Integrated Trichoderma harzianum—Vicia faba Approach for Soil Bioremediation and Health Risk Assessment Under Wastewater Irrigation

The increasing of treated wastewater for irrigation in water-scarce regions increases the risk of heavy metals soil contamination, threatening food safety and human health. This study investigated the synergistic potential of the fungi Trichoderma harzianum and three icia faba L. varieties (Agadulce, Hiba, and Reina mora) for soil bioremediation under wastewater irrigation. A split-plot design under controlled greenhouse conditions assessed the impacts of irrigation type and Trichoderma harzianum inoculation on soil heavy metal content and plant uptake. Although metal concentrations remained within WHO permissible limits, T. harzianum significantly reduced soil metal loads. Specifically, the ‘Reina mora’ cultivar exhibited the superior performance in this dual myco-phytoremediation approach, achieving the highest reduction in soil metal concentrations. Conversely, the ‘Hiba’ variety demonstrated a distinct advantage for food safety by exhibiting the lowest heavy metal accumulation in plant tissues. Risk assessments based on deterministic models indicated negligible non-carcinogenic and carcinogenic risks for both adults and children. This study presents a dual myco-phytoremediation approach as a promising and practical strategy for mitigating heavy metal risks and supporting sustainable crop production in wastewater-irrigated regions.