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

Because potential Naturally Occurring Radioactive Materials (NORMs) generated from oil and gas extractions in Albania have been disposed without regulatory criteria in many decades, an extensive survey in one of the most productive regions (Vlora-Elbasan) has been performed. Among 52 gamma-ray spectrometry measurements of soil, oil-sand, sludge, produced water and crude oil samples, we discover that relatively low activity concentrations of 226Ra, 228Ra, 228Th and 40K, which are 23 +/- 2 Bq/kg, 23 +/- 2 Bq/kg, 24 +/- 3 Bq/kg and 549 +/- 12 Bq/kg, respectively, come from oil-sand produced by hydrocarbon extraction from molasses formations. The mineralogical characterization together with the 228Ra/40K and 226Ra/40K ratios of these Neogene deposits confirm the geological and geodynamic model that predicts a dismantling of Mesozoic source rocks. The average activity concentrations (+/- standard deviations) of the radium isotopes (226Ra, 228Ra) and of the 228Th and 40K radionuclides in soil samples are determined to be 20 +/- 5 Bq/kg, 25 +/- 10 Bq/kg, 25 +/- 9 Bq/kg and 326 +/- 83 Bq/kg, respectively. Based on these arguments, the future radiological assessment of other fields in the region can be strategically planned focusing on the oil-sands from molasses sediments. No disequilibrium in the 228Ra decay segment has been observed in soil, sludge and oil-sand samples within the standard uncertainties. After a detailed radiological characterization of the four main oilfields, we can conclude that the outdoor absorbed dose rate never exceeds the worldwide population weighted average absorbed dose rate in outdoor air from terrestrial gamma radiation.Comment: 21 pages, 5 figures, 2 tables, Chemosphere 201

Radiometric Mapping for Naturally Occurring Radioactive Materials (NORM) Assessment in Mamuju, West Sulawesi

Mamuju has been known to have high radiation dose rate which is comes from NORM in rock and soil. Major concern is due to its location which is near inhabitant settlement area. Preliminary research has been done by environmental team which is limited to main access road only, while some remote area has left untouched. The purpose of the research is to delineate the location and distribution of thorium and uranium anomaly in Mamuju, and also to provide adequate information regarding the anomaly and high dose rate area to decision makers and stakeholders in neither local nor central government. Method applied is radiometric mapping using spectrometer RS-125 with NaI(Tl) detector in the area of interest Geological Formation of Adang Volcanic, which is more than 800 square km in size. The radiometric mapping method is widely used in uranium/thorium exploration, and now has been added with the measurement of radiation dose rate which is appropriate to environmental surveys. The mapping has been successfully delineated the area of NORM or the area with thorium and uranium anomaly. Thorium and uranium anomaly identified related with multi-geological-process resulting the increase of grade into several fold from its original state.Received: 08 November 2013; Revised: 20 February 2014; Accepted: 10 March 201

Radiometric Mapping for Naturally Occurring Radioactive Materials (NORM) Assessment in Mamuju, West Sulawesi

Mamuju has been known to have high radiation dose rate which is comes from NORM in rock and soil. Major concern is due to its location which is near inhabitant settlement area. Preliminary research has been done by environmental team which is limited to main access road only, while some remote area has left untouched. The purpose of the research is to delineate the location and distribution of thorium and uranium anomaly in Mamuju, and also to provide adequate information regarding the anomaly and high dose rate area to decision makers and stakeholders in neither local nor central government. Method applied is radiometric mapping using spectrometer RS-125 with NaI(Tl) detector in the area of interest Geological Formation of Adang Volcanic, which is more than 800 square km in size. The radiometric mapping method is widely used in uranium/thorium exploration, and now has been added with the measurement of radiation dose rate which is appropriate to environmental surveys. The mapping has been successfully delineated the area of NORM or the area with thorium and uranium anomaly. Thorium and uranium anomaly identified related with multi-geological-process resulting the increase of grade into several fold from its original state.Received: 08 November 2013; Revised: 20 February 2014; Accepted: 10 March 201

Application of Geophysics for Quick Determination of Deposit in Mineral Exploration - A Case Study

