Concentrations Of Metal Elements Research Articles

Chemical characterization of PM2.5 emissions and atmospheric metallic element concentrations in PM2.5 emitted from mobile source gasoline-fueled vehicles

Fine particulate matter with an aerodynamic diameter of <2.5 μm (PM2.5), particularly from the in-use gasoline-fueled vehicles, is a leading air quality pollutant and the chemical composition of PM2.5 is vital to the practical issues of climate change, health effects, and pollution control policies, inter alia. These atmospheric fine particulate matters (PM2.5) emitted from the exhausts of mobile source gasoline-fueled vehicles constitute substantial risks to human health through inhalation, and most importantly, affect urban air quality. Therefore, in order to explicitly determine the inhalation risks of PM2.5 which could potentially contain a significant amount of chemicals and metallic elements (MEs) concentration, we investigated the chemical composition (comprising of carbonaceous species and metallic elements) of PM2.5 emissions from mobile source gasoline-fueled vehicles. To further examine the chemical composition and metallic elements concentration in PM2.5 from the exhausts of mobile source gasoline-fueled vehicles, we systematically investigated PM2.5 emission samples collected from the exhausts of fifteen (15) mobile source gasoline-fueled vehicles. Our study has equally also determined the chemical compositions based on carbonaceous species (organic carbon - OC and elemental carbon - EC). Furthermore, the concentrations of PM2.5 and metallic elements (Ca, Al, Zn, K, Ca, Fe, Mg and Cr) in PM2.5 were analyzed with the help of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The details of the tested gasoline-fueled vehicles cover the model years, consisting of the vehicles registered from 2000 to 2017 from several vehicle manufacturers (or brands) with various running mileages ranging from 123.4 to 575,844 km (average 123,105 km). Our results established that elemental carbon (EC) and organic carbon (OC) were the most significant concentrations of carbonaceous species. The concentration of metallic elements in PM2.5 and chemical characterization were studied by their relationship with atmospheric PM2.5 and the results showed that the metallic elements concentration in PM2.5 were in descending order as follows: Ca > Al > Zn > K > Fe > Mg > Cr. These results will help us to further understand how PM2.5 emissions from the exhausts of in-use gasoline-fueled vehicles contribute to both chemical and atmospheric metallic elements concentration in the ambient air.

Use of Wood Ash in the Forest and its Effect on the Concentration of Essential and Heavy Metallic Elements in Soil and Blueberries &lt;i&gt;(Vaccinium myrtillus L.)&lt;/i&gt;

The aim of this research is to evaluate the influence of wood ash as an additive fertilizer to forest soil and growing blueberries (Vaccinium myrtillus L.) in terms of metallic element content. To evaluate the effect of wood ash on the forest ecosystem, was selected two forest areas which was fertilized with a certain amount of wood ash (bottom ash and fly ash). The selected forest areas were divided into two types of sampling plots (fertilized with ash and control). Obtained results showed that in the bottom ash dispersion area the concentration of Ca, K, Ni, Cu is almost twice higher in the fertilized plots than control plots. In the blueberries, metallic element content is similar and does not depend on the type of sampling plot.

Heavy metals accumulation in Hertia cheirifolia along the highway in Setif region, Algeria

Abstract. Belguidoum A, Lograda T, Ramdani M. 2020. Heavy metals accumulation in Hertia cheirifolia along the highway in Setif region, Algeria. Biodiversitas 21: 2786-2793. The aim of this work was to study the possibility of using Hertia cheirifoia spontaneous plant, generally present in uncultivated environments, as an indicator of pollution. The aerial parts of ten H. cheirifolia populations were collected along the East-West highway. Sampling is carried out in areas considered polluted or low contaminated in the region of Setif. Nine metallic trace elements concentrations (Pb, Zn, Cu, Fe, Mn, Cd, Ag, Bi, and Sb) were determined, for each population, by Atomic Absorption Spectrophotometry with Flame (AASF). Statistical analyzes were performed using mainly box and whisker diagrams, principal component analysis, and UPGMA. The concentrations detected for contaminants (MTE), in general, were very high, far exceeding international certified standards. The MTE concentrations in different populations were calculated for each metal and a positive correlation is observed. The order of MTE in the plant was found as follows: Fe &gt; Zn &gt; Mn &gt; Pb &gt; Sb &gt; Cu &gt; Bi &gt; Ag &gt; Cd. The Fe concentrations are very high in H. cheirifolia with an average of 3600 ± 1491.5 mg/kg. The populations of H. cheirifolia have shown a significant capacity to accumulate heavy metals. The presence of metal ions in the aerial parts of the plant designates that H. cheirifolia is a super accumulator of MTE and can be used as a bioindicator, which opens up prospects for its application to soils phytoremediation.

