Solubility Of Trace Elements Research Articles

Hydrochemical Characterization, Geothermometry, and Origin of Ain Al-Harrah Hot Spring and Its Relationship to Al-Lith Geothermal System, Saudi Arabia.

The Al-Lith geothermal field in western Saudi Arabia is a characteristic medium-high enthalpy geothermal system, exhibiting features associated with tectonic activities linked to the Red Sea rifting. Ain Al-Harrah hot spring is located in the Al-Lith field, with discharge temperatures varying from 56 to 81 °C. The determination of water temperature and composition in a geothermal reservoir is critical to the design of utilization strategies, surface production facilities, and choice of materials. This research presents a comprehensive hydrochemical characterization of the Ain Al-Harrah hot spring and its relationship with the underlying geothermal system. This study was conducted in two main phases; first, the fieldwork involved the collection of water samples from the hot spring, measuring the temperature, pH, and electrical conductivity (EC) of the water. The second phase involved laboratory analyses of the collected samples, including major and trace element analyses, isotopic analysis, and geothermometry. The dominant hydrogeochemical processes in the region were determined by analyzing the hydrochemistry of the water samples. Thermal waters analyzed exhibited high concentrations of Na+ (410-463 mg/L), HCO3 - (64.48-90 mg/L), and Cl- (472.76-581.95 mg/L), intermediate levels of K+ (50.2-93.0 mg/L), and low levels of Mg2+ (1.27-2.04 mg/L). The total dissolved solids (TDS) concentration ranges between 1830 and 2055 mg/L. The hot spring is categorized as Na-HCO3 type facies that are moderately alkaline, with pH values ranging between 7.9 and 8.2. Analysis of trace element concentrations revealed that the hydrochemical processes were primarily governed by the abundance and solubility of trace elements in the rocks surrounding the hot spring, the pH, and the temperature of the hot spring water. The stable isotope data for δD (-12.36 to 15.21%) and δ18O (-2.84 to -3.38%) provided evidence that the thermal spring is of meteoric origin. Based on Na-K-Ca, K2/Mg, and quartz geothermometers, the temperature range of the reservoir was determined to be between 150 and 205 °C. The temperature range suggests a medium-to-high enthalpy geothermal system.

Aerosol trace element solubility determined using ultrapure water batch leaching: an intercomparison study of four different leaching protocols

Abstract. Solubility of aerosol trace elements, which determines their bioavailability and reactivity, is operationally defined and strongly depends on the leaching protocol used. Ultrapure water batch leaching is one of the most widely used leaching protocols, while the specific leaching protocols used in different labs can still differ in agitation methods, contact time, and filter pore size. It is yet unclear to which extent the difference in these experimental parameters would affect the aerosol trace element solubility reported. This work examined the effects of agitation methods, filter pore size, and contact time on the solubility of nine aerosol trace elements and found that the difference in agitation methods (shaking vs. sonication), filter pore size (0.22 vs. 0.45 µm), and contact time (1 vs. 2 h) only led to small and sometimes insignificant difference in the reported solubility. We further compared aerosol trace element solubility determined using four ultrapure water leaching protocols, which are adopted by four different labs and vary in agitation methods, filter pore size, and/or contact time, and observed good agreement in the reported solubility. Therefore, our work suggests that although ultrapure water batch leaching protocols used by different labs vary in specific experimental parameters, the determined aerosol trace element solubility is comparable. We recommend that ultrapure water batch leaching be one of the reference leaching schemes and emphasize that additional consensus in the community on agitation methods, contact time, and filter pore size is needed to formulate a standard operating procedure for ultrapure water batch leaching.

Recovery and reuse of phosphogypsum: Effect of ternary cementitious materials on the performance of phosphogypsum pavement base layers

In this paper, the performance of a new type of phosphogypsum (PG) pavement material is studied under the joint action of ternary cementitious materials (cement, mineral powder, and fly ash), CaCl2 and gravel. The experimental results of mechanical properties and durability of the material system, including compressive strength, splitting strength, dry and wet cycle, freeze-thaw cycle, etc., confirm that the material system can meet the design standards for road base material design standards for highways and primary highway sub-base. The test results of SEM, XRD, EDS, contact angle, and solubility of trace elements show that the material system does not cause secondary pollution to the environment, and its strength mainly comes from the C-S-H gel and calcium alumina (AFt) generated by the reaction of the reactive substances in the cementitious materials with PG in an alkaline environment. Finally, the optimal ratio of modified PG: mineral powder: cement: fly ash: gravel: water: CaCl2 was 50:8:3:0:39:11:0.22, and its 7d compressive strength, splitting strength, loss of strength in dry and wet cycles, loss of strength in freezing and thawing cycles, and water absorption were 6.41 MPa, 6.84 MPa, 3.01%, 16.22%, and 8.87%, respectively.

