Mycoremediation and Soil Quality of Hydrocarbon Impacted Sites At Abandoned Artisanal Refining In Ahuda East Local and Ogba Egbema L.G.A, River State, Nigeria

Oil pollution from artisanal refining has posed significant environmental challenges in the Niger Delta, Nigeria, contaminating soils with polycyclic aromatic hydrocarbons (PAHs) and heavy metals. This study evaluated the bioremediation potential of two white-rot mushrooms, Lentinus subnudus and Calocybe indica, on crude oil-contaminated soils from Ahoada West (AWS) and Ogba Egbema (OES), compared to non-contaminated control soils. A 2 × 3 factorial experiment in a completely randomized design (CRD) with three replicates was established, comprising two fungal species (Lentinus subnudus and Calocybe indica) and three soil categories (AWS contaminated soil, OES contaminated soil, and non-contaminated control soil). Soil samples (250 g each) were placed in experimental pots, inoculated with 50 g of mushroom spawn prepared on Potato Dextrose Agar (PDA), and incubated for 12 weeks. Sampling was carried out biweekly to monitor PAH concentrations, nine heavy metals (iron, Fe; manganese, Mn; copper, Cu; zinc, Zn; chromium, Cr; cadmium, Cd; lead, Pb; nickel, Ni; and vanadium, V), and selected soil physicochemical parameters. Data obtained were subjected to analysis of variance (ANOVA), and means were separated using the least significant difference (LSD) at 5%. Results indicated that Lentinus subnudus reduced PAH levels in AWS and OES soils by 54.2% and 61.5%, respectively, while Calocybe indica achieved reductions of 63.4% and 68.7% over the 12-week period. Heavy metal concentrations also declined significantly; for example, copper residues decreased by 48.2–79.0%, and zinc by 42.5–75.1%, depending on the fungal species and soil type. Both fungi enhanced microbial community abundance and diversity, facilitating pollutant degradation and improving soil quality. These findings demonstrate that Lentinus subnudus and Calocybe indica are effective, eco-friendly agents for the bioremediation of PAH- and heavy metal-contaminated soils, offering sustainable strategies for soil reclamation in tropical oil-impacted environments. Keywords: Mycoremediation, Lentinus subnudus, Calocybe indica, PAHs, Heavy metals.