Total Trace Elements Research Articles

The dietary fiber and micronutrient composition of traditional foods from Lebanon and their contribution to dietary adequacy: A call for action

Traditional Lebanese cuisine is based on traditional dishes, where Arabic sweets play an important role in daily consumption. This study focuses on the evaluation of total fibers and trace elements, especially vitamins A, D, E, and C of traditional foods and Arabic sweets commonly consumed in Lebanon by chemical analysis. A total of thirty types of Arabic sweets were chosen from reputable confectionery establishments, while thirty varieties of traditional Lebanese dishes were collected from central kitchens in the main Lebanese governorates. It was discovered that 23% percent of Arabic sweets and 30% of traditional dishes were rich in total dietary fiber. Moreover, Arabic sweets had trace amounts of vitamin A, vitamin E, and vitamin C. In specific sweets, vitamin A content showed variability, with values ranging from 8ug to 15 ug per 100 g of edible portions. Most of the traditional dishes contained traces of vitamin C. However, Tabboula stood out as the only dish that contributed to over 23% of the recommended daily value for vitamin C. Trace amounts of vitamins A, D, E, and C were present in almost all traditional Lebanese foods and Arabic sweets. This study revealed that these foods lack essential micronutrients and total dietary fibers.

Serum trace elements show association with thyroperoxidase autoantibodies in Thyroid Imaging Reporting and Data System (TI-RADS) 4 nodules

Thyroid nodule (TN) has been becoming a great concern worldwide due to its high incidence. Although some studies have reported associations between trace elements exposure and the risk of TNs, the linkage was not inconclusive. The present study aimed to identify the association of selected serum trace elements (Ca, Mg, V, Fe, Co, Cu, Zn, Se, Mn and Mo) with TNs among general adults. A cross-sectional study was conducted in January 2021 in Chengdu, China. 1282 subjects completed the questionnaire and gave at least one human biological material after an overnight fast, venous blood, and urine, including 377 TN participants defined through ultrasound. Various trace elements in serum specimens were determined by inductively coupled plasma mass spectrometry. Thyroid functions were tested by chemiluminescent microparticle immunoassay (CMIA). The associations between trace elements levels and the risk of TNs were examined by restricted cubic splines (RCS) regression and bayesian kernel machine regression (BKMR) models. TNs were more common in females (P < 0.001) and in the elderly (P < 0.001) and that they were also frequently associated with fertility, marital status, annual household income, drinking, anxiety, vitamin supplement, tea consumption, hypertension and hyperlipidemia. After adjusting for confounders by a propensity score matching model, the association between trace elements concentrations and TNs risk was found to be statistically insignificant in the RCS (P for nonlinear > 0.05) and BKMR models. FT3 or T4 (total or free) increased significantly with increasing total trace elements mixture levels. In TI-RADS-4 TN subjects, TPO-Ab level increased significantly with increasing total trace elements mixture levels in the high-dose range. Ca, Zn, Mo at their 75th percentile showed positive individual effects on TPO-Ab, which was examined to be interactive. The detection of trace elements for TNs in general adults may be of no significance, but once individuals classified as TI-RADS-4 TNs are detected with abnormal TPO-Ab, Ca, Zn and Mo level are recommended to measure. The substantive association on it still needs to be continuously explored in the future.

Exploring the potential of wild leafy vegetables widespread in European Alps as functional food

Wild leafy vegetables, historically vital for Alpine biodiversity and nutrition during hardship, are regaining importance due to the demand for healthy and sustainable food. This study evaluated mineral and phytochemical compositions of eight species: Achillea millefolium, Alchemilla xanthochlora, Bistorta officinalis, Blitum bonus-henricus, Phyteuma betonicifolium, Plantago lanceolata, Silene vulgaris, Taraxacum sect. Taraxacum. Total trace element concentrations ranged from 26 mg kg−1 (T. officinalis) to 92 mg kg−1 (B. officinalis), and potential toxic elements were below legal limits. The sum of the phenolic compounds analysed ranged from 155.30 mg GAE 100 g−1 FW (A. millefolium) to 1200.38 mg GAE 100 g−1 FW (A. xanthochlora). Flavanols were the most abundant phenolic class, but cinnamic acids, flavonols, benzoic acids and vitamin C also showed high values in the analysed species, contributing to high antioxidant activity (from 0.59 μmol TE g−1 FW in A. millefolium to 149.39 μmol TE g−1 FW in A. xanthochlora for DPPH). Overall, A. xanthochlora stood out for its richness in phenolic compounds. These findings underscore wild vegetables potential as functional foods, offering bioactive compounds comparable to or exceeding cultivated plants. Emphasizing preservation of traditional diets and rural innovation, this research supports the integration of wild leafy vegetables into contemporary nutrition strategies.