Trace Element Partitioning Between Saline Aqueous Fluids and Subducted Metasediments, and the Origin of the “Sediment Fingerprint” in Arc Magmas

AbstractIsotopic and elemental signatures in arc magmas bear similarities to marine sediments from the forearc. Partial melts of subducted sediments were previously invoked as the predominant carrier of material between the slab and mantle wedge, whereas aqueous fluids were deemed too inefficient at mobilizing trace elements to account for arc magma compositions. However, trace element solubility in aqueous fluids may be significantly affected by the formation of chloride complexes. We introduced NaCl into the sediment‐H2O system, and re‐investigated trace element partitioning between aqueous fluids and metasediments in a series of piston cylinder experiments at 2.5–4.5 GPa and 600–700°C. The diamond trap method was employed to separate the fluids, which were analyzed in the frozen state. Trace element compositions of fluids and all solid phases were obtained by LA‐ICP‐MS. We combined our data with published literature to demonstrate that saline fluids and sediment melts have a comparable efficiency in extracting incompatible elements from subducted sediments, producing similar element fractionation during mobile phase expulsion. Accessory phases such as allanite may only be stable in particularly Rare Earth Elements‐enriched lithologies. The Sr, Pb and Nd isotopic signatures of arc magma suggest that the mantle wedge is infiltrated by mobile phases derived from both the sediment and basalt sections of the subducted oceanic crust. Up to several percent of either sediment‐derived saline fluid or melt can account for the isotopic and elemental compositions of most arc magma. Geochemical similarities between arc magma and forearc sediments are not necessarily evidence of slab melting.

Fine particle pollution during megafires contains potentially toxic elements

Wildfires that raged across Australia during the 2019–2020 ‘Black Summer’ produced an enormous quantity of particulate matter (PM) pollution, with plumes that cloaked many urban centres and ecosystems along the eastern seaboard. This has motivated a need to understand the magnitude and nature of PM exposure, so that its impact on both built and natural environments can be more accurately assessed. Here we present the potentially toxic fingerprint of PM captured by building heating, ventilation, and air conditioning filters in Sydney, Australia during the peak of the Wildfires, and from ambient urban emissions one year later (Reference period). Atmospheric PM and meteorological monitoring data were also assessed to determine the magnitude and source of high PM exposure. The wildfires were a major source of PM pollution in Sydney, exceeding the national standards on 19 % of days between November–February. Wildfire particles were finer and more spherical compared to Reference PM, with count median diameters of 892.1 ± 23.1 versus 1484.8 ± 96.7 nm (mean ± standard error). On an equal-mass basis, differences in potentially toxic elements were predominantly due to higher SO42−-S (median 20.4 vs 4.7 mg g−1) and NO3−-N (2.4 vs 1.2 mg g−1) in Wildfire PM, and higher PO43−-P (10.4 vs 1.4 mg g−1) in Reference PM. Concentrations of remaining elements were similar or lower than Reference PM, except for enrichments to F−, Cl−, dissolved Mn, and particulate Mn, Co and Sb. Fractional solubilities of trace elements were similar or lower than Reference PM, except for enhanced Hg (12.1 vs 1.0 %) and greater variability in Cd, Hg and Mn solubility, which displayed upper quartiles exceeding that of Reference PM. These findings contribute to our understanding of human and ecosystem exposures to the toxic components of mixed smoke plumes, especially in regions downwind of the source.

GEOTRACES: Fifteen Years of Progress in Marine Aerosol Research

The international GEOTRACES program has allowed unprecedented access to aerosols in the remote marine environment, moved the community toward standardized methodologies, and contributed to expanding research capabilities around the globe. A key aspect of GEOTRACES aerosol research is the quantification of deposition fluxes of trace elements and isotopes to the surface ocean as a source for biolimiting nutrients and anthropogenic contaminants. New methods for quantifying flux have been developed that leverage radioisotope tracers in the surface ocean to estimate bulk deposition rates on longer and more relevant timescales. The question as to what fraction of aerosols is soluble remains and is a source of continuing uncertainty. To that end, the community has engaged in coordinated study to address questions regarding the fractional solubility of aerosol trace elements and isotopes through the evaluation of widely used dissolution and extraction techniques. Intercalibration efforts, method standardization, and normalization of open-access data archiving will be the legacy of GEOTRACES-era aerosol research.

