Determination of naturally occurring radioactive materials (NORM) in formation water during oil exploration

The present study is conducted, in order to contribute to a future waste management policy related to the presence of technologically enhanced natural occurring radioactive material (TENORM) in Iran petroleum industry. Samples were collected from offshore oil company for analysis of ²³⁸U, ²³⁵U, and ²³²Th series in produced waters. The activities of samples were determined by high-purity germanium detector, well for lowlevel activity γ-spectrometry. The results have shown that, ²²⁶Ra concentration ranges from 5.26 Bq/L to 27.93 Bq/L. Also the total activity in produced water is in the range of 16–840 Bq/L were mainly due to enhanced levels of dissolved ²²⁶Ra, ²¹⁴Pb, ²¹⁴Bi ions. Also, enhanced dissolution of elements such as radium by increasing of salinity, result in higher concentration of NORM in old oil region. Measured values are above EPA regulation (40 CFR 141055) & aqueous Derived Release Limit (DRL) of Canadian guideline for the management of (NORM). Therefore produced water has to dispose in pits which have to design for decrease the environmental effects. Also according to this study, re-injection of produced water in to abandon well of Iran Offshore Oil Company in Persian Gulf, have preference over discharging to the pits.     

Leachability of naturally occurring radioactive materials

Summary Naturally occuring radioactive materials (NORM) are present in the environment and can be concentrated by technical activities, particularly those involving natural resources. These NORM deposits are highly stable and very insoluble under environmental conditions at the earth's surface. However, reducing or oxidant conditions or pH changes may enable a fraction of naturally occurring radionuclides to eventually be released to the environment. In this paper the leachability of²¹⁰Pb and²¹⁰Po was determined in three samples coming from a refractories production plant (dust, sludge, finished product), in one dust sample from a steelwork and in one ash sample coming from an electric power station. A sequential extraction method consisting of five operationally-defined fractions was used. The average leaching potential observed in the samples from the refractory industry is very low (mean values: 5.8% for²¹⁰Pb and 1.7% for²¹⁰Po). The²¹⁰Pb and²¹⁰Po leachability increases for the ash sample coming from an electric power plant using carbon (17.8% for²¹⁰Pb and 10.0% for²¹⁰Po); for the dust sample coming from a steelwork, the percent soluble fraction is 41.1% for²¹⁰Pb and 8.5% for²¹⁰Po. For all samples the results obtained show that²¹⁰Pb is slightly more soluble than²¹⁰Po.     

Radiological dose assessment of naturally occurring radioactive materials in concrete building materials

Previous studies have shown that the natural radioactivity contained in building materials have significantly influenced the dose rates in dwelling. Exposure to natural radiation in building has been of concerned since almost 80 % of our daily live are spend indoor. Thus, the aim of the study is to assess the radiological risk associated by natural radioactivity in soil based building materials to dwellers. A total of 13 Portland cement, 46 sand and 43 gravel samples obtained from manufacturers or bought directly from local hardware stores in Peninsular of Malaysia were analysed for their radioactivity concentrations. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the studied building materials samples were found to be in the range of 3.7–359.3, 2.0–370.8 and 10.3–1,949.5 Bq kg^?1 respectively. The annual radiation dose rates (μSv year^?1) received by dwellers were evaluated for 1 to 50 years of exposure using Resrad-Build Computer Code based on the activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K found in the studied building material samples. The rooms modelling were based on the changing parameters of concrete wall thickness and the room dimensions. The annual radiation dose rates to dwellers were found to increase annually over a period of 50 years. The concrete thicknesses were found to have significantly influenced the dose rates in building. The self-absorption occurred when the concrete thickness was thicker than 0.4 m. Results of this study shows that the dose rates received by the dwellers of the building are proportional to the size of the room. In general the study concludes that concrete building materials; Portland cements, sands, and gravels in Peninsular of Malaysia does not pose radiological hazard to the building dwellers.     

Measurement of radioactive samples in Marinelli beakers by gamma-ray spectrometry

Radioactivity measurement of environmental samples is frequently assayed by gamma-ray spectrometry using Marinelli beakers. In this work, self-absorption and coincidence summing effects arising in activity measurements for Marinelli beaker geometry have been studied with a Ge detector. Three types of Marinelli beakers which have capacities of 450 mL, 1 L, and 2 L were developed. Self-attenuation effects for density variation of radioactive samples in each type of the Marinelli beakers were measured as a function of gamma-ray energy, and also the results were compared with calculated values by mathematical model. Meanwhile, the coincidence summing effects of¹²⁵Sb and¹⁵⁴Eu nuclides were obtained from the determination of the full-energy peak and total efficiencies for a Ge detector.     

Study of naturally occurring radioactive material (NORM) in top soil of Punjab State from the North Western part of India

The concentration levels of ²³⁸U, ²³² Th, ⁴⁰K and ¹³⁷Cs in top soils of State of Punjab located in the North Western part of India were measured using conventional low background gamma ray spectrometric setup as well as Compton suppressed gamma ray spectrometric setup. The radioactivity level of ²³⁸U and ²³²Th was found to vary between 15 Bq/kg and 27 Bq/kg and between 16 Bq/kg and 57 Bq/kg respectively. The radioactivity level of ⁴⁰K was found to vary between 266 Bq/kg and 799 Bq/kg. The mean radioactivity level of the NORM in general was found to be similar to what is expected as a result of their normal abundance.     

