A critical review on phytoremediation of environmental contaminants in aquatic ecosystem

The rapid urbanization and economic development have resulted in an unprecedented pollution of the entire biosphere. Aquatic ecosystems have become a sink for the discharge of numerous pollutants ranging from nutrients, heavy metals, volatile organic compounds, hydrocarbons, pesticides, medicines, pathogens, and explosives. The accumulation of these pollutants poses a serious threat to aquatic biodiversity, and drinking contaminated water poses severe health hazards in humans. Phytoremediation, an eco-accommodating process, aids in the maintenance of aquatic ecosystem functionality by detoxifying, decomposing, converting, or chelating contaminants, allowing for the proper treatment of wastewater-contaminated water bodies. The development of phytoremediation technology was facilitated by the economic aspects and side effects of conventional treatment technologies. Nevertheless, constructed wetlands have acquired popularity among the numerous accessible methods for treating and recycling diverse wastewaters because they fulfill the criteria of sustainability, public health maintenance, esthetic balance, design intricacy, and cost. The prolonged-release of untreated industrial waste, domestic sewage, accidental spills, rainfall run-off, and direct solid waste disposal all have a substantial influence on aquatic environments. Both live and dead macrophyte biomass may be utilized in phytoremediation; however, dead biomass is typically favored for treating industrial effluents due to lower cost, ease of disposal, and lack of active biochemical machinery that causes metal toxicity and plant death. Some of the barriers to translating phytoremediation technology from the lab to the field include the issue of disposing of biomass and the seasonal growth of aquatic macrophytes. Yet, via numerous works, an eco-sustainable model has been created that could mitigate some of the restrictions. Macrophyte waste biomass has a wide range of productive uses. Future potential for the utilization of macrophytes in phytoremediation investigations includes genetic engineering, biodiversity exploration, and X-ray diffraction spectroscopy. This emerging technology may advance environmental science and technology using a multidisciplinary and integrated approach. This review, thus focuses on the various contaminants found in aquatic ecosystems, their treatment by various phytoremediation processes, some successful phytoremediation studies conducted so far for remediation purposes, and myriad types of constructed wetlands utilized for attenuating pollution levels in various types of wastewaters to bring them down to permissible levels.