Determination of Water-Soluble Trace Elements in the PM10 and PM2.5 of Palermo Town (Italy)

This study contributes to the current knowledge on the solubility of trace elements in the atmospheric particulate matter of the urban area of Palermo. Daily sample filters of PM10 and PM2.5 were collected in monitoring stations within and outside the urban area, characterized by variable traffic density. The bulk of compositions in PM10 and PM2.5 were determined by ICP-MS. The water-soluble trace elements (WSTE) and major ion components of particulate matter were determined by ICP-MS and ion chromatography, respectively. A significant difference in the metals content was observed between the samples taken in urban areas and those from suburban areas. The calculated enrichment factor highlights the high values for Cu, Mo, Sb, V, and Zn, confirming the contribution of human activities. The leaching test was applied to PM10 and PM2.5 filters and showed different behaviors and transport of metals and metalloids. The calculated leaching coefficient highlights the metals typically produced by anthropic activities, compared to those of geogenic origin, are much more soluble in water and have greater mobility. The factor analysis was used to identify the sources of water-soluble ions. The main sources are anthropic, geogenic, and sea spray. The final objective of this study is to obtain, with the aid of leaching experiments on PM2.5 and PM10 filter samples, information about the bioavailability and mobility of the different metals and metalloids that could be used as the scientific basis for public health intervention and to raise the prevention and control of heavy metal pollution in the urban environment, especially in densely populated areas.

Characterization of trace elements in coal fly ash by extraction, micro-PIXE, TOF-SIMS, and XAFS

Coal fly ash (CFA) contains considerable amounts of potentially hazardous trace elements. Characterization of trace elements in CFA is essential for the safe disposal and recycle of CFA. The objectives of this study were i) to determine and predict the solubility of trace elements in CFA in relation to their chemical and mineralogical properties, and ii) to characterize trace elements using the surface chemical analysis including time-of-flight secondary ion mass spectrometry (TOF-SIMS) and accelerator-based micro particle induced X-ray emission (PIXE) analysis, in combination with X-ray absorption fine structure (XAFS) spectroscopy with a primary focus on As and Cr. The CFA samples from 12 thermal power plants contained B (ave. 203 mg kg−1), F (90 mg kg−1), Cr (63 mg kg−1), As (21 mg kg−1), and Se (3.2 mg kg−1), in which the water soluble fraction relative to the total concentration decreased in the order B (24 %) > Se (23 %) > F (20 %) > As (1.7 %) > Cr(IV) (0.71 %). A regression model indicated that water extractable As and Cr(VI) from CFA increased linearly with increasing SiO2 and CaO in CFA, respectively. The SIMS images showed that B was finely and heterogeneously distributed on CFA, whereas F was distributed homogeneously on CFA. The combined results from micro-PIXE and XAFS revealed that i) As was distributed on about 50-μm particles in the form of As(V) associated with Al and Ca, and ii) Cr was co-located with Fe and Ca on about 50-μm particles and was present as Cr(III). This study demonstrated that the combined results from TOF-SIMS, micro-PIXE, and XAFS techniques enable trace elements in CFA to be better characterized in terms of spatial distribution and chemical speciation.

Does phosphogypsum application affect salts, nutrients, and trace elements displacement from saline soils?

Salinity and sodicity are the most agricultural challenges in arid and semi-arid regions. A pot experiment was undertaken, to evaluate the effect of Phosphogypsum (PG) and Gypsum (G), to remove salts, nutrients and trace elements in leached water from saline and saline-sodic soils. In order to determine the efficiency and safety of these amendments, as an affordable strategy, for overcoming salinity and sodicity stress. The PG at 0, 15, 30 and 45 t/ha and G at 15 t/ha were mixed with the upper 9 cm soil in the pot before being leached. The soils were collected from Sed El Masjoune and Sidi El Mokhtar areas of morocco with ECe of 140.6 mS/cm and 11.7 mS/cm respectively. The highest doses of PG (≥30 t/ha) removed significant amount of salts and nutrients. Calcium sulfate supplies calcium ions to replace salt ions (sodium, especially). The replaced salts are leached from the soil. The PG was more efficient compared to G in terms of salts leaching. Quantities of trace elements in the leachate, for most analyzed elements, were below the recommended limits of drinking and irrigation water. Because the experiment’s alkaline conditions (basic water and soil) reduce the solubility and mobility of trace elements. The amendment application did not affect saturation index (SI) of the main minerals. However, water passing through the soil increased the SI. which could result in groundwater mineral precipitation.

