Phytoremediation Potential of Amaranthus viridis and Lactuca sativa: Assessing Physicochemical and Nutrient Dynamics in Heavy Metal Contaminated Soils

Abstract

This study investigated the phytoremediation potential of Amaranthus viridis and Lactuca sativa in soils contaminated with Cd, Pb, Hg, and Zn, assessing concurrent changes in soil physicochemical properties. Pot experiments (56 days) measured pH (5.90–6.78), EC (1.23–3.10 dS/m), organic carbon (1.90–3.10 g/kg), and macronutrients (N, P, K) across metal concentration gradients. Results demonstrated that both species effectively restored soil quality within permissible limits (FAO/USDA standards), with distinct remediation profiles: A. viridis showed superior heavy metal stabilization (97.8% EC reduction for Cd) while L. sativa enhanced nutrient levels (N: 110.25±8.34 mg/kg) through rapid biomass turnover. The 86.7% Nitrogen reduction by A. viridis and its 35% higher stomatal conductance (p<0.05) revealed species-specific remediation mechanisms, including differential root exudation and microbial associations. These findings provide critical insights for tailored phytoremediation strategies, recommending A. viridis for metal stabilization and L. sativa for nutrient recovery in contaminated soils, with important implications for sustainable land management in tropical regions.