Genesis of the Neoarchean Algoma-type banded iron formation: constraints from Fe isotope and element geochemistry of the Qian’an iron deposit, eastern North China craton

The Neoarchean Qian’an BIF deposit in eastern Hebei, eastern North China Craton has attracted extensive attention of study in the last decades, but the genesis, e.g., Fe sources, metallogenic mechanism, as well as tectonic attributes of the BIFs remains highly disputed. Based on field investigations, microscopic observations and geochemical analysis, this study tries to unravel the source characteristics of ore-forming materials in the Qian’an deposit. The results show that the chemical compositions of the BIF ore samples are mainly composed of TFe2O3 and SiO2, with minor Al2O3 and TiO2. The total trace element contents of the samples are relatively low. The PAAS-normalized REE distribution patterns of the ores show LREE depletion and HREE enrichment, with robust positive anomalies of Eu, Y and La. These characteristics indicate that the BIFs are attributed to dominant chemical precipitation originated from paleo-ocean with obvious volcanic hydrothermal contributions and minor clastic input. Their positive to no Ce anomalies and positive δ56Femagnetite values unveil that the iron was precipitated at low oxygen fugacity. These results, in collaboration with evidence from previous lithological, structural geology, metamorphic P-T paths, geochemistry, geochronology and numerical modeling studies, support a mantle plume model to explain the complicated tectono-thermal processes, and the sources of BIFs in Eastern Hebei, eastern North China Craton.

Shallow-water redox changes and nitrogen cycles in the early Cambrian Nanhua Basin, South China

Widespread oceanic anoxia has been frequently invoked for metazoan extinctions during the Cambrian. However, this hypothesis remains to be debated. In this study, we measured total organic carbon (TOC), total bulk nitrogen (TNbulk), iron speciation, major and trace elements, and isotopic compositions of sedimentary bulk nitrogen (δ15Nbulk) for the Shiyantou Formation in the Meishucun section. Our results suggest ferruginous conditions and high productivity in the lower member (LM: 0–16.0 m), dominantly suboxic conditions and low productivity in the middle member (MM: 16.0–23.7 m), and oxic conditions and low productivity in the upper member (UM: 23.7–28.0 m). Low δ15Nbulk values (average 1.0 ‰) in the LM suggest quantitative assimilation of NH4+ and strong nitrogen fixation as a consequence of high primary productivity and widespread water-column reducing conditions in the Nanhua Basin. δ15Nbulk values close to 0 ‰ in the MM suggest intense nitrogen fixation owing to quantitative denitrification and anammox in an oligotrophic environment. Low δ15Nbulk values (average 1.2 ‰) in the UM are indicative of marine nitrogen limitations in an oligotrophic environment. These findings suggest a similar range of low δ15Nbulk values might result from different environments. In comparison with marine redox conditions and δ15Nbulk data from the other coeval sections in the Nanhua Basin, we propose that widespread anoxic conditions might cause the extinction of small shelly faunas. More importantly, the oligotrophic environment and anoxic conditions might delay the recovery of small shelly faunas in the shallow and deep waters of the Nanhua Basin, respectively.

Effect of steam cooking and particle size on the nutritional composition, phytochemicals and antioxidant activities of oyster mushroom (Pleurotus ostreatus) powder.

In this study raw and steamed Pleurotus ostreatus were dried and ground and fractionated by sieving into four granulometric classes (< 200µm, 200-250µm, 250-355µm and > 355µm) and unsieved powders. The combined steam cooking and sieving improved the content of total polyphenols (+ 59.45%), flavonoids (+ 76.47%), condensed tannins (+ 68.75%) and trace elements (+ 45.51% Fe, + 63.63% Cu, + 62.42% Mn, + 121.11% Zn, and + 53.52% Se) as well as in-vitro and in-vivo antioxidant activities in the finest fraction < 200µm compared to the raw powder. It was found that the intake at a dose of 250mg/kg body weight of the finest fractions of raw and steamed powders by the stressed rats had more of a hepatoprotective effect marked by a reduction in the level of transaminases ALAT and ASAT. This work opens a new approach for valuing edible mushrooms in the development of new food products with high antioxidant value.

