[4-[[4-anilino-1-naphthyl][4-(dimethylamino)phenyl]methylene]cyclohexa-2,5-dien-1-ylidene]dimethylammonium acetate

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of N-(4-((4-(dimethylamino)phenyl)(4-(phenylamino)naphthalen-1-yl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetate for effects in the environment:

 

The chemical N-(4-((4-(dimethylamino)phenyl)(4-(phenylamino)naphthalen-1-yl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetate (CAS no. 83803-79-6) is used in inks, paper, markers and agrochemicals etc.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled forN-(4-((4-(dimethylamino)phenyl)(4-(phenylamino)naphthalen-1-yl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetate. 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 fulfils the P criterion within Annex XIII based on the assessment that here follows:

 

Biotic degradation

Biodegradability of N-(4-((4-(dimethylamino)phenyl)(4-(phenylamino)naphthalen-1-yl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetate (CAS no. 83803 -79 -6) is predicted using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 25.65% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical N-(4 -((4 -(dimethylamino)phenyl)(4 -(phenylamino)naphthalen-1 -yl)methylene) cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetate was estimated to be not readily biodegradable in water.

 

Estimation Programs Interface Suite (EPI suite, 2017) was run to predict the biodegradation potential of the test compound   N-(4 -((4 -(dimethylamino)phenyl)(4 -(phenylamino)naphthalen-1 -yl)methylene)cyclohexa-2,5 -dienylidene)-N-methylmethanaminium acetate (CAS no. 83803 -79 -6) in the presence of mixed populations of environmental microorganisms. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical N-(4 -((4 -(dimethylamino)phenyl)(4 -(phenylamino)naphthalen-1 -yl)methylene)cyclohexa-2,5 -dienylidene)-N-methylmethanaminium acetate is expected to be not readily biodegradable.

 

Experimental results from the read across substances (CAS: 569-64-2 and 15233-47-3) also indicate that they are not readily biodegradable.

 

Environmental fate

According to the fugacity model levels III, the most likely environmental fate for this test chemical is soil (i.e. estimated to 51.7%). In soil,N-(4-((4-(dimethylamino)phenyl)(4-(phenylamino)naphthalen-1-yl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetatewas expected to have negligible mobility based upon a Log Koc value of 5.103, respectively. The half-life in soil (360 days estimated by EPI suite) indicates that the chemical is persistent in soil and the exposure risk to soil dwelling animals is moderate to high.

 

If released in to the environment, 47.8% and 0.563% of the chemical will partition into sediment and water according to the Mackay fugacity model level III in EPI suite version 4.1 (2017). However, the half-life (180 days in water and 1620.83 days in sediment as estimated by EPI suite) indicates that the substance is persistent in both the compartments.

 

Although the half-life values indicate the chemical to be Very persistent (vP), since only predicted data is available for the substance, it has been concluded thatN-(4-((4-(dimethylamino)phenyl)(4-(phenylamino)naphthalen-1-yl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetateis likely to be 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 database was determined to be in the range 3.162 to 601, respectively and the octanol water partition coefficient of the test chemical is -1.5 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 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 estimations for fish, invertebrates and algae for the substance indicates the LC50/EC50 value to be in the range 0.037 – 14.8 mg/L. These value suggest that the substance is likely to be hazardous to Aquatic organisms at environmentally relevant concentrations and can be considered to be classified in ‘Aquatic Acute Category 1’ as per the CLP regulation.

 

There are no available long-term toxicity evaluations forN-(4-((4-(dimethylamino)phenyl)(4-(phenylamino)naphthalen-1-yl)methylene)cyclohexa-2,5-dienylidene)-N-methylmethanaminium acetate. By speculation, long-term NOEC for aquatic organisms were expected for the substance at concentration below 0.01 mg/L based on the data mentioned above

 

The chemical was therefore 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 P and T criterion but does not fulfil the B criterion and has therefore not been classified as a PBT compound within Annex XIII.