Assessment of Physical and Chemical Methods for the Remediation of NORM-Contaminated Soil and Its Generated Radioactive Liquid Waste at the Southern Al-Rumaila Oilfield, Iraq

This study aims to quantify the activity concentrations of 226Ra and 228Ra in Technologically Enhanced Naturally Occurring Radioactive Material (TENORM) contaminated soils from selected sites within the South Rumaila oilfield, Basra Governorate, southern Iraq, and to evaluate physical and chemical remediation options to reduce contamination below IAEA limits. Using High-Purity Germanium (HPGe) gamma-ray spectrometry, the mean activity concentrations were 7.67× 104; ± 1.5% and 6.26× 103 ± 1.43% Bq/kg for 226Ra and 228Ra, respectively (n = 25). Physical separation by particle size and sequential chemical leaching were applied as remediation approaches. The highest leaching efficiencies (78.4% and 80.6% for 226Ra and 228Ra, respectively) were achieved using acetic acid (2M CH3COOH) at a liquid-to-solid ratio of 5:1 mL/g, 40°C, and 2 h contact time. The resulting radioactive leachate was subsequently treated with a MnO2-modified Na2SO4@zeolite-NaA composite adsorbent (mass ratio 1:0.5 g/g, pH 6.3), achieving maximum removal efficiencies of 76.2% and 78.9% for 226Ra and 228Ra, respectively.