Phytoremediation of Nickel-Contaminated Soils: An Integrative Review of Plant Species, Remediation Mechanisms, and Soil Factors

Increasing soil contamination by potentially toxic elements (PTEs) compromises environmental quality and ecosystem health, reinforcing the need for effective remediation strategies. Phytoremediation uses plants to remove, immobilize, or neutralize contaminants and represents a sustainable approach for restoring contaminated soils. Although nickel (Ni) is an essential plant micronutrient, elevated concentrations can cause phytotoxicity. This integrative review aimed to synthesize and critically analyze the scientific literature on the phytoremediation of Ni-contaminated soils published between 2000 and 2026, focusing on the plant species evaluated, their phytoremediation potential, and the main research trends and knowledge gaps. The Web of Science Core Collection search identified 230 records. Original research articles addressing the phytoremediation of Ni-contaminated soils and providing sufficient information to characterize phytoremediation potential were considered eligible, resulting in 91 included studies. Plant responses varied according to species and Ni concentration. Among 449 plant records, defined as the occurrence of a plant taxon within a study, more than 86% corresponded to herbaceous plants; Poaceae accounted for 27.2% of the records, followed by Brassicaceae (15.1%). Brassica juncea was consistently identified as a promising species for Ni phytoremediation, showing Ni tolerance, phytoextraction, and hyperaccumulation across different studies. Alyssum murale stood out among the reported hyperaccumulators for its high Ni accumulation and phytoextraction potential. Overall, the reviewed evidence supports phytoremediation as a sustainable strategy for Ni-contaminated soils. However, important knowledge gaps remain, particularly the scarcity of long-term field studies, methodological heterogeneity, limited understanding of plant–soil–microbiota interactions, underrepresentation of major Ni-producing regions, and insufficient evidence on technical and economic feasibility. Future research should address these gaps through standardized approaches and integrated field assessments under contrasting edaphoclimatic conditions to advance the effective and sustainable application of Ni phytoremediation.