Decanoic acid, mixed diesters with octanoic acid and propylene glycol

Endpoint summary

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 checkCCH-D-2114546495-41-01/Fnew studies with the registered substance will be conducted in the future. The finalised studies will be reported in an updated dossier until19 October 2022and the hazard assessment will be re-evaluated accordingly. Thus, the strategy for 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 checkCCH-D-2114546495-41-01/Fnew studies with the registered substance will be conducted in the future. The finalised studies will be reported in an updated dossier until19 October 2022and the hazard assessment will be re-evaluated accordingly. Thus, the strategy for 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.

 

Two studies are available investigating effects on different species of the terrestrial compartment for the category members decanoic acid, mixed diesters with octanoic acid and propylene glycol (CAS 68583-51-7) and butylene glycol dicaprylate / dicaprate (CAS 853947-59-8). Acute toxicity studies with the earthworm resulted in no mortality up to a concentration of 1000 mg/kg soil dw. The category member butylene glycol dicaprylate / dicaprate exhibited effects on the freshweight of Avena sativa resulting in an EC50 of 263.79 mg/kg soil. This endpoint was the most sensitive among others tested in the available study. All tested species showed the same effects, 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 the available data it can be concluded that the terrestrial toxicity of the Glycol Esters category members is low. All substances within the category are characterized by similar physico/chemical parameters like low water solubility (< 0.05 mg/L), high log Koc (> 3) and high log Kow (> 5), indicating a similar behaviour in the environment. They are all esters of EG, PG or 1,3-BG with varying fatty acid chain lengths (C8-C18 and C18 unsaturated) and thus, a similar metabolic pathway is expected. Consequently, bioaccumulation is not expected due to rapid metabolisation.

No studies are available investigating the effects on soil microorganisms. Therefore, all available related data is combined in a Weight of Evidence (WoE) approach, which is in accordance to the REACh Regulation (EC) No 1907/2006, Annex XI, 1.2, to adapt the data requirements of Regulation (EC) No 1907/2006 Annex VII - X (ECHA guidance section R.7.11.5.3, page 121).

Available read-across data in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5 from the structurally related category members butylene glycol dicaprylate / dicaprate (CAS 853947-59-8) and decanoic acid, mixed diesters with octanoic acid and propylene glycol (CAS 68583-51-7) did not show any mortality to earthworms (Eisenia fetida) in acute terrestrial toxicity tests according to OECD 207 and EU Method C.8, respectively (LC50 > 1000 mg/kg soil dw). A plant study with butylene glycol dicaprylate/dicaprate according to OECD 208 with three species from different taxonomic groups resulted in an EC50 of > 100 mg/kg soil for all tested species (three plant species). Moreover, the read-across substance butylene glycol dicaprylate / dicaprate did not show any chronic effects up to the limit of water solubility on the water flea Daphnia magna in a study according to OECD 211 and no effects were observed on the respiration rate of activated sludge microorganisms. Available reliable read-across data for toxicity to aquatic microorganisms for the Glycol Esters category members supports the determination of a lack of toxicity to soil microorganisms. No inhibition of respiration rate of aquatic microorganisms was observed in any of the available studies for the Glycol category members. The Guidance Document (ECHA, 2012, page 122) states that a test on soil microbial activity will only be additionally necessary for a valid PNEC derivation if inhibition of sewage sludge microbial activity has occurred and this is clearly not the case. This is supported by further evidence from literature data. This data showed that soil microorganism communities are well capable of degrading fatty acid esters and use them as energy source. Based on the available information, effects on soil microorganisms are not expected to be of concern, and consequently, no further testing is required.

Acute studies with terrestrial organisms from different taxonomic groups are regarded sufficient for the assessment of terrestrial toxicity since the category members are readily biodegradable and chronic aquatic data indicated no effects up to the limit of water solubility.