Authors: Paago, J.B. and Oborie, E.
Abstract
An assessment of soil and groundwater quality in the oil spill affected parts of Agbura, Bayelsa State, Nigeria, was carried out to evaluate the concentration of key physicochemical parameters and determine the level of contamination
in the area. Soil and groundwater samples were collected from five boreholes drilled to 6m depth at distances ranging from 100m to 500m from the primary oil spill site. Results of laboratory analysis indicate that the groundwater pH and electrical conductivity (EC) were within World Health Organisation (WHO) and Environmental Guidelines and Standards for the Petroleum Industry in Nigeria (EGASPIN) limits with values ranging from 6.1 to 6.9 and 37.45to257.38μS/cm respectively. Turbidity was higher than the recommended standard, and biochemical oxygen
demand (BOD) exceeded acceptable limits across all samples. Total petroleum hydrocarbon (TPH) levels varied from 0.2310 to 0.9382 mg/l, with values at the impact site significantly above regulatoryvalues. Heavy metals such as
Fe and Pb were found in concentrations surpassing recommended limits in most of the samples analysed. The water quality index (WQI) revealed that thegroundwater quality deteriorated closer to the spill site, with samples from the impact site classified as “unsuitable” and”poor,” while samples away from the spill site were classified as “good.” Soil analysis showed TPH concentrations that ranged from 0.294 to 1.0661 mg/kg, with levels decreasing with depth and distance from the spill site. Other heavy metals showed variable contamination patterns, influenced by proximity to the spill. These findings highlight significant contamination of groundwater and soil, particularly near the spill site, emphasizing the need for continuous monitoring and remediation efforts in the study area.