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Diss Factsheets

Ecotoxicological information

Sediment toxicity

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Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

Justification for grouping of substances and read-across

There are no data available on the toxicity to sediment organisms of Fatty acids, C18-unsaturated, trimers, hydrogenated. According to the standard requirements set in Regulation (EC) No. 1907/2006, Annexes VII-IX information regarding sediment toxicity does not need to be presented at this tonnage band (100-1000 t/y). Nevertheless, in accordance with the Guidance on information requirements and chemical safety assessment, Chapter R7.b (ECHA, 2012), should be considered for highly hydrophobic substances (log Kow > 5) such as Fatty acids, C18-unsaturated, trimers, hydrogenated. Therefore, read-across from a structurally similar substance is 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 and environmental 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 physicochemical, toxicological and ecotoxicological properties may be predicted from data for reference substance(s) by interpolation to other substances on the basis of structural similarity, Fatty acids, C18-unsatd., trimers (CAS No. 68937-90-6) is selected as read-across substance for assessment of sediment toxicity.

The read-across is based on structural similarity as a result of common origin and production process line. Shortly, the source and target substances are derived from catalytically di- and trimerised long-chain fatty acids; dimers and trimers are separated by distillation and unsaturated alkyl chains are hydrogenated as specifically required. A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

Table: Sediment toxicity of target and source substances


Fatty acids, C18-unsaturated, trimers, hydrogenated (a)

Fatty acids, C18-unsatd., trimers (b)




Sediment toxicity

RA CAS 68937-90-6

Experimental result:

LC50 > 12187 mg/kg dw

NOEC = 6095 mg/kg dw

(a) The substance subject to the REACh Phase-in registration deadline of 31 May 2013 is indicated in bold font. Only for this substance a full set of experimental results and/or read-across is given.

(b) Reference (read-across) substances are indicated in normal font. Lack of data for a given endpoint is indicated by “--“.

The key study conducted with Fatty acids, C18-unsatd., trimers (CAS No. 68937-90-6) was performed according to the OSPAR guideline, Part A and GLP (Staniland, 2005). The test organism Corophium sp. was exposed to the test substance at nominal concentrations of 764, 1524, 3047, 6095, 12187 mg/kg dry sediment for 10 days. The NOEC was determined to be 6095 mg/kg dry sediment and the LC50 > 12187 mg/kg dry sediment.

Thus, based on the above mentioned result, and due to the structural and profile similarities of the substances, as are explained with in the overall endpoint summary 6.2 it can be concluded that the toxicity of Fatty acids, C18 unsaturated, trimers, hydrogenated to sediment organisms is presumably low.