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Environmental fate & pathways

Adsorption / desorption

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Description of key information

The test item Phosphonic acid, P,P'-(1-hydroxyethylidene)bis-, compd. with 2-aminoethanol is an UVCB substance. The substructures etidronic acid forms with the triethanolamine a salt like structures, which in the aquatic milieu of the environment are expected to dissociate into etidronic acid and ethanolamine.


Therefore, for etidronic acid CAS: 2809-21-4 and ethanolamine CAS: 141-43-5 KOC values were determined:

etidronic acid : log KOC -1.32 (QSAR modelling KOCwin v. 2.00)

ethanolamine: log KOC -0.23 (QSAR modelling KOCwin v. 2.00), a similar value in a comparable range is also available from a REACH dossier for ethanolamine with log KOC -0.78.


The log KOC value of etidronic acid was further used to derive by EPM method the PNEC values for soil and sediment organisms. Etidronic acid (CAS: 2809-21-4) is not readily biodegradable, and therefore is expected to be more relevant for the environment than ethanolamine, which is readily biodegradable.

Key value for chemical safety assessment

Koc at 20 °C:

Additional information

[LogKoc: -1.32]