Temporal and spatial characteristics of particulate matters in metro stations of Shanghai, China

The aim hereof is designed to understand the temporal and spatial characteristics and influencing factors of particulate matter (PM) in Shanghai Metro stations. A field measurement campaign was performed in two Shanghai Metro stations for 26 days of one year to detect the concentrations of PM10 and PM2.5 (particles with an aerodynamic diameter of 10 or 2.5 μm or less) at different sites. Significant seasonal variations in PM were observed and higher PM concentrations were obtained during the autumn and winter. The spatial distribution of PM was characterized by a tendency to increase with distance from the ground, and the highest PM levels were observed in tunnel. The PM levels were also higher in rush hours than in off-rush hours. The contribution of PM2.5 to PM10 was higher in autumn and winter than that in spring and summer. Fifteen elements in PM2.5 were measured by inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of all elements in tunnel were higher than the atmospheric environment except for As and Se. The relatively high concentrations of metal elements in metro particles were Fe, Al, Ba and Mn. The enrichment factors (EF) showed that Cd, Cu, Zn, Se, Fe, Pb, Ba, Cr, Mn, Co originated from anthropogenic sources. This study showed that PM pollution existed in Shanghai metro stations and the PM levels were affected by outdoor air and train operation. Further monitoring and intervention action is needed to improve metro microenvironment.

Chemical Compositions and Sources Contribution of Atmospheric Particles at a Typical Steel Industrial Urban Site

Online monitoring concentrations of PM at five sites were obtained from 01/01/2016 to 31/12/2016 in Laiwu, China, and PM2.5 filters were manually sampled for total 34 days at the same sites in four seasons in 2016. PM pollution sources, including soil dust, urban dust, construction dust, coal-fired power plants dust, steel plant dust and motor vehicle exhaust dust were sampled, respectively. The overall mean PM2.5/PM10 ratio (0.57) in Laiwu was at a relatively lower level compared with that in other Chinese cities, which was higher in winter, indicating fine particulate was the main contributor of atmospheric pollution in this period. NH4+ mainly existed in the form of NH4NO3 and (NH4)2SO4 during the sampling periods. Higher sulfate and NH4+ concentrations were in summer while higher nitrate concentrations prevailed in winter. The annual value of OC/EC was (5.38 ± 1.70), higher in summer and lower in winter, and the calculated SOC/OC value (%) was (43.68 ± 12.98)%. The characteristic components were Si, Fe and Ca in urban dust and soil dust; Ca, Mg, and NH4+ in construction dust; Fe, Ca and SO42− in steel dust; OC, EC and Si in motor vehicle exhaust dust; SO42−, Al and NH4+ in power plant dust. Compared with other cities at home and abroad, it was found that the concentrations of metal elements in Laiwu were significantly higher than those in foreign cities, and at a medium level in China. With the improved CRAESCMB model, the urban dust was regarded as the receptor and the source of PM2.5 and apportioned its secondary sources contributions to PM2.5. The CMB results showed the contributions of secondary sources including sulfate (17%), nitrate (17%) and SOC (13%) to PM2.5 accounted for nearly half of all sources. Therefore, more attentions should be paid on secondary sources from the primary emission sources of the motor vehicle exhaust, coal combustion sources especially.

