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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

BCF 0.893 - 12.5 L/kg (BCFBAF v3.01)

Key value for chemical safety assessment

Additional information

No experimental studies investigating the bioaccumulation potential of sorbitan C16-18 (even numbered) fatty acid esters, ethoxylated (1-6.5 moles ethoxylated) are available. Therefore, the bioconcentration factor (BCF) of the substance was estimated using a reliable QSAR model (BCFBAF v3.01; Adaktylou, 2016). Using the Arnot-Gobas method, including biotransformation (BCFBAF v3.01), BCF values from 0.89 to 12.5 L/kg were calculated for the 4 main constituents (Adaktylou, 2016). An exclusion of biotransformation resulted in higher BCF values of 0.893 - 1082 L/kg, indicating that extensive metabolism occurs and significantly reduces the bioaccumulation potential in a short period of time. The QSAR estimated biological half-life is 0.01 – 14.93 d. The higher molecular weight components of the substance are not within the applicability of the model and the calculated BCF values should be taken with caution. However, they are expected to have a limited potential for bioaccumulation. According to ECHA Guidance R.11 (ECHA, 2014) substances with high molecular weight (> 1100 g/mol) and high log Kow (> 9.3) are expected to have a reduced potential for bioaccumulation and are not likely to meet the B criterion. The substance components which are not in the applicability domain of the model exhibit a molecular weight of 1032 – 1492 g/mol and high log Kow values of 11.33 - 20.76. Thus, they are not expected to have a significant potential for bioaccumulation. Furthermore, the substance can be digested by metabolic hydrolysis and other common metabolic pathways, which enhances the assumption of no bioaccumulation in organisms. For a detailed review on metabolism of the substance, please refer to the toxicokinetics statement in IUCLID section 7.1. Consequently, it can be concluded that sorbitan C16-18 (even numbered) fatty acid esters, ethoxylated (1-6.5 moles ethoxylated) has a low potential for bioaccumulation.