Phytomanagement of shooting range soils contaminated by Pb, Sb, and as using Ricinus communis L.: effects of compost and AMF on PTE stabilization, growth, and physiological responses.

Abstract

Shooting ranges represent a critical case of soil contamination due to the accumulation of Pb, Sb, and As from bullet residues. Effective and sustainable remediation strategies are required to mitigate environmental and health risks while enabling land valorization. This study investigates the potential of Ricinus communis L. for phytomanagement of Pb-, Sb-, and As-contaminated soils, evaluating the combined effects of compost, mineral fertilizer, and arbuscular mycorrhizal fungi (AMF) on plant growth, PTE accumulation and bioavailability, and biomass production. A mesocosm experiment was conducted using highly contaminated soil (about 5000 mg kg⁻¹ Pb, 100 mg kg⁻¹ Sb). Despite severe contamination, Ricinus communis L. achieved stable biomass and seed yield (about 5.7 Mg ha⁻¹ seeds, 2-3 Mg ha⁻¹ oil), similar to values reported in non-contaminated soils of the Mediterranean area. Compost and AMF increased PTE bioavailability in the rhizosphere, likely due to root exudate activity, but maintained low translocation factors (TF < 1), indicating limited PTE uptake into aerial biomass. These findings confirm the phytostabilization potential of Ricinus communis L., reducing PTE dispersion while promoting renewable energy production preventing competition for land used for growing food crops.