Transfer Factor of Heavy Metals due to Mining Activities in Plateau State, Nigeria (Health Implications on the Inhabitants)

Accumulation of heavy metals in agricultural soils is instigated by industrial and other human activities such as mining, smelting, cement-pollution, energy and fuel production, power transmission, traffic activities, intensive agriculture, sludge dumping and melting operations. Plants received heavy metals from soils through ionic exchange, redox reactions, precipitation-dissolution, and so on. Which implies that the solubility of trace elements based on factors like minerals in the soil (carbonates, oxide, hydroxide etc.), soil organic matter (humic acids, fulvic acids, polysaccharides and organic acids), soil pH, redox potential, content, nutrient balance, other trace elements concentration in soil, physical and mechanical characteristics of soil, soil temperature and humidity, and so on. In this study, the soil-edible plant and soil-water Transfer Factor (TF) for various metals showed that the TF values differed slightly between the locations. On soil-edible plant transfer, the mean TF for different heavy metals in soil-edible plants decreased in the following order: As (0.6) mg/kg > Cd (0.1) mg/kg > Cr (0.06) mg/kg > Pb (0.003) mg/kg > Ni (0.001) mg/kg. The total TF for different location decreases in the following order: Barkin Ladi (1.0) mg/kg > Jos South and Jos East (0.7) mg/kg > Bassa and Mangu (0.6) mg/kg. On soil-water transfer, the mean TF for different heavy metals in soil-edible plants decreased in the following order: Cd (0.001) mg/l > As (0.0007) mg/l > Cr (0.0005) mg/l > Pb (0.0001) mg/l and Ni (0.0001) mg/l. The total TF for different location decreases in the following order: Jos South (0.003) mg/kg > Barkin Ladi, Bassa, Jos East and Mangu (0.002) mg/kg. Based on the findings of this study, it can be concluded that the water and edible plants in the study area are good for public consumption, even though, regular checking of heavy metals in the study area is recommended.

Solubility of aerosol minor and trace elements in Xiamen Island, Southeast China: Size distribution, health risk and dry deposition

Aerosol element solubility is essential to evaluate the damage to the environment and human health. In this work, the size distribution of total and soluble elements in eight particle size ranges with diameter <0.25, 0.25–0.44, 0.44–1.0, 1.0–1.4, 1.4–2.5, 2.5–10, 10–16 and >16 μm was investigated in Xiamen Island, southeast China from March 2018 to June 2020. The results showed that both total and soluble elements exhibited significant size dependence without obvious seasonal variations, and their relative contributions to PM1 mass were much lower than in particles larger than 1 μm. The correlations between some elements in soluble fraction were quite different from those in total fraction and the correlations also varied with particle size due to their different solubility. The solubility of Al, Fe, Ag and Cr was relatively low compared with other elements. Moreover, the solubility of Na, Mg, Ca, Mn and Ag was less dependent on particle size while Al, Fe and other trace elements exhibited the highest solubility in PM1 and the lowest in PM>10. Overall, the solubility of elements is primarily a function of aerosol origin and size. The carcinogenic risks of metal exposure via inhalation for children (3.31 × 10−6) and adults (4.42 × 10−6) were slightly higher than the guideline of cancer risk with >60 % from V. As for non-carcinogenic risk, the hazard index values for children and adults were 1.59 and 0.53, respectively, with Mn, V and Ni together accounting for >85 % of the risk. >85 % of the size-dependent dry deposition fluxes of the selected soluble elements over the Xiamen Bay were contributed by particles larger than 10 μm due to their high deposition velocities. The atmospheric inputs of bioavailable Fe and Cu to the sea exceeded the required amounts relative to inorganic nitrogen to meet the growth of phytoplankton.

