Decanoic acid, mixed esters with heptanoic acid, octanoic acid, pentaerythritol and valeric acid

Long-term toxicity to aquatic invertebrates

Description of key information

An experimental study is planned for tetra-esterification products of C5, C7, C8, C10 fatty acids with pentraerythritol (CAS 68424-31-7), however based on available data no chronic toxic effects up to the limit of water solubility were observed in any of the read across studies.

Additional information

There is no long-term test on aquatic invertebrates available for pentaerythritol tetraesters of n-decanoic, n-heptanoic, n-octanoic and n-valeric acids (CAS 68424-31-7).Since all substances within this polyol esters category are readily biodegradable, it is not foreseen that they will pose a risk to aquatic invertebrates on the long-term.However, due to the poor water solubility of the test substance and as long term toxicity to aquatic organisms is a mandatory endpoint in accordance to Regulation (EC) No 1907/2006, Annex IX 9.1 Aquatic toxicity, we propose a read across to proposed tests on long term toxicity to invertebrates for the PE esters CAS 68424-31-7 (tetra-esterification products of C5, C7, C8, C10 fatty acids with pentraerythritol), CAS 15834-04-5, CAS 68424-30-6 and CAS 85049-33-8.  CAS 68424-31-7 (C5, C7, C8 and C10) is a highly complex UVCB, with varying chain lengths and combinations of structures. CAS 15834-04-5 has the shortest chain length (C5) of PE esters, it is a mono-constituent and often is a constituent with many of the other polyol esters. Due to its smaller molecular size it is expected to have the highest bioavailability. CAS 68424-30-6 (C5, C7, C9 iso) was chosen on the basis of its isononanoic acid content to evaluate possible adverse effects.CAS 85049-33-8 was selected in order to confirm that no chronic toxicity to aquatic organisms occurs for the polyol esters with medium chain length of the category C8-C16 (even numbered).

Reliable tests on the long-term toxicity to aquatic invertebrates are also provided which indicate that the polyol esters will not exhibit long-term effects to aquatic invertebrates up to the limit of water solubility.

The first study with the read-across substance decanoic acid, mixed esters with heptanoic acid, octanoic acid, pentaerythritol and valeric acid (CAS No. 71010-76-9) was conducted under semi-static conditions according to OECD 211 using Daphnia magna as test organism (Letinski & Bragin, 2011).The test solution was prepared by adding the appropriate amount of test substance with subsequent stirring and sampling of the aqueous portions (WAFs) through the outlet at the bottom of the vessels. A loading rate WAF of 135 mg/L (nominal) was applied in a limit test. No significant effect on reproduction was observed in the treatment throughout the test period of 21 d. Hence, the 21 d-NOELR is determined to be > 135 mg/L on the basis of the nominal test concentration.

The second study investigating the long term toxicity to aquatic invertebrates was performed with the read-across substance fatty acids, C8-10 (even numbered), di-and triesters with propylidynetrimethanol (CAS 11138-60-6) according to OECD guideline 202 "Daphnia sp. Acute Immobilization Test and Reproduction Test", Part 2 (1993) under semi-static conditions (Low, 1996). This test guideline is similar to OECD 211 which was adopted in 1998. The study period of 15 days does not meet the criteria of today standard methods recommending 21 days study duration. However, according to the Guidance on information requirements and chemical safety assessment, Chapter R7.b (ECHA, 2012) the study can be regarded as valid for a long-term evaluation as corresponding criteria were fulfilled (e.g. 80% survival in the control, surviving females produce three broods in 21 days or less, > 60 brood neonates per female in the control on average). In addition, all requested endpoints could be determined (time to first brood, number of offspring produced per female, growth and survival) and NOELR values for survival or reproductive endpoints could be calculated. In this study Daphnia magna were exposed to nominal concentrations of 0, 24, 97, 242, 1018 and 2570 mg/L (prepared as water accommodated fraction, WAF). No effects were observed up to the highest test concentration resulting in a NOELR of ≥ 2570 mg/L based on reproduction and immobilization.

As it can be seen in the data matrix of the category justification in section 13 and the overall endpoint summary IUCLID 6.1, all reliable data in the category support the hazard assessment of each category member by showing a consistent pattern of results, i.e. no toxic effects to aquatic organisms were observed up to the limit of water solubility.