4-(2-chlorophenyl)-N-cyclohexyl-N-ethyl-5-oxo-4,5-dihydro-1H-tetrazole-1-carboxamide

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

The criteria given in the “Guidance on information requirements and chemical safety assessment, chapter R.11: PBT Assessment” (ECHA, 2017) are used to decide if the substance fulfils the PBT/vPvB-criteria.

 

Persistence Assessment

In a screening study (1999) with activated sludge 0% biodegradation was observed. Thus, the test substance is not readily biodegradable according to the OECD criteria. Further simulation studies with paddy soils investigated the biodegradation potential of the substance (1995, 1997b). Under the laboratory conditions chosen (experiments were conducted at 28 °C) these studies resulted in a maximum half-life of 46 days. However, according to the ECHA guidance "Guidance on Information Requirements and Chemical Safety Assessment. Chapter R.7b: Endpoint specific guidance. Version 4.0" (2017) the preferred temperature for simulation degradation studies is 12 °C, which corresponds to average temperature of European surface waters. Where this condition is not met a temperature correction should be considered based on the Arrhenius equation and half-lives be re-calculated. For first order kinetics this was done and the half-life of 46 days (at 28 °C) was re-calculated to 199 days (at 12 °C), respectively. Data from a short communication (2001) referring to a field test indicate shorter half-lives. However, the information provided is insufficient for assessment. Thus, based on a worst case assumption and all available data the substance has to be regarded as being very persistent.

Bioaccumulation Assessment

The potential for bioaccumulation was investigated in a study using radiolabeled test substance (2007).The substance accumulated in bluegill sunfish with a total residue kinetic bioconcentration factor of about 275.5 to 289.8 X for whole fish (sum of radio labelled compounds, parent substances, metabolites and mineralization products). When exposure ceases, the residues were depurated with a half-life of about 0.42 to 0.55 days. After 14 days in uncontaminated water 100 % of the mean plateau radioactivities were depurated from whole fish in both test levels. Accumulations of total residues in edible parts were less (116.9 – 153.6 X) than in whole fish (275.5 – 289.8 X). Taking into account that about 30 % parent compound were detected in edible parts and about 16% parent compound in non-edible (viscera) parts after 15 days of exposure the steady-state-BCF for parent (based on whole fish, wet weight) is about 71, the steady-state-BCF for parent (normalised to 6% lipid content) is about 54.

Thus, the substance has a low potential to bioaccumulate in aquatic organisms.

Toxicity Assessment

Based on the available data the substance is considered to be toxic. The substance is classified as H373 according to Regulation (EC) No 1272/2008 and thus meets the T-criterion.

 

In conclusion, the substance is not PBT/vPvB.