Exploring the phytoremediation capacity of Amaranthus species in trace metal(loid)-impacted terrestrial environments

Environmental contamination by trace metal(loid)s threatens human health and ecological sustainability. Plants possess natural mechanisms to mitigate contaminated environments. This review synthesizes current evidence on the phytoremediation potential of Amaranthus spp. a widely distributed genus characterized by rapid growth, high biomass production, and tolerance to metal stress. Available controlled-environment and field studies show that Amaranthus spp. can contribute to the phytoextraction or phytostabilization of Cd, Pb, Cu, Zn, Cr, Ni, Ba, Cs, and other trace metal(loid)s. However, performance varies strongly among species, contaminants, soil conditions, and enhancement strategies. Mechanistic evidence indicates that transporter-mediated uptake, chelation, vacuolar sequestration, antioxidant defense, microbial interactions, and genetic/proteomic regulation support metal tolerance and accumulation. Moreover, we evaluate the effectiveness of Amaranthus spp. in the removal of metal contaminants through agronomic practices, genetic improvement, and microbial associations. Importantly, the review often overlooked food safety and health risks associated with the dual use of Amaranthus spp. as both a phytoremediator and an edible or medicinal plant. By identifying current limitations, knowledge gaps, and future research priorities, this review establishes Amaranthus spp. as a versatile yet complex candidate for sustainable remediation of trace metal(loid)-contaminated terrestrial ecosystems and provides a framework for their safe and effective deployment.