Fatty acids, C8-10, C8-10-alkyl esters

Toxicity to terrestrial plants

Additional information

In accordance with Regulation (EC) No. 1907/2006, Annex IX, column 2, 9.4 further studies on the effects on terrestrial organisms do not have to be conducted since the chemical safety assessment indicates that there is no need.

No experimental data on toxicity to terrestrial arthropods are available for Fatty acids, C8-C10, C8-10-alkyl esters (CAS 129677-93-6). The test substance is characterised by a high log Kow indicating a considerable potential for adsorption to soil particles.. Due to the high potential of the substance to adsorb to soil, the long-term testing on terrestrial invertebrates was considered most suitable to fully assess the potential soil hazard of the target substance. Tests with soil-dwelling organisms like earthworms which allows potential uptake via surface contact, soil particle ingestion and pore water (Guidance on information requirements and chemical safety assessment, Chapter R.7c, (ECHA, 2017)) is most relevant for the evaluation of soil toxicity of Fatty acids, C8-C10, C8-10-alkyl esters.

Read-across in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 from the structurally related source substance Fatty acids, C8-10, C12-18-alkyl esters (CAS 95912-86-0) resulted in low toxicity to terrestrial macroorganisms (NOEC (56 d) 500 mg/kg soil dw). This result is considered being suitable for the assessment of terrestrial toxicity taking into account further evidence from the aquatic studies and bioavailability as outlined below.

No acute and chronic effects were observed in the available aquatic studies. Thus, no selective toxicity was observed for the aquatic compartment. According to ECHA guidance (Chapter R.7c: Endpoint specific guidance, 2017, page 149) an invertebrate test (earthworm or collembolan) is preferred in the absence of a clear indication of selective toxicity covering different pathways of exposure (via surface contact, soil particle ingestion and pore water). Further testing with terrestrial plants is not considered being necessary due to the very low water solubility of the substance. The main uptake route for terrestrial plants is via dissolved concentrations in the pore water (root uptake). Since this route is negligible based on the low water solubility and algae did not turn out being the most sensitive species, testing with plants is not considered relevant for Fatty acids, C8-C10, C8-10-alkyl esters..

Exposure and bioavailability within the soil compartment is generally considered to be low. Even if exposed to the soil the substance is readily biodegradable indicating that it will not be persistent in the environment. As a result of the high adsorption potential of the substance (3.90 – 4.94, KOCWIN v2.00) a removal from the water column to a significant degree by adsorption to sewage sludge can be expected (Guidance on information requirements and chemical safety assessment, Chapter R.7b, (ECHA, 2017)). Indirect exposure via irrigation or atmospheric transport is considered to be negligible based on the physico-chemical properties of the substance (water solubility: 4.6 µg/L; vapour pressure: 0.000115 - 0.0152 Pa at 20 °C). Considering this, it is assumed that the availability of Fatty acids, C8-10, C8-10 alkyl esters (CAS 129677-93-6) in the soil compartment is very low, which reduces the probability of exposure, in particular long-term exposure, of soil organisms in general.

Overall, due to the low toxicity observed in the long-term earthworm study, the absence of chronic or long-term effects in aquatic organisms up to the water solubility limit, a removal from the water column to a significant degree by adsorption to sewage sludge, a low bioavailability and a low bioaccumulation potential, no further study on the effects on terrestrial organisms needs to be conducted for C8-10, C8-10 alkyl esters (CAS 129677-93-6).