Investigation of Petroleum Hydrocarbons in Soil from Auto-mobile Mechanic Workshops within Ikot Akpaden, Mkpat Enin L.G.A Akwa Ibom State Nigeria

Abstract

This study investigates the concentrations of total petroleum hydrocarbon (TPH) and total hydrocarbon content (THC) in soil samples from auto-mobile mechanic workshop in Ikot Akpaden, Mkpat Enin. Soil samples were collected in triplicate at different points within the vicinity of auto-mobile mechanic workshop at Ikot Akpaden represented as site A and control samples were obtained within the frontage of Chemistry Department, AKSU represented as site C. Soxhlet extraction and shaking methods were used for the extraction of the total petroleum hydrocarbons and total hydrocarbon content respectively. Each of the sample extracts were purified using column chromatography to remove moisture, polar hydrocarbons, colour interferences and any impurities before GC analysis. Total petroleum hydrocarbons and THC were analyzed using Gas Chromatography (GC-FID) and UV-VISIBLE spectrophotometer respectively. The results obtained from TPH analysis indicates that; 15,223.4 mg/kg was recorded from the auto-mobile mechanic workshop and 808.507 mg/kg was recorded from the control samples. The results from the two stations were higher than the department of petroleum resources (DPR) permissible limit of 50 mg/Kg for soils. There was significant difference in the concentration of total hydrocarbon content, the result obtained showed that, the three sampling point at the mechanic workshop has THC level in the order; A1>A3>A2. The concentration of THC obtained in the three points were greater than the 0.6 mg/Kg limit of total hydrocarbons content allowed by the DPR. The study revealed that the soils were polluted as a result of indiscriminate disposal of waste petroleum products (used engine oil, petrol, diesel and other lubricants) directly on the soil, as well as dumping and burning of waste at the auto-mobile mechanic workshops. Hence, there is need for a holistic and sustainable monitoring and remediation of the environment for a cleaner and healthier environment.