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Environmental fate & pathways

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No data on any of the environmental endpoints is available for sodium 2 -mercaptoethanolate. Read across can however be made to 2- mercaptoethanol (CAS 60 -24 -2). The (sodium) 2-mercapthoethanolate ion is a conjugated base, the read across substance 2-mercaptoethanol its undissociated acid. With a pKa value of ca. 9.5 for both substances, in an aqueous environment with pH 7 (such as in a STP system), they will be present almost exclusively as 2-mercaptoethanol.

The log Kow for the read-across substance 2-mercaptoethanol is -0.056. Based on this log Kow value, the log BCF value is estimated to be 0.5 (BCFBAF; v3.01) and therefore no bioaccumulation needs to be expected. Furthermore, based on a very high water solubility (>1E+05 mg/L) and an estimated log Koc value of 0.28 (KOCWIN; v2.00) the substance is expected to be very mobile in the aqueous phase and not to adsorb to sediment and/or soil.

The measured water solubility of (sodium) 2-mercaptoethanolate is >900 g/L and the log Kow is estimated to be < -4.9. Therefore, the same reasoning as for the read-across substance may be assumed to apply for environmental conditions with higher pH values in which an increased concentration of the 2 -mercaptoethanolate will be present.