The Impact Of Used Transformer Oil On The Physicochemical Characteristics And Persistent Organic Pollutant Levels In Soils Around Transformer Installation Areas

Transformer oil spillage into the soil, if not properly handled, can lead to ground water and soil pollution, there by posing serious environmental and health threat. The transformer oil contaminated soils around transformer installation areas in Ile-Ife were collected at 0-15 cm and 15-30 cm depths. Soil physicochemical parameters (pH, available phosphorous, soil organic carbon (SOC), NO3-, total nitrogen, calcium, magnesium, potassium, sodium, and cation exchange capacity (CEC)) were analysed using standard analytical techniques). Persistent organic pollutants (POP) were extracted from the soil samples using soxhlet extraction technique, and n-hexane/dichloromethane (4:1, v/v) as the solvent. The extracts were analyzed using Gas Chromatography coupled with mass spectrometer (GC-MS) Detector. The results showed that the mean values of the total nitrogen, available phosphorus and organic carbon of the oil contaminated soils were higher than their critical values; while the NO3-, pH, and CEC values were lower than their critical values. The analysed soils contained higher percentage of sandy soil than clay and silt, which is inherent of the parent rock. The analysis of variance (ANOVA) showed that in terms of depth and sample type there was significant difference in the soil physicochemical parameters. The oil contaminated soils contained large number of alkanes and iso-alkanes, alongside non-carcinogenic. The study concludes that the presence of transformer oil in the contaminated soils altered the soil physicochemical parameters and soil quality, and also introduced a substantial quantity of polycyclic aromatic hydrocarbons (PAHs) into the soils there by exposing the residence and workers to chronic health risk.