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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

TMBPA is not readily biodegradable (~4% degradation within a 28 -d study period) and therefore meets the screening criterion for "vP (and P)". Based on the log Kow value of 4.51, the substance meets the screening criterion for qualification as "vB (and B)". However, REACH guidance R.11 on PBT assessment states that “for organic substances with a log Kow value below 4.5 it is assumed that the affinity for the lipids of an organism is insufficient to exceed the (definitive) B criterion, i.e. a BCF value of 2000 L/kg” and “at log Kow values between 4 and 5, log BCF increases linearly with log Kow”. When calculating the BCF values for aquatic and terrestrial organisms using the log Kow relationships of Veith et al. (1979) and Jager (1998), both incorporated in the EUSES model, this yields values of 1360 and 389 L/kg ww, respectively. Based on all this information and with the log Kow being so close to the screening criterion, pending the outcome of the proposed fish bioaccumulation test, preliminary qualification as “vB (and B)” is considered to be overly conservative. Therefore the substance is qualified as "B not vB". Finally, based on the available information on the aquatic and mammalian toxicity of TMBPA, none of the T criteria are met. Consequently, the substance is assessed as not PBT and not vPvB.