Safe trapping of Cs radionuclides in sintered matrix of zeolites

Cesium aluminosilicate phases are of the great interest as possible host for Cs immobilization in radioactive waste management. The possibility to use zeolite as a host material for radioactive Cs immobilization was investigated. Cs-exchanged forms of clinoptilolite and 13X which were prepared by ion-exchange treatment were compacted. The powders compacts of exchanged zeolites were thermally treated at 1200 °C. The XRD analysis showed that Cs was successfully immobilized after heat treatment by formation of stable cesium-aluminosilicate ceramic forms. Thermal and mechanical properties of the sintered samples were investigated. From the perspective of these characteristics, Cs-exchanged zeolite (clinoptilolite and 13 X) can be considered as a potential material for safe waste disposal

Heavy Metals Distribution, Environmental and Health Risk, Sources, and Origin in Soil from European Beech Forests

Forests cover about 40% of Earth’s surface, while is 42% of the European Unions’ total land area is covered by forests and wooded land [1]. Forest ecosystems are open and dynamic systems that exchange matter with other systems such as the atmosphere, hydrosphere, and biosphere [1]. Nowadays, in addition to the exchange of substances necessary for its functioning, there is also an exchange of polluting substances. Heavy metals in forest soil can originate from natural and anthropogenic processes and their high concentration can be toxic for ecosystems and humans [2]. The aim of this study is to determine: (i) heavy metal distribution in forest soil; (ii) environmental and health risk; (iii) the source of heavy metals; (iv) the origin of heavy metals; and (v) influence of the geological substrate on heavy metal contents. Soil samples were collected from European mountain beech forests in 11 countries: Bosnia and Herzegovina, Bulgaria, Czech Republic, Germany, Italy, Poland, Romania, Serbia, Slovakia, Slovenia, and Spain. Since European beech forests grow on a wide range of geological settings, during this research terrestrial ecosystems that lie on five major bedrock groups (andesite, carbonate, conglomerate, granite, and sandstone) were investigated. The average abundance order of heavy metal contents in forest soil samples is Cr > Zn > Ni > Pb > Cu > Co > Cd. According to geo-statistical analysis soil samples with the lowest heavy metal contents belong to cambisol soil type, on sandstone, and granite substrate, and with the highest contents belong luvisols and rendzina soil types on limestone and dolomite substrate. The concentration of most heavy metals doesn’t show a systematic pattern with depth. Considering enrichment factor (EF) Pb, Sb, Cd and As, have moderate enrichment, or moderately severe enrichment in the surface soil layer. Mercury has severe enrichment. The highest values of hazard quotient pathways are noticed for ingestion in the children population, especially in the case of Pb. The Pearson correlation coefficient revealed a positive correlation among most of the elements indicating one or more common sources of heavy metals. Based on the Positive Matrix Factorization (PMF) V, Ni, Cu and Th were provided the highest percentage contribution for Factor 1, As, and Se for Factor 1 and Factor 3, Hg for Factor 4, and Cd for Factor 5. Principal Component Analysis (PCA) showed that Principle Component 1 (PC1) was mainly loaded with V, Ni, Cu, As, Se, and Th with similar high values, and Cd and Hg were strongly correlated in the Principle Component 2 (PC2). Taking into account all results it can be concluded that heavy metal concentrations in European beech forests soil are mainly determined by the geological substrate

Effect of Sample Preparation on Portable X-Ray Fluorescence Spectrometry Analysis of Contaminated Soils

