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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

Koc at 20 °C:
5 012

Additional information

Data for MBT.

ZMBT is an organic complex, in which MBT structure is present. The dissolution of MBT determines the hazard profile of ZMBT aqueous solution; and hence the environmental fate and behavior of MBT is used as read-across approach to support the risk assessment of ZMBT.

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. Considering the lower water solubility of ZMBT in comparison to MBT but higher Log Pow, the adsorption potential of ZMBT is expected to be higher than MBT. However the lower log Koc of 2.51 is used to estimate PNECs for sediment and soil compartment as a worst case.

[LogKoc: 3.7]