No abstract

The combination of chemical analyses and bioassays allows the identification of potentially mutagenic compounds in different types of samples. Dyes can be considered as emergent contaminants and were detected in waters, under the influence of textile activities. The objective of this study was to evaluate the contribution of 9 azo dyes to the mutagenicity of representative environmental samples. Samples were collected along one year in the largest conglomerate of textile industries of Brazil. We analyzed water samples from an important water body, Piracicaba River, upstream and downstream two main discharges, the effluent of a wastewater treatment plant (WWTP) and the tributary Quilombo River, which receives untreated effluent from local industries. Samples were analyzed using a LC-MS/MS and tested for mutagenicity in the Salmonella/microsome microsuspension assay with TA98 and YG1041. Six dyes were detected in the collected samples, Disperse Blue 291, Disperse Blue 373, Disperse Orange 30, Disperse Red 1, Disperse Violet 93, and Disperse Yellow 3. The most sensitive condition for the detection of the mutagenicity was the strain YG1041 with S9. The concentration of dyes and mutagenicity levels varied along time and the dry season represented the worst condition. Disperse Blue 373 and Disperse Violet 93 were the major contributors to the mutagenicity. We conclude that dyes are contributing for the mutagenicity of Piracicaba River water; and both discharges, WWTP effluent and Quilombo River, increase the mutagenicity of Piracicaba River waters in about 10-fold. The combination of chemical analysis and bioassays were key in the identification the main drivers of the water mutagenicity and allows the selection of priority compounds to be included in monitoring programs as well for the enforcing actions required to protect the water quality for multiple uses.

h i g h l i g h t s g r a p h i c a l a b s t r a c t Disperse Red 1 dye was found in river waters in concentrations above the PNEC.The PNEC was based on toxicity endpoints for a commercial dye and its purified form. The CRED method was used to evaluate the quality of endpoints used in PNEC derivation. a b s t r a c tWater quality criteria to protect aquatic life are not available for most disperse dyes which are often used as commercial mixtures in textile coloration. In this study, the acute and chronic toxicity of the commercial dye Disperse Red 1 (DR1) to eight aquatic organisms from four trophic levels was evaluated. A safety threshold, i.e. Predicted No-Effect Concentration (PNEC), was derived based on the toxicity information of the commercial product and the purified dye. This approach was possible because the toxicity of DR1 was accounting for most of the toxicity of the commercial mixture. A long-term PNEC of 60 ng L À1 was proposed, based on the most sensitive chronic endpoint for Daphnia similis. A short-term PNEC of 1800 ng L À1 was proposed based on the most sensitive acute endpoint also for Daphnia similis.Both key studies have been evaluated with the new "Criteria for Reporting and Evaluating ecotoxicity Data" (CRED) methodology, applying more objective criteria to assess the quality of toxicity tests, resulting in two reliable and relevant endpoints with only minor restrictions. HPLC-MS/MS was used to quantify the occurrence of DR1 in river waters of three sites, influenced by textile industry discharges, resulting in a concentration range of 50e500 ng L À1 . The risk quotients for DR1 obtained in this work Chemosphere 156 (2016) 95e100 Mixture PNEC suggest that this dye can pose a potential risk to freshwater biota. To reduce uncertainty of the derived PNEC, a fish partial or full lifecycle study should be performed.

We have optimized an SPE-LC-ESI-MS/MS method and used it to monitor disperse azo dyes in environmental aquatic samples. Calibration curves constructed for nine disperse dyes-Red 1, Violet 93, Blue 373, Orange 1, Orange 3, Orange 25, Yellow 3, Yellow 7 and Red 13-in aqueous solution presented good linearity between 2.0 and 100.0 ng mL(-1). The method provided limits of detection and quantification around 2.0 and 8.0 ng L(-1), respectively. For dyes at concentrations of 25.0 ng mL(-1), the intra- and interday analyses afforded relative standard deviation lower than 6 and 13%, respectively. The recovery values obtained for each target analyte in Milli-Q water, receiving waters and treated water samples spiked with the nine studied dyes at concentrations of 8.0, 25.0 and 50.0 ng L(-1) (n = 3) gave average recoveries greater than 70%, with RSD <20%. Statistical evaluation aided method validation. The validated method proved to be useful for analysis of organic extracts from effluents and receiving water samples after an SPE extraction step. More specifically, the method enabled detection of the dyes Disperse Red 1, Disperse Blue 373 and Disperse Violet 93 at concentrations ranging from 84 to 3452 ng L(-1) in the treated effluent (TE), affluent and points collected upstream and downstream of the drinking water treatment plant of a textile dye industry in Brazil.

Although tons of disperse dyes are used worldwile, little information on their ecotoxicity is available. While in silico models can be used to predict their ecotoxicity, experimental results from Daphnia can show significantly higher toxicity than predicted. Thus the objective of this work was to extend the knowledge base in this area by evaluating the ecotoxicity of three widely used disperse dyes and comparing the results to predicted values. Bearing in mind that generating ecotoxicity data on azo disperse dyes is complicated because they are not readily found as homogeneous compounds, we employed chromatographic methods to purify three commercially dyes C.I. Disperse Violet 93, Blue 291, and Blue 373 already found in the aquatic environment. No acute toxicity was observed for Daphnia similis. These results seems to be in general agreement when compared with ECOSAR predicted values. We hypothesize that differences in Kow values could explain the variations in results.