Screening of Azolla caroliniana for Metal Related Bio-Potential Factors

Heavy metals are widespread environmental contaminants that raise significant concerns due to their toxic, persistent, and non-biodegradable nature. Understanding the biological interactions of metals within plants is essential for the phytoremediation process, as it sheds light on the plants' ability to absorb metals, their movement within plant tissues, and their accumulation in above-ground biomass. This study aims to analyze the Bioconcentration Factor (BCF), Bioaccumulation Factor (BAF), Metal Enrichment Factor (MEF), and Metal Translocation Factor (MTF) of the floating macrophyte species Azolla caroliniana through a hydroponic bioassay. The aquatic vascular plant Azolla caroliniana was examined for its capacity to remove heavy metals. A hydroponic bioassay utilizing a synthetic metal solution was conducted from June 2018 to December 2022, exposing Azolla caroliniana to a mixed metal solution to assess its ability to absorb, transfer, accumulate, and enrich heavy metals, thereby evaluating its potential for phytoremediation. The results of this study underscored the metal phytoremediation capabilities and accumulation patterns of ten heavy metals: As, Cd, Cr, Co, Cu, Fe, Mn, Ni, Pb, Sr, and Zn across different plant organs of Azolla caroliniana. The findings revealed that the order of BCF for the metals was Fe>Zn>Mn>Cu>Pb>Cd>Cr>Ni>Co>Sr>As, while the MEF order was Fe>Zn>Cu>Mn>Pb>Cd>Cr>Ni>Co>Sr>As. The ranking of BAF for the studied metals was Fe>Zn>Mn>Cu>Cd>Pb>Cr>Ni>Co>Sr>As, and the MTF order was Ni>Cu>Mn>Cd>Zn>Co>Pb>As>Cr>Fe>Sr. Importantly, Azolla caroliniana demonstrated hyperaccumulation for Zn, Fe, Mn, Cu, Cd, Pb, Ni, Co, Cr, Sr, and As, as indicated by a BCF greater than 1.