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Classification & Labelling & PBT assessment

PBT assessment

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Administrative data

PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB

Classification of 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride for effects in the environment:


The chemical 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride (CAS no. 29556-33-0) is used as a hair dyeing agents in cosmetics. It is widely used as a dye in processing fluorescent yellow tennis balls and acrylic fibers.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride. 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 fulfils the P criterion within Annex XIII based on the assessment that here follows:


Biotic degradation

An experiment was performed by using 42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical 2-[7-(diethylamino)-2-oxo- 2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride, CAS No. 29556-33-0. The test system included control, test item and reference item. The concentration of test and reference item ( Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/L. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD42 value of 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1Hbenzimidazolium chloride was observed to be 0.8 mgO2/mg. ThOD was calculated as 1.97 mgO2/mg. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle Test was determined to be 40.6%. The % degradation of procedure control (reference item) was also calculated using the values of BOD & ThOD and was determined to be 72.28 % at 20 ± 1°C. Degradation of Sodium Benzoate exceeds 45.18 % on 7 days & 59.03 % on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. Based on the results, the test item, under the test conditions, was considered to be ultimate inherently biodegradable in nature. 


Thus, based on the available information,it has been concluded that test chemical12-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chlorideis considered to beultimate inherently biodegradable.


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 3.162 L/kg, respectively and the octanol water partition coefficient of the test chemical was determined to be 1.63, 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 indicates the LC50/EC50 value to be in the range 25.63 to >100 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 for2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride. 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 does not fulfil the P, B and T criterion and has therefore not been classified as a PBT compound within Annex XIII.