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Long-term toxicity to aquatic invertebrates

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An experimental study is planned according to OECD 211.

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There is no long-term test on aquatic invertebrates available for Fatty acids, C16-18 (even numbered) and C18-unsatd., branched and linear, di- and triesters with trimethylolpropane (former CAS 85005-23-8). 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 to test the long term toxicity on invertebrates in order to confirm that no chronic toxicity to aquatic organisms occurs for the polyol esters with longer, unsaturated chain lengths. In particular, Fatty acids, C16-18 (even numbered) and C18-unsatd., branched and linear, di- and triesters with trimethylolpropane (former CAS 85005-23-8) was selected as a representative test substance for this chain length, but it was also selected in order to cover saturated and branched C16/C18 chain lengths

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 read-across study investigated the chronic toxicity of Fatty acids, C16-18 and C18-unsatd., triesters with trimethylolpropane (CAS 68002-78-8) to aquatic invertebrates according to OECD 211 (Grell, 2013). Daphnia magna were exposed to the test substance in a semi-static test system. The water accommodated fraction (WAF) was used for the preparation of the test solutions. During the exposure period of 21 days the mortality and reproduction rate of the test animals was recorded. The substance affected neither the survival rate nor the reproduction rate of D. magna. Based on the loading rate a NOELR ≥ 0.11 g/L was determined. Thus toxic effects C16-18 and C18-unsatd., triesters with trimethylolpropane (CAS 68002-78-8) were not observed within the limit of water solubility (WS<0.05 mg/L).

The second read across study was chosen as it should have a theoretically higher bioavailability (even though all are insoluble) than the target substance due to the lower chain lengths (C8-C10) This test can therefore confirm that no chronic toxicity to aquatic organisms occurs for the polyol triesters with shorter chain lengths (C8-10 ) with propylidynetrimethanol. In this GLP study on the long-term toxicity of fatty acids, C8-10 (even numbered), di-and triesters with propylidynetrimethanol (CAS No. 11138-60-6) was performed according to the OECD guideline 202 part 2 (Low, 1996). The test organism Daphnia magna was exposed to the test substance in a semi-static system for 15 days. Though the exposure time does not meet the recommended 21 days test duration for long-term tests the study is considered as valid. According to the ECHAs 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). Thus 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. Effects on the reproduction or mobility of Daphnia magna were not observed at the tested concentrations. A NOELR of 2570 mg/L is reported. The concentration is based on the water accommodated fraction (WAF) of the substance.

As soon as further chronic toxicity data for Fatty acids, C16-18 (even numbered) and C18-unsatd., branched and linear, di and triesters with trimethylolpropane becomes available the chemical safety assessment will be updated accordingly.

Based on these already available results from 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, it can be concluded that Fatty acids, C16-18 (even numbered) and C18-unsatd., branched and linear, di- and triesters with trimethylolpropane (former CAS 85005-23-8) will not exhibit long-term toxic effects to aquatic invertebrates up to the limit of water solubility.