Behavior of free-floating macrophyte masses of Eichhornia crassipes and Pistia stratiotes in the absorption of contaminants in a eutrophic freshwater system in central Mexico

Recently, non-conventional strategies for water treatment strongly point to the implementation of wetlands. The objective of this investigation was to describe the physicochemical behavior in the biosorption of contaminants through macrophyte masses (MM) formed by Eichhornia crassipes and Pistia stratiotes dispersed over a eutrophic lake and its tributaries to define a proposal for their sustainable management. For this purpose, physicochemical parameters in water and plant were analyzed. MM presented a biosorption of CO32-, B, N, P, Fe, V and Sr. Areas with the presence of MM reduced the pH compared to areas free of macrophytes. In the plant tissue analyzed, an accumulation of the following elements was found: Mn, K, V, Cu, Pb, Ni, Sr, N, Zn, Li, Cr, Ti, Mo, Sb, Ca, Mg, Na, and Si. In this wetland system, macrophyte populations are typically controlled through shredding or herbicide application. However, this study proposes their removal and conversion into biogas, resulting in a residual sludge that requires treatment due to its content of toxic metals. This strategy would offer both environmental and economic benefits, while also contributing to the continuous improvement of water quality.