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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 4-aminoazobenzene-3,4'-disulphonic acid for effects in the environment:

In determining the classification appropriate to 4-aminoazobenzene-3,4'-disulphonic acid, it is necessary to consider all available evidence concerning its persistence, potential to accumulate and predicted or observed environmental fate and behaviour that may present a long-term and/or delayed danger to the structure and/or functioning of aquatic ecosystems. The PBT assessment were based on toxicological information in conjunction with standardized environmental fate- and bioaccumulation models. These points are considered below. 

Persistence assessment

Available predicted data indicates that 4-aminoazobenzene-3,4'-disulphonic acid is not persistent in the aquatic and soil environment. Moreover, its persistent characteristics is only observed in the sediment compartment but Fugacity modelling shows that sediment is not an important environmental fate (less than 0% when estimated by EPI Suite version 4.1). Hence it has been concluded that 4-aminoazobenzene-3,4'-disulphonic acid is not persistent in nature.  

Thus, 4-aminoazobenzene-3,4'-disulphonic acid is classified as a not persistent chemical (Not P/ vP). 

Bioaccumulation assessment

The BCF value was estimated based on regression based method to 3.162 L/Kg wet-weight (calculated by EPI suite version 4.1). The log Kow was also below the threshold value of 4.5 (Log Kow = -0.91). Hence, this compound was predicted to have low potential of bioaccumulation in fish and food chains.


Thus, 4-aminoazobenzene-3,4'-disulphonic acid does not satisfy the criterion for classification as bioaccumulative (Not B/vB).

Toxicity assessment

The toxicity values of fish, invertebrates and algae are LC50 = 291 and 54315.48 mg/L, EC50 = 148 mg/L and LC 50 = 2749.32 mg/L, respectively. These values suggest classification for aquatic toxicity will not be applicable for all of the tropic levels and the same is based on the above mentioned estimation studies.

In addition to aquatic toxicity, the substance, 4-aminoazobenzene-3,4'-disulphonic acid, is not classified as carcinogenic (category 1A or 1B), germ cell mutagenic (category 1A or 1B), or toxic for reproduction (category 1A, 1B or 2) according to CLP (Regulation (EC) No 1272/2008) and there is no evidence of chronic toxicity, as identified by the classification STOT (repeated exposure) according to Regulation (EC) No 1272/2008.

Thus, 4-aminoazobenzene-3,4'-disulphonic acid does not meet the Annex XIII criterion for classification as toxic (Not T).

In accordance with the requirements of Annex XIII; it can be inferred that 4-aminoazobenzene-3,4'-disulphonic acid is a not a PBT (including vPvB) substance.