High Element Concentrations Research Articles

The discovery and global distribution of hyperaccumulator plants: A personal account

AbstractAn instance of extreme accumulation of Zn by a plant species was found in the 19th century, and observations of unusually high concentrations of other elements (Cu, Co, Ni, Cd, Pb, As, Se) were recorded between the 1920s and 1970s. Of relevance to the study of ultramafic areas and their floras is the occurrence of extreme Ni accumulation. The term “hyperaccumulator” was introduced in 1976 to signify a species exhibiting a concentration that can be hundreds or thousands of times greater than that usually found in plants on most common soils. Concentration criteria that allow a species to be regarded as a hyperaccumulator have been defined and refined from time to time. The following account details my own involvement in the discovery of new examples of metal hyperaccumulation, with particular emphasis on Ni accumulation by plants of ultramafic floras worldwide. The interest in hyperaccumulators has prompted investigations into different aspects of the biota of metalliferous soils. The search for new examples of hyperaccumulation continues, aided in part by non‐destructive X‐ray fluorescence scanning of herbarium specimens, which previously served as a resource providing small fragments for sensitive but destructive analysis. Identification of species as hyperaccumulators must be supported by further field exploration to understand the factors governing the level of metal uptake, and to stimulate further work on plant systematics, biochemistry, genetics, and molecular biology. Applications to phytoremediation and agromining are worth pursuing in some cases. Conservation issues are important because many hyperaccumulators are rare and restricted in their distribution.

Mineralogy and Geochemistry of High-Sulfur Coals from the M8 Coal Seam, Shihao Mine, Songzao Coalfield, Chongqing, Southwestern China

Mineral matter, including minerals and non-mineral elements, in coal is of great significance for geological evolution, high-value coal utilization, and environment protection. The minerals and elemental geochemistry of Late Permian coals from the M8 coal seam, Shihao mine, Songzao coalfield in Chongqing, were analyzed to evaluate the sediment source, sedimentary environment, hydrothermal fluids, and utilization prospects of critical metals. The average total sulfur (4.21%) was high in coals, which mainly exists in the forms of pyritic sulfur. Kaolinite, pyrite, calcite, quartz, illite and illite/smectite (I/S) mixed layers, and anatase predominated in coals, with trace amounts of chlorite, ankerite, and siderite. Epigenetic cell- and fracture-filling pyrite, veined calcite, and ankerite were related to hydrothermal fluids and/or pore water after the diagenesis stage. Compared to the world’s hard coals, As and Cd are enriched in the Shihao M8 coals, and Li, Cr, Co, Zr, Mo, Pb, and Tb are slightly enriched. These high contents of sulfophile elements may be related to seawater intrusion. The terrigenous clastics of the Shihao M8 coals originated from the felsic–intermediate rocks atop the Emeishan Large Igneous Provinces (ELIP) (Kangdian Upland), while the roof and floor samples were derived from Emeishan high-Ti basalt. Through the combination of sulfur contents and indicator parameters of Fe2O3 + CaO + MgO/SiO2 + Al2O3, Sr/Ba and Y/Ho, the depositional environment of peat swamp was found to be influenced by seawater. Although the critical elements in coal or coal ash did not reach the cut-off grade for beneficial recovery, the concentration of Li and Zr were high enough in coal ash.

