Spatial Distribution of Physicochemical and electrical Properties in soils around abandon illegal Refineries Sites

This study assessed how residual petroleum hydrocarbons influence both the physicochemical and electrical properties of soil. Soil samples were collected from five spatial locations near clusters of abandoned artisanal refineries. The concentrations of total hydrocarbons content (THC), copper (Cu), lead (Pb), nickel (Ni), cadmium (Cd), as well as the electrical resistivity (ρ) and dielectric constant (ɛʹ) values of the soil samples presumed to be contaminated and those from the reference point, were determined following approved standard guidelines. The findings indicated the presence of residual petroleum hydrocarbons in the sites of the old refineries, as evidenced by significantly higher THC values in the soil samples collected from the abandoned refinery sites compared to the control soil (p ≤ 0.05). It was observed that the THC levels ranged from 1052 to 4024 mg/kg, significantly exceeding the result (71 mg/kg) recorded at the control point. The concentrations of Cu, Ni, Pb, and Cd ranged from 3.63 to 8.10 mg/kg, 5.73 to 9.10 ppm, 5.13 to 8.30 ppm, and 0.90 to 1.53 mg/kg, respectively. Conversely, at the reference location, concentrations of Cu, Ni, Pb, and Cd were recorded as 2.27, 2.67, 3.70, and 0.08 mg/kg, respectively. The results revealed that ρ across the five sampled points varied from 451.00 to 836.00 Ωm, while ɛʹ values ranged between 3.16 and 3.73. As evidenced by the results, proper remediation of areas where illegal refineries were once located is crucial to mitigate the risks associated with petroleum toxicity.