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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:

Data for the definitive conclusion on the PBT or vPvB properties of disulfiram (CAS No. 97-77-8) are available, except for those regarding the Bioaccumulation (B) criterion. Thus, the screening criteria given in the “Guidance on information requirements and chemical safety assessment, chapter R.11: PBT assessment” (ECHA, 2008) are used as surrogate information to decide whether this substance meets the B criterion and further on, may potentially fulfill the PBT or vPvB criteria.

Persistence (P):

According to the criteria stated in Regulation (EC) 1907/2006, Annex XIII, persistence can be determined through the evaluation of the dissipation half-lives of a substance in different environmental compartments. The biodegradation of disulfiram in water, sediment and soil could be investigated using data from an analogue substance. Hydrolysis (half-lives of 68.5 days, 3.5 days and 6.9 hours at pH 5, 7 and 9) and photolysis (half-life < 10 days) are expected to contribute significantly to the degradation of this substance in water. Disulfiram will be also rapidly degraded in water/sediment and soil systems, in which half-lives below 2 days and 10 days were reported, respectively. Thus, the P criterion is not met for this substance.

Bioaccumulation (B):

Experimental data determining the BioConcentration Factor (BCF) of disulfiram in aquatic organisms are not available. Nevertheless, the log Pow of the substance is considered as a surrogate for the evaluation of the B criterion. According to the screening criteria stated in the “Guidance on information requirements and chemical safety assessment, chapter R.11: PBT assessment” (ECHA, 2008) substances with log Pow values below 4.5 are not considered as B or vB. Based on this information, disulfiram does not meet the B criterion (log Pow = 3.6).

Toxicity (T):

According to the criteria stated in Regulation (EC) 1907/2006, Annex XIII, the toxicity of a certain substance can be assessed based on the available toxicity data on aquatic organisms and mammals. The long-term study performed testing the chronic effects on fish species (based on data from an analogue substance) resulted in a NOEC value of 4.6 µg a.i./L. Furthermore, this substance is classified as Xn, R48, harmful. Considering this information, the substance meets the T criterion.

Conclusion

The substance is not considered to be PBT or vPvB.