2-Naphthalenesulfonic acid, 4-hydroxy-3-[2-[2-methoxy-5-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-7-[(sulfomethyl)amino]-8-[2-[2-sulfo-4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, sodium salt (1:5)

PBT assessment

PBT assessment: overall result

Reference

Name:

Reactive Red F01-0481

Type of composition:

legal entity composition of the substance

State / form:

solid: particulate/powder

Reference substance:

Reactive Red F01-0481

PBT status:

the substance is not PBT / vPvB

Justification:

Persistence Assessment

Reactive Red F01-0481 displays very low biodegradability in a test for ready biodegradability. According to literature, microbial decolourization of azo dyes in an anaerobic environment occurs as a result of reduction of azo bonds, the resulting aromatic amines are further degraded and mineralised under aerobic conditions. Studies on direct phototransformation in water are not available but it was found that the sulfonated azo dyes can be destroyed by UV photooxidation process. The kinetics of the degradation depends on the azo, benzene and naphthalene groups of the dyes. The first step of the degradation is related to cleavage of the azo bond of the molecule and naphthalene ring, which leads to further degradation until complete mineralization.

Furthermore, the substance hydrolyses under normal environmental conditions. Experimental studies on hydrolytic effects demonstrated that the substance does undergo rapid hydrolysis at environmentally relevant pH, (t½ < 1 day at pH 7 and pH 9), indicating the potential for significant removal by hydrolysis. At use conditions during dyeing (pH > 10 at ≥ 60°C) the substance is hydrolytically unstable; as such, degradation is anticipated via this route.

It is concluded, therefore, that abiotic processes would contribute significantly to the depletion of the substance within the environment. Due to the effects of hydrolysis at environmentally relevant pHs, it is proposed that the substance cannot be considered to have a half-life in fresh water higher than 40 days, despite the limited ability to readily biodegrade.  

Based on its high water solubility, low partition coefficient and fairly rapid hydrolysis rate at environmentally relevant pHs, it can be concluded that it is unlikely that Reactive Red F01 -0481 could potentially be persistent within the environment. Abiotic effects will result in eventual removal from the environment and hence significant contact with the organisms in the food chain can be considered to be minimised. As such, the substance does not fulfil the requirements of Annex XIII, Para 1.1 based on evaluation of available data, and cannot be considered a “vP” based in this data. However, the substance is considered to be "P".

 

Bioaccumulation Assessment

Reactive Red F01 -0481 has a log Kow of <-2 which indicates that possible bioaccumulation in the food chain is not anticipated. Given the fact that the substance is subject to hydrolysis at biologically relevant pHs, it is anticipated that bioaccumulation of the substance itself would not occur, as hydrolytic effects in association with metabolic effects would result in removal of the substance.

Based on the physico-chemical and environmental data for the substance, it is proposed that the substance does not fulfil the requirement of Annex XIII, Para 1.2 based on evaluation of available data, and cannot be considered a “B” or “vB” based on the available data.

 

Toxicity Assessment

The substance or its structural analogues did not cause any hazardous effects to any of the trophic levels in the aquatic organisms examined in the acute toxicity studies. The substance is not considered as harmful to aquatic organisms, nor did it demonstrate significant toxicity in any of the mammalian studies conducted on the substance. 

As such, the substance does not fulfil the requirements of Annex XIII, Para 1.3 based on evaluation of available data, and cannot be considered as “T” for the purposes of the assessment.

 

Summary and overall Conclusions on PBT or vPvB Properties

The substance cannot be considered to fulfil all the criteria for Persistence, Toxicity or Bioaccumulation, as specified in REACH Annex XIII. As such, the substance cannot be considered a PBT or vPvB substance, based on the available data.