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Adsorption / desorption

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Description of key information

A high log Koc for Fatty acids, C18-unsaturated, dimers (CAS No. 61788-89-4) is expected: log Koc > 5 

Key value for chemical safety assessment

Additional information

Because the substance is a composition of different homologues, the Koc values of well-defined representative structures were calculated with EPISUITE (KOCWIN v2.00) (Bucior, 2012a, b, d, e, f, g) and a weight of evidence approach is applied.

The main factor determining the log Koc value of fatty acids is the carbon chain length. For monomers (C18), the calculated log Koc values are between 3.7 (octamethyldecanoic acid, MCI method) and 4.7 (octadecanoic acid, Kow method). It can be concluded that the overall contribution of monomers fulfills the condition: 4 < log Koc (monomers) < 5. The calculated results for dimeric constituents (C36) are considerably higher: log Koc from ca. 7.4 (Kow method) to ca. 9.1 (MCI method). As the main fraction represented in the substance is the dimeric fraction, it is concluded that for Fatty acids, C18 unsaturated, dimers (CAS 61788-89-4) adsorption to organic carbon in soils and sediments is to be expected. Log Koc is very high: log Koc > 5.

No additional tests on adsorption/desorption are to be conducted. The result is used for the chemical safety assessment.

References:

Bucior, K. (2012a) EPIsuite v 4.10 calculation with octadecanoic acid, dimer. Testing Laboratory: Knoell Consult, Mannheim, Germany. Owner Company: Members of Dimerised Fatty Acids Consortium. Report No. 20120301-buc-2.

Bucior, K. (2012b) EPIsuite v 4.10 calculation with octadecanoic acid. Testing Laboratory: Knoell Consult, Mannheim, Germany. Owner Company: Members of Dimerised Fatty Acids Consortium. Report No. 20120314-buc-7.

Bucior, K. (2012d) EPIsuite v 4.10 calculation with linoleic acid. Testing Laboratory: Knoell Consult, Mannheim, Germany. Owner Company: Members of Dimerised Fatty Acids Consortium. Report No. 20120314-buc-6.

Bucior, K. (2012e) EPIsuite v 4.10 calculation with branched oleic acid. Testing Laboratory: Knoell Consult, Mannheim, Germany. Owner Company: Members of Dimerised Fatty Acids Consortium. Report No. 20120314-buc-8.

Bucior, K. (2012f) EPIsuite v 4.10 calculation with branched linolenic acid. Testing Laboratory: Knoell Consult, Mannheim, Germany. Owner Company: Members of Dimerised Fatty Acids Consortium. Report No. 20120314-buc-9.

Bucior, K. (2012g) EPIsuite v 4.10 calculation with octamethyldecanoic acid. Testing Laboratory: Knoell Consult, Mannheim, Germany. Owner Company: Members of Dimerised Fatty Acids Consortium. Report No. 20120301-buc-1.

U.S. Environmental Protection Agency (2009). Risk-Based Prioritization Document. Initial Risk-Based Prioritization of High Production Volume (HPV) Chemicals – Fatty Acid Dimers and Trimer Category. pp 1-19. Report date: April 2009.