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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:

Classification of Benzimidazole for effects in the environment:

 

The chemical Benzimidazole (CAS no. 51-17-2) is used as an antifungal agent. It is used as anticorrosive in metal & water treatment. Also used as drug intermediate for vet. It is also used as a UV absorber for plastics and polymers etc. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for Benzimidazole. The PBT criterion was herein assessed based on experimental data in conjunction with standardized environmental fate models. Here follows a description of the PBT assessment.

 

Persistence assessment

The tested substance does not fulfil the P criterion within Annex XIII based on the assessment that here follows:

 

Biotic degradation

On the basis of various experimental results of biodegradation studies for the target chemical Benzimidazole (CAS no. 51-17-2), it indicates that chemical Benzimidazole can be expected to be readily biodegradable in water and thus likely to be not persistent (not P) in nature.

 

Environmental fate

According to the fugacity model levels III, the most likely environmental fate for this test chemical is soil (i.e.estimated to be 73.6%). In soil,Benzimidazolewas expected to have moderate mobility based upon a Log KOC value ranging from 1.687 to 2.331, respectively. The half-life in soil (30 days estimated by EPI suite) indicates that the chemical is not persistent in soil and the exposure risk to soil dwelling animals is moderate to low.

 

If released in to the environment, 25.5% of the chemical will partition into water according to the Mackay fugacity model level III in EPI suite version 4.1 (2017). However, the half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low.

 

Moreover, its persistent characteristic is only observed in the sediment compartment but Fugacity modelling shows that sediment is not an important environmental fate (less than 1% i.e reported as 0.256% when estimated by EPI Suite version 4.1).

 

Hence it has been concluded thatchemical Benzimidazoleis not persistent in nature.

 

 

Bioaccumulation assessment

The tested substance does not fulfil the B criterion within Annex XIII based on the assessment that here follows:

 

The estimated BCF value from authoritative databases was evaluated to beranges from 1 to 5.93, respectively and the octanol water partition coefficient of the test chemical was determined to be 3.626, respectively, which is less than the threshold of 4.5. If this chemical is released into the aquatic environment, there should be a low risk for the chemical to bioaccumulate in fish and food chains.

 

Toxicity assessment

The tested substance does not fulfil the T criterion within Annex XIII based on the assessment that here follows:

 

Mammals

The tested chemical is regarded to be not classified for carcinogenicity, mutagenicity and reprotoxicity, Further, there is no evidence of chronic toxicity, as identified by the classifications STOT (repeated exposure), category 1(oral, dermal, inhalation of gases/vapours, inhalation of dust/mist/fume) or category 2 (oral, dermal, inhalation of gases/vapours, inhalation of dust/mist/fume).

 

Aquatic organisms

All of the available short-term eco-toxicity data for fish, invertebrates and algae for the substanceBenzimidazoleindicates the LC50/EC50 value to be in the range 26.8 to >200 mg/L, respectively. These value suggest that the substance is likely to be hazardous to Aquatic organisms at environmentally relevant concentrations but since the chemical is determined to be readily biodegradable, it can concluded that chemicalBenzimidazole can be expected to be non-toxic and thus can be considered to be ‘not classified’as per the CLP regulation

 

There are no available long-term toxicity evaluations forBenzimidazole. By speculation, long-term NOEC for aquatic organisms were not expected for the substance at concentration below 0.01 mg/L based on the data mentioned above.

 

The chemical was therefore not considered as hazardous to aquatic environments as per the criteria set out in Annex XIII.

 

Conclusion

Based on critical, independent and collective evaluation of information summarized herein, the tested compound does not fulfil the P, B and T criterion and has therefore not been classified as a PBT compound within Annex XIII.