Petrogenesis of early Paleozoic peraluminous A-type granites from southern China

ABSTRACT Early Paleozoic A-type granites in South China are rare, and their petrogenesis is still highly debated. This study focuses on the controversial Epo pluton in the Wuyi-Yunkai Orogen and conducts petrological and petrogeochemical research to discuss its origin. The Epo granites were emplaced at approximately 414 Ma and exhibit petrological and geochemical features of A-type granites. They contain only one ferromagnesian mineral, ferrum biotite. The granites mostly have high alkalis contents (Na2O + K2O = 6.48–8.85 wt.%), high field strength element (HFSE) contents (Zr + Nb + Ce + Y = 353–461 ppm), and high Ga/Al (104×Ga/Al = 2.50–3.72) and FeOT/(FeOT + MgO) (0.74–0.85) ratios. Besides, they formed under high-temperature (>850°C) and low-pressure (≤5 kbar) conditions. Their high A/CNK (average 1.20) and Eu/Eu* (average 0.46) values as well as Sr (average 128 ppm) and Ba (average 628 ppm) contents but relatively low Zr contents (approximately 200 ppm) further suggest a strongly peraluminous A-type affinity, a distinctive subtype of A-type granites. The Epo granites display enriched Sr-Nd-Hf isotope compositions with a whole-rock87Sr/86Sri average ratio of 0.712, whole-rock εNd(t) values ranging from − 8.9 to − 7.6, and zircon εHf(t) values clustering at − 8. Their two-stage Nd and Hf isotope model ages are 1.7 Ga to 2.0 Ga, suggesting ancient crustal sources. Furthermore, Nb/U (average 7.46), Ce/Pb (average 4.06) and other trace element ratios indicate negligible contributions from juvenile mantle materials. Our data on the Epo pluton, coupled with other contemporary A-type granites in South China, suggest that the high-temperature melting of metasedimentary basements generated strongly peraluminous A-type granites, while the involvement of metaigneous rocks or mantle-derived magmas resulted in metaluminous to weakly peraluminous A-type granites. Source diversity leads to different aluminium saturations. The heat required to produce high-temperature A-type magmas was supplied by upwelling mantle-derived magma in a postcollisional extensional setting.

Age, clinopyroxene geochemistry and petrogenesis of post-collisional magmatic rocks in the Jonob-e-Sechangi area, Lut block, eastern Iran

The Lut-Sistan region, eastern Iran has an extensive record of Eocene-Oligocene magmatism the origin of which is not fully understood. In this study, we analyze a set of volcanic rocks in the Jonob-e-Sechangi area of the Lut block. U-Pb zircon analyses demonstrate that magmatism can be divided into two age groups. Group 1 formed at ∼45 Ma and involved different felsic (calc-alkaline rhyolitic to dacitic) and intermediate (high-K calc-alkaline andesitic) rocks. All samples from Group 1 display nearly identical initial 87Sr/86Sr values (87Sr/86Sri = 0.7045-0.7056). However, the felsic rocks show higher ԐNdt (+2.21 to +2.73) and lower TDM (0.51-0.61 Ga). In contrast, intermediate rocks have ԐNdt values of +1.27 to +2.23 and TDM values between 0.63 and 0.74 Ga. Additional geochemical variations suggest that the felsic and intermediate rocks of Group 1 are not co-genetic. The felsic extrusive rocks in the Jonob-e-Sechangi area likely formed from the partial melting of the amphibolitic arc crust. In contrast, the high-K calc-alkaline andesitic rocks of Group 1 may have originated from low-degree partial melting of a spinel-peridotite mantle source.Group 2 formed basaltic andesite to andesitic rocks at37-40 Ma, showing high-K calc-alkaline to shoshonitic compositions, relatively high 87Sr/86Sri (0.7047- 0.7076) and relatively low ԐNdt (0.48 to-5.86). These geochemical features require magma derivation from a mantle source that is not only elementally but also isotopically enriched, followed by variable fractionation and crustal contamination. The enriched mantle source was most likely resided in the lithosphere and formed by metasomatism by continental crust-derived materials. Clinopyroxene trace elements compositions display marked variations between different magmatic rocks. Clinopyroxene in dacitic samples of Group 1 shows relatively high contents of Sr, Rb, and Ba whereas that in Group 2 rocks has relatively high contents of Sc, V, Ga, Nb, Zr, Hf, Y and rare earth elements (REE). The findings of this study show that the intricate interactions between the lithosphere and asthenosphere, stemming from post-collisional delamination processes following the closure of the Sistan Ocean and the collision of the Lut-Afghan blocks, led to differing levels of partial melting in the region's heterogeneous metasomatized mantle. This phenomenon explains the diverse range of volcanic rocks found not just in the Jonob-e-Sechangi area but also in other regions of the Lut Block.

