Effect of Silver Nanoparticles (AgNPs) on Aquatic and Wetland Plants

Among nanomaterials, silver nanoparticles (AgNPs) are cost-effective and exhibit unique physicochemical properties that enable them to become the most used agents for the manufacture of various products known as nano-enabled, including those for personal care, drugs, fabrics, sprays, disinfectants, vacuum cleaners, and air conditioners, with a continuous expansion to different sectors. Industrial discharges, the disposal of wastewater treatment effluents, and indirect runoff from the soil are some factors that are increasing the accumulation of AgNPs in aquatic and wetland ecosystems. Herewith, we critically analyze the progress in the research of the uptake and translocation of AgNPs in aquatic and wetland plants and their phytotoxic effect that depends on the concentration, size, distribution, morphological shape, surface characteristics and chemical composition of the nanoparticles, as well as the plant genotypes, among other factors. Due to biological plasticity, the toxicity level of AgNPs may vary among plant species, which may be further affected by the mode of application, time of exposure, and plant conditions (e.g., agronomic management, growth rate, phenological stage, etc.). Therefore, it is possible to identify and select competent plants for phytoremediation purposes, including superior capabilities for phytoextraction, phytofiltration, and phytostabilization. The review also identifies the main gaps that require attention in future research in order to elucidate a more integrative map aimed to reduce the potential threats to the environment and living organisms including humans.