Phytoremediation of microplastics by water hyacinth

Abstract

Microplastics have emerged as pervasive environmental pollutants, posing significant risks to both terrestrial and aquatic ecosystems worldwide. Current remediation strategies—including physical, chemical, and microbial methods—are inadequate for large-scale, in situ removal of microplastics, highlighting the urgent need for alternative solutions. Phytoremediation, an eco-friendly and cost-effective technology, holds promise in addressing these challenges, though its application to microplastic pollution remains underexplored. Here we show the capacity of Eichhornia crassipes (water hyacinth), a fast-growing, floating aquatic plant, to remove microplastics from contaminated water. Our results show that within 48 h, water hyacinth achieved removal efficiencies of 55.3 %, 69.1 %, and 68.8 % for 0.5, 1, and 2 μm polystyrene particles, respectively, with root adsorption identified as the primary mechanism. Fluorescence microscopy revealed that the extremely large and abundant root caps, featuring a total surface area exceeding 150,000 mm² per plant, serve as the principal sites for the entrapment of microplastics. Furthermore, a unique “vascular ring” structure within the stem prevents the translocation of microplastics to aerial tissues, safeguarding leaves for potential downstream applications. This study offers the first microstructural insight into the mechanisms underpinning water hyacinth's exceptional microplastic adsorption capacity and resilience, providing a promising framework for developing phytoremediation strategies to mitigate microplastic pollution in aquatic ecosystems.