Trisodium bis[3-hydroxy-4-[(2-hydroxy-1-naphthyl)azo]-7-nitronaphthalene-1-sulphonato(3-)]chromate(3-)

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Three studies according OECD guideline 302 B are available. The biodegradation found in these inherent biodegradable studies were 13 % respectively 26.8 % in two static tests. One test was conducted with adapted sludge (adaption 28 days) and showed a biodegradation of 69 % in 20 days. Although the criteria for inherently biodegradability are not fulfilled the results shows that the substance has the potential to biodegrade particularly in an environment with adapted microorganisms which will be found in the STP of the dye factories. The ‘P’ criterion according to Annex XIII is fulfilled for environmental compartments.

The partition coefficient (octanol /water) of the test subbstance hase been determined by the shake flas method (logPow= -1.74) and estimated by the calculation from the solubilities in water and octanol (logPow= -2.11). The ‘B’ criterion for Acid Black 172 is NOT fulfilled.    

The substance is classified as hazardous to the aquatic environment (long-term) – Aquatic Chronic 2. This classification results from eleven aquatic toxicity tests. The lowest value is the 96-hour LC50 of 3 mg/l for freshwater fish. The criteria for T are not fulfilled. The 'T' criterion for Acid Black 172 based on the lowest aquatic (acute) toxicity result is NOT fulfilled as the toxicity value of 3 mg/l is above the toxicity criteria of 0.1 mg/l for the aquatic compartment.

Overall, for Acid Black 172, ‘P’ criterion is fulfilled but ‘B’ and ‘T’ criteria are not. Therefore, Acid Black 172 is neither a 'PBT' nor a 'vPvB' substance.