The Effect of Mycoremediation on the Physicochemical Properties of Hydrocarbon-Polluted Soils of Niger Delta, Nigeria

Abstract

Crude oil exploration and pipeline vandalism have left extensive areas of the Niger Delta contaminated with petroleum hydrocarbons, degrading soil quality and constraining agricultural productivity. This study evaluated the effectiveness of mycoremediation—the use of fungi to degrade organic pollutants—in restoring the physicochemical properties of hydrocarbon-polluted soil sampled from an impacted site in Ogoniland, Rivers State. A completely randomized design was used, comprising four treatments (uninoculated control, and soil inoculated separately with Aspergillus niger, Penicillium chrysogenum, and Pleurotus ostreatus) replicated three times and incubated for 90 days under laboratory microcosm conditions. Soil pH, electrical conductivity, total organic carbon (TOC), total petroleum hydrocarbon (TPH), total nitrogen, available phosphorus, and moisture content were measured at 0, 30, 60, and 90 days and analyzed using one-way ANOVA with Duncan's Multiple Range Test. All three fungal treatments significantly reduced TPH relative to the control by day 90 (p < .001), with Pleurotus ostreatus achieving the greatest reduction (78.4%), followed by Penicillium chrysogenum (69.1%) and Aspergillus niger (65.6%), compared with only 17.6% attenuation in the control. Fungal treatments were also associated with significant improvements in pH, total nitrogen, and available phosphorus relative to the control, consistent with the release of nutrients as hydrocarbons were metabolized. These findings demonstrate that mycoremediation, particularly using ligninolytic white-rot fungi such as P. ostreatus, offers an effective, low-cost, and environmentally compatible approach for restoring hydrocarbon-degraded soils in the Niger Delta and warrants field-scale evaluation.