Mechanical properties and microstructure characterization of GTAW of micro-alloyed hot rolled ferritic XPF800 steel

The gas tungsten arc weldability of micro-alloyed hot-rolled ferritic XPF800 steel, which is newly produced by Tata Steel, has been studied. The weld geometry profile, mechanical properties and microstructure affected by heat input have been investigated. The micro examination of the welded joint has been characterized utilizing optical microscope and scanning electron microscope. Atomic concentrations of metallic elements in carbides have been determined by energy dispersive X-ray spectrometry. The optimum parameters for current, welding speed and heat input have been found to be 140 A, 100 mm/min and 0.62 kJ/mm in the GTAW of XPF800 plates, respectively.

A Study on Characteristics of Heavy Metal Elements in Atmospheric PM2.5 During Winter in Chengdu

This paper conducted an in-depth analysis on the characteristics of components of heavy metals in PM2.5 by studying the atmospheric heavy metal elements during winter in Chengdu. On the basis of the limiting value of heavy metal element concentration in PM2.5 in major cities at home and abroad and the national standard limiting value on heavy metal element concentration, this paper compared and evaluated the pollution level of heavy metal elements in PM2.5 during winter in Chengdu and analyzed the typical characteristics of heavy metal elements in haze days and non-haze days as well as the potential sources. The following conclusions were drawn: 1) in PM2.5 during winter in Chengdu, the major component was K, minor components were Fe, Ca, Zn, Cu, Pb, Ba, Mn, As, Cr and Cd, trace components were Se, Ag, Hg, Ni, V, Au and Ga and ultra-trace components were Co, Sb, Ti and Sn, and the proportion of the aforementioned components was 2.10706%, 2.14783%, 0.01933% and 0.00009% respectively; 2) the major component, minor component, trace component and ultra-trace component of heavy metal elements respectively accounted for 1.621%, 1.641%, 0.016% and 0.00004% of PM2.5; 3) the proportion of all the heavy metal components in PM2.5 in haze days was lower than that in non-haze days, which indicates that the relatively high concentration of PM2.5 might be caused by non-metallic salts; 4) in PM2.5, the proportion of Pb, Cd, Mn and Cu was lower than both the domestic average level and the international average level; the proportion of Zn and Ni was at the domestic average level but slightly higher than the international average level; and the proportion of As was at both the domestic average level and the international average level; 5) the mean value of Pb concentration during winter was 0.08717µg/m3, which was lower than the limiting value of the national standard GB 3095-2012; and 6) there was a rather high level of consistency between such elements as were K, Ca, Fe, Zn and Ag as well as PM2.5 on the typical haze day, which shows that obvious colinearity existed in the emission source of the aforesaid elements and such elements might come from road dust sources; on the typical non-haze day, random-peak daily variation occurred in heavy metal components, which might result from unorganized emission from peripheral pollution sources; however, the proportion of ultra-trace components of heavy metals on the typical non-haze day was slightly higher than that on the typical haze day, which might be closely related to the local background transmission.

Seasonal variation of biomarker responses in Cantareus aspersus and physic-chemical properties of soils from Northeast Algeria.

This study belongs to the biomonitoring program of soil qualities using a land snail, Cantareus aspersus, as bioindicator. The metal-soil contamination in some sites (National Park of El Kala (NPK), El Bouni, Sidi Amar, Nechmaya, and Guelma) located in Northeast Algeria were determined during two seasons (winter and spring 2015, 2016). Glutathione (GSH) content and acetylcholinesterase (AChE) activity were significantly decreased in snails collected during spring as compared with those noticed during winter under bioclimate change. In addition, a significant difference between various sites was observed, depending on the proximity to pollution sources. The significant variation of biomarker levels is a function of the physic-chemical properties of soils when they positively correlated with EC, H, and OM, and negatively correlated with all metallic elements. Moreover, Fe and Al2O3 are the most abundant in all the sites, and the most polluted site was found as that of El Bouni, followed by Sidi Amar, Nechmaya, and Guelma, since NPK is the less polluted site and considered a reference site. The tested biomarkers are sensitive oxidative parameters in snails exposed to pollution correlated significantly with the soil physic-chemical properties and metallic element contents in soil. Indeed, C. aspersus could be used as sentinel species in field monitoring of Mediterranean climate regions.

