N,N-dimethyl-p-toluidine

PBT assessment

PBT assessment: overall result

Reference

Name:

N,N-dimethyl-p-toluidine

Type of composition:

boundary composition of the substance

State / form:

liquid

Reference substance:

N,N-dimethyl-p-toluidine

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of N,N-dimethyl-p-toluidinefor effects in the environment:

 

The chemical N,N-dimethyl-p-toluidine (CAS no. 99-97-8) is used to accelerate polymerization of ethyl methacrylate. It is also used in artificial nail application. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for N,N-dimethyl-p-toluidine. 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:

 

Environmental fate

According to the fugacity model levels III, the most likely environmental fate for this test chemical is soil (i.e.estimated to 78%). In soil, N,N-dimethyl-p-toluidine was expected to have moderate mobility based upon a Log KOC value ranging from 2.1 to 2.8, respectively. The half-life in soil (75 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, 21.8% 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 (37.5 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 0.175% when estimated by EPI Suite version 4.1).

 

Hence it has been concluded that chemical N,N-dimethyl-p-toluidine is likely to be not persistent (not P) in nature.

 

Bioaccumulation assessment

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

 

Theestimated BCF value from authoritative databases and secondary source was determined to be ranges from 29.09 to 33.19, respectively and theoctanol water partition coefficient of the test chemical from reliable handbook and various databases, it was evaluated to be 2.61 to 2.99, 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 fulfils the T criterion within Annex XIII based on the assessment that here follows:

 

Mammals

The tested chemical is regarded to be classified for carcinogenicity in ‘’Carc. category 1B’’, reprotoxicity in ‘’Reprotox category 2’’ as per theCLP Regulation.

The tested chemical is regarded to be ‘’not classified’’ for mutagenicity.

Further, there is evidence of chronic toxicity, as identified by the classifications STOT (repeated exposure), category 2 (oral).

 

Aquatic organisms

All of the available short-term eco-toxicity estimations for fish, invertebrates and algae for the substance indicates the LC50/EC50 value to be in the range 10.34 to 78.62 mg/L. These value suggest that the substance is likely to be hazardous to Aquatic organisms at environmentally relevant concentrations and hence, considered to be classified in ‘Aquatic Chronic Category 3’ as per the CLP regulation.

 

There are no available long-term toxicity evaluations for chemical N,N-dimethyl-p-toluidine. 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 fulfils the T criterion but does not fulfil the P and B criterion and has therefore not been classified as a PBT compound within Annex XIII.