Trace Mineral Solubility and Digestibility in the Small Intestine of Piglets Are Affected by Zinc and Fibre Sources

Findings that Zn and fibre source affected the nutrient apparent total tract digestibility (ATTD), made us hypothesize that interactions could occur affecting the apparent digestibility of Zn and trace elements (TEs) interacting with Zn in the digestive tract. Therefore, the study investigated the effects of Zn and fibre sources on the apparent digestibility and solubility of TEs (Zn, Cu, Fe, Mn) and pH in the small intestinal segments of 40-days-old piglets. In vitro solubility of TEs was estimated using a simulated digestion assay. Feed supplementation with potato fibre (PF) affected the ATTD of all TEs and dry matter as well as mineral solubility in the ileum and/or jejunum without any effect on pH in the small intestine. Intake of PF enhanced Zn and Cu absorption (p &lt; 0.01), but significantly decreased ATTD of Fe and Mn (p &lt; 0.001). Diet supplementation with Zn glycinate decreased Zn absorption in the gut (p &lt; 0.01) and affected the solubility of other TEs in the different digestion phases. Although in vitro solubility of TEs does not provide a good prediction of mineral bioaccessibility, using a combination of in vitro and in vivo methods can enable prediction of the trace mineral absorption.

Bioavailability and Solubility of Heavy Metals and Trace Elements during Composting of Cow Manure and Tree Litter

Objectives. To characterize the total content of heavy metals (Cd, Cr, Cu, Hg, Mo, Ni, Pb, and Zn) and trace elements (As and Se) of interest, their bioavailability and solubility during the composting of cow manure and tree litter in piles inoculated with beneficial microorganism (IBM), or not inoculated (NBM), on the university campus of the Universidad Nacional Agraria La Molina (UNALM). Methods. The investigation evaluated composting in six piles, three IBM piles and three NBM piles, for 120 days. Every 30 days, a composite sample was taken from each pile. The raw materials used were cattle manure and tree litter. The variables analyzed were the total concentrations (content) of metals and trace elements of interest, extracted with diethylenetriaminepentaacetic acid/pentatetic acid (DTPA) (for the bioavailability study) and extracted with deionized water (for the solubility study). Results. The average values (n = 3) of the total content (mg·kg−1) on day 120 in IBM were in the following order: Zn (404.33) &gt; Cu (86.33) &gt; Pb (71.2) &gt; Cr (34.33) &gt; As (28.0) &gt; Ni (13.83) &gt; Mo (2.86) &gt; Se (1.38) &gt; Cd (1.32) &gt; Hg (0.39) and in NBM: Zn (466.0) &gt; Cu (112.23) &gt; Pb (73.23) &gt; Cr (35.33) &gt; As (29.67) &gt; Ni (14.37) &gt; Mo (3.23) &gt; Se (1.55) &gt; Cd (1.38) &gt; Hg (0.38). The values complied with the Austrian Compost Standard for Landscaping and Land Rehabilitation and the Peruvian Standard for Nonorganic Agriculture. Significant differences were observed in some elements ( p &lt; 0.05) between 0 and 120 days in both types of pile (IBM and NBM). Conclusions. For nonorganic agriculture in Peru, urban compost is recommended, whereby raw organic materials are inoculated with beneficial microorganisms during the composting process to reduce the bioavailability of Cu and Zn, as these elements showed less bioavailability than noninoculated piles. The composting process for both piles (IBM and NBM) reduced the solubility in Cu, Pb, and Zn.

Chemical characterization and sources of PM2.5 at a high-alpine ecosystem in the Southeast Tibetan Plateau, China