In situ gamma spectrometry of terrestrial naturally occurring radioactive materials and radiation hazard assessment of Kebbi State,Nigeria

Journal of Radioanalytical and Nuclear Chemistry - Environmental monitoring was performed in order to measure the activity concentrations of U-238, Th-232 and K-40. In situ gamma spectrometric...     

Radiometric analysis of some building materials using gamma-ray spectrometry

Journal of Radioanalytical and Nuclear Chemistry - The present study focuses on the effect of natural radioactivity of some common building materials to humans. The main radiological risk...     

An in situ method for remediating 137Cs-contaminated wetlands using naturally occurring minerals

Cesium's enhanced bioavailability in contaminated wetlands onthe U.S. Department of Energy's Savannah River Site (SRS) is thoughtto be due to the low clay fraction of SRS soils, and that the clay mineralogyis dominated by kaolinites. Remediation of the wetlands is problematic becausecurrent technologies are destructive to the sensitive ecosystems. We tested11 clay minerals (two micas, a vermiculite, six illites, a kaolinite, anda smectite) for their propensity to sorb and retain ¹³⁷Cs. Twominerals were subsequently chosen as candidates for in situ remediation amendmentmaterials because they had ¹³⁷Cs distribution coefficients (K d) well in excess of 10,000 ml . g –1 , and desorbed less than 20% ofthe Cs when mixed in a 0.1M NH 4 Cl solution. Incremental additions of thecandidate minerals to ¹³⁷Cs-contaminated sediments appreciablyintercepted and retained desorbed ¹³⁷Cs in the presence of highlevels of NH₄ . Implications for using the minerals as a nondestructive,in situ remediation technique are discussed.     

Adsorption of technetium on selected inorganic ion-exchange materials and on a range of naturally occurring minerals under oxic conditions

The adsorption of Tc^95m, as TcO₄⁻, on a weakly basic organic ion-exchange resin was studied as a function of pH in 0.1M solutions of Na₂SO₄, NaCl and NaNO₃. A similar study was performed with the adsorbents ZrO₂ and Al₂O₃. In addition, adsorption on ZrO₂ was investigated in 0.01 and 0.25M NaCl. An unusual pH profile of the distribution coefficient was found for the polymer, [(CHg₃O)Cl]_n in 0.1 and 1M NaCl and 0.1N Na₂SO₄, in as much as the D values increased with pH rather than decreased as was observed in all prior examples. In a number of selected systems, the adsorption of I¹³¹, as I⁻, was studied to aid in the characterization of the mechanisms.In addition, the adsorption properties of 37 minerals with respect to TcO₄⁻ were investigated in 0.1M NaCl as a function of pH. For the minerals, montmorillonite, illite, kaolinite and monazite this work was expanded to include 0.01, 1.0 and 4.0M NaCl solutions. In general, the distribution coefficients observed under the oxic conditions employed here were small and could be adequately accounted for by an ion-exchange mechanism.     

Validation of the quantification of natural radionuclides in raw materials and by-products using gamma-ray spectrometry

The validation of a method for the indirect quantification for ²³⁸U, ²²⁶Ra, and ²³²Th activity and the direct quantification for ⁴⁰K activity using gamma-ray spectrometry was performed in view of consistency, reliability, and accuracy of the results. The gas tightness of Al containers used to confine the radon gas was verified from the establishment of the secular equilibrium between ²²⁶Ra and its indicator. To evaluate validation parameters such as linearity, range, and accuracy, it was important to verify the equilibrium state of the reference materials (RM) for U and Th, because the ingrowth of progenies in the uranium decay series can affect the quantification of ²²⁶Ra activity even if based on a certified reference material (CRM), while the ingrowth of ²²⁸Ra from the thorium decay series should be secured in order to use ²²⁸Ac as an indicator of ²³²Th. In addition, the ruggedness of the method regarding different materials was checked using two kinds of CRM, namely bauxite as an example of a raw material and coal fly ash as a by-product.     

Analyses of radionuclides in the Oued Awlitis 001 and Galb Inal lunar meteorites by HPGe gamma-ray spectrometry

Highly sensitive nondestructive HPGe gamma-ray spectrometry was used for the analysis of the cosmogenic (²⁶Al) and primordial (⁴⁰K, ²³⁸U, and ²³²Th) radionuclides in the Oued Awlitis 001 and Galb Inal lunar meteorites. The measured ²⁶Al activities were very different (84.0?±?4.8 dpm/kg vs. 8.4?±?1.2 dpm/kg, respectively), mainly because of different cosmic-ray exposure ages of the investigated meteorites. The pre-atmospheric radii were 5?±?1 cm and 11?±?2 cm, respectively, which would result in total pre-atmospheric masses in the range of 0.7–2.5 kg and 7–23 kg, respectively.