Centennial-millennial scale global climate-linked monsoonal and non-monsoonal changes in the eastern Arabian Sea during the last 42,800 years

The Arabian Sea significantly impacts the global climate due to its hosting of one of the largest sedimentary bodies in the Modern Ocean basin and thickest oxygen minimum zone. It makes the study of fine-scale evolutionary changes in the Arabian Sea imperative to address the ongoing challenges in developing a strong and cohesive model for predicting rapid climate change in the future. Therefore, this study carried out environmental magnetic, grain size, stable isotope, total organic carbon (TOC), trace elements (TE), and rare earth elements (REE) investigations on a well-dated 2.68 m long sediment core from the eastern Arabian Sea to understand the fluctuation in monsoon and non-monsoon-driven sediment supply and associated primary productivity changes during the late Quaternary. The careful observations of chronological changes in the investigated parameters concerning coeval major global events enabled us to successfully identify the response of major global climatic events that occurred around 42.8–28 ka, 17 ka, 14.5 ka, 11.7 ka, 9.7 ka, 8.2 ka, 4.6–3.9, and 2–0.6 ka. These global events also played a crucial role in co-regulating the water column oxygen conditions in the Arabian Sea. Comparing our record with a sedimentary record from off Chennai, Bay of Bengal, suggests that opposite variations (anti-phasing) between southwest (SW) monsoon and northeast (NE) monsoon is a post-25 ka phenomenon. Pre-25 ka SW and NE monsoon showed similar variations (same phase), and we speculate that this anti-phasing between the SW and NE monsoon was cyclically driven by the earth's axial precession cycle.

Wide Riparian Zones Inhibited Trace Element Loss in Mining Wastelands by Reducing Surface Runoff and Trace Elements in Sediment.

The diffusion of trace elements in mining wastelands has attracted widespread attention in recent years. Vegetation restoration is an effective measure for controlling the surface migration of trace elements. However, there is no field evidence of the effective riparian zone width in mining wastelands. Three widths (5 m, 7.5 m, and 10 m) of Rhododendron simsii/Lolium perenne L. riparian zones were constructed in lead-zinc mining wastelands to investigate the loss of soil, cadmium (Cd), copper (Cu), arsenic (As), lead (Pb), and zinc (Zn). Asbestos tiles were used to cut off connections between adjacent plots to avoid hydrological interference. Plastic pipes and containers were used to collect runoff water. Results showed that more than 90% of trace elements were lost in sediment during low coverage and heavy rainfall periods. Compared with the 5 m riparian zone, the total trace element loss was reduced by 69-85% during the whole observation period in the 10 m riparian zone and by 86-99% during heavy rain periods in the 10 m riparian zone, which was due to reduction in runoff and concentrations of sediment and trace elements in the 10 m riparian zone. Indirect negative effects of riparian zone width on trace element loss through runoff and sediment concentration were found. These results indicated that the wide riparian zone promoted water infiltration, filtered soil particles, and reduced soil erosion and trace element loss. Riparian zones can be used as environmental management measures after mining areas are closed to reduce the spread of environmental risks in mining wastelands, although the long-term effects remain to be determined.

Application of compatible lignocellulolytic fungal consortia for quality composting of leaf litter and assessment of the end products

Leaf litter still remains one of the most overlooked organic waste in the present scenario. This study aims to examine the composting efficacy of leaf litter employing different compatible lignocellulolytic fungal consortia. The experiment was carried out in seven treatments (T1-T7) and lasted for 65 days. Based on the results of temperature and pH variations, total organic carbon (TOC), macronutrients (N, P, K, Ca, Mg), trace elements (Fe, Mn), and plant growth assessment, the final compost (T3) treated with fungal consortia consisting of Pseudoplagiostoma eucalypti (LLF10) and Purpureocillium lilacinum (LLF22) was found to be the best quality compost. Ascomycota (∼100 %), Cercozoa (> 65 %), Ciliophora (>45 %), Mucoromycota (>35 %), and Basidiomycota (∼30 %) were the dominant fungal phyla in the T3. In conclusion, compatible and effective lignocellulolytic fungal consortia can be tremendous candidates for composting of leaf litter and other lignocellulosic wastes for the generation of quality compost.

