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The purpose of the study is to define the level of combined radiological and chemical contamination from the activities of soil and moss samples collected from the Eastern Black Sea region in Turkey and to assess the risk caused by the environmental radioactivity and chemical pollutants. The gamma, gross beta and gross alpha activities were measured in the soil and moss samples. The 238U, 232Th, 40K and 137Cs activity concentrations in the soil samples were measured in the range of 7.0 and 72 Bq kg-1 for 238U, 8.1 and 86 Bq kg-1 for 232Th, 203 and 1190 Bq kg-1 for 40K and 0.71 to 66 Bq kg-1 for 137Cs. In the moss samples, the 137Cs, 40K, 232Th, and 238U activity concentrations were found in the range of 1.03±0.27-24.23±1.39, 137±7-1340±68, 3.58±0.32-5.93±0.44 and 0.88±0.09-2.25±0.23 Bq kg-1, respectively. Contamination from toxic metals in the soils is categorized into enrichment factor, geoaccumulation risk, potential ecological risk and pollution load index. Co, Ni, As and Pb enrichments were determined in the extreme category in the 6 sampling sites. The pollution load index for the selected metals was found to be greater than 1. The geo-accumulation index in one sampling site showed contamination from heavy to severe levels of arsenic and lead. [ABSTRACT FROM AUTHOR]

This work is focused on testing the implementation of k-INAA using Kayzero for Windows and k0-IAEA software packages at the ITU TRIGA Mark II research reactor. The neutron spectrum parameters were determined using the bare triple-monitor method with Au and Zr monitors. The k-INAA performance was tested by analysis of NIST SRMs 2711 Montana Soil and 1547 Peach Leaves. The performance assessment based on the E criterion showed that the concentrations of a number of elements in both NIST SRMs determined by both software packages are in agreement with NIST values. [ABSTRACT FROM AUTHOR]

Twelve samples of lignite from several places and depths of the Kışlaköy open cast mine in the south eastern Turkey were characterized by k-NAA with emphasis on the potentially hazardous elements, such as As, Cd, Co, Cr, Mn, Ni, S, Sb, U. In total 39 elements were determined at least in some of the samples. The results showed a low quality and elemental inhomogeneity of the lignite material, which is used in the nearby thermal power plant. Mean values of element contents were also compared with older data from the same locality and to the world average lignite composition. [ABSTRACT FROM AUTHOR]

The present study involves selenium (IV) adsorption onto organic pillared bentonite using batch experiments and kinetic modeling, at two different temperatures.selenium (IV) remediation in an aqueous environment, such as contaminated drinking water, groundwater, and industrial wastewater, is the aim of this study. The experimental data were tested with both surface reaction-based and diffusion-based kinetic models to clarify the controlling mechanism of the adsorption process from both microscopic and macroscopic point of view. Among all the investigated models, the most appropriate was the pseudo-second-order surface reaction-based kinetics model. The obtained results proved that the adsorption process at a selenium dioxide concentration of 300 mg L−1is controlled by the diffusion rate of penetrated selenium (IV) into the reacted layer. [ABSTRACT FROM AUTHOR]

The aims of the present study were to measure the concentrations of As, Cr, Co, Fe, and Zn in soils from two heavily industrialized areas and to assess the degree of heavy metal pollution by using the indices enrichment factor and the geo-accumulation index, as well as assessing the potential ecological risk. The concentrations of the selected elements in the environmental samples were determined by the neutron activation analysis. The pollutant concentrations in the studied areas showed that the soils were characterized by a high pollution from As and Cr due to the industrial facilities in the area. The concentrations in the Tuzla industrial area were 79–1215 mg/kg of Cr, 17–84 mg/kg of As, 22,000–54,000 mg/kg of Fe, 101–258 mg/kg of Zn, and 8–23 mg/kg of Co. The results for the Cerkezkoy industrial area were found to be 46–196 mg/kg of Cr, 6–24 mg/kg of As, 17,000–25,000 mg/kg of Fe, 67–136 mg/kg of Zn, and 7–10 mg/kg of Co. The contamination in the soils from heavy metals was assessed based on enrichment factor, geo-accumulation factors, and ecological risk indices. The results were compared with the data from other industrial areas in Turkey. It was found that the metals As and Cr showed higher concentrations in Tuzla than in other examined industrial areas. The results for Cerkezkoy industrial area indicate that the area is not as contaminated as the other industrial areas in Turkey. [ABSTRACT FROM AUTHOR]

The objective of this work was to study the sorption of uranium (VI) ions on magnesium oxide (MgO) from aqueous solutions. The MgO has been prepared via hydroxide precipitation followed by thermal decomposition of the hydroxide. MgO was characterized by X-ray powder diffraction, scanning electron microscope, and multipoint Brunauer, Emmett, and Teller. The relative importance of test parameters such concentration of adsorbate, pH, contact time, and temperature on adsorption performance of MgO for U(VI) ion were studied and the optimum sorption efficiency was found as 87.61 ± 3.10%. Desorption tests were also carried out and desorption efficiency was found as 100% with NH4Cl and NaNO3 solutions containing 0.1 M on a single step. Typical sorption isotherms (Freundlich and Dubinin-Raduskevich) were determined for the mechanism of sorption process and thermodynamic constants (Δ H°, Δ S°, and Δ G°) were calculated as −8.738 kJ mol−1, −21.68 kJ mol−1, and 0.102 kJ mol−1 K−1, respectively. © 2011 American Institute of Chemical Engineers Environ Prog, 2011 [ABSTRACT FROM AUTHOR]

A significant pathway for human exposure to environmental pollutants is the metal transfer from soil to plants. In this study accumulation of different metals was investigated and natural radioactivity levels were measured in the soil--thyme system. It was found that the soil had higher concentrations of Br, Cr, Mn, Ni, and Pb than the world average and P, Ca, and Zn had higher transfer factors. The natural radioactivity level in the soils is similar to the World average. For thyme samples the average values for 226Ra, 232Th and 40K were found as 22.7 ± 10.9 Bqkg-1, 61.3 ± 19.9 Bqkg-1 and 722 ± 391 Bqkg-1, respectively. The health and ecological risks of soil were evaluated. The total hazard index of the child was 1.453 on average, greater than that of the adult (0.175), primarily due to the contribution of Cr. Ecological risk assessed based on various indices indicated that Pb and Ni show environmental contamination risk. Our findings confirm that metal concentrations in plants are influenced by metal concentrations in soil, and that metal interactions are important for pollution risk management. [ABSTRACT FROM AUTHOR]

Abstract: Lead borate based glass formulations with high chemical durability and lower melting temperatures compared to the currently used glasses were developed as candidates for the vitrification of radioactive waste. Properties including chemical durability, glass transformation temperature, and melting temperature were analyzed. The chemical durability of PbO–B2O3 glasses with PbO contents ranging from 30 to 80mol% was determined. An average dissolution rate of 0.2gm−2 day−1 was obtained for the composition 80PbO⋅20B2O3. These glasses were studied under simulation conditions and showed good potential as a vitrification matrix for radioactive waste management. Clear vitrified waste products containing up to 30mol% SrO and 25mol% Cs2O could be obtained. Leaching rates are about hundred times higher in low PbO glasses compared to high PbO glasses. These results are encouraging since they open up new horizons in the development of low melting temperature lead borate glass for waste immobilization applications. [Copyright &y& Elsevier]