Duckweeds for Phytoremediation of Polluted Water

Abstract

Tiny aquatic plants from the Lemnaceae family, commonly known as duckweeds, are often regarded as detrimental to the environment because of their ability to quickly populate and cover the surfaces of bodies of water. Due to their rapid vegetative propagation, duckweeds have one of the fastest growth rates among flowering plants and can accumulate large amounts of biomass in relatively short time periods. Due to the high yield of valuable biomass and ease of harvest, duckweeds can be used as feedstock for biofuels, animal feed, and other applications. Thanks to their efficient absorption of nitrogen- and phosphate-containing pollutants, duckweeds play an important role in the restorative ecology of water reservoirs. Moreover, compared to other species, duckweed species and ecotypes demonstrate exceptionally high adaptivity to a variety of environmental factors; indeed, duckweeds remove and convert many contaminants, such as nitrogen, into plant biomass. The global distribution of duckweeds and their tolerance of ammonia, heavy metals, other pollutants, and stresses are the major factors highlighting their potential for use in purifying agricultural, municipal, and some industrial wastewater. In summary, duckweeds are a powerful tool for bioremediation that can reduce anthropogenic pollution in aquatic ecosystems and prevent water eutrophication in a simple, inexpensive ecologically friendly way. Here we review the potential for using duckweeds in phytoremediation of several major water pollutants: mineral nitrogen and phosphorus, various organic chemicals, and heavy metals.

Organic Amendments: Enhancing Plant Tolerance to Salinity and Metal Stress for Improved Agricultural Productivity

“…Duckweed extracts have been employed as biostimulants for olive plant growth [78]. Notably, duckweed can withstand pollutants such as ammonia and HMs, marking its potential as a purifier for agricultural and industrial wastewater [79]. However, some research indicates that DW efficacy in HM (Ni, Cd) pollutant removal diminishes under salt stress [80].…”

Duckweed: Research Meets Applications

“…Duckweeds have long been considered as potent candidates for wastewater management. As reviewed by Zhou et al [ 20 ], these fragile plants were true giants in reclaiming contaminated waters while providing valuable biomass at the end of the process.…”

Contrasting patterns of 5S rDNA repeats in European and Asian ecotypes of greater duckweed, Spirodela polyrhiza (Lemnaceae)

“…For example, duckweed biomass is rich in proteins, carbohydrates, crude fiber, and minerals, making it an attractive source of feed for animals (particularly aquaculture) and humans ( Appenroth et al., 2017 ). Additionally, duckweeds have been widely used for wastewater treatment ( Zhou et al., 2018 ), biosensing ( Ziegler et al., 2019 ), and phytoremediation ( Ekperusi et al., 2019 ; Zhou et al., 2023 ).…”