Environmental and Health Impacts of Petroleum-Derived Pollutants in Ughelli South, Delta State, Nigeria: Chemical Characterisation, Toxicological Evaluation, Mathematical Modelling, and Public Health Analysis

Source abstract

Petrol exploration and production may lead to large-scale environmental pollution and human exposure to harmful pollutants. The objective of this research was to evaluate petroleum-related environmental contamination, exposure pathways, health risks, and health outcomes among the inhabitants of Ughelli South, Delta State, Nigeria. Samples of soil, groundwater, surface water, sediment, and air environment were tested for physicochemical properties, total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAHs), air pollutants, and heavy metals. Contamination indices, food-chain transfer, and non-carcinogenic and carcinogenic risks were calculated. Health questionnaires, clinical measurements and urinary biomarkers were used to evaluate the participants. Independent predictors of selected health outcomes were determined in multivariable logistic regression. Environmental contamination: a linear increase was found with increasing exposure intensity. The high-exposure zone had significantly higher concentrations of both TPH and PAHs, as well as heavy metals, PM₂.₅, PM₁₀, NO₂ and VOCs compared to the low-exposure zone. Additionally, locally consumed fish and crops were found to be contaminated, suggesting possible exposure through the food chain. The adult cumulative hazard indices were 9.83, 4.20, and 1.21, and the child indices were 17.71, 7.43, and 2.17 for the high-, moderate-, and low-exposure zones, respectively. High-exposed residents reported significantly higher rates of respiratory, dermatological, and other systemic symptoms. There was also an increase in urinary 1-hydroxypyrene and trans,trans-muconic acid levels. High exposures independently predicted multiple concurrent symptoms (AOR=4.73), whereas exposures to PM, NO₂, groundwater TPH, and urinary 1-hydroxypyrene predicted individual dimensions of health effects. The petroleum contamination in Ughelli South is accompanied by significant environmental degradation and high health risks and exposure indicators, highlighting the need for exposure reduction, biomonitoring, continuous public health surveillance, and remediation.