Effect of crude oil spillage on chemical properties of soils of moran and duliajan oil fields of Assam

Crude oil spillage is a regular phenomenon in the oil drilling sites and due to raining and flooding the spilled oil spread to the nearby cultivated field causing soil pollution and considerable reduction in the crop yield. Therefore, present investigation aimed to study the effect of crude oil spillage on chemical properties of soils of two major oil fields in Assam, India viz. MFN oil field, Moran and Kathalguri, HYR, Duliajan oil field. Five soil samples were collected in triplicates at an interval of 50 m from three directions (E, W& S) from the spilled areas upto 200 m horizontally and one sample from each direction was collected from adjacent unpolluted areas i.e. beyond 200 m as control. Standard analytical procedures were followed to determine soil pH, EC, organic carbon, total petroleum hydrocarbon, available nutrients, and exchangeable elements. Results revealed pH of the soils remarkably dropped towards spillage point making the soil strongly acidic in nature whereas the organic carbon content increased near the point of spillage in both oil fields. The total petroleum hydrocarbon (TPH) was recorded maximum at spillage point in both Moran and Duliajan oil fields and was negligible beyond 200m. The available N and P₂O₅ were low near the spillage point and substantially increased with distance. Conversely, available K₂O, exchangeable Ca²⁺ and Mg²⁺ significantly increased near the spilled point.

Highlights

• Chemical properties of agricultural soil nearby the oil fields were highly affected by presence of crude oil and detrimentally effected soil fertility status making it unfit for cultivation.