Paleoenvironmental Evolution and Organic Matter Accumulation in a Hydrocarbon-Bearing Depression in the East China Sea

Investigating the paleoenvironment and characteristics of source rocks in sedimentary basins is crucial for understanding organic matter accumulation and guiding hydrocarbon exploration. The Lishui Sag, a significant hydrocarbon-bearing depression in the East China Sea, has experienced extensive marine transgression and increasing salinity in the Paleocene, but the changes in accumulation factors of organic matter during this evolution process remain unclear. Through a comprehensive analysis of total organic carbon (TOC), major and trace elements, and biomarker data, this study investigates the characteristics of source rocks from two lithostratigraphic units, namely the Paleocene Yueguifeng and Lingfeng formations, to gain deep insight into the effects of paleoenvironment on organic matter accumulation and hydrocarbon distribution. Our results indicate that the Lishui Sag transitioned from a closed lake to an open-marine environment in the Paleocene, with a shift from warm-humid to arid climate conditions. The biomarker distribution suggests a change in the origin of organic matter, with a higher input of terrestrial organic matter in the Lingfeng Formation. During the early stage, the lacustrine source rocks in the lower Yueguifeng Formation were formed in a relatively humid and anoxic environment within brackish water, resulting in a substantial influx of terrestrial and lacustrine algae organic matter. In contrast, in the late stage, the marine source rocks in the overlying Lingfeng Formation were developed in an arid and oxidizing environment. The lacustrine source rocks in the Yueguifeng Formation were notably more favorable to developing good-quality source rocks. Compared with the other regions, the western and northeastern parts of the study area have greater hydrocarbon generation potential due to the wider distribution of high maturity and organic-rich source rocks, with higher terrestrial and algal organic matter input. Moreover, considering the practical circumstances in the exploration, the northeastern part of the Lishui Sag is recommended as the next exploration target zone.

Generation and expulsion of Lower Jurassic hydrocarbon in different source rocks in the Taibei Sag, Turpan-Hami Basin, northwest China

Source rocks in the first (J1s1) and second (J1s2) members of the Lower Jurassic Sangonghe Formation (J1s) in the Taibei Sag, Turpan-Hami Basin, NW China, are shore-shallow lacustrine mudstone and semi-deep to deep lacustrine mudstone. These two sets of mudstones provide an excellent opportunity for investigating the origin and expulsion patterns of hydrocarbon from source rocks under different environments. Through systematic geochemical analysis, including total organic carbon (TOC), Rock-Eval analysis, GC-MS analysis, and major and trace element analysis, the geochemical characteristics and sedimentary environment of the Sangonghe Formation (J1s) source rocks were evaluated. By integrating kerogen kinetics modeling, a more precise assessment of the hydrocarbon generation and expulsion characteristics of the source rocks from both members of the Sangonghe Formation is achieved. The fine-grained sediments of the Sangonghe Formation were formed in a weakly oxidized brackish water body. The J1s1 mudstone was deposited in a shore-shallow lacustrine environment. The repeated river influx increased the input of terrestrial higher plants, which complicated the maceral composition and diluted the abundance of organic matter. The J1s2 source rocks were formed in the semi-deep to deep lacustrine environment during the maximum transgression period with a large thickness and high TOC values, the maceral composition was dominated by a mixed source of aquatic organisms and terrestrial plants. Consequently, the source rocks of J1s2 exhibit higher initial hydrogen index (HI0), hydrocarbon generation potential (Qg) and transformation ratio (Tr) compared to those of the J1s1 source rocks, while the interbedded mudstone with limited thickness in J1s1 exhibits a higher hydrocarbon expulsion efficiency (Re).

