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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Due to the calculated Koc for the uncharged molecule, adsorption to the solid soil phase (e.g. clay) is not expected.

Key value for chemical safety assessment

Koc at 20 °C:
10

Additional information

The major constituent TEA is not expected to adsorb to suspended solids and sediment based upon the log Koc as calculated for the uncharged molecule. However, a pka value of 7.86 indicates that the molecule will partly exist as a cation in the environment and cations generally adsorb more strongly to the soils organic carbon and clay than their neutral counterparts. According to a calculation based on the formula as given by Franco & Trapp, 2008, the fully charged molecule has a log Koc value of 1.24 at pH 7.0.

In a study conducted by West in 1996 it was demonstrated, that TEA rapidly degrades according to the definition as laid down in the

Guidance on the application of CLP criteria (Guidance to regulation (EC) No 1272/2008 on classification, labelling and packaging (CLP) of substances and mixtures), further it also rapidly degrades in soil with a half-life of 1.8 days. Additionaly, in a ready test performed by Gerike (1978) according to a precursor of the Modified OECD Screeening Test (OECD TG 301 E) the substance turned out to be readily biodegradable.

According to the REACH legislation Annex VIII 9.3.1 a study on the adsorption/desorption does not need to be conducted if the substance and its relevant degradation products decompose rapidly. Therefore, a screening test on the adsorption of TEA is not required.