A century of oil and gas exploration in Albania: Assessment of Naturally Occurring Radioactive Materials (NORMs)

摘要

The Naturally Occurring Radioactive Materials (NORMs) that are potentially generated from oil and gas\udextractions in Albania have been disposed of without regulations for many decades, and therefore, an\udextensive survey in one of the most productive regions (Vlora-Elbasan) was performed. A total of 52\udgamma ray spectrometry measurements of soil, oil-sand, sludge, produced water and crude oil samples\udwere performed. We discovered that relatively low activity concentrations of 226Ra, 228Ra, 228Th and 40K,\udwith concentrations of 23 ± 2 Bq/kg, 23 ± 2 Bq/kg, 24 ± 3 Bq/kg and 549 ± 12 Bq/kg, respectively, came\udfrom the oil-sands produced by the hydrocarbon extraction of the molasses formations. The mineralogical\udcharacterizations and the 228Ra/40K and 226Ra/40K ratios of these Neogene deposits confirmed the predictions\udof the geological and geodynamic models of a dismantling of the Mesozoic source rocks. The\udaverage activity concentrations (±standard deviations) of the radium isotopes (226Ra and 228Ra) and of\udthe 228Th and 40K radionuclides in soil samples were 20 ± 5 Bq/kg, 25 ± 10 Bq/kg, 25 ± 9 Bq/kg and\ud326 ± 83 Bq/kg, respectively. Based on the measurements in this study, the future radiological assessments\udof other fields in the region should be strategically planned to focus on the oil-sands from the\udmolasses sediments. Disequilibrium in the 228Ra decay segment was not observed in the soil, sludge or\udoil-sand samples within the standard uncertainties. After a detailed radiological characterization of the\udfour primary oil fields, we concluded that the outdoor absorbed dose rate never exceeded the worldwide\udpopulation weighted average absorbed dose rate in outdoor air from terrestrial gamma radiation.