Distribution and Speciation of Trace Elements in Soils of Four Land-Use Systems

Land use has a greater impact on trace element (TE) concentration present in soils. In mountainous regions of the western Himalayas, some dominating geogenic and human-dependent anthropogenic factors are involved in the spatial distribution of TEs in various land uses. Soil samples were collected from permafrost, pasture, forest, and agricultural land-use systems of Babusar Valley and Fairy Meadows in Diamer districts and the Rama region in Astore Districts in replications for investigation of three TEs, i.e., copper (Cu), zinc (Zn), and nickel (Ni). These samples were analyzed for exchangeable, adsorbed, organically bound, carbonate precipitated, and residual forms. Significant differences among these TEs were observed. Differences in the levels of TEs within soil samples were observed to be influenced by land usage patterns. The physicochemical properties of soil samples were also investigated. Additionally, the total metals (Ni, Zn, Cu) were extracted and their concentrations were measured in all samples. The concentration of soil TEs was observed in the following order: adsorbed &lt; organically bound &lt; exchangeable &lt; residual &lt; carbonate precipitated form across all the land uses. The results indicate that the contents of TEs (Ni, Zn, Cu) in agricultural soils were greater than in the permafrost pasture and forest soil samples. The total TE concentration varied as Zn &gt; Ni &gt; Cu irrespective of the area and land uses. We believe this work will open avenues for researchers to explore TEs in various regions of the world.

Sedimentary records of contaminant inputs in Frobisher Bay, Nunavut

Contaminants, such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), heavy metals, and per and polyfluoroalkyl substances (PFASs), primarily reach the Arctic through long-range atmospheric and oceanic transport. However, local sources within the Arctic also contribute to the levels observed in the environment, including legacy sources and new sources that arise from activities associated with increasing commercial and industrial development. The City of Iqaluit in Frobisher Bay, Nunavut (Canada), has seen rapid population growth and associated development during recent decades yet remains a site of interest for ocean protection, where Inuit continue to harvest country food. In the present study, seven dated marine sediment cores collected in Koojesse Inlet near Iqaluit, and from sites in inner and outer Frobisher Bay, respectively, were analyzed for total mercury (THg), major and trace elements, PAHs, PCBs, and PFASs. The sedimentary record in Koojesse Inlet shows a period of Aroclor 1260-like PCB input concurrent with military site presence in the 1950–60s, followed by decades of input of pyrogenic PAHs, averaging about ten times background levels. Near-surface sediments in Koojesse Inlet also show evidence of transient local-source inputs of THg and PFASs, and recycling or continued slow release of PCBs from legacy land-based sources. Differences in PFAS congener composition clearly distinguish the local sources from long-range transport. Outside Koojesse Inlet but still in inner Frobisher Bay, 9.2 km from Iqaluit, sediments showed evidence of both local source (PCB) and long-range transport. In outer Frobisher Bay, an up-core increase in THg and PFASs in sediments may be explained by ongoing inputs of these contaminants from long-range transport. The context for ocean protection and country food harvesting in this region of the Arctic clearly involves both local sources and long-range transport, with past human activities leaving a long legacy insofar as levels of persistent organic pollutants are concerned.

Essential role of multi-element data in interpreting elevated element concentrations in areas impacted by both natural and anthropogenic influences.

This article presents a detailed analysis of a dataset consisting of 27 elements found in soils, soil eluates, and vegetables from private gardens in a region with a long history of coal mining and burning. With coal being one of the world's most significant energy sources, and previous studies highlighting elevated element levels in vegetables from this region, the objective of this study was to identify the factors that impact soil geochemistry and metal(loid) uptake in plants. Total major and trace element concentrations were analyzed in soils, soil eluates and vegetables by high resolution inductively coupled plasma mass spectrometry. The vegetable samples included six species: fennel, garlic, lettuce, parsley, onion, and radicchio. Each plant was divided into roots, stems, leaves, and/or bulbs and analyzed separately. In addition, the soil pollution status, bioavailable fractions and transfer factors from soil and soil eluates to different plant parts were determined. The comprehensive dataset revealed that, apart from the substrate enriched with various elements (Al, As, Co, Cr, Mo, Ni, Pb, Sb, Sn, Ti, U, V, and Zn), other anthropogenic factors such as the legacy of coal mining and combustion activities, associated industries in the area, transport, and agricultural practices, also influence the elevated element concentrations (Cd, Cu, Fe, Mn, and Se) in locally grown vegetables. The transfer factors based on element concentrations in aqueous soil eluates and element bioavailable fractions confirmed to be an effective tool for evaluating metal uptake in plants, emphazising to some extent the effects of plant species and revealing unique patterns for each pollution source within its environmental context (e.g., Cd, Mo, S, and Se in this case). The study highlights the crucial importance of utilizing comprehensive datasets that encompass a multitude of factors when interpreting the impacts of element uptake in edible plants.

