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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:

(Benzothiazol-2-ylthio)acetic acid being released into the waste water and the atmosphere undergo different degradation reactions. It is expected that the reaction pathways and relevant metabolites are identical to the ones already described in the appendix A of the EU-Risk Assessment for CBS (N-cyclohexylbenzothiazole-2-sulfenamide; CAS: 95-33-0) from 2008. 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). All these compounds are detected in waste water and environmental compartments; therefore they are included into the PBT/vPvB assessment.

PERSISTENCE ASSESSMENT

The registration substance does not hydrolyze (IUCLID Chapter 5.1.2) and is not readily biodegradable (IUCLID Chapter 5.2.1). Based on the UV Spectrum of the registration substance it absorbs light at >290 nm so that direct photolysis may occur. Indirect photolysis in air, water and soil may be possible. The property estimation program US EPA AOPWIN estimates a Half-life of 0.2h for the registration substance.

As the registration substance and the potential degradation products described in the EU-RAR for CBS, which are expected to be the same for the registration substance (S and MBT, BT and BTon), are resistant to both biotic and abiotic degradation the registration substance can be considered as provisionally persistent in the environment without the need of further evidence.

Therefore the 'vP' criteria of the vPvB / PBT Assessment is fulfilled.

 

BIOACCUMULATION ASSESSMENT

The registration substance has a measured Log Kow of 1.6 (see IUCLID Chapter 4.7).

In addition, BCF values have been calculated with US EPA software EPWWIN v4.1, BCFBAF v3.01. All calculated BCF values are below 35 L/kg ww.

Based on the measured Log Kow the Exposure modelling program EUSES 2.1 estimates a BCF fish of 4.57 L/kg wwt and a BCF worm of 1.32 L/kg wwt.

The BCFs of the registration substance and all of its potential metabolites are smaller than 2000, either from experiment (MBT, BT and MBTS) or from estimation (BTon and MeSBT). In conclusion, the registration substance together with its potential metabolites does not fulfil the ‘B’ criterion for the vPvB / PBT Assessment.

 

TOXICITY ASSESSMENT

In acute toxicity tests for the aquatic compartment on daphnia, algae, fish and microorganism no hazard was identified below 0.01 mg/l (see IUCLID Chapter 6.1). Fish is the most sensitive species with NOEC=6.25 mg/L and LC50=14.5 mg/l.

No human health hazard regarding carcinogenicity, mutagenicity, chronic toxicity, germ cell mutagenicity or specific target organ toxicity after repeated exposure was identified.

The substance is classified as toxic for reproduction category 2. Therefore the 'T' criteria of the PBT / vPvB Assessment is fulfilled.

 

CONCLUSION

In conclusion the registration substance is not PBT / vPvB.