Toxic metals in soil are routinely determined by several analytical spectroscopic techniques (Atomic Absorption Spectrometry AAS, Inductively Coupled Plasma Optical Emission Spectrometry ICP-OES,and Inductively Coupled Plasma Mass Spectrometry ICPMS)[1]. Those techniques measure metals from aqueous samples. Procedures of sample dissolution or extraction typically involve a lengthy process which requires the use of harsh conditions. Sample preparation procedures make these routinely used techniques generally time-consuming and too expensive [2]. On the other side, the need for reliable, economical, and environmental friendly technique for soil composition measuring has been growing in the environmental field, so has the demand for time and cost-efficient analytical methods for soil analysis [3]. X-ray fluorescence spectrometry (XRF) is a multi-element analytical technique for direct, non-destructive analysis of various materials (including soils) with minimal sample preparation. The most attractive advantage of XRF is the wide dynamic range (from mg kg-1 to 100%). A portable X-ray fluorescence spectrometer (PXRF) is also capable of in-situ analysis in a short time (30–120 s) [4]. In situ PXRF analysis provides flexibility and allows rapid collection of data for a large number of samples, andproduces real-time data that can be used for rapid decision making. It is well-known that the physical characteristics of the sample play an important role in obtaining accurate results when it comes to XRF methods. Therefore it is important to determine how reliable in situ PXRF results are. Analytical accuracy and precision could be generally improved if adequate sample preparation procedure is applied compared to in situ measurements. The aim of this research was to determinate in what extent sample preparation procedure changes measured concentrations of elements and is that change the same for all investigated elements. Does soil sample homogenization or further pressing into the compact pellet systematically affect measured concentrations? Soil samples from 32 industrial, potentially contaminated sites were collected from a depth of 10 cm, 30 cm, and 50 cm. Such soils provide wide concentration range of different elements. Samples were first directly analyzed in the field, without any sample preparation using the Thermo Scientific™ Niton™ XL3t GOLDD+ PXRF Analyzer. The second PXRF analysis was performed in the laboratory on the dry,ground, and homogenized soil powder sample. One aliquot of soil powder was digested for AAS analysis, while another aliquot was pressed into a 32 mm diameter pellet and analyzed using PXRF. The quality control program involves comparison of the results with AAS reference technique. Additionally, certified reference materials of stream sediment (STSD-3) and soil (NCS DC 77301) are analyzed with different sample preparation procedures

Toxic Metals in 3 Fractions (d<63µm, d63-250µm and d250-1000µm) of Dust Collected on Roads of Industrial Town Kostolac, Serbia

Kostolac is a town exposed to several serious sources of toxic metals and other inorganic pollutants. They arrive from sources typical for urban environments such as traffic, but also from various heavy industry sources: coal mining, burning of coal in power plants, ash landfills, and steel factory. Toxic metals in the air are concentrated in particulate matter. Their transport and health risks depend strongly on the size of dust particles. Goals of the research were to estimate: 1. how much does traffic contributes to the total pollution load compared to the natural sources and the industry; 2. how is pollution distributed in different fractions of the dust; 3. are there any spatial trends present and is there any correlation between vicinity of pollution sources and concentrations of toxic elements in different fractions of the dust. Samples of dust were collected from 10 locations in July and in September. Each location had one sampling site on a major road with intensive traffic and the other site on auxiliary road with much less traffic, located 10- 20 m away from the major road. The dust was dried, sieved through sieves with 3 different apertures (d=63µm, 250µm and 1000µm) and pressed into 32 mm diameter pellets. The samples were analysed by WD-XRF standardless method. The results showed that Al, P, K, V, Mn, Fe, Co, Zr, Rb and Ti have the highest concentrations in the smallest fraction (d<63µm) and the lowest concentrations in the most coarse fraction with stat. significant differences among concentrations. Concentrations of: Mg, S, Zn and Cu have the same trend as previous group of elements but no stat. significant differences, wile conc. of Si and Ca have the opposite trend. Neither the time of the year nor the intensity of the traffic have had any significant effect to the concentrations, therefore it can be concluded that industrial sources of pollution have significantly higher attribution to the total pollution load than traffic. The trend that toxic elements are more concentrated in the smallest fraction of the dust indicates that the source of the pollution is rather anthropogenic than natural. Concentrations of elements in dust collected on sites from our research were compared to concentrations of the same elements in the soil collected by SEPA (Serbian Environmental Protection Agency). Although locations from both researches were in close proximity, no significant correlation between concentrations was observed. The lack of correlation can be explained by several hypotheses which should be further investigated in future researches

Bioelements and Non-Essential Elements in Honeybees and Their Hemolymph, Larvae, Pupae, Honey, Wax, Propolis and Bee Bread

