Octyl laurate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

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

Remarks:

Summary of available data used for the endpoint assessment of the target substance.

Adequacy of study:

key study

Justification for type of information:

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.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

mortality (fish)

Remarks on result:

other: Source: CAS 84713-06-4, C. carpio, 96 h

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

2 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Source: CAS 34316-64-8, D. rerio, 96 h

Description of key information

No toxic effects up to the limit of water solubility; read-across

Additional information

Since no studies investigating the short-term toxicity of octyl laurate (CAS 5303-24-2) to fish are available, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5 a read-across to the structurally related source substances isooctyl laurate (CAS 84713-06-4) and dodecanoic acid, hexyl ester (CAS 34316-64-8) was conducted. The source substances are considered to be representative to evaluate the short-term toxicity of octyl laurate to fish.

The source substance isooctyl laurate is characterized by the same fatty acid chain length (lauric acid) and a similar alcohol component (octanoic acid compared to isooctanoic acid for the source substance). The second source substance dodecanoic acid, hexyl ester is characterized by the same fatty acid (C12) and a slightly longer alcohol chain (C10 compared to C8). 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.

The experimental study conducted with the source substance dodecanoic acid hexyl ester (CAS 34316-64-8) was performed according to the guideline ISO 7346-1 (similar to OECD 203), in a semi-static system using Brachydanio rerio as test organism (Guhl, 2005). The fish were exposed to nominal test concentrations of 100, 300, 700, 1000, 3000 and 10000 mg/L during 96 h. Significant mortality occurred at the two highest test concentrations, and a LC50 of 2200 mg/L was derived. However, the test concentrations in this study were far above the saturation limit of the test substance, and undissolved test material was not removed from the test solutions. The sudden increase in mortality from 0% at concentrations 100 – 1000 mg/L to 70% at 3000 mg/L is better explained by a physical effect, caused by the amount of undissolved material in the test solution, rather than by a systemic toxic effect. It is therefore probable that no toxic effects occurred up to the limit of water solubility of the test substance.
The second study with the source substance dodecanoic acid isooctyl ester (CAS 84713-06-4) was performed according to OECD guideline 203 and GLP (Bogers, 1997). The test organism Cyprinus carpio was exposed to the test substance in a static system for 96 hours, at the nominal test concentration of 10000 mg/L. Only the separated water phase was used in the test solutions. No mortality occurred at any of the test concentrations, and the LC50 (96 h) was reported to be < 10000 mg/L.
Thus, based on the above mentioned results, and due to the structural similarities and a similar ecotoxicological profile of the two substances, as are explained with in the overall endpoint summary 6.1 it can be concluded that no toxicological short-term effects on fish are expected up to the limit of water solubility for octyl laurate.