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PBT assessment

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PBT assessment: overall result

2-[[4-[ethyl(2-hydroxyethyl)amino]phenyl]azo]-6-methoxy-3-methylbenzothiazolium acetate
Type of composition:
boundary composition of the substance
State / form:
Reference substance:
Composition 1
PBT status:
the substance is not PBT / vPvB

Classification of 2-((4-(Ethyl(2-hydroxyethyl)amino)phenyl)azo)-6-methoxy-3-methylbenzothiazolium acetatefor effects in the environment:


The chemical 2-((4-(Ethyl(2-hydroxyethyl)amino)phenyl)azo)-6-methoxy-3-methylbenzothiazolium acetate (CAS no. 84051-87-6) is used in the textile dyestuff industry.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for 2-((4-(Ethyl(2-hydroxyethyl)amino)phenyl)azo)-6-methoxy-3-methylbenzothiazolium 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

In a prediction done by using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound2-((4-(Ethyl(2-hydroxyethyl)amino)phenyl)azo)-6-methoxy-3-methylbenzothiazolium acetate(CAS no. 84051-87-6)in the presence of mixed populations of environmental microorganisms was estimated. 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 2-((4-(Ethyl(2-hydroxyethyl)amino)phenyl)azo)-6-methoxy-3-methylbenzothiazolium acetateis expected to be not readily biodegradable.


Experimental results from the read across substances also indicate that they are not readily biodegradable.


Thus, based on the available information, it indicates that chemical 2-((4-(Ethyl(2-hydroxyethyl)amino)phenyl)azo)-6-methoxy-3-methylbenzothiazolium acetate can be expected to be not readily biodegradable in water and thus likely to be persistent (P) in nature.


Bioaccumulation assessment

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


Theoctanol water partition coefficient of the test chemical was determined to be 1.297, 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:



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 substance 2-((4-(Ethyl(2-hydroxyethyl)amino)phenyl)azo)-6-methoxy-3-methylbenzothiazolium acetate indicates the LC50/EC50 value to be in the range > 12.5 mg/l to 34.935 mg/L, respectively. 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 chronic category 3’ as per the CLP regulation.


There are no available long-term toxicity evaluations for chemical 2-((4-(Ethyl(2-hydroxyethyl)amino)phenyl)azo)-6-methoxy-3-methylbenzothiazolium acetate. 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.




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