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Classification & Labelling & PBT assessment

PBT assessment

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PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB

The PBT Assessment for Sorbitan tristearate (CAS No. 26658-19-5) is based on the criteria set out in the “Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT Assessment” (ECHA, 2008).


The read-across substance Sorbitan stearate (CAS No. 1338-41-6) is readily biodegradable in one study according to OECD 301 C (88% (O2 consumption) after 28 d). Thus, the test substance does not meet the screening criterion for persistence and it is not considered to be P or vP.


Due to the low water solubility, rapid environmental biodegradation and metabolism via enzymatic hydrolysis of the Sorbitan esters category members, a relevant uptake and bioaccumulation in aquatic organisms is not expected. Enzymatic breakdown will initially lead to the free fatty acid and D-glucitol. From literature it is well known, that these hydrolysis products will be metabolised and excreted in fish effectively (Heymann, 1980; Lech & Bend, 1980; Lech & Melancon, 1980; Murphy & Lutenske, 1990). This is supported by low calculated BCF values of 0.9 - 36.5 L/kg ww (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic) for the category members. Please refer to IUCLID Section 5.3 for a detailed overview on bioaccumulation of the Sorbitan esters category members.


No effects up to the limit of water solubility occurred in the long-term toxicity test with Daphnia magna (OECD 211) with the read-across substance Sorbitan stearate. Moreover, Sorbitan tristearate is not classified according to Directive 67/548/EEC and Regulation (EC) No. 1272/2008. Thus, the criteria set out in Annex XIII of Regulation (EC) No. 1907/2006 are not met and Sorbitan tristearate is not considered to meet the T criterion.