Extreme hydrological regimes of a small urban river: impact on trace element partitioning, enrichment and fluxes.

The input of trace elements from a small urban river (Las River, Toulon, France) located on the northern Mediterranean coast was studied during both base flow and flood events. A 2-year monitoring period of water flow and suspended particulate matter (SPM) showed a typical Mediterranean hydrological regime: a strong increase in water flow and SPM during short flood periods. During the flood event, an up to 2-fold increase in dissolved trace element (DTM) concentrations and particulate trace element content in SPM (PTM) was observed compared to the baseline discharge. The enrichment factor of elements in the SPM ranges from low or moderate for Co, Ni and Cr (1.0-4.7) to extremely high for Cd (157). However, the enrichment factors decrease from base flow to flood, indicating a dilution effect with a large yield of weathering particles with higher particle size. The most significant total trace element loading occurred during flood, ranging from 78% for As and Ni to 91% for Pb, while PTM loading during flood ranged from 35% for As to 77% for Pb. The specific dissolved fluxes during the flood are significantly higher for Pb, Cu and Zn than in the surrounding rivers, indicating specificity in the catchment (lithology). This study shows the importance of monitoring the transport of pollutants through small urban rivers and their potential impact on the coastal region, especially when they enter small and closed bays, as a receiving pool.

Benthic foraminifera as proxies for assessing the effects of a pier marina construction: A case study in the naturally stressed environment of the Saco da Ribeira (Flamengo Bay, SE Brazil)

Brazilian coastal areas have been exposed to various anthropic influences including physical alteration such as marina construction. To assess the impact of the pier marina construction in the Saco da Ribeira cove (Flamengo Bay, SE Brazil), sedimentological (grain size), geochemical (organic and trace elements) parameters and benthic foraminifera were analyzed on a 50-cm-long dated sediment core covering the last century. The multiproxy approach applied to a numerical hydrodynamic model shows that the circulation in the study area underwent an overall reduction (ca. 30 %) after the pier marina construction in the 1970s, promoting an increase of mud accumulation and higher concentrations of total organic carbon and trace elements (i.e., Enrichment Factor Cu from 0.80 to 1.4) as well as a shift in the benthic foraminiferal assemblages (i.e., foraminiferal density from 63 to 23.20 specimens per 10 cm3 and dominance from 0.13 to 0.73). On the basis of these integrated data, better environmental conditions occurred before the 1970s, then an overall increase in environmental stress took place after the pier's marina construction. Our results provide a baseline for future biomonitoring projects in a stressed region and exemplify the strong capability and reliability of benthic foraminifera as bioindicators of paleoenvironmental changes in coastal environments and for understanding how human pressure might induce such changes.

Impact of agrochemicals application on soil quality indicators and trace elements level of wetlands under different uses

An attempt to boost agricultural production has led to increased agrochemical usage. Continuous agrochemical usage for decades has brought changes to soil properties. The study assessed the impact of agrochemicals (fertilizers and pesticides) on wetland characteristics in Abeokuta, Nigeria. Five wetlands under maize, plantain, rice, vegetable productions, and control site were studied. Profiles were dug on each wetland, and soil samples were collected from pedogenic horizons and analysed using appropriate techniques. The morphological properties like colour, texture, structure, and consistency differ across the wetlands. The particle size fraction showed that the sand content was higher than silt and clay contents. Soil chemical indicators like pH, OM, TN, and K were lower in agrochemicals applied fields than in the control site, whereas available P was increased in these fields. The total trace element contents were highly affected and their levels have almost reached the permissible limit of WHO standards for agricultural purposes. Nutrient depletion and trace element build-up were more prominent in agrochemicals applied fields as against the control field. Information gathered from this study can help the policymakers on the proper usage and management of these wetlands on a productive and sustainable basis. To reduce agrochemicals impact which majorly contributed to the differences in the soil quality indicators and trace elements level, it is our opinion that planning to shift toward organic agriculture with no or minimal use of agrochemicals are to be considered.

