An integrated investigation of hydrocarbon pollution in Ahoada area, Niger Delta Region, Nigeria

Abstract

This study investigates hydrocarbon pollution in Ahoada community of the Niger Delta region of Nigeria.The study uses geographic information system (GIS) for mapping oil spill hotspots in the region. Resistivity method was used for delineating the extent of hydrocarbon pollution to a depth of 19.7m at Ahoada area of the region. Three categories of soil samples:impacted soil (IMS), remediated soil (RS) and control soil (CS) were collected and analyzed for the presence of BTEX, PAH, TPH, TOC and TOG. The concentrations of the samples from the IMS and RS were compared to that of the CS to determine the extent of pollution. The GIS mapping shows that the most polluted areas in the Niger Delta Region are Rivers, Bayelsa, and Delta states. Results of the geophysical images revealed contaminants presence to depths beyond 20m at some locations in the study area. The highest depth of contaminant travel was at Ukperede. Soil samples analysis showed that the range of concentrations of TPH in IMS at Oshie was 17.27 -58.36 mg/kg; RS was 11.73 -50.78 mg/kg which were higher than the concentrations of 0.68 mg/kg in the CS. PAH are more prevalent in Ukperede ranging from 54.56 -77.54 mg/kg. BTEX concentrations ranged from 0.02 -0.38 mg/kg for IMP, 0.01 -2.7 mg/kg for RS against CS value of 0.01 mg/kg. Study revealed that there are characteristically high resistivity values in the samples which were corroborated by the ndings from the resistivity survey. TOC was found to be higher in the IMS and RS than in the CS demonstrating that signi cant quantity of the hydrocarbon has undergone appreciable decomposition.

Ecotoxicity Assessment of the Water Extracts from Metal-Contaminated and Hydrocarbon-Contaminated Soils

“…The monoaromatic fraction (BTEX) is a water-soluble hydrocarbon with low octanol: water partition coefficient (K OW ), indicating high polarity, and is classified as a priority toxic pollutant by the US Environmental Protection Agency [86]. The existence of BTEX deserves serious attention as it can have a significant burden on humans and other organisms of the environment through migration to vadose zone and groundwater environments [87,88]. Thus, petroleum hydrocarbon-contaminated soils cause high potential ecological risks and hazardous impacts on humans and other living organisms surrounding the contaminated aquatic and terrestrial ecosystems.…”