The Balatindi Mineral Prospect, Guinea, is a multi-element mineral prospect that hosts commercial quantities of gold, uranium and copper. A major challenge for exploration activities within the area is the turnaround time for assay results due to the unavailability of a nearby assay laboratory and the high cost of analysis. This therefore delays assay results which are needed for quick decisions during field work. There is therefore the need to find a faster and cheaper way of delineating mineral anomalies. Magnetic and radiometric geophysical techniques were considered because of the rapid and cost-effective ways in which data is acquired and they yield substantial quantity of accurate data enhancing interpretation and deduction. Down hole drill data for 37 HQ size diamond drilled holes of about 9200 m were used for the analysis. Magnetic susceptibility data were secured from 24 drill hole data for the Central Polymetallic Prospect  area, whiles radiometric data were taken for the 23 drill holes in the other areas. The data were correlated with the laboratory assay results for gold and uranium respectively.  Strip logs and statistical analysis were used to interpret magnetic susceptibility readings against gold assay values, and radiometric readings against uranium assay values. Maximum and minimum values of -2.46 × 10-3 and 546.5 × 10-3 magnetic susceptibility were respectively recorded whiles 45 cps and 7250 cps were the maximum and minimum radiometric readings obtained. Magnetic susceptibility values did not show any preferential correlation with gold mineralisation.  Radiometric cps values showed a very strong direct correlation with uranium mineralisation. This is because the radiometric cps is a function of the radiometric mineral present and therefore, radiometric survey can be used as a faster and cost-effective way of delineating uranium anomaly within the Balatindi prospect. Keywords: Balatindi, Magnetic susceptibility, Radiometric count, Multi-element mineral deposit. DOI: 10.7176/JNSR/11-18-04 Publication date:September 30th 202

Determination of Natural Radioactivity Levels due to Mine Tailings from Selected Mines in Southwestern Uganda

The aim of this study was to determine the natural radioactivity levels of primordial radionuclides in soil mine tailings from selected mines in Southwestern Uganda. This was achieved by analyzing thirty six samples of soil mine tailings from three mining sites using NaI(Tl) gamma ray spectrometer. The specific activity concentrations of 238U (Uranium), 232Th (Thorium) and 40K (Potassium-40) in the samples were computed. The specific activity concentrations varied from 35.5 to 147.0 Bq kg-1 for 238U, 119.3 to 376.7 Bq kg-1 for 232Th and 141.0 to 1658.5 Bq kg-1 for 40K. The outdoor absorbed dose rates in air 1.0 m above the ground level were determined. The mean absorbed dose rates for Mashonga Gold Mine, Kikagati Tin Mine and Butare Iron Ore mine were 181.2±66.8 nGy h-1, 167.2±43.0 nGy h-1 and 191.6±29.6 nGy h-1 respectively which are more than three times the world wide average value of 59 nGy h-1. The mean outdoor annual effective dose rates for the three mines were 0.37±0.14 mSv y-1, 0.34±0.09 mSv y-1 and 0.39±0.06 mSv y-1 respectively which are more than five times the world average value of 0.07 mSv y-1. Thus the mine tailings (soil) from these areas must not be used as major building material to minimize radiological hazards. Key words: Activity concentration, Gamma index, Soil mine tailing

Distribution of radionuclides and assessment of risk exposure to the miners on a kaolin field

Mining of kaolin deposits are common in Nigeria without considering the background radiation in such environment and the health risks it might pose on the miners. In this study, in-situ measurements of the naturally occurring radionuclides were carried out with the aim of determining the distribution of these radionuclides on the mining field and estimation of the hazard indices exposure risks (γ- and α-radiation risks) to the miners. The study was achieved with the aid of gamma ray detector Super-Spec (RS-125) and global positioning system. The detector used has ability to measure activity concentrations of 238U, 232Th and 40K and gamma doses. For the purpose of this study, only the concentrations of the three radionuclides were considered. For each location, measurements were taken four times, while its mean value was estimated for better accuracy. In all, nineteen locations were occupied in order to cover the study area. Basic kriging method was adopted for the production of spatial distribution of these radionuclides and their corresponding γ- and α-radiation hazard indices. The mean values of 238U, 232Th and 40K are 46.7, 71.8 and 108.7 Bq kg-1 , respectively. When compared to the global standard, it was revealed that 238U and 232Th are greater than the global standard, while 40K fall below the permissible limit. The γ- and α-radiation exposure risks estimated revealed that the mean values of Iγ and Iα are 0.6 and 0.2 respectively. Though the estimated γ- and α-radiation indices showed that the kaolin field is safe for the miners, periodic check is required in order to monitor the rate at which these natural primordial radionuclides (238U and 232Th and their progenies) are being enhanced

Terrestrial Gamma Radiation in Phuket Island, Thailand

The aim of this study was to evaluate the level of terrestrial radioactivity on Phuket Island, which used to be the richest tin province in Thailand. We measured 124 survey points of terrestrial gamma dose rate at one meter above the surface of local soil along roads in the environs of Phuket Island. Another 31 survey points were examined inside an old ore-dressing plant. The terrestrial gamma dose rate of the Island (excluding the abandoned area of the old dressing plant) ranges from 20 to 900 nGy h-1, while the geometric mean Island value was 190 nGy h-1. Soil samples were also collected from selected areas having high gamma dose rates to analyze for activity concentrations of 226Ra, 232Th and 40K. Based on these soil activities, the calculated terrestrial gamma dose rate found to range between 25 and 520 nGy h-1. The corresponding annual effective doses varied between 0.03 and 0.6 mSv y-1. The results of the terrestrial gamma dose rate obtained from direct measurement in the old tin dressing plant ranged from 110-17,170 nGy h-1 with a mean value of 1410 nGy h-1. The terrestrial gamma dose rate calculated from soil samples in the dressing plant ranged from 590 to 206,080 nGy h-1 which corresponding to annual effective dose of 0.7-250 mSv y-1. Thus, the dose rates on much of Phuket Island are within typical background values while the dose rates within the old tin dressing plant are elevated by as much as 16 times background