Abstract The study of atmospheric chemical compositions in remote areas is of great significance for understanding the biogeochemical impact of atmospheric dry deposition on ecosystems. In this study, a total of 50 p.m.2.5 samples were collected at a high alpine forest of Mt. Gongga, Eastern Tibetan Plateau from May 2015 to May 2016 to investigate the characteristics of PM2.5 mass concentration and its major compositions including elemental carbon (EC), organic carbon (OC), and 24 trace elements. The average PM2.5 mass concentration was 17.19 ± 8.81 μg/m3, which was at an intermediate level compared with other areas of Tibetan Plateau. The yearly average concentrations of OC and EC were 2.98 ± 1.95 and 0.43 ± 0.33 μg/m3, accounting for 19.49% and 2.51% of PM2.5 mass, respectively, and the sums of the total concentrations of the 24 analyzed trace elements were 3.70 ± 0.80 μg/m3, accounting 27% of PM2.5 mass concentration. PM2.5, EC and OC showed the higher concentrations and larger fluctuation in the dry season (October 2015 to May 2016) compared with those in the wet season (June 2015 to September 2015), which was attributed to the multiple factors including the increases of biomass burning and fossil fuel emissions, the relatively shallow boundary layer height and lower temperature, and the less precipitation. Two distinct seasonal patterns were observed for the 24 analyzed trace elements in PM2.5: the crustal-derived trace elements like Fe, Al, Mn and Sr showed the higher concentrations in the wet season, while anthropogenic-derived elements such as Cd, Pb, Ni and Zn exhibited the higher level during the dry season. Six sources were identified for PM2.5 at Mt. Gongga with the application of the positive matrix factorization (PMF). Biomass burning (27.06%) and crustal source (26.93%) were the two main sources, followed by secondary formation (16.41%), traffic-related source (12.89%), coal burning (10.57%) and industrial metallurgical process (6.15%). Finally, it was proposed that the atmospheric acidic processing could not only promote the dissolution of Fe, but also enhance the solubility of the other trace elements in the atmosphere during the transport. Accordingly, this would increase the bioavailability and/or toxicity to the biotic and plants.

Geochemical signature of superhigh organic sulphur Raša coals and the mobility of toxic trace elements from combustion products and polluted soils near the Plomin coal-fired power station in Croatia

In the northern Adriatic coast of Croatia, combustion of super-high organic sulphur rich Raša coal was common between 1970 and 2000. These Late Paleocene coals are enriched in a number of trace elements. This work aims to provide a detailed study on the distinctive geochemical patterns of the Raša coal and investigate the environmental effects of the coal and combustion by-products on the area. Several analytical techniques were used to study the mode of occurrence, distribution, levels and solubility of major and trace elements in the Raša coal, fly ash, slag and soils in an area within 10 km from the power station. Due to the sulphur-rich calcareous depositional environment of the Raša coal, the combustion by-products are enriched in S and Ca. Fly ash and slag are enriched in potentially harmful trace elements i.e. Se, Mo, Hg, V and U. Similar enrichment pattern was found for soils suggesting that resuspension and deposition of airborne coal and fly ash particles, transport of gaseous species in the flue gas by dominant winds and/or leaching from ash deposits may have affected the wider environment. Whilst a large number of trace elements were found to be poorly soluble across samples, the leachable concentrations of Se, Cr and Mo in fly ash and slag are noteworthy. Their organic association in coal enhances volatilisation during combustion and then further condensation on ash particles as readily soluble oxyanionic species. Other oxyanionic metalloids such as As or V were insoluble in fly ash and slag, due to precipitation of solubility-limiting Ca-bearing species.

Combination of soil organic and inorganic amendments helps plants overcome trace element induced oxidative stress and allows phytostabilisation

Trace element (TE)-contaminated soils require the improvement of their physico-chemical properties in order to allow their restoration through phytostabilization technologies. This study aimed to determine the usefulness of oxidative stress related parameters to validate the suitability of two different combinations of organic (solid fraction of pig slurry) and inorganic (paper mill sludge or a commercial red mud derivative) amendments for the phytostabilization of an acidic (4.2) TE-contaminated mine soil from SE Spain. Two wild species (Silybum marianum and Piptatherum miliaceum) were greenhouse cultivated and the development of the plants, their ionome, and oxidative stress related parameters were determined. Both amendment combinations increased significantly soil pH (to 5–6) and soil/pore water total organic C and total N concentrations, allowing an adequate plant growth and development (plants did not grow in untreated soils). The combination of amendments significantly reduced metal availability and showed to be effective (specially the one including the red mud derivative) in limiting shoot TE concentrations, which were all within common ranges (exclusion based tolerance of these species). Both protein carbonylation and lipid peroxidation were significantly higher in S. marianum plants from phytostabilized soils than in those from non-contaminated soils, which confirms the oxidative stress these plants suffer despite their satisfactory growth in the treated soils. P. miliaceum plants showed no differences between phytostabilized and non-contaminated soils. Therefore, the combination of amendments and TE-tolerant autochthonous species would be a suitable option for the phytostabilisation of soils contaminated by mining activities, reducing TE solubility and allowing an adequate plant growth.

