Effect of Varying E-Safe Concentrations on Physicochemical Properties and Hydrocarbon Remediation of Aged Crude Oil-Polluted Soil

Background and Objective: Crude oil contamination significantly alters the physicochemical properties of soil, posing long-term threats to soil fertility, microbial life, and food security, especially in developing countries like Nigeria. While various remediation products exist, region-specific and affordable solutions remain limited. This study aimed to evaluate the effectiveness of different concentrations of E-safe in remediating aged crude oil-impacted soil by assessing its impact on key physicochemical parameters and hydrocarbon degradation. Materials and Methods: A laboratory-based experiment was conducted using soil collected from a crude oil-contaminated site in Rivers State. The topsoil (0-30 cm) was sieved and artificially treated with five concentrations of E-safe (0, 1.5, 3, 6, and 12 mL/kg of soil) in a Completely Randomized Design. Each treatment was applied to 1 kg of soil and monitored for 8 weeks. Total petroleum hydrocarbon (TPH), polycyclic aromatic hydrocarbons (PAH), pH, nitrate, and phosphate were analyzed using standard analytical procedures. Data were presented in charts and tables, with means separated using DMRT at p<0.05. Results: The E-safe significantly enhanced hydrocarbon degradation and improved soil conditions. The highest TPH degradation (98.79%) was observed at 12 mL/kg E-safe, while the control showed the least degradation (13.37%). The PAH removal ranged from 80.16% to 98.78% across treated groups. Soil pH shifted from slightly acidic to basic with increasing E-safe concentration. All E-safe treatments demonstrated over 60% improvement in degradation compared to the control. Conclusion: The E-safe effectively improved the remediation of aged oil-contaminated soils, particularly at higher concentrations. These findings support its potential use in developing countries where crude oil pollution is a persistent problem. Future studies should investigate long-term soil health and microbial recovery following E-safe application to refine optimal dosing and environmental safety.