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Environmental fate & pathways

Adsorption / desorption

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Description of key information

LogKoc values increase with increasing chain length indicated by estimated Koc values ranging from 1.02 for azelaic acid (C9) up to 4.71 for stearic acid (C18).

Key value for chemical safety assessment

Additional information

Koc values were calculated with the US EPA EPI suite interface using QSAR/QSPR predictions (KOCWIN v. 2.00) with input of log Kow-values.The estimated Koc values increase with increasing chain length and decreasing water solubility indicated by Koc values ranging from 10.57 for azelaic acid (C9) to 51,050 for stearic acid (C18). According to the Guidance Document Chapter R.7a, substances with Koc values below 500–1,000 L/kg are generally unlikely to adsorb to sediment. Thus, remarkable adsorption potential is predicted for fatty acids starting at a chain length of 12 and higher.

Substance

log Koc

Koc

124-07-2, C8

1.84

69.63

123-99-9, C9

1.02

10.57

334-48-5, C10

2.42

261.8

143-07-7, C12

2.92

834.4

544-63-8, C14

3.54

3,430

57-10-3, C16

4.12

13,230

57-11-4, C18

4.71

51,050

 

The resulting worst-case Koc-values were used for PNECsedimentand PNECsoil calculation.