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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

Classification of 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acidfor effects in the environment:


The chemical4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid(CAS no. 87-03-6) is used as a dye intermediate. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid. 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 4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid (CAS no. 87 -03 -6) is predicted using OECD QSAR toolbox version 3.4 with logKow as the primary descriptor. Test substance undergoes 0.5% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaphthalen-2 -yl)amino]naphthalene-2-sulfonic acid 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 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaphthalen-2 -yl)amino]naphthalene-2 -sulfonic acid (CAS no. 87 -03 -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 4 -hydroxy-7 -[(5 -hydroxy-7 -sulfonaphthalen-2 -yl)amino]naphthalene-2 -sulfonic acid is expected to be not readily biodegradable.


Experimental results from the similar substances (CAS: 4198-19-0, 6449-35-0, 20324-87-2 and 2429-74-5) 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 sediment (i.e.estimated to 53.3%). The half-life in sediment (337.5 days estimated by EPI suite) indicates that the chemical is very persistent in sediment and the exposure risk to soil dwelling animals is moderate to high. 


If released into the environment, 44.3% of the chemical will partition into soil according to the Mackay fugacity model level III in EPI suite version 4.1 (2017). In soil,4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acidwas expected to have negligible to slow mobility based upon a Log KOC ranging from 4.23 to 5.92. However, the half-life (75 days estimated by EPI suite) indicates that the chemical is not persistent in sediment and the exposure risk to aquatic animals is moderate to low.


Moreover, its persistent characteristic is not observed in the water compartment with a half-life of 37.5 days (estimated by EPI Suite version 4.1), indicating that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low.


Although the half-life value in sediment compartment indicate the chemical to be Very Persistent (vP), since only predicted data is available for the substance, it has been concluded that4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acidis considered 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:


Theestimated BCF value from authoritative database was determined to be in the range from 1 to 3.162, respectively and theoctanol water partition coefficient of the test chemical is -1.83 ± 1.44 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 estimations for invertebrates and algae for the substance indicates the LC50/EC50 value to be in the range 177.02– 3579.372 mg/L. These value suggest that the substance is not likely to be hazardous to Aquatic organisms at environmentally relevant concentrations and can be considered to be ‘not classified’ as per the CLP regulation.


There are no available long-term toxicity evaluations for4-hydroxy-7-[(5-hydroxy-7-sulfonaphthalen-2-yl)amino]naphthalene-2-sulfonic acid. 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.