Urban forests near municipal solid waste incinerators do not show elevated trace metal or rare earth element concentrations across three cities in the northeast USA.

With the World Bank estimating global municipal solid waste MSW to increase to 3.4 billion tonnes by 2050, municipal solid waste incineration (MSWI) needs to be considered as part of sustainable waste management. In spite of major advancements in air pollution control systems and emission regulations, emissions of trace metals (TMs) (As, Cd, Cu, Ga, Mn, Ni, Pb, V, W, Zn) and rare earth elements (REEs) (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb) may occur. Here, leaves, wood, forest floor, and A horizons in urban forests were assessed to determine if TM and REE concentrations show enrichment near MSWI relative to other urban areas for three cities in the northeastern USA. Vegetation and soil concentrations measured were generally comparable to concentrations observed in previous studies in non-urban sites. Overall, higher TM and REE in forest floor, A horizons, leaves, and wood were not observed consistently for MSWI sites when compared to city sites. Although pooled forest floor Ni and V and A horizon La and Nd concentrations were significantly different, they were not consistent but driven by a large difference at one of the three cities. This indirect study suggests air pollution control systems have prevented or have reduced TM and REE emissions to local urban forests to negligible amounts. Further studies are needed to evaluate potential interferences from other urban air pollution sources, and conduct direct emission measurements to validate MSWIs are not emitting TMs and REEs.

Solid state diffusion of metallic impurities from crucible and coating materials into crystalline silicon ingots for PV application

A setup for annealing experiments was developed which allows the detailed investigation of metal impurity solid state diffusion into silicon crystals. In order to simulate the impurity diffusion into multicrystalline or mono-cast silicon ingots during directional solidification processes, small cuboidal Czochralski silicon ingots with extremely low metal contamination, placed on various substrates, were annealed for several hours at temperatures just below the melting point of silicon. As substrates, different crucible materials, partly including SiO2 diffusion barrier layers as well as different Si3N4-coatings with widely varying content of metals (Fe, Cr, Ti, Cu, Co and Ni) were used. After ingot annealing, vertical samples were prepared out of the ingot center and the red zone dimensions were determined by lifetime measurements. Additionally, highly sensitive neutron activation elemental analysis was carried out on the silicon samples. In combination with the concentrations of transition elements of various crucible materials and silicon nitride powders the solid state diffusion process of these impurity species into and through the silicon was investigated. The results indicated, that the red zone area mainly contains the fast and intermediate diffusing elements Fe, Co, Cr and Cu. By variation of certain metal element concentration (Fe, Cr, Co, Ni, Cu and Ti) in the substrates it turned out that Fe and Co have the major impact on red zone formation and charge carrier lifetime reduction. Whereas for increasing Fe concentrations in the substrate material (>1017 at/cm3) no further increase of red zone can be observed due to the formation of precipitates in the lower areas of the red zone, fast diffusing Co atoms are able to reduce also the charge carrier lifetime in the center of the silicon samples.

Assessment of Heavy Metal Pollution in Surface Dust of Lanzhou Schools Based on Random Forests

In this study, seven types of heavy metal elements and 11 types of characteristic parameters affecting heavy metal pollution and accumulation in surface dust were selected. Based on the comprehensive pollution index (PN) and potential ecological risk index (RI) calculated from the heavy metal element content of the school dust in the main urban area of Lanzhou City in 2018 as the training set, the PN and RI of the information sampling points were estimated using random forests. Then, the temporal and spatial characteristics of heavy metals in school dust in the main urban area of Lanzhou were analyzed. Finally, the correlation coefficient was used to evaluate the advantages and disadvantages of the traditional interpolation results and the random forest interpolation results. The results showed that the concentrations of heavy metals in the dust were higher than the local background values. The over standard rate of a single sample is 100%, Zn is 5 times higher than the background value, and Pb is 4 times higher than background value. PN in the study area was in the order Chengguan > Xigu > Anning > Qilihe, and RI was in the order Chengguan > Xigu > Qilihe > Anning. PN and RI exhibited very similar spatial distribution characteristics, both located in transportation hubs or downtown. In winter and summer, PN exhibited a high value, whereas RI had a high value. The reason for the high value of PN and RI in winter was the increase of coal sources in winter. The comparison of spatial interpolation results shows that the correlation coefficient between the results of random forest interpolation and traffic flow and normalized building index is greater than that of the traditional algorithm.

