Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol]

Endpoint summary

Additional information

There are no data available for toxicity to soil macroorganism of Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol] (CAS 91050-80-5). In order to fulfil the standard information requirements set out in Annex IX, 9.4, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from one structurally related substance was conducted.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 whereby substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

Ecotoxicological parameters for the terrestrial toxicity of the target substance Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol] and the source substance 1,2,3 -propanetriol, homopolymer, diisooctadecanoate are presented in the following table.

CAS	91050-80-5	63705-03-3
Chemical Name	Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol]	1,2,3 -propanetriol, homopolymer, diisooctadecanoate
MW	807.32 – 1604.56	358.56 – 891.48
Toxicity to soil macroorganisms	RA: CAS 63705-03-3	NOEC (56 d): 250 mg/kg soil dw
Toxicity to terrestrial arthropods	Waiving based on CSA	Waiving based on CSA
Toxicity to terrestrial plants	Waiving based on CSA	Waiving based on CSA
Toxicity to soil microorganisms	Weight of Evidence (WoE)	Weight of Evidence (WoE)

CSA: Chemical Safety Assessment

The above mentioned substances are considered to be similar on the basis of the structural similar properties and/or activities. The available endpoint information is used to predict the same endpoints for Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol].

A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

In accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5, grouping and read-across, the target substance Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol] (CAS 91050-80-5) and the source substance 1,2,3 -propanetriol, homopolymer, diisooctadecanoate (CAS 63705-03-3) show similar toxicity profile to aquatic organisms based on the results from short-term studies with fish and algae. Both substances are structurally similar. They are both esters with similar main fatty acid components (target: C16-C18; source: C18 iso). The target substance is an ester consisting on tri-, tetra- and pentaesters of glycerol, diglycerol and triglycerol in comparison to an ester of mono-, di- and triesters of glycerol, diglycerol and triglycerol for the source substance. Thus, the source substance 1,2,3 -propanetriol, homopolymer, diisooctadecanoate is a very close analogue to the target substance Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol].

The water solubilities (target substance: < 0.05 mg/L; source substance: < 0.15 mg/L) and log Kow values (log Kow > 4) of both substances are comparable. The log Kow values of these substances indicate adsorption potential to soil. Therefore, 1,2,3 -propanetriol, homopolymer, diisooctadecanoate can be used as read across substance in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5.

The experimental study investigating the toxicity of the source substance 1,2,3 -propanetriol, homopolymer, diisooctadecanoate to soil macroorganism was conducted according to OECD 222 under GLP conditions (Moser & Scheffczyk, 2013). Eisenia fetida was exposed to five nominal concentration between 62.5 and 1000 mg test item/ kg soil dw for 56 d. Significant effects on reproduction were observed at the two highest test cocnentrations resulting in a NOEC (56 d) of 250 mg/kg soil dw. Based on the results obtained for the structurally analogue substance (in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5), it can be concluded that Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol] (CAS 91050-80-5) will show a similar toxicity profile to soil macroorganisms.

In accordance with Regulation (EC) No. 1907/2006, Annex IX,column 2 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. The test substance is characterised by a high log Koc (log Koc > 5) indicating a considerable potential for adsorption to the soil particles. Due to the low water solubility (< 0.05 mg/L), only low concentrations are expected in the pore water, which is the main exposure route for terrestrial plants. Therefore, tests soil-dwelling organisms like earthworm which allows potential uptake via surface contact, soil particle ingestion and porewater (ECHA, 2012), are most relevant for the evaluation of soil toxicity of Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol]. In addition, in the absence of a clear indication of selective toxicity, an invertebrate (earthworm or collembolan) test is preferred, as outlined in ECHA guidance section R.7.11.5.3, page 122 (ECHA, 2012). Thus, it can be assumed that earthworms would be highly exposed to toxicants in soil and hence are most sensitive to the potential adverse effects of the substance.

Moreover, Fatty acids, C16-18, tetraesters with 3,3'-oxybis[1,2-propanediol] is readily biodegradable and a toxicity control in the biodegradation study shows no inhibition to aquatic microorganisms resulting in a NOEC (14 d) of ≥ 20 mg/L BOD. The applied test concentration is in the range of concentrations that can be expected in the influent of a sewage treatment plant, as the substance has low water solubility (< 0.05 mg/L). The Guidance Document R.7c (ECHA, 2012) 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. As marine microorganisms from natural seawater were used, which were known as more sensitive as freshwater and activated sludge microorganisms, comparable microbial activity will be expected for activated sludge microorganisms.

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 toxicity to other terrestrial organisms other than to soil macroorganisms is not expected to be of concern.

A detailed reference list is provided in the technical dossier (see IUCLID, section 13) and within CSR.