Potentially Toxic Elements (PTEs) in Plants and Animals: Environmental Pathways, Toxicity Mechanisms, and Biomonitoring Insights

ABSTRACT Potentially toxic elements (PTEs) are persistent environmental contaminants that traverse abiotic compartments and biological kingdoms, producing effects from molecular dysfunction to ecosystem disruption and human health impacts. This review presents a novel, cross‐kingdom synthesis of major PTEs—including arsenic, cadmium, lead, chromium, mercury, zinc, and copper—integrating their environmental pathways, cellular and physiological toxicity mechanisms, and ecological and socioeconomic consequences. Essential metals such as copper and zinc become toxic above permissible limits (Cu > 2 mg L − 1 ; Zn > 3 mg L − 1 ), whereas nonessential metals such as lead and cadmium exert toxicity even at trace levels (Pb > 0.01 mg L − 1 ; Cd > 0.003 mg L − 1 ). Cross‐kingdom commonalities, including oxidative stress, enzyme inhibition and genotoxicity, are highlighted, alongside differences in exposure pathways and trophic transfer, with mercury biomagnifying up to 10‐fold in aquatic food webs. Mechanistic endpoints are linked to population‐ and ecosystem‐level impacts. Remediation strategies are reviewed, emphasizing phytoremediation (up to 80% removal efficiency for zinc and cadmium), microbial‐assisted approaches, physicochemical treatments, and governance measures. Key research gaps include speciation‐aware monitoring, mixture‐toxicity studies under realistic exposure scenarios, and long‐term, trans‐disciplinary investigations connecting molecular biomarkers to ecosystem outcomes. Addressing these priorities will advance evidence‐based environmental management, sustainable remediation and provide a comprehensive framework for future cross‐kingdom ecotoxicology research.