAS 17671-27-1) to fish are available for this endpoint, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read across to the two structurally related read-across substances dodecyl oleate (CAS 36078-10-1) and fatty acids, C16-18, C12-18-alkyl esters (CAS 95912-87-1) was conducted. The read-across substance dodecyl oleate is characterized by a smaller fatty acid chain (C18 unsatd. compared to C22 unsatd. (target)) and a smaller fatty alcohol chain length (C12 compared to C18 unsatd. (target)). The second read-across substance fatty acids, C16-18, C12-18-alkyl esters is a UVCB substance showing a similar structure to the target substance. The smaller alcohol and fatty acid chain length increases the water solubility and therefore the bioavailability in the water phase. 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 first study conducted with the read-across substance fatty acids, C16-18, C12-18-alkyl esters (CAS 95912-87-1) was performed according to the EU Method C.1 (GLP) with the zebrafish Brachydanio rerio (Stelter, 1994). A static exposure regime was chosen. Three concentrations of nominal 1000, 3000 and 10000 mg/L were directly applied to the test vessels without a filtration step. Undissolved test material floated on top of the water surface but no effects were observed by the dissolved and even by the undissolved test substance present in the water. Even though the undissolved particles were not removed this approach can be considered as a worst case since possible effects of dissolved and undissolved fractions were evaluated. Thus, a LC50 (96 h) of > 10000 mg/L (nominal) was derived.

The second study with the read-across substance dodecyl oleate (CAS 36078-10-1) was performed according to OECD 203 under GLP conditions with the zebrafish Danio rerio (Hafner, 2013). A limit test with a Water Accommodated Fraction (WAF) of 100 mg/L (nominal) did not result in any mortality after 96 h. Thus, a LL50 (96 h) of > 100 mg/L was derived based on the nominal loading rates. The chemical analysis resulted in concentrations below the analytical detection limit of 0.005 mg/L reflecting the very low water solubility of the test item.

Based on the available results from two structurally related read-across substances (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which are 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 fish up to the limit of water solubility.