Water hyacinth as a phytoremediation agent for wastewater in Mexico: a review

Abstract

This systematic review evaluates the use of Eichhornia crassipes as a phytoremediation agent in Mexico, based on scientific studies published between 1990 and 2023 following PRISMA guidelines. The analyzed works were classified into four categories: heavy-metal removal (54%), treatment of water with high organic load (15%), dye removal (18%), and other uses (13%). The geographical analysis identified the Mexican states where biomass was collected for phytoremediation experiments. In heavy-metal removal, 87.5% of studies specified collection sites, mainly in the State of Mexico; in organic-load treatment, 66.7% reported works in Baja California Norte, Sinaloa, Tabasco, and Tlaxcala; while in dye removal, 87.5% documented biomass origin, mostly from Mexico City. Results across categories showed reproducible performance in both field and laboratory conditions. For metal remediation, E. crassipes exhibited high bioaccumulation capacity, with removal efficiencies of about 90% for Pb and 85% for Cd, concentrated in roots. In waters with high organic content, constructed and free-surface wetland systems achieved reductions above 60–90% in COD, BOD₅, total nitrogen, and phosphorus, depending on design and retention time. It should be emphasized that the dye-related studies using Eichhornia crassipes tissues as a metabolically inactive sorbent, rather than in situ phytoremediation based on living plants.  Regarding dyes, cyclic biosorption with dried or treated tissues achieved near-complete color removal and maintained adsorption efficiency over multiple cycles, evidencing long-term stability of the bioadsorbent. Additionally, some studies emphasized its potential for pesticide retention and nanoparticle synthesis, suggesting emerging research directions that expand its application beyond conventional wastewater treatment.

Keywords: Eichhornia crassipes, Mexico, phytoremediation.