A New Albite Microanalytical Reference Material from Piz Beverin for Na, Al and Si Determination, and the Potential for New K‐Feldspar Reference Materials

Determination of alkali elements is important to Earth scientists, yet suitable and reliable microanalytical reference materials are lacking. This paper proposes a new albite reference material and evaluates the potential for future K‐feldspar reference materials. The proposed Piz Beverin albite reference material from Switzerland yields a homogeneous composition at the centimetre‐ to micrometre‐scale for Si, Al and Na with &lt; 2000 μg g‐1 total trace elements (mostly heterogeneously distributed Ca, K and Sr). EPMA and LA‐ICP‐MS measurements confirm a composition of 99.5(2)% albite component, which is supported further by bulk XRF measurements. A round robin evaluation involving nine independent EPMA laboratories confirms its composition and homogeneity for Si, Al and Na. In addition, a set of five distinct clear K‐feldspar samples was evaluated as possible reference materials. The first two crystals of adular and orthoclase yield unacceptable inhomogeneities with &gt; 2% relative local variations of Na, K and Ba contents. The three other investigated sets of K‐feldspar crystals are yellow sanidine crystals from Itrongay (Madagascar). Despite distinct compositions, EPMA confirms they are each homogeneous at the centimetre to micrometre scale for Si, Al and K and have no apparent inclusions; further investigation to find larger amounts of these materials is therefore justified.

Attenuation of Barium, Strontium, Cobalt, and Nickel Plumes Formed during Microbial Iron Reduction in a Crude-Oil-Contaminated Aquifer

We assessed the spatial distribution of 35 elements in aquifer sediments and groundwater of a crude-oil-contaminated aquifer and show evidence of the dissolution of barium (Ba), strontium (Sr), cobalt (Co), and nickel (Ni) during hydrocarbon oxidation coupled to historic microbial Fe(III)-reduction near the oil. Trace element plumes occur in the crude-oil-contaminated aquifer, where 50% Co, 47% Ni, 24% Ba, and 15% Sr have been mobilized from the sediment near the oil into groundwater, resulting in dissolved masses >33, 18, three, and two times greater than estimated dissolved masses prior to contamination, respectively. Ba2+ and Ni2+ concentrations exceeded the World Health Organization’s drinking-water guidelines of 700 and 20 μg/L, respectively. Sediments attenuate trace element plumes in two geochemically distinct zones, resulting in <0.01% total trace element masses dissolved in groundwater, despite the substantial mobilization near the oil body. Geochemical modeling of the modern Fe(III)-reducing zone suggests trace elements are likely attenuated via coprecipitation with/without sorption on iron carbonate precipitates. In the suboxic transition zone at the leading edge of the plume, Fe(III)-hydroxides sorb Ba2+, Sr2+, Co2+, and Ni2+. This study emphasizes that slow but persistent biogeochemical activity can substantially alter aquifer chemistry over decadal timeframes, a phenomenon we term biogeochemical gradualism.

Fluctuations of continental chemical weathering control primary productivity and redox conditions during the Earliest Cambrian

The Ediacaran – Cambrian transition witnessed dramatic changes in the marine environment that are thought to have strongly influenced biological evolution. Previous studies have linked biological innovations to palaeo‐redox changes and suggested that increased productivity is the primary driver of the marine environment. However, the primary productivity and redox control mechanism still need to be clarified. Here, we present new organic carbon isotopes, total organic carbon contents, major elements, and trace and rare earth elements in drill‐core ZK107 from South China to reveal the continental chemical weathering, primary productivity, and redox control mechanism during the Earliest Cambrian (E‐C). Our studies have shown intense continental weathering, and primary productivity fluctuations that were supported by weathering (CIA, Rb/Al) and productivity (Babio, P) indicators. Additionally, the quantitative reconstructed productivity proxies (PP18, PP21, PP23) indicate a high primary productivity level in the E‐C ocean, surpassing that of the modern oceans. The strengthening of continental weathering mainly causes high primary productivity because it can alter the nutrient supply to the oceans. We suggest that changes in primary productivity closely associated with continental weathering are the leading cause of marine anoxia during the E‐C. This study establish a linkage between the land and marine system during the E‐C, confirming the terrestrial controls on the marine chemical changes and providing new insights into understanding the evolution of the Earth's surface changes during the Ediacaran – Cambrian transition.