Chemical assessment and spatial distribution of selected elements in aquatic sediments in the region of Peja (Kosovo)

In Kosovo, the supply of potable water from water sources is represented by about 40%. This study represents the geochemical analyses of sediments, spatial and statistical analyses of major elements in sediments (fraction < 63 µm) of water sources in the Drini i Bardhë River basin. For a better understanding of the geochemical consistency of sediments, inductively coupled plasma-mass spectrometry (ICP-MS) was used and the amounts of P and S were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). By comparing the concentrations of Ba, Se, and P with the existing criteria, it was found that 26 of 50 sample points exceed recommended norms, which cause low/significant toxic effects and 23 of 50 sample points include anomalies of the analyzed elements. In terms of statistical interpretation, the average concentration of the studied elements decreased in such order: Ca > Al > Mg > K > S > P > Na > Ba > Sr > Li > Rb > B > Ga > Cs > Be > Se. In terms of correlation analyses, elements such as Li, Be, Mg, P, and Ba did not show a significant positive correlation with any element. Cluster analysis of R-modality shows a branch of dendrogram linked with Ca, Al, Mg, S, K, P, Na, Ba, Sr, Cs, B, Ga, Se, Be, Rb, and Li. Spatial distribution maps of major elements show that high concentrations of Li, Ca, and Ba were located mostly in the northern part, high concentrations of B, Na, Mg, Sr, and Cs were located in the north-east part, high concentrations of Be and Al were located in the north and south part and high concentrations of P, S, K and Rb were located mostly in the south-east part of the catchment basin. This high concentration of elements is impacted by the lithology of rocks and by the minor influence of human activity (the case of P).

Longitudinal Gradient and Historical Trends of Arsenic and Metals in a Tropical Reservoir

This study aimed to establish the longitudinal gradient and historical trends of arsenic and metals in a tropical reservoir. Water and sediment samples were collected along the Rio Bonito reservoir (Espírito Santo, Brazil), and a sediment core was obtained from the lacustrine zone. Plasma spectrometric techniques were employed to determine concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, and Pb in water and sediment samples, and the sediment samples were dated using high-resolution gamma spectrometry. Higher concentrations of elements were observed in surface water samples from the riverine zone and bottom water samples from the transition zone. Concerning surface sediment samples, elevated concentrations were noted in the transition and lacustrine zones, where deposition is more intense. The sediment core was dated to 1940, before the reservoir dam construction, utilizing 210Pb dating. Certain elements exhibited progressively increasing concentrations over time. Enrichment factor, pollution load, and ecological risk indexes indicated the need for continuous monitoring of this reservoir

Mafic Alkaline Magmatism and Rare Earth Element Mineralization in the Mojave Desert, California: The Bobcat Hills Connection to Mountain Pass

AbstractOccurrences of alkaline and carbonatite rocks with high concentrations of rare earth elements (REE) are a defining feature of Precambrian geology in the Mojave Desert of southeastern California. The most economically important occurrence is the carbonatite stock at Mountain Pass, which constitutes the largest REE deposit in the United States. A central scientific goal is to understand the genesis of the carbonatite ore body in the context of widespread REE‐rich igneous activity. A swarm of mafic alkaline (shonkinite) dikes has been mapped and sampled at Bobcat Hills, 65 km southeast of the Mountain Pass mine. Whole‐rock geochemistry and zircon geochronology demonstrate a clear affinity to the ca. 1.4 Ga Mountain Pass intrusive system. Bobcat Hills dikes have comparably high REE concentrations (La ∼1,000× chondritic) and an error‐weighted mean 207Pb/206Pb zircon crystallization age of 1,426 ± 2 Ma (2σ). Unlike the alkaline intrusions at Mountain Pass, which have abundant inherited zircon from Paleoproterozoic basement rocks and crustally influenced oxygen isotope compositions (δ18Ozircon = 6.5–7.5‰), the Bobcat Hills dikes lack any evidence of crustal assimilation and have oxygen isotope values that overlap a mantle range (Bobcat Hills average δ18Ozircon = 5.6 ± 0.3‰). The dikes were a high‐temperature, early center of mafic alkaline magmatism in the Mojave Desert that serve as a snapshot of melt generation from a spatially extensive, metasomatized mantle source. We propose that modification of the crust over many tens of Myr at Mountain Pass created an environment that favored crustal assimilation and enabled ascent of late‐stage, REE‐rich carbonatite magmas.