Characterization of the Leachate from the Municipal Landfill of Akouédo (Abidjan, Côte d´Ivoire)

Municipal solid waste in developing countries especially in Africa are commonly managed by discharging in uncontrolled landfill. This leads to the generation of huge amounts of leachate that are rejected in the nature without any treatment. This study consisted in characterizing the leachate from the Landfill of Akouedo in the District of Abidjan (Cote d’Ivoire) despite the completion of filling operations in 2019. The physico-chemical composition of raw leachate suggested a stabilized landfill, with alkaline pH (i.e. ~ 8.85±0.03). However, the concentrations of nutrients and organics such as NH 4 + (212.5±0.31 mg.L -1 ), NO - 2 (257.5±0.42 mg.L -1 ), NO - 3 (301.85±0.16 mg.L -1 ), BOD 5 (1015±0.12 mg O 2 L -1 ) et COD (9640±0.4 mg O 2 L -1 ) obtained in Landfill of Akouedo were slightly weak, compared to the FEPA’s standard (1991). This could confirm the stabilization of the leachate, with a BOD 5 / COD ratio of around 0.1 ± 0.05. In addition, most of the metallic trace element contents (i.e. Iron, Copper, Nickel, Zinc and Lead) were below FEPA’s standard (1991). To further investigate, humic acid (HA), fulvic acid (FA) and humin were extracted from the humic substance of this leachate. Thus, about 91 % and 9 % were obtained for humic acid and fulvic acid + humin, respectively. For better understanding, synthetic humic acid (SHA) was used as the reference material. The DRIFT analysis helped determine some difference between the LHAs of the leachate and SHA. However, the characteristics of the functional groups of the LHA and SHA molecules were essentially similar. The data on the characteristics of the HS shown in the results of the landfill leachate can be used in several related research areas, such as the optimization of leachate treatment processes and the remediation of groundwater contaminated with leachate. Keywords : Municipal solid waste, Landfill, Leachate, humic substance, humic and fulvic acid. DOI: 10.7176/JEES/10-4-03 Publication date: April 30 th 2020

Recovery of Gold and Other Precious Metal Resources from Environmental Polluted E-waste Printed Circuit Board by Bioleaching Frankia

The physicochemical profiling of e-waste was done by AAS, XRD, and SEM with EDX that reveals the composition of valuable metals like Au−, Ag−, Zn−, and Cu−. Thus, the present findings provide the important resource of precious metal in the e-waste (PCBs) as pollutant in the environment and human impact. The native isolates Frankia sp. DDNSF-01 and Frankia casuarinae DDNSF-02 were subjected for bioleaching of gold and precious elements bearing e-waste under one and two-step leaching methods. The two-step bioleaching protocol was found effectual in expression with high level of metal leaching within the culture medium of Frankia metabolites and organic acids which were obtained by the leaching of metals. The presence of organic acids functional groups was determined by FT-IR spectrum and by low pH of growth medium. The AAS analysis quantified the initial concentration of metals and their significant increase brought by the leaching. The initial concentration of precious metal elements was found in the e-waste like Au−, Ag−, Cu−, and Zn− (0.04, 0.05, 0.35, 0.1 mg/g) respectively. Frankia sp. leached out precious metals like Au−, Ag−, Cu−, and Zn− (0.2, 0.14, 0.68, 0.2 mg/g) respectively. Frankia casuarinae leached out precious metals like Au−, Ag−, Cu−, and Zn− (0.25, 0.15, 0.55, and 0.2 mg/g) respectively. The precious metal gold was highly leached out by F. casuarinae than Frankia sp.. The valuable metal copper was significantly increased by Frankia sp. than F. casuarinae. Higher gold recovery, at 75%, was obtained for F. casuarinae and copper 94% recovery by Frankia sp. bioleaching of the biooxidised e-waste at 0.2% low pulp densities. The results were confirmed by XRD and SEM with EDX analysis.

