This study provides a comprehensive environmental assessment of three oil-affected sites in Bayelsa State, Nigeria, Oloibiri, Ikarama, and Agudama, by analysing total petroleum hydrocarbons (TPH), nutrient levels, heavy metals, and key physicochemical parameters. Field surveys were conducted using the quadrat sampling method. A distinct pollution gradient was observed, with Ikarama being the most contaminated site (TPH ≈ 5,150 mg/kg; Fe = 5.01 mg/L; PO₄³⁻ = 20.01 mg/L), followed by Oloibiri, while Agudama showed the least impact. Several parameters, including Fe, NH₄⁺, NO₃⁻, total dissolved solids (TDS), and electrical conductivity, exceeded the environmental safety thresholds set by the World Health Organisation (WHO) and Nigerian Industrial Standards (NIS). Statistical analysis confirmed significant differences among the three sites (p < 0.05), underscoring the substantial impact of oil contamination on water and soil quality. The findings indicate that contamination levels are closely tied to human activities and provide valuable insights into the resilience and adaptive capacity of native plant species in these environments. To foster ecosystem recovery, it is recommended to engage in small-scale planting of tolerant species, alongside community training programs to enhance awareness of the ecological significance of these plants in soil restoration. Priority interventions are essential in Ikarama and Oloibiri, where elevated levels of Fe, NH₄⁺, and TPH pose the greatest environmental risks. Suggested remediation strategies include bioremediation, phytoremediation, and soil washing. Ultimately, this research establishes a crucial baseline for assessing plant community structures and pollutant-tolerant species, offering scientific guidance for ecosystem recovery efforts. restoration and phytoremediation strategies in the Niger Delta.