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Diss Factsheets

Environmental fate & pathways

Adsorption / desorption

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Description of key information

The measured logKoc-values for different tested soil types were in the range of 2.51 - 3.13, and for the tested sediment types between 3.33 - 3.55 (CMA, 1989). The described metabolites of MBT, such as MBTS, BT and MeSBT, mostly have logKoc higher than 3. Only BTon has a very low estimated logKoc of 1.93 (EU-risk assessment, 2008).

Key value for chemical safety assessment

Additional information

SMBT is an organic salt of strong base NaOH and weak acid of MBT and it is solely marketed as aqueous solution. The presence of MBT determines the hazard profile of SMBT aqueous solution; and hence the environmental fate and behavior of MBT is used as read-across approach to support the risk assessment of SMBT.

According to the classification scheme of Swann et al. (1983) experimentally estimated log Koc-values lower than 3.7 indicates a moderate to strong sorption potential to soil and sediment and suggests a slow migration potential to ground water. As a worst-case assumption, the lowest log Koc of 2.51 is used for further assessment such as distribution modelling and PNECs through EPM method.