Particles Released by Abused Prismatic Ni-rich Automotive Lithium-ion Batteries

The particulate matter released by lithium-ion batteries during eruption and combustion caused by thermal runaway may contain heavy metal pollution elements. The aim of this study is to reveal four heavy metal element content and size distribution of particulate matter released by abused prismatic Ni-rich automotive lithium-ion batteries. A fully charged commercial 50 Ah Li(Ni0.6Mn0.2Co0.2)O2 cell was triggered by heating in a sealed chamber at nitrogen environment. The particulate matter with size being below 500 μm were divided into three samples using sieves. Four soil pollution elements, including nickel, copper, zinc, chromium, were detected, and sizes were analyzed. The results show that all these four elements are found, and nickel and copper are found in all samples. Among the four elements, Ni had the largest mass percentage, followed by Cu, Zn and Cr. These particulate matter account for 1.7% of the cell mass, with the minimum size and median size being approximately 1.45 μm and 162.9 um. The element content reveals the pollution from LIBs and the size distribution provides a basis for the design of the particle filter pore.

Main nutrients and functional ingredients in flowers of Polygonatum cyrtonema and P. filipes

To reveal the main nutrients and functional ingredients in the flowers of Polygonatum cyrtonema and P. filipes, the content of the polysaccharides, saponins, amino acids, total phenols, mineral elements, and the DPPH free radical scavenging rates were determined. The flowers and rhizomes of P. cyrtonema were collected from Qingyang in Anhui and Qingyuan in Zhejiang, while the flowers and rhizomes of P. filipes were collected from Longyou in Zhejiang, respectively. The results showed that the polysaccharides content in flowers varied from 60.88 to 97.00 mg·g~(-1), about half of that in rhizomes. The saponins content in flowers varied from 32.55 to 40.93 mg·g~(-1), which was close to the content in rhizomes. The content of total phenols ranged from 40.79 to 50.95 mg·g~(-1), approximately 4.5 times of that in rhizomes. The total amino acids content in flowers was 111.85 to 131.03 mg·g~(-1), about 2.3 times of the content in rhizomes. The essential trace element content was abundant in flowers. The contents of heavy metal elements were all within the limits set by the standards. The DPPH free radical scavenging rate IC_(50) varied from 1.77 to 3.25 mg·mL~(-1), less than one-fifth of that in rhizomes, showing a significant superiority of antioxidant activity compared to rhizomes. The results initially revealed the fundamental of &quot;the flowers exceed the rhizomes in effect&quot;, the common saying about the traditional Chinese medicinal herbs over the years, indicating a great developing potential of the flowers. Besides, as polysaccharides, saponins, amino acids, total phenols and other nutritive substances in flowers differ widely among species and provenances, it's important to develop variety breeding to improve the quality and yield of flowers.

Spatial Distribution characteristics and Ecological risk Assessment of heavy Metal As, Ba in soil of a Chemical Slag Field in Sichuan Province

45 boreholes were determined according to the situation of an industrial slag field in Sichuan Province. According to 10~20cm stratification as soil sampling, the content and characteristic distribution of heavy metal elements, such as barium (Ba), arsenic (AS) in soil, were determined, and the spatial distribution characteristics of As, Ba were studied by Geostatistics method. The pollution and ecological risk of As, Ba in the industrial slag site were analyzed by using the single factor index method, the Nemerow index method and the potential risk index evaluation. The results show that barium is the main pollution factor of waste residue, with an average value of 127576μg/L, which is mainly distributed in the range of 2.908~2667000 μg/L. The mean value of arsenic was 8.72 mg/kg, respectively.

