Absorption of three different forms of arsenic in water by three aquatic plants and their bioremediation potential

Abstract

Arsenic (As) is a highly toxic carcinogen. Its pollution spreads to soil and water, posing a threat to the global environment, crop production and food safety. In this study, to explore the recovery potential of different aquatic plants to As polluted water, three submerged plants Hydrilla verticillata L., Ceratophyllum demersum L., and Potamogeton malaianus M. were took as material, the absorption and accumulation of arsenic was investigated. The experimental plants were grown in standard Hoagland solution containing 3 form of As: As(V), dimethylarsinic acid (DMA) and As(III) at different concentrations for 10 days in a greenhouse, at 1.0 mg · L−1 for a time-course study to evaluate arsenic uptake by the tested plants at different times (0, 2, 4, 6, 8, and 10 days). The subcellular location and compartmentalization of As in plants were also studied in this study. The findings revealed that the biomass of the tested plants was drastically decreased when 3.0 and 5.0 mg · L−1 of As(III) and As(V) was applied. Aside from this, the biomass of studied plants was reduced more effectively by As(III) compared to As(V), and absorption decreased in As(III) > DMA > DMA manner. Arsenic absorption was high in all three plants but H. verticillata had a greater accumulation of arsenic than C. demersum and P. malaianus when exposed to the As(III), As(V), and DMA compounds. The inorganic arsenic species As(V) and As(III) were mostly detected in the cell wall and cytoplasm, while the organic species (DMA) were mostly identified in the cell wall. In a word, the aquatic macrophytes, particularly H. verticillata, aid in the phytoremediation of aquatic environments against both inorganic and organic As species. This study is expected to provide a reference for a phytoremediation method for removing As.