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Environmental fate & pathways

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Additional information

Adsorption:

The Koc for o-toluidine was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v 4.11. The Koc was estimated to be 47.63 L/kg (logKow method), and 115 L/kg (MCI method). The results relate to the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.

The coefficient of distribution (Kd) between the sediment extracted from an aquifer was measured in columns. o-Toluidine was pumped in the columns and then analysed with HPLC. A Kd of 0.013 was observed for o-toluidine, the Koc was calculated to be 87. This value shows a good correlation to calculated values. During the ICCA initiative the content of organic carbon for the sediment used in this study was misinterpreted. Therefore, in the OECD SIDS (2004) the reported value for o-toluidine was undervalued for two orders of magnitude.

However, adsorption of o-toluidine in soil is influenced by ion-ion interactions. The mechanism responsible for adsorption of o-toluidine and other amines was investigated on montmorillonite. The maximum adsorption occurs when the pH is approximately equal to the pKa (4.44 - 4.45) of the protonation reaction.

Volatilisation:

The experimentally determined Henry's Law constant was 0.201 Pa m³/mol at 25°C. This value indicates that the substance is slightly volatile from water.