Abstract
This study presents a comprehensive radiological characterization of petroleum-derived NORM waste collected from engineered landfill cells at a major petroleum production facility. High-resolution gamma spectrometry was employed to quantify the activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K, which exhibited wide variability among samples and frequently exceeded internationally recommended limits. The exceptionally elevated ²³²Th and ²²⁶Ra concentrations resulted in significantly high absorbed dose rates in air (ADR). Annual effective doses (AED), and excess lifetime cancer risks (ELCR), that indicating substantial occupational and environmental hazards. Correlation analyses revealed a strong geochemical association between ²²⁶Ra and ²³²Th, consistent with the behavior of TE-NORM residues in the petroleum operations. Comparative evaluation with global datasets further demonstrated that the studied waste ranks among the highly contaminated categories were reported worldwide. The findings underscore the urgent need for rigorous monitoring, strict regulatory compliance, and targeted remediation, including chemical leaching, while supporting the controlled reused of low-activity waste under stringent radiological safety criteria.