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Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Justification for grouping of substances and read-across

There are no data available on the biodegradability of Fatty acids, C18-unsaturated, trimers, hydrogenated. In order to fulfil the standard information requirements set out in Annex VII, Section, in accordance with Annex XI, Section 1.5 of Regulation (EC) No 1907/2006, read-across from structurally similar substances 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., dimers (CAS No. 61788-89-4), Fatty acids, C18-unsatd., dimers, hydrogenated (CAS No. 68783-41-5) and Fatty acids, C18-unsatd., trimers (CAS No. 68937-90-6) are selected as read-across substances for assessment of biodegradation.

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: Environmental fate properties of target and source substances


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

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

Fatty acids, C18-unsatd., dimers, hydrogenated

Fatty acids, C18-unsatd., trimers







RA CAS 61788-89-4

RA CAS 68783-41-5

RA CAS 68937-90-6

Experimental result:

not readily biodegradable

Experimental result:

not readily biodegradable

Experimental result:

not readily biodegradable



log Koc > 5


log Koc > 5


log Koc > 5


log Koc > 5

(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 “--“.

Environmental fate

Fatty acids, C18 unsaturated, trimers, hydrogenated is poorly soluble in water, has high adsorption potential and has a low vapour pressure. Its main environmental target compartments are therefore expected to be soil and sediment. However, due to its low water solubility, Fatty acids, C18 unsaturated, trimers, hydrogenated is expected to be removed in the primary settling tank or fat trap of sewage treatment plants. Significant release into surface waters is thus not expected, and exposure of sediment is thereby unlikely. Fatty acids, C18 unsaturated, trimers, hydrogenated is expected to be hydrolytically stable under environmental conditions, and significant biodegradation of the substance is not expected.

Despite of its high log Kow value, bioaccumulation of Fatty acids, C18 unsaturated, trimers, hydrogenated is considered unlikely for several reasons. First, uptake is expected to be low due to the large molecular size of the constituents. Second, if taken up, rapid metabolism is expected. Third, exposure of aquatic organisms will be extremely low due to the low water solubility of the substance.