Fatty acids, C16-18, esters with ethylene glycol

Toxicity to terrestrial plants

Description of key information

The assessment of the terrestrial toxicity should be based on the outcome of aquatic toxicity testing. Pursuant to ECHA decision on a compliance check CCH-D-2114551285-49-01/F new studies with the registered substance will be conducted in the future. The finalised studies will be reported in an updated dossier until 22 July 2024 and the hazard assessment will be re-evaluated accordingly. Thus, the strategy of terrestrial toxicity will be evaluated later when all aquatic toxicity studies are available. For further details, please refer to the category concept document attached to the category object (linked under IUCLID section 0.2) showing an overview of the strategy for all substances within the glycol esters category.

Additional information

The assessment of the terrestrial toxicity should be based on the outcome of aquatic toxicity testing. Pursuant to ECHA decision on a compliance check CCH-D-2114551285-49-01/F new studies with the registered substance will be conducted in the future. The finalised studies will be reported in an updated dossier until 22 July 2024 and the hazard assessment will be re-evaluated accordingly. Thus, the strategy of terrestrial toxicity will be evaluated later when all aquatic toxicity studies are available. For further details, please refer to the category concept document attached to the category object (linked under IUCLID section 0.2) showing an overview of the strategy for all substances within the glycol esters category.

The Chemical Safety Assessment according to Annex I of Regulation (EC) No 1907/2006 does not indicate the need to investigate the long-term effects to terrestrial plants. One study investigating the toxicity to terrestrial plants is available for the structurally similar category member butylene glycol dicaprylate / dicaprate (CAS 853947-59-8). 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 study was performed according to OECD 208 with two dicotyledon (Raphanus sativus & Glycine max) and one monocotyledon species (Avena sativa) (Spatz, 2002). Five different concentrations up to 1000 mg/kg soil were tested and the effect parameters germination, phytotoxicity, growth stages, mortality and fresh weight were measured after 21 d. The most sensitive species based on fresh weight was Avena sativa with an EC50 of 263.79 mg/kg soil (NOEC 39 mg/kg soil), followed by Raphanus sativus and Glycine max with an EC50 of 526.47 and 2978.54 mg/kg soil, respectively. Moreover, the test substance caused a statistically significant reduction in germination of Raphanus sativus (from 444 mg/kg soil onwards) but did not affect germination rate of Avena sativa and Glycine max. Phytotoxic effects appeared as reduction of growth stages of Raphanus sativus and Avena sativa. No mortality occurred in soil treated plants exposed to the test substance. In conclusion all EC50 values are clearly > 100 mg/kg indicating a low toxicity. All tested species showed the same effects (e.g. reduced fresh weight), which are not typical phytotoxic effects as known for plant protection products (e.g. chlorosis and necrosis). The effects are resembled more growth depression like caused by a permanent water deficiency from the beginning of germination. Observed effects might have been caused by obstruction of water uptake through the roots. Based on these results from this structurally related read-across substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which is characterized by an equal ecotoxicological profile, it can be concluded that effects of fatty acids, C16-18, esters with ethylene glycol to terrestrial plants will be in the same range. In addition, there are two reliable short-term earthworm studies available for decanoic acid, mixed diesters with octanoic acid and propylene glycol (CAS 68583-51-7) and ethylene distearate (CAS 627-83-8) investigating the mortality on earthworms showing no toxicity up to a nominal concentration of 1000 mg/kg soil. The earthworm is considered to be the most appropriate organism since testing allows to determine possible effects via different ways of exposure (e.g. via the surface, via soil particle ingestion and pore water). Testing with plants only covers the effects via pore water. The exposure via pore water is not considered to be relevant since the substance has a very low water solubility of < 0.05 mg/L. Furthermore, due to the ready biodegradability of fatty acids, C16-18, esters with ethylene glycol, long-term exposure in soil is considered to be not relevant as well, as the test substance will be degraded quickly in the terrestrial environment. In accordance with ECHA Guidance R.7c (p. 121/R.7.11.5.3) the data requirements of Annex IX and X can be modified if there are no effects up to the water solubility limit in chronic aquatic studies or no effects within the solubility range above 10 mg/L in acute aquatic studies. No effects were observed for fatty acids, C16-18, esters with ethylene glycol in acute and chronic aquatic studies, respectively. Taking all these information into account (low toxicity to plants and earthworm, low water solubility, readily biodegradability, no effects in acute and chronic aquatic studies) there is no need to perform further a long-term study with terrestrial plants.