     

Crystal structure of naturally occurring mercury(II) amidonitrate

A naturally-occurring mercuroammonium compound from Pitkin County, Colorado, is shown to be the natural analog of synthetic HgNH₂NO₃. The crystals are isometric, P4₁32 or P4₃32, with a = 10.254(1)Å and twelve formula weights per cell. Using 437 symmetry-independent reflections, the crystal structure was partially determined and refined to a residual of 0.090. The positions of the Hg atoms and the N and O atoms of the nitrate group were determined, but the amide ion could not be located, probably due to positional disorder. The structure contains mercury atoms arranged in equilateral triangles 3.421(1) Å on a side. These triangles are linked through shared vertices into helical chains wound around the fourfold screw axes. Similar triangular units occur in other inorganic Hg(II) compounds. The distortion of the nitrate ion from trigonal planar symmetry is also discussed.     

Chromium(III) complexes of naturally occurring amino acids

Summary Amino acid complexes of CrCl₃Py₃ have been prepared and studied by elemental analysis, magnetic susceptibility, vibrational (i.r.), electronic and circular dichroism spectroscopy. Two peaks in the visible spectra are assigned to a d-d transition in pseudo octahedral symmetry. The spectrochemical parameters (Dq, B and ₃₅) for the complexes were calculated which confirm that pyridine nitrogen and/or chlorine are not removed. Prolonged heating or bubbling of air through the solution of CrCl₃-Py₃ containing l-(-)-histidine or l-(-)-threonine for several hours enhanced formation of chromium (VI).     

Determination of macroconstituents and trace elements in naturally occurring radioactive material in oil exploration waste products

Naturally occurring radioactive materials (NORM) contain radionuclides, such as radium, thorium, and uranium. The existence of NORM remains an issue for oil and gas exploration because once the material becomes concentrated through technological activity, it becomes a radioactive contamination hazard or a radioactive waste. Pipes and tanks used to handle large volumes of produced water at some oil-field sites are coated with scale deposits that contain high levels ²²⁶Ra, ²²⁸Ra and ²¹⁰Pb. Experiments were conducted using thermal and epithermal neutron activation analysis and Compton suppression for the determination of macroconstituents and trace elements in the radioactive scale sample.     

Environmental monitoring of134Cs in beach sand using a coincident spectrometer

Environmental samples of beach sand taken at northern Taiwan have been monitored using a coincident gamma-ray spectrometer. The concentration of¹³⁴Cs, under intense interference from natural and other artificial radioactivity, is determined as low as 0.2 Bq/kg dry. The accumulation of trace levels of¹³⁴Cs originates from the discharge of nuclear power plants nearby.     

First synthesis of naturally occurring (±)-epi-conocarpan

(±)-epi-Conocarpan 1 was synthesized via the key intermediate 5-bromo-cis-2-(4-methoxyphenyl)-3-methyl-2,3-dihydrobenzofuran 6 which was synthesized by a ruthenium(II) porphyrin-catalyzed intramolecular C-H insertion reaction using aryl tosylhydrazone salt 5 as the carbene source, starting from the commercially available 5-bromo-2-hydroxyacetophenone.     

Determination of naturally occurring formaldehyde levels in sap and wood tissue of maple trees using gas chromatgraphy/mass spectrometry

The occurrence of formaldehyde in sap and wood tissue of treated and untreated maple sugar trees was investigated using GC/MS. Samples were collected at different periods of the 2009 season and at different locations in Quebec, Canada. The natural concentration of formaldehyde found in untreated samples varied according to periods and locations and ranged from below the LOQ to 1.82 mg/kg for sap samples and from 2.39 to 8.92 mg/kg of fresh tissue for wood samples. Late season samples tended to have higher concentrations of formaldehyde. Samples of sap and wood tissue from tapholes treated with solutions of formaldehyde showed increased concentrations of formaldehyde for many days after treatment and were clearly distinct from untreated samples. These results will be useful to elaborate new inspection procedures for sugarbushes to control the illegal use of formaldehyde.     

Determination of iodine in biological materials by pseudo-cyclic epithermal INAA using anti-coincidence gamma-ray spectrometry and estimation of expanded uncertainties

Epithermal instrumental neutron activation analysis (EINAA) technique in conjunction with anti-coincidence gamma-ray spectrometry (AC) has been applied for the determination of ppm to ppb levels of iodine in biological materials containing high levels of Al, Br, Cl, K, Mn, and Na. Both conventional EINAA-AC and pseudo-cyclic EINAA-AC (PC-EINAA-AC) methods using a combination of Cd and B filters have been developed using Dalhousie University SLOWPOKE-2 reactor (DUSR) facility. The expanded uncertainties (EU), at about 95% confidence level, for iodine in biological materials by EINAA-AC varied between 6 and 10%. The advantages of the non-destructive PC-EINAA-AC method has been successfully demonstrated by analyzing the NIST Pine Needles (SRM 1575) containing a low amount of iodine in presence of high quantities of Mn and other interfering elements where an iodine content of 92.8 μg kg⁻¹ with an EU of 6.1 μg kg⁻¹ and a detection limit of 40 μg kg⁻¹ has been obtained at the end of fourth cycle.