Potential of two floating aquatic macrophytes in improving water quality: A case study in two tropical streams

The expansion of urbanization has led to significant adverse environmental effects, including the disposal of domestic sewage without treatment in water bodies. This impact contributes to the deterioration of water quality and poses serious risks to human health and the environment. In this context, effective and sustainable methods to mitigate the impacts should be explored, such as the use of plants capable of removing or degrading contaminants from water. The present study aimed to assess the phytoremediation potential of two free-floating aquatic macrophytes (Eichhornia crassipes and Pistia stratiotes) systems for enhancing the water quality collected from two polluted urban streams. The trials were performed in 25-L experimental units for seven days under ambient conditions. The water quality variables after the exposure period were compared to those at the beginning of the experiment to assess the potential improvements due to the presence of macrophytes. The systems with E. crassipes exhibited good performance in water samples from both streams, with reductions reaching 29.2% in dissolved solids, 36.8% in electrical conductivity, 44% in biochemical oxygen demand, 57% in nitrogen, and 45% in phosphorus. The systems with P. stratiotes also exhibited satisfactory outcomes, including 90 and 76.2% reductions in phosphorus levels of Santa Rita Stream and Galinha Stream, respectively, and 54% turbidity, and 38% biochemical oxygen demand in both streams. These findings highlight the potential of the two plant species for phytoremediation of polluted waters, considering their performance on short-term exposure. Therefore, this approach consists of a sustainable alternative by utilizing natural elements for environmental restoration, and the outcomes can contribute to future applications of phytoremediation techniques in developing countries.