Activity concentrations of 40K, 232Th, 226Ra and radiation exposure levels in the Tabaka soapstone quarries of the Kisii Region, Kenya

A radiological study was carried out in the soapstone quarries of Tabaka region of Kisii district in the Southern Nyanza province, Kenya, where soapstone has been mined and used as a carving medium for hundreds of years. To achieve this, 14 soil and rock samples collected from five quarries were analyzed using high-resolution gamma-ray spectroscopy. The activity concentrations of 232Th, 40K and 226Ra in the samples as well as other radiological parameters were determined. These ranged from 38.6 to 271.7 Bqkg-1 for 232Th, 43.1 to 360 Bqkg-1 for 226Ra, and 245 to 1780 Bqkg-1 for 40K. The absorbed dose rates were measured 1metre above the ground at each quarry using a Canberra radiagem 2000 model. The average absorbed dose rate for the five quarries was found to be 541.4 nGyh-1 1m above the ground level while the calculated total absorbed dose rates were found to average 177.6 nGyh-1 below the surface. This is about 4 times higher than the world average of 43 nGyh-1. Assuming a 40% occupancy factor, the corresponding annual effective dose rates due to the radionuclides 232Th, 226Ra and 40K in the quarries ranged from 0.215 to 0.875 mSvy-1, with a mean of 0.44 mSvy-1. This corresponds to an excess lifetime cancer risk of 0.07%. The internal and external hazard indices (1.03 and 1.27, respectively) were found to be more than unity, hence slightly exceeding the permissible limits set by the International Commission on Radiation Protection (ICRP). The annual effective dose rate in the quarries was found to be 0.44 mSvy-1 and is less than the 1 mSvy-1 upper limit recommended for the public by the ICRP.Key words: Soapstone, quarries, spectroscopy, absorbed dose, hazard index

Radon exhalation of building materials

>Magister Scientiae - MScPublic concern about all radiation and radon exhalation from building materials has been highlighted recently. The purpose of this study is to address this public concern and to investigate the contribution of building materials to indoor radon levels. As in soil and rocks, radon gas is formed inside the building materials by decay of the parent nuclide 226Ra. It is not possible to determine the radon exhalation rate simply from the activity concentration of 226Ra, instead one must measure radon exhalation rates directly from the surface of the material. 222Rn has been identified as an important factor that could result in a health hazard by studies all around the world. The exhalation experiments were done at the UWC physics department, in the Nuclear Physics Lab. A RAD7 radon detector was used to measure the radon concentration in an air tight chamber that contained various building material samples. The RAD7 records the number of alpha particles with energy of 6.11 MeV which results from the decay of 218Po, the daughter of 222Rn. The RAD7 detector converts counts into Becquerel’s per cubic metre (Bq/m3). The building materials tested were the raw materials used in construction such as two different types of building sand, building stones, coarse aggregate, floor and roof tiles, various granites from across the world that were sourced locally and uranium bearing sandstone originating from a Beaufort-West prospecting site. Stones from this site were used as filler material in the construction of two farm houses. Most building materials were found to have a very low rate of radon exhalation. The only materials that had any significant radon exhalation were 2 granite samples with a maximum exhalation rate of 1.5 Bq.m-2.h-1 and the uranium bearing sandstone. It is safe to say that the overwhelming majority of building materials tested are safe to use but some granites may require further study. The uranium bearing sandstone is a definite radiation protection issue and should not be used in any construction

Selenium and molybdenum enrichment in uranium roll-front deposits of Wyoming and Colorado, USA

Acknowledgements The authors wish to thank Cal VanHolland, Jim Bonner and John Cooper of Ur-Energy (Casper, Wyoming) for their assistance with sampling, data provision and feedback. We are grateful to Adrian Boyce and Alison McDonald of the Isotope Community Support Facility at SUERC for technical support with isotope sample preparation and analyses. Critical comments that greatly improved the manuscript from Samuel Spinks and Marat Abzalov are gratefully acknowledged. Funding This research was supported by a grant from the Natural Environment Research Council (NERC) (NE/M010953/1).Peer reviewedPublisher PD