The Effects of the Recycled Polyethylene on the Properties of Special Material Blends for Pipe and Final Products

A detail comparison between recycled polyethylene (RPE) compounds and special material for pipe in respects of mechanical properties, antioxidant performance, metal contents and rheological behaviours was performed. The results showed that the MFR, the content of ash and typical metallic element of blends increased with the RPE component, while the OIT, fracture strain and impact strength tend to decrease. However, for those unused waste PE there’s no significant difference in most performance parameters compared with the new ones, especially when the RPE content was lower. In contrast, the content of typical metallic element such as Ferrum (Fe) and Calcium (Ca) can still be a crucial indicator for distinguishing the existence of RPE. Undoubtedly, the test of pipe products proved that the introduction of RPE caused the decrease of pressure resistance and resistance to slow cracking.

The effect of dealuminated jellyfish in mitigating toxicity on mice exposed to aluminum

In the present study, the removal effect of dealuminated jellyfish on Aluminum (Al) in mice was evaluated. The results showed that the consumption of dealuminated jellyfish significantly decreased Al accumulation in the liver of mice, indicating an Al-removing effect of dealuminated jellyfish on Al-enriched mice. In addition, the effect of dealuminated jellyfish consumption on an Al-overload model was further evaluated. The result showed that the Al content in different tissues and organs of mice was significantly reduced, but it had no significant effect on the other metallic element content. These results indicated that the samples from oral administration have a certain Al-removing effect in Al-overloaded mice. Moreover, the cluster analysis of differentially expressed proteins in blood and liver showed that a high dose of dealuminated jellyfish improve the expression of amine oxidase B and enhance the effect of Al discharge.

Accumulation of metals and changes in composition of freshwater lake organic sediments during the Holocene

The distribution of metals in the strata of sediments deposited in the freshwater environment formed during the Holocene in the territory of Latvia has been studied rather insufficiently. Considering the large volume of accumulated organic matter in sediments, studies on the content of metallic elements in sediments can help to determine the peculiarities of the metal accumulation process in limnic systems and the biogeochemical cycling of metals. Lake Pilvelis, which is located in the eastern part of Latvia (the northern part of Europe), was selected as the main study site. Lake Pilvelis is a small lake of a glacial origin, and >90% of its depression is filled with organic-rich sediments. The development stages of Lake Pilvelis since circa 10,000 cal BP are described in detail via reconstruction of the Holocene palaeoenvironmental conditions using multi-proxy sedimentary records. The elemental composition and content of metallic elements in sapropel are analysed with the main objectives of characterising the accumulation rate of metals in the full profile of sapropel and determining the anthropogenic impact depending on the evolution of the lake and the genesis of sediment organic matter. The correlation among the components characterising sediments such as sapropel and metallic elements revealed that the elemental distribution could be divided into three main groups according to the content of the elements associated with organic compounds (e.g., for Zn and Mn) and mineral compounds (for Ni, Co, Cr, K, Fe, Mg, and Cu). Ni and Co are partly associated with mineral compounds and partly associated with carbonates. A principal component analysis revealed the main factors indicating the origin of metallic elements and the accumulation tendencies of metals in sediment layers: the input of the mineral matter, the characteristics of organic matter, and human impact. The content of metallic elements in sapropel from Lake Pilvelis is mainly affected by the composition of mineral matter, not by the size of the particles.

Effect of drying treatment on the leachability of metallic elements from weathered solid mine wastes

Leaching of toxic metallic elements (Cu, Zn, As, Cd, and Pb) from two solid mine wastes was characterized under different drying treatments. During 14 batch decant-refill leaching steps, samples were intermittently dried four times in 40 °C oven or −20 °C freezer. For all leachates, the pH, pE, Fe2+/Fe3+, and SO42− were analyzed. The parameters of the two-site model (kfast, kslow, and ffast) and labile fractions (F1 + F2) were determined. High levels of toxic metallic elements were determined in waste samples; however, their leaching was limited, as evidenced by the magnitudes of F1 + F2, ffast, and kslow. Leachate solutions were acidic, at pH 3–4, and oxic, at 150 mV < Eh 300 < mV, thus having negligible Fe2+. Leachate concentrations of toxic metallic elements increased (4–58%) after drying at 40 °C and were strongly correlated (r2 = 0.780) with those of sulfate