Progress in biostimulation-based remediation of TPH-contaminated soils: a comprehensive review

Background Petroleum pollution in soils poses a significant global environmental threat, primarily due to increased industrial activities and oil spills. Biostimulation, a bioremediation strategy that enhances indigenous microbial activity through nutrient amendment, has gained prominence for its sustainability and effectiveness. Methods This review consolidates findings from 276 peer-reviewed studies published between 2000 and 2025, covering the application of organic amendments, mineral nutrients, and biochar. It further analyzes microbial community responses, degradation efficiency, and synergistic treatment outcomes under varied environmental conditions. Results Biostimulants such as compost, nitrate, and phosphate significantly enhance microbial degradation of total petroleum hydrocarbons (TPHs), especially when used in combination. Biochar improves soil aeration and supports functional gene expression. Integrated treatments demonstrate superior removal efficiencies compared to single-agent approaches. Conclusion Biostimulation is a promising, scalable solution for TPH-contaminated soils. However, optimization of nutrient ratios, consideration of site-specific variables, and real-time monitoring systems are essential for effective field deployment.