9-Octadecenedioic acid

Endpoint summary

Additional information

There are no data available investigating the aquatic toxicity of octadec-9-enedioic acid (EC 802-122-7) to fish, algae, and microorganisms. In order to fulfil the standard information requirements, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from structurally related substances 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 aquatic 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 aquatic toxicity of the target and the source substances are provided in the following table:

ID	CAS	Short term toxicity to fish	Long term toxicity to fish	Short term toxicity to aquatic invertebrates	Long term toxicity to aquatic invertebrates	Toxicity to aquatic algae	Toxicity to microorganisms
Target	n.a. EC list No. 802 -122 -7	RA: CAS 20701-68-2	--	Experimental result: LC50 (96 h) >100 mg/L	--	RA: CAS 20701-68-2	RA: CAS 20701-68-2
Source 1	20701-68-2	Experimental result: LC50 (96 h) >100 mg/L	--	Experimental result: ≤100% of filtered solution prepared at a nominal loading rate of 100 mg/L; LOELR = 100 mg/L	--	Experimental result: ErL50 (72 h) > 100 mg/L NOErL < 100 mg/L	Experimental result: EC50 (30 min) >1000 mg/L

The above mentioned substances are considered to be similar on the basis of the structural similar properties and/or activities. The available endpoint information on the source substances is used to predict the same endpoints for octadec-9-enedioic acid (EC 802-122-7). Based on their chemical structure, both the target substance (Octadec-9-enedioic acid, EC 802-22-7) and the source substance ((Z)-9-Octadecen-1,18-dioic acid, CAS 20701-68-2), belong to the family of linear monounsaturated dicarboxylic acids. While the target substance contains a cis- and trans-isomer, the source substance consists of the cis-isomer.

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

All available experimental data on the source substances performed according to internationally accepted guidelines indicate no evidence of acute and chronic toxicity to aquatic organisms. Data for all three trophic levels are available. No toxicity was observed up to the limit of water solubility in all available experimental studies. The water solubility of the target substance was determined to be 300.7 µg/L at 20 °C.

The short-term toxicity to fish was determined in a standard OECD guideline study according to OECD 203 (from the source substance (Z)-9-Octadecen-1,18-dioic acid (CAS 20701-68-2)). No mortality was observed after 96 h resulting in a LC50 > 100 mg/L (i.e. above the water solubility limit). In the short-term toxicity test to aquatic invertebrates conducted with the target substance octadec-9-enedioic acid (EC 802-122-7) an EC50 of 258 mg/L was determined. Short-term toxicity to aquatic algae also resulted in no effects up to the water solubility limit with an ErL50 > 100 mg/L.

The degradation process in sewage treatment plants is not suspected to be inhibited by the target substance (Octadec-9-enedioic acid, EC 802-22-7). Available information taken from a biodegradation study performed with activated sludge from sewage treatment plants did not indicate a risk since biodegradation was not inhibited.

Based on the result from both, the target and the structurally related read-across substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) it can be concluded that octadec-9-enedioic acid, EC 802-22-7 exhibits no toxic effects on freshwater organisms up to the limit of the water solubility. As it can be seen in the data matrix of the analogue justification in IUCLID Section 13, all reliable data from the target and the source substance support the read-across by showing a consistent pattern of results.