In our previous research we have explored concentrations of 16 elements in samples collected from 3 different environments: Golija (rural region), Belgrade (urban region) and Zajača (industrial region). These three locations were chosen due to their distinctly different degrees of urbanization and industrialization. Macroelements (Ca, K, Mg, Na), microelements (Cu, Fe, Mn, Zn) and non-essential elements (Al, Ba, Cd, Co, Cr, Ni, Pb, Sr) were determined in the whole body of honeybees, but the major novelty of the research was that hemolymph of the bees was analysed as well. Significant spatial but also seasonal variations in content of bioelements and non-essential elements were observed. These findings have raised several important questions which are addressed in our current study. In order to better understand how bees’ environment does affects concentrations of elements mentioned above, dust and pollen collected from the same locations were analysed. They represent 2 major sources of bio elements and toxic elements for the bees: food and atmospheric deposition. For the better understanding of dynamics of investigated elements the scope of our research was further extended to the analysis of bee bread, honey, crops, wax, propolis, larvae and pupae. The samples were digested in accordance with the US EPA SW-846 Method 3052. Closed microwave digestion system (ETHOS 1, Advanced Microwave Digestion System, Milestone, Italy) was used for digestion with 5 to 8 ml of concentrated HNO3 and 1 or 2 ml of concentrated H2 O2 (depending on the mass and type of the sample). Concentrations of: Al, Ba, Cd, Co, Cr, Cu, Ca, Fe, K, Mg, Mn, Na, Ni, Pb, Sr and Zn were determined by ICP-OES (iCAP 6500Duo, Thermo Scientific). Very low concentrations of: Co, Cr, Cd and Pb, which occurred in some samples were confirmed by ICP-MS (iCAP-Q-ICP-MS, Termo Scientific). Ratios between concentrations in the samples from industrial region and urban region were calculated and compared for different matrices. Concentrations of toxic metals such as Pb and Cd were significantly elevated in dust samples from the industrial site, and similar trend was observed for pollen, bee bread, wax, propolis, and the whole bees. Elevation of concentrations was not observed (or it was present in significantly lesser extent) for the samples of honey, larvae and pupae

Extreme floods of Venice: characteristics, dynamics, past and future evolution (review article)

Floods in the Venice city centre result from the superposition of several factors: astronomical tides; seiches; and atmospherically forced fluctuations, which include storm surges, meteotsunamis, and surges caused by atmospheric planetary waves. All these factors can contribute to positive water height anomalies individually and can increase the probability of extreme events when they act constructively. The largest extreme water heights are mostly caused by the storm surges produced by the sirocco winds, leading to a characteristic seasonal cycle, with the largest and most frequent events occurring from November to March. Storm surges can be produced by cyclones whose centres are located either north or south of the Alps. Historically, the most intense events have been produced by cyclogenesis in the western Mediterranean, to the west of the main cyclogenetic area of the Mediterranean region in the Gulf of Genoa. Only a small fraction of the inter-annual variability in extreme water heights is described by fluctuations in the dominant patterns of atmospheric circulation variability over the Euro-Atlantic sector. Therefore, decadal fluctuations in water height extremes remain largely unexplained. In particular, the effect of the 11-year solar cycle does not appear to be steadily present if more than 100 years of observations are considered. The historic increase in the frequency of floods since the mid-19th century is explained by relative mean sea level rise. Analogously, future regional relative mean sea level rise will be the most important driver of increasing duration and intensity of Venice floods through this century, overcompensating for the small projected decrease in marine storminess. The future increase in extreme water heights covers a wide range, largely reflecting the highly uncertain mass contributions to future mean sea level rise from the melting of Antarctica and Greenland ice sheets, especially towards the end of the century. For a high-emission scenario (RCP8.5), the magnitude of 1-in-100-year water height values at the northern Adriatic coast is projected to increase by 26–35 cm by 2050 and by 53–171 cm by 2100 with respect to the present value and is subject to continued increase thereafter. For a moderate-emission scenario (RCP4.5), these values are 12–17 cm by 2050 and 24–56 cm by 2100. Local subsidence (which is not included in these estimates) will further contribute to the future increase in extreme water heights. This analysis shows the need for adaptive long-term planning of coastal defences using flexible solutions that are appropriate across the large range of plausible future water height extremes

The prediction of floods in Venice: methods, models and uncertainty (review article)

This paper reviews the state of the art in storm surge forecasting and its particular application in the northern Adriatic Sea. The city of Venice already depends on operational storm surge forecasting systems to warn the population and economy of imminent flood threats, as well as help to protect the extensive cultural heritage. This will be more important in the future, with the new mobile barriers called MOSE (MOdulo Sperimentale Elettromeccanico, Experimental Electromechanical Module) that will be completed by 2021. The barriers will depend on accurate storm surge forecasting to control their operation. In this paper, the physics behind the flooding of Venice is discussed, and the state of the art of storm surge forecasting in Europe is reviewed. The challenges for the surge forecasting systems are analyzed, especially in view of uncertainty. This includes consideration of selected historic extreme events that were particularly difficult to forecast. Four potential improvements are identified: (1) improve meteorological forecasts, (2) develop ensemble forecasting, (3) assimilation of water level measurements and (4) develop a multimodel approach