Evaluation of the Potential Toxicity of Effluents from the Textile Industry before and after Treatment

The textile industry has an important role in the economic development of several countries; however, it consumes large amounts of water and generates huge quantities of wastewater. These effluents are of great environmental concern due to their complex chemical content, known by their toxicity and low biodegradability, which can cause harmful effects to the aquatic environment. In the present study, bioassays with aquatic species were employed to evaluate the toxicity of effluent samples collected before and after the treatments performed by the textile company. The toxic effects were investigated using four organisms, namely Aliivibrio fischeri, Raphidocelis subcapitata, Daphnia magna and Lemna minor, to represent different trophic levels. The ecotoxicological data confirmed that the raw textile effluent was very toxic, with A. fischeri being the most sensitive organism. While the toxicity of the effluent collected after the treatment performed by the textile company was clearly reduced, we still recorded sublethal toxicity to D. magna. These results highlight the importance of the bioassays for continuous monitoring of the toxicity of the treated effluents to prevent adverse effects on the environment. Further, results suggest that ecotoxicological data should be required in parallel with chemical data to better evaluate the safety of environmental discharges of wastewaters.