Meteorological effects on trace element solubility in Mississippi coastal wetlands

Trace elements (TEs) vary in toxicity and should be closely monitored to manage their accumulation in marine organisms, which may pass on to the food web. This study utilizes the National Oceanic and Atmospheric Administration’s (NOAA), Data Integration Visualization Exploration and Reporting (DIVER), National Centers for Environmental Information (NCEI), and Drought Monitor Systems to acquire arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), and zinc (Zn) concentrations in marsh soils along the Mississippi Gulf Coast area using the precipitation and drought data for the two sampling periods in 2010 and 2011. Results revealed that Zn had a significantly high correlation (r = 0.80 and p < 0.05) between soil concentrations and daily rainfall amounts, whereas Pb concentrations in soil were shown to occur after heavy storms. There was also significant variation between the months for Cd, Cr, and Pb, over the sampling periods. Arsenic remains relatively stable and statistically similar in the sediment averaging 21.09 µg/kg. Coastal soils were significantly higher in Cd and Cr concentrations in 2010 (28.89 µg/kg for Cd and 28.91 µg/kg for Cr) compared to 2011 (both 9.16 µg/kg). The trace elements, Cd and Cr showed negative correlation (r = −0.63 and −0.27) to increasing drought intensities. Most of these responses can be explained by a redox process where TEs were sequestered or released as solids and subsequently becomes saturated or dried out. It was observed that soils in Mississippi’s Gulf Coast study areas have the ability to be a sink or reservoir during various weather conditions thereby entrapping or releasing TEs, which becomes more available to organisms.

Meteorological effects on trace element solubility in Mississippi coastal wetlands

Trace elements (TEs) vary in toxicity and should be closely monitored to manage their accumulation in marine organisms, which may pass on to the food web. This study utilizes the National Oceanic and Atmospheric Administration’s (NOAA), Data Integration Visualization Exploration and Reporting (DIVER), National Centers for Environmental Information (NCEI), and Drought Monitor Systems to acquire arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), and zinc (Zn) concentrations in marsh soils along the Mississippi Gulf Coast area using the precipitation and drought data for the two sampling periods in 2010 and 2011. Results revealed that Zn had a significantly high correlation (r = 0.80 and <em>p</em> &lt; 0.05) between soil concentrations and daily rainfall amounts, whereas Pb concentrations in soil were shown to occur after heavy storms. There was also significant variation between the months for Cd, Cr, and Pb, over the sampling periods. Arsenic remains relatively stable and statistically similar in the sediment averaging 21.09 µg/kg. Coastal soils were significantly higher in Cd and Cr concentrations in 2010 (28.89 µg/kg for Cd and 28.91 µg/kg for Cr) compared to 2011 (both 9.16 µg/kg). The trace elements, Cd and Cr showed negative correlation (r = −0.63 and −0.27) to increasing drought intensities. Most of these responses can be explained by a redox process where TEs were sequestered or released as solids and subsequently becomes saturated or dried out. It was observed that soils in Mississippi’s Gulf Coast study areas have the ability to be a sink or reservoir during various weather conditions thereby entrapping or releasing TEs, which becomes more available to organisms.

Meteorological effects on trace element solubility in Mississippi coastal wetlands

Meteorological effects on trace element solubility in Mississippi coastal wetlands

Interaction between sequestered supercritical CO2 and minerals in deep coal seams

This study investigates the interaction between supercritical CO2 (scCO2) and minerals in coal that may occur during CO2 sequestration into deep coal seams. Two low-rank coals with low-ash content, one low-rank coal with high-ash content and one high-rank coal with low-ash content were used to study the interactions. A coal-CO2 geochemical interaction experiment with a typical high-ash coal was conducted to investigate change of the water-soluble elements after scCO2 interaction. X-ray powder diffraction (XRD) was used to determine the effects of scCO2–H2O on the minerals in the four coals. In addition, the influence of scCO2 on pore structure of four coals was studied based on liquid nitrogen adsorption experiment. The results suggest that scCO2 can effectively enhance the solubility of all elements from coal in water because of scCO2 interaction. ScCO2 can significantly improve the solubility of trace elements than that of major elements. Because of the relatively low mineral content in coals and the short experimental period, secondary minerals formed by scCO2-mineral-water interaction were not determined with XRD. However, the content of primary minerals changed; the apparent content of quartz increased and the content of kaolinite, carbonate minerals and pyrite decreased. For the experimental coals in this study, scCO2 can enlarge the pore size of the micropores for low-ash coal and mesopores for low-rank coal, but shrinks that of micropores for high-ash coal and mesopores for high-rank coal.