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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
Justification:

CBS (95-33-0) being released into the wastewater and the atmosphere undergo different degradation reactions. The known reaction pathways and relevant metabolites of CBS are already described in the EU-risk assessment for CBS from 2008: A hydrolysis rate of 1 µg/hr and t1/2 of 12.5 hours were determined for CBS (pH 7, 25°C; Monsanto, 1984) with the sole hydrolysis product as benzothiazole (CAS: 95-16-9) identified. Cyclohexylamine (CAS: 108-91-8) as a potential degradation product was not identified (Monsanto, 1984). Further a number of benzothiazole derivatives are formed as abiotic breakdown products in vulcanisation. These described metabolites are MBT (CAS: 149-30-4), MBTS (CAS: 120-78-5), BT (CAS: 95-16-9), BTon (CAS: 934-34-9), MeSBT (CAS: 615-22-5), and MeBT (CAS: 120-75-2). In literature, further benzothiazole derivatives are tentatively described. But their concentrations are below the concentrations of the derivatives considered above and were not taken further into account within the risk assessment (EU risk assessment, 2008).

As a conclusion the degradation products have to be considered in the PBT assessment for CBS as parent compound, as well.

CBS: not P (vP), not B (vB), T

MBT: not P (vP), not B (vB), not T

MBTS: vP (P), not B (vB), not T

BT: vP (P), not B (vB), T not assessed

BTon: vP (P), not B (vB), T not assessed

MeSBT: vP (P), not B (vB), T not asessed

MeBT: P (vP) not assessed, not B (vB), T not assessed

As a conclusion B (vB) is not fulfilled for either CBS nor one of the corresponding degradation products and therefore CBS (and the degradation products) is not PBT nor vPvB.