New benzotriazoles generated during textile dyeing process: Synthesis, hazard, water occurrence and aquatic risk assessment

Highlights: • Two new phenylbenzotriazoles, non-Cl PBTA-9 and PBTA-9, were synthetized. • Both compounds were more mutagenic and toxic for aquatic organisms than the parental dye DV93. • An analytical method for their simultaneous detection in surface waters was developed. • Non-Cl PBTA-9 was detected in sites under the influence of textile discharges. • No risk to aquatic life was verified in the preliminary risk assessment. Phenylbenzotriazoles (PBTA) can be generated unintentionally during textile dyeing factories by reduction of dinitrophenylazo dyes and their subsequent chlorination in disinfection process. Eight non-chlorinated PBTAs (non-Cl PBTA) and their related chlorinated PBTAs have been found in rivers and presented mutagenic activity. No data on their aquatic toxicity are available. In this work, two new phenylbenzotriazoles, non-Cl PBTA-9 and PBTA-9, derived from the dye C.I. Disperse Violet 93 (DV93) were synthesized and chemically/toxicologically characterized. Both compounds were more mutagenic than the parental dye in the Salmonella/microsome assay in the presence of metabolic activation (S9). Mutagenicity studies in vivo with mammals would confirm their potential hazard to humans. The two compounds were acutely toxic to Daphnia similis. We developed an analytical method to simultaneously quantify non-Cl PBTA-9, PBTA-9 and DV93 in river waters. Non-Cl PBTA-9 was found in sites under influence of textile effluents but at concentrations that do not pose risk to the aquatic life according to the P-PNEC calculated based on the acute toxicity tests. PBTA-9 was not detected in any samples analyzed. More studies on the aquatic toxicity and water occurrence of PBTAs should be conducted to verify the relevance of this class of compounds as aquatic contaminants.