Occurrence and ecotoxicity of selected artificial sweeteners in the Brno city waste water

This study focused on the appearance of the most commonly used artificial sweeteners (acesulfame K, cyclamate, saccharin, and sucralose) in waste and discharged water and the evaluation of their possible negative effects on the water ecosystem. Samples of raw and treated wastewater were collected at the inflow and outflow of the Wastewater Treatment Plant in Brno-Modřice (Czech Republic). The target compounds were isolated by solid phase extraction and determined by liquid chromatography with mass spectrometric detection. The ecotoxicity of target compounds expressed as the ErC20, LC20, and EC20 values was evaluated by a battery of tests using representatives of producers and consumers in the water ecosystem as testing organisms (Lemna minor, Thamnocephalus platyurus, and Daphnia magna). The results proved that the acute toxicity of individual artificial sweeteners does not pose a significant risk to the aquatic ecosystem. The compound showing the highest concentration in raw wastewater (in the range of tens of µg L−1) and negligible removal during the wastewater treatment process was sucralose, but its ecotoxicity was the lowest of the ASs studied. The highest ecotoxicity showed saccharin, but its removal in a wastewater treatment plant was almost complete. However, additional studies are needed to evaluate the chronic toxicity of ASs and also possible synergistic or antagonistic effects in ASs mixtures.