2,4-diaminobenzenesulphonic acid

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of 2,4-diaminobenzenesulphonic acid for effects in the environment:

 

The chemical 2,4-diaminobenzenesulphonic acid (CAS no. 88-63-1) is used as an intermediate and as a laboratory chemical. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for 2,4-diaminobenzenesulphonic 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 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 64.9%). In soil, 2,4-diaminobenzenesulphonic acid was expected to have rapid to moderate mobility based upon a Log KOC value of 1. 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 low.

 

If released in to the environment, 35 % of the chemical will partition into water according to the Mackay fugacity model level III in EPI suite version 4.1 (2016). However, the half-life (37.5 days estimated by EPI suite) indicates that 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% when estimated by EPI Suite version 4.1). Hence it has been concluded that 2,4-diaminobenzenesulphonic acid is not 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 BCF value is estimated as 1 L/kg at 25ºC (Chemspider - ACD/PhysChem Suite, 2012) and the experimental log octanol-water partition coefficient (log Kow) was reported as -4.65 (reported in Danish QSAR report, 2016). 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:

 

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

Most of the available short-term eco-toxicity estimation for fish, invertebrates and algae for the substance as well as its read-across substances indicates the LC50/EC50 value are above 100 mg/L indicating that the substance is classified as non-hazardous as per the CLP criteria. The QSAR predictions estimated the EC50 values for invertebrate and algae were in the range of 91.3 to 71.3 mg/L respectively. Based on these values, 2,4-diaminobenzenesulphonic acid was suggested to be classified as ‘Aquatic chronic Category 3’ but since the partition coefficient (log Kow) of the test chemical is not ≥ 4 (i.e, reported as -4.65), test chemical can be considered as non-hazardous to aquatic organisms as per the CLP criteria..

 

There are no available long-term toxicity evaluations for 2,4-diaminobenzenesulphonic acid. NOEC values for the read-across substance (CAS: 98-37-3) in a 72 hour study on algae are reported as 1000 mg/L. By speculation, although the substance is classified as per the CLP criterion, classification for aquatic toxicity will not be applicable as per Annex XIII criteria for all of the tropic levels since the minimum LC50/EC50 is well above 10 mg/L and the same is based on the above mentioned studies.

 

Conclusion

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.