Sediments and morphology of deep lakes of Central Tunguska Plateau (Krasnoyarsk krai, Evenkia): on the problem of the Tunguska Event at 1908

The shape of the bottom and the thickness of sediments of small lakes Zapovednoye and Peyungda, located 50-60 km from the supposed epicenter of the “Tunguska Event” of 1908, were studied using echo-sounding and seisimo-acoustic profiling, and their age was estimated using 137Cs, 210Pb, 14C. It was revealed that both lakes have funnel shape with a depth of 60 and 34 m, respectively, and are similar in shape and size to Lake Cheko, which, according to some researchers, is an impact crater formed by a celestial body as a result of the “Tunguska Event 1908”. The examples of lakes Zapovednoye and Peyungda show that the shape of Lake Cheko is not unique to this area. The age of the bottom sediments of lakes Zapovednoye and Peyungda exceeds several thousand years. In the sediments of lakes Zapovednoe and Peyungda, a layer with a high content of terrigenous elements was identified, presumably formed due to the input of disturbed soil layer as a result of the massive fall of trees after the “Tunguska 1908”. Thus, the presence of two deep funnel-shaped lakes near the epicenter of the “Tunguska 1908” much older than 1908, casts doubt on the uniqueness of Lake Cheko, and therefore its impact origin. In addition, according to our estimate, the age of Lake Cheko is no less than 300 years, which contradicts the hypothesis of its origin as a result of the “Tunguska 1908”.

Contribution by Giant petrels and Brown skuas to soil phosphatization in Harmony Point - Maritime Antarctica.

This research was conducted for the purpose to evaluate the contribution Giant petrels and Brown skuas nestings in the formation of ornithogenic soils by the phosphatization process in Harmony Point, Maritime Antarctic. Ten nests were selected to collect topsoil samples (0-20 cm), from 0 m up to 20 m away, with regular spacing of 2 m. The analysis of the samples included the physical, chemical, mineralogical and geochemical analyzes. Phosphate minerals were identified. The presence of high content of some trace elements, such as Zn, Cu and Sr is associated with the bird's excrements. Total-P and bioavailable-P recorded higher levels. This result demonstrates the importance of the time factor in the bird's nesting, as well as in the development of the soil in these soil-forming environment. Phosphatization in these areas is not restricted to the specific location of the nest, since high values of P have been identified at distances between 8 and 12 m, from de nest's top. This suggests the transport of P rich solutions and phosphatized material along fractures by the freeze-thaw cycles, contributing to increase the geographical expression of this phenomenon in this ice-free area, consequently the development of soils and the establishment of vegetation.

Study and Assessment of Mineralogical, Chemical and Granulometric Composition of Volatile Soil-Sand Aerosols from Dried Out Part of Aral Sea

This article presents the results of a comprehensive study of the chemical composition, structural characteristics, and porous structure of soil and sand in the dried-out part of the Aral Sea. Chemical analysis of soil samples revealed a high content of basic elements, such as oxides of silicon, aluminium, iron, calcium, and magnesium, which affect chemical activity and interaction with the environment. The structural characteristics of the samples taken in the dried part of the Aral Sea made it possible to evaluate their ability to adsorb and interact with water and other substances. The study of soil's adsorption and porosity characteristics has revealed its ability to retain moisture and other important components in the porous structure. The results obtained allow us to better understand the mechanisms of interaction of soil and sand with water. Data can serve as a basis for developing effective and sustainable water management practices and optimizing the use of soil materials.

Evaluation of environmental pollution by heavy metals in the waters of Al-Ezz River north of Basra

This study was conducted on the Al-Ezz River in the Al-Qurna district, north of Basra city, seasonally from Autumn 2022 to summer 2023 at five stations along the river. The purpose of the study was to assess the river's pollution and determine the highest concentrations of certain heavy elements in its water (Cobalt Co, Cadmium Cd, Manganese Mn, Zinc Zn, Iron Fe, Chrome Cr, Lead Pb, and Copper Cu). The highest concentrations of these elements were (0.095, 0.238, 0.323, 1.461, 1.592, 2.801, 8.015, 695.423) mg/l respectively, while the lowest concentrations of heavy elements were (Co=Not Detected, Fe= Not Detected, Mn= Not Detected, Cd=0.010, Zn= 0.033,Pb= 0.062, Cr= 0.129) mg/l. The strongest correlation is between lead and iron (r=0.99). Cadmium shows a positive correlation (r=0.97) with chrome, while copper has a positive correlation (r=0.97) with cobalt. There is a strong positive correlation between iron (r=0.99) and manganese, as well as between manganese (r=0.99) and iron. Zinc also exhibits a positive correlation (r=0.99) with cobalt, and chrome (r=0.98) shows a positive correlation with cadmium and cobalt (r=0.99) with zinc.

