Title : Evaluation of a pilot-scale constructed wetland planted with Limnocharis flava for the treatment of gold mining-impacted waters in Ayapel, Cordoba.
Abstract:
Heavy metal contamination associated with gold mining represents one of the most critical environmental issues affecting aquatic ecosystems in Colombia, due to its adverse effects on water quality, biodiversity, and productive activities related to water supply and agriculture. In regions where mining activities are carried out intensively, the release of toxic elements such as mercury (Hg), lead (Pb), chromium (Cr), and manganese (Mn) has generated significant environmental degradation processes that impact both surface water bodies and the ecological dynamics of wetlands and tropical floodplain systems. In this context, the present study evaluated the efficiency of a pilot-scale batch-type constructed wetland planted with Limnocharis flava as a sustainable and low-cost alternative for the remediation of contaminated waters in the Ayapel swamp system, Córdoba, Colombia.
The experimental design included the initial physicochemical characterization of contaminated water, considering parameters such as pH, electrical conductivity, dissolved solids, and dissolved oxygen, as well as the assessment of the phytoremediation capacity of the species through bioconcentration factor (BCF), translocation factor (TF), and transfer coefficient (CT) analyses. In addition, the effect of three planting densities (low, medium, and high) on the removal of the evaluated metals was analyzed over a 30-day experimental period.
The results demonstrated an overall removal efficiency greater than 78% for the analyzed metallic contaminants, reaching maximum efficiencies of up to 91.6% for Hg removal. Simultaneously, significant improvements in the physicochemical characteristics of the treated water were observed, reflected in pH stabilization, conductivity reduction, and increased dissolved oxygen levels. Furthermore, a density-dependent response was identified: low planting densities mainly promoted metal retention in root tissues, whereas medium and high densities enhanced the translocation of metals toward aerial plant structures. Overall, the findings demonstrate that Limnocharis flava has considerable potential for phytoremediation applications in constructed wetlands, highlighting planting density as a key parameter for optimizing treatment performance and supporting the recovery of water systems impacted by mining activities in tropical ecosystems.
Keywords: Phytoremediation, Limnocharis flava, Heavy metals, Artificial wetland, and Water quality.
