Determination of the physico-chemical properties and selected heavy metal concentration in soils around Kolo creek oil well head in Bayelsa State, Nigeria

Abstract

Environmental impact of crude oil exploration and exploitation has become worrisome leading to the discharge of toxic elememts into the environment. Soils samples obtained from Kolo Creek oil well head 22T in Bayelsa State, Nigeria were analysed for their physic-chemical properties using standard analytical methods while the heavy metals (Co, Cr, Ni, Pb, Fe and Cu) were analysed using Atomic Absorption Spectrometer (AAS). The results obtained for the physic-chemical properties such as pH, electrical conductivity and total carbon ranged from 7.70±0.006 to 8.20±0.06, 24.00±0.58 to 37.00±0.58 µS/cm and 0.28±0.01. to 0.39±0.01% respectively while the selected heavy metal levels (in mg/kg) ranged from BDL to 967±0.33(Co), 12.33±0.33 to 38.66±0.88(Cr), 11.33±0.33 to 15.66±0.33 (Ni), 31.33±0.33 to 173.66±0.33 (Pb), 15123.67±0.33 to24211.33±0.33 (Fe) and 11.33±0.88 to 21.33±0.88(Cu). These results showed that iron had the highest concentration while cobalt lowest. The levels of heavy metals in this study area were below the DPR maximum allowable limits for these heavy metals in Nigeria soils. However, the amount of lead in the top ad middle soil were higher than the Department of Petroleum Resources (DPR) target value but lower than the intervention value. Hence, there is need for regular monitoring of the crude exploration activities in Bayelsa state to prevent direct discharge of untreated effluents containing heavy metals into the environment. Furthermore, constant maintenance of the oil pipelines and well heads to prevent corrosion is recommended to help avert this environmental menace.