Ecotoxicological Dynamics of the Coastal Soil Ecosystem of Oil Producing Regions of Ondo State, Nigeria

摘要

The industrial revolution marked the beginning of unprecedented anthropogenic growth and technological advancement that also inadvertently led to acute environmental degradation. This technological advancement was driven by the use fossil fuels such as crude oil. Crude oil extraction through drilling has resulted in widespread environmental pollution and deterioration of natural habitats. The Ondo State region in Nigeria presents one such expanse where large scale crude extraction operations have caused hazardous environmental pollution and toxic substance contamination. This study is a comprehensive and holistic study of the terrestrial soil ecosystem aimed towards elucidating the potential ecotoxicity that may have adversely affected the area. The results indicated that the terrestrial soil ecosystem was largely acidic (~pH6) and the organic matter content ranged from 6% to 12% indicating the soil was hydric. The results also indicated that the terrestrial soil environment was contaminated with toxic heavy metals including cadmium (Cd), chromium (Cr), lead (Pb) and arsenic (As). The toxic heavy metal concentration of the soil ecosystem was higher during the dry season. The Cr concentration in the soil samples was >3 ppm in most of the sampling sites, which exceeded WHO maximum permissible limit. Mean concentrations of the heavy metals in the soil samples in both seasons were of the order: Cr > Pb > Cd > As. The soil ecosystem was also characterized by a diverse and large population of microorganisms including bacteria like Enterobacter, Escherichia coli, and several species of fungi.