Nonessential elements (Al, As, Cd, & Pb) in shrimps and mussels from southeastern Brazil

The bioaccumulation of nonessential elements (Al, As, Cd, & Pb) in shrimps and mussels from southeastern Brazil (21°S–23°S) were compared. The objective was to verify and confirm the differential responses of elemental assimilation at both the taxonomic and spatial level. Two hypotheses were predicted: i) shrimps have lower element concentrations than mussels, and ii) both shrimps and mussels from the highly polluted site have higher element concentrations. The results confirmed the first hypothesis. The intense filter feeding activity of mussels explains the taxonomic difference. The second hypothesis was not validated. Both shrimps and mussels from the highly polluted site (Guanabara Bay) have lower elemental concentrations than individuals from the less polluted site. This finding is explained by the large inputs of sewage that result in partially reducing conditions of the water and high sedimentation rates, maintaining elements buried in anoxic sediment and making them unavailable for biological uptake. To understand what drives the bioaccumulation of chemical elements in marine animals it is necessary to know the species feeding habits and physiology, and the habitat characteristics in each region.

From E-Waste to High-Value Materials: Sustainable Synthesis of Metal, Metal Oxide, and MOF Nanoparticles from Waste Printed Circuit Boards.

The exponential growth of electronic waste (e-waste) has raised significant environmental concerns, with projections indicating a surge to 74.7 million metric tons of e-waste generated by 2030. Waste printed circuit boards (WPCBs), constituting approximately 10% of all e-waste, are particularly intriguing due to their high content of valuable metals and rare earth elements. However, the presence of hazardous elements necessitates sustainable recycling strategies. This review explores innovative approaches to sustainable metal nanoparticle synthesis from WPCBs. Efficient metal recovery from WPCBs begins with disassembly and the utilization of advanced equipment for optimal separation. Various pretreatment techniques, including selective leaching and magnetic separation, enhance metal recovery efficiency. Green recovery systems such as biohydrometallurgy offer eco-friendly alternatives, with high selectivity. Converting metal ions into nanoparticles involves concentration and transformation methods like chemical precipitation, electrowinning, and dialysis. These methods are vital for transforming recovered metal ions into valuable nanoparticles, promoting sustainable resource utilization and eco-friendly e-waste recycling. Sustainable green synthesis methods utilizing natural sources, including microorganisms and plants, are discussed, with a focus on their applications in producing well-defined nanoparticles. Nanoparticles derived from WPCBs find valuable applications in drug delivery, microelectronics, antimicrobial materials, environmental remediation, diagnostics, catalysis, agriculture, etc. They contribute to eco-friendly wastewater treatment, photocatalysis, protective coatings, and biomedicine. The important implications of this review lie in its identification of sustainable metal nanoparticle synthesis from WPCBs as a pivotal solution to e-waste environmental concerns, paving the way for eco-friendly recycling practices and the supply of valuable materials for diverse industrial applications.

Tetrad Effect of Rare Earth Element Fractionation in Zircon from the Pegmatite of the Adui Massif, Middle Urals

The zircon from the pegmatite of the Adui granitic massif displays the unique the rare earth element (REE) distribution spectrum with the tetrad effect in REE fractionation. The tetrad effect often occurs in granitoid rocks, but it is rarely encountered in minerals, e.g., zircon. Fluid saturated with volatiles, water and trace elements is a factor responsible for the tetrad effect in the zircon. The detailed isotopic-geochemical study of the zircon has revealed several zones differing in internal structure (in the back-scattered electron (BSE) image), composition and REE distribution. The zones indicate changes in the crystallization environment provoked by the evolution of the pegmatite-forming melt. They occur as the gradually growing changes in composition from the unaltered zones that are light-colored in BSE to the altered zones that are dark-colored in BSE. The unaltered zones are consistent in composition and geochemical features with magmatic zircons. The high content of trace (U, Th, REE) and volatile elements (F, Cl) in water suggests its crystallization from the fluid-saturated magmatic melt. The altered zircon zones occur as recrystallized zones with high content of non-formula elements (Y, Ca, Sr, Nb, P), a non-differentiated REE distribution spectrum and an absent Ce anomaly. These features are consistent with those of hydrothermal-metasomatic zircon.

