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Environmental fate & pathways

Adsorption / desorption

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Description of key information

According to the model in the EC guidance document, the Koc of FAT 60'253/A is estimated to be in the range of 8100 L*kg-1.

Key value for chemical safety assessment

Koc at 20 °C:
1 800

Additional information

Adsorption and desorption were estimated according to a QSAR procedure as described in the "Technical Guidance Document" of the European Community.

Instead of the adsorption constants for the three types of soil, the normalized value, expressed as Koc was estimated. Koc describes the ratios of the concentrations on the soil/sediment (ug substance per g of Organic Carbon) and in solution (ug substance per mL water) at the equilibrium. It should be noticed that Koc has to be determined for each substance and should not be derived from a mixture.

It can be expected that chemical substances with a Kow of >0 (Kow = Octanol/water partition coefficient) tend to adsorb on soil. According to the model in the EC guidance document, the Koc of FAT 60'253/A is estimated to be in the range of 8100 L*kg-1.

A Koc value of 1 indicates an equal distribution between soil and water. The higher the value above 1 the more pronounced is the tendency to adsorb onto soil.

The value of 8100 L*kg-1 indicates that FAT 60'253/A will be adsorbed by organic carbon in soil and therefore remains predominantly in soil.