5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

According to ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R.11: PBT/vPvB assessment (Version 3.0 June 2017) a PBT assessment must take into account the PBT/vPvB properties of relevant constituents and relevant transformation and/or degradation products. Although 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione undergoes non-hydrolytic transformation when exposed to a protic solvent, the transformation is more accurately described as tautomerization. Tautomers are considered to be the same compound of the parent substance; therefore, PBT Assessments of each tautomer would not be appropriate.

Persistence (P)

In an OECD Guideline 301B study, conducted according to GLP, 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione achieved 0% biodegradation after 28 days and is therefore considered as not readily biodegradable (Harlan Laboratories, Ltd, 2016).

According to Table R.11-4 of ECHA’s guidance on information requirements and chemical safety assessment chapter R11 (v3.0, June 2017, p.49), 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione should be considered as potentially P or vP.

 

Bioaccumulation (B)

In a study conducted according to GLP, the partition coefficient (log Pow) of 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione estimated based on the ratio of n-octanol solubility and water solubility is 1.46 at 25 ± 1°C (Intertek Pharmaceutical Services Manchester, 2016).

According to Figure R.11-4 of ECHA’s guidance on information requirements and chemical safety assessment chapter R11 (v3.0, June 2017, p.68), 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione should be considered as not B and not vB.

 

Toxic (T)

As the substance does not meet the B/vB criteria, no assessment is needed on the T criterion and the substance is not considered PBT or vPvB,

Overall Summary:

According to ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R.11: PBT/vPvB assessment (Version 3.0 June 2017) 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione should not be considered as PBT or vPvB.

 

Likely routes of exposure:

Based upon the hazard profile, 5,5'-Dithiodi-1,3,4-thiadiazole-2(3H)-thione is classified as Aquatic Chronic Category 2, Toxic to aquatic life with long lasting effects

. 

During normal industrial activities no release directly to the environment is expected. The generation of waste should be avoided or minimized wherever possible. 

The following environmental RMM must be followed:

Do not intentionally release the substance or products containing the substance directly to the environment;

 

Prevent discharge of un-dissolved substance to or recover from onsite wastewater;

 

Avoid dispersal of spilled material and runoff and contact with soil, waterways, drains and sewers;

 

Use appropriate storage containment to avoid environmental contamination;

 

The generation of waste should be avoided or minimized wherever possible.

 

Disposal of this product, solutions and any by-products should at all times comply with the requirements of environmental protection and waste disposal legislation and any regional local authority requirements;

 

Waste should be recycled wherever possible;

 

Incineration of waste or landfill should only be considered when recycling is not feasible;

 

Dispose of surplus and non-recyclable products must be via a licensed waste disposal contractor;

 

Waste packaging should be recycled;

 

Care should be taken when handling emptied containers that have not been cleaned or rinsed out;

 

Emissions from ventilation or work process equipment should comply with the requirements of local environmental protection legislation;

 

Fume scrubbers, filters or engineering modifications to the process equipment should be considered to minimalise emissions.