Simplified framework for efficient utilization of municipal solid waste incinerator bottom ash as construction material via systematic classification and characterization

The incinerator bottom ash (IBA) constitutes approximately 80% of the municipal solid waste (MSW) incineration residues. To minimize the end-waste, one of the sustainable solutions is to utilize IBA. IBA is often utilized directly with or without simple pre-treatment after receiving from the incineration plant. However, the significant heterogeneity in the physicochemical composition of the IBA has hindered its widespread utilization. The given study proposes a simplified framework to improve the utilization efficiency of IBA via a systematic classification and characterization approach. The IBA was classified into ten classes (classified IBA) according to the four particle size ranges and three mineralogical categories. A comprehensive characterization of chemical/mineralogical compositions of classified IBA using state-of-the-art techniques was then conducted to understand the properties of each class, which aid in determining the appropriate applications for each category of classified IBA. The leaching behavior of the classified IBA was also studied to evaluate the environmental safety of the classified IBA classes and suggested avoiding categories with high concentrations of leachable toxic elements. The framework developed in this study for efficiently utilizing IBA is demonstrated for IBA collected from a local incineration plant.

Fractal modeling for geochemical data of deep-sea surface sediments: A case study from Zhongsha Island, Southern China Sea

This study applied principal component analysis (PCA), concentration-area (C-A) and spectrum-area (S-A) fractal models to identify geochemical element combination anomalies related to heavy metals from the data for 43 geochemical elements in surface sediments of the Zhongsha Islands. The relationships between these 43 elements were first examined by applying correlation and cluster analysis to the surface sediment sample dataset. The multifractal spectral functions of the 43 elements were then calculated and all elements were classified using the curve shape of the spectral function. The results of classification were consistent with that of cluster analysis, thereby verifying the reliability of fractal analysis of the study area. PCA was then used to identify element combination anomalies and to assess high-value areas of element contents, and the S-A model was used to distinguish between the anomaly and background signal. The results of this multiple-analysis approach show that the element combination anomaly is mainly located in the deep-sea plain area, with a few elevated values in the Zhongsha South Basin. This study showed that quantitative evaluation of anomalies of multi-element associations can effectively delineate a target area and that anomalies of element associations extracted by the S-A fractal method can provide a more accurate outline areas containing high contents of combined elements. This study can act as a theoretical reference for the environmental assessment of the Zhongsha sea area.

Egg- and seashell waste as a calcium source in snail (Cornu aspersum Müller, 1774) feed: I. Growth, mineral distribution in meat, shell and faeces, and environmental effects

ABSTRACT This study evaluates the effect of diets containing three different sources of calcium (limestone, eggshell, and seashell) on the mineral composition of meat, shell, and faeces and their effect on shell structure and growth of Cornu aspersum. The diets were designated by the calcium source in their diets: chicken eggshell with its membrane (EG), seashell (SS), and limestone (LM). The results showed that the calcium content and mineral concentrations in the diet groups varied significantly depending on the calcium sources. The calcium sources influence the growth and excretion of minerals in the flesh, shell and faeces of the snails. The EG-feed had higher phosphorus (P) and zinc (Zn) levels than SS-feed and LM-feed. At the end of the experiment, the EG-group had grown larger than the other groups. The SS-group showed the lowest growth rate due to the high concentration of non-nutrient elements. Considering environmental implications, the lowest level of phosphorus, potassium and harmful heavy metals was found in the faeces of the EG group and the maximum amount in the SS group. In summary, the study shows that using eggshells offers a dual environmental benefit by recycling waste eggshells and releasing less P and K into the environment.

The role of chemical properties of the material deposited in nests of white stork in shaping enzymatic activity and fungal diversity

Organic debris accumulated in bird nests creates a unique environment for organisms, including microbes. Built from various plant materials that are typically enriched by animal residues, bird nest favours the development of various fungal groups. The aim of this study was to investigate the chemical properties of the material deposited in the white stork Ciconia ciconia nests and the link between extracellular enzyme activity and the diversity and composition of culturable fungi. Our findings revealed low C/P and N/P ratio values in the nest materials, which indicate a high P availability. Nest material C/N/P ratio ranged from 67/8/1 to 438/33/1. Enzymatic activity strongly correlated with the content of carbon, nitrogen, and pH of the material deposited in the nests. A total of 2726 fungal isolates were obtained from the nests, from which 82 taxa were identified based on morphology and DNA sequence data. The study indicates that white stork nests are microhabitat characterised by diverse chemical and biochemical properties. We found relationship between the fungal richness and diversity and the C/P and N/P ratios of materials from the nests. Our study showed that culturable fungi occurred frequently in materials with high levels of C, N, and P, as well as high concentrations of base alkaline elements (Ca, Mg, and K).

РОЛЬ МСКТ И МРТ В ДИФФЕРЕНЦИАЛЬНОЙ ДИАГНОСТИКЕ ОСЛОЖНЕНИЙ СРЕДНЕЙ ЗОНЫ ЛИЦА У ПАЦИЕНТОВ С ПАТОЛОГИЕЙ ГРИБКОВОЙ ЭТИОЛОГИИ

Abstract. Introduction. Fungi are one of the constituents of an ecosystem. There are about 250 known human- pathogenic fungi species: From the widely spread Candida to the pathogene of aspergillosis that may lead to fatal consequences in certain conditions. Studies performed by Russian and foreign authors show the increase in the frequency of chronic sinusitis determined by the presence of fungi or fungal-microbial associations. Aim of this study is to perform the differential diagnosis of midface complications in patients with fungal pathology according to multispiral computed tomogrsphy and magnetic resonance tomography. Materials and Methods. A retrospective study was conducted based on the findings of multispiral computed and/or magnetic resonance tomographies of 68 patients. Presence of a fungal process was confirmed by histopathologic, mucroscopic, and cultural investigations. Results and Discussion. Histological investigations of surgical specimen detected the presence of fungal bodies formed by mycelium, i.e., a cluster of densely, compactly located fungal flocci in 28 of 48 (58.3 %): In 28 patients with maxilla sinus lesions, in 14 patients with sohenoidal sinus lesions, and in 5 patients with ethmoidal sinus lesions. In case of acute invasive fungal rhinosinusitis, the computed tomography of paranasal sinuses detected mucosal thickening and the bone density decrease associated with an erosive process. Unilateral lesions, erosions, and thinning of the sinus bone walls. According to magnetic resonance tomography, there was low signal in T2 mode, which is determined by the high concentrations of various metal elements in fungi, as well as by a high protein level and low free water contents in mucine. Conclusions. Visualization is essential to staging the disease and assessing the involvement of deeper structures, which may be clinically unmanifest. Although both computed tomography and magnetic resonance tomography are useful, the contrast-enhanced magnetic resonance tomography is the method of choice and helps assess the spread of the disease, especially regarding the deep extension into maxilla-facial area and brain.

High-precision zirconium isotope analysis of Pacific seawater reveals large mass-dependent fractionations in the ocean

Zirconium (Zr) stable isotopes recently emerged as potential tracers of magmatic processes and, as a result, their behavior in high-temperature environments have been the focus of extensive characterization. In contrast, few studies have focused on Zr behavior and isotopic fractionation in low temperature or aqueous environments. Here, we describe a new analytical routine for highly precise and accurate analysis of Zr isotopes of water samples, using a combination of double-spike and iron co-precipitation methods. To assess the impact of potential systematic biases a series of experiments were conducted on natural and synthetic water samples. Our results show that the spike-to-sample ratio, matrix composition, and high field-strength element (HFSE) concentration have negligible effects on measured seawater Zr isotopic compositions, and that the Fe co-precipitation method used yields accurate and precise Zr isotope data. We thus apply this method to natural seawater samples collected from a water column profile in the Pacific Ocean off the coast of California, with depths ranging from 5 to 711 m. We find that the natural seawater samples are highly fractionated relative to solid-Earth values and display marked variability in δ94/90Zr as a function of depth, ranging from ∼ +0.650 ‰ near the surface, to + 1.530 ‰ near the profile bottom, with an analytical uncertainty of ± ∼0.045 ‰ (2 SE, external reproducibility). The δ94/90Zr value of seawater is much higher than that of Earth’s mantle and continental crust, which has a δ94/90Zr value near zero, indicating the presence of processes in the hydrosphere capable of inducing large mass-dependent fractionation. Furthermore, the seawater δ94/90Zr value exhibits systematic variations with respect to water depth and salinity, suggesting that Zr isotopic compositions may be sensitive to seawater chemical properties and source highlighting its potential utility as a tracer of biogeochemical processes within the ocean.