The problem with benzotriazole ultraviolet stabilizers in the environment ‐ are the aquatic plants the solution for them?

Abstract

The present work describes the studies on the usefulness of Wolffia arrhiza (L.) Horkel ex Wimm., Lemna minor L., Spirodela polyrhiza (L.) Schleid. and Azolla caroliniana Willd. for the removal of five benzotriazole UV filters (BUVs): 2-(2-hydroxy-5-methylphenyl)benzotriazole (UV-P), 2-tert-butyl-6-(5-chloro-2 H-benzotriazol-2-yl)− 4-methylphenol (UV-326), 2,4-di-tert-butyl-6-(5-chloro-2 H-benzotriazol-2-yl)phenol (UV-327), 2-(2 H-benzotriazol-2-yl)− 4,6-di-tert-pentylphenol (UV-328), and 2-(2 H-benzotriazol-2-yl)− 4-(1,1,3,3-tetramethylbutyl)phenol (UV-329) from polluted waters. The optimal conditions for the removal of BUVs by phytoremediation were selected. The effect of the real matrix (treated and raw wastewater) on the removal efficiency was checked. The kinetic and the mechanisms of removal processes were established. Optimal culture conditions were: 0.5 g W. arrhiza per 100 mL of the model solution, light exposure 16 h, and pH 6.5; 0.5 g S. polyrhiza per 100 mL of the model solution, light exposure 16 h, and pH 9; 2.2 g A. caroliniana per 100 mL of the model solution, light exposure 10 h, and pH 9. Sorption was the mechanism that accounted for most of the removed BUVs in the cultures with A. caroliniana and S. polyrhiza. The UV-326 was removed the fastest in cultivation with L. minor, S. polyrhiza, and A. caroliniana. S. polyrhiza removed BUVs from solutions with laboratory medium most effectively. W. arrhiza removed three of the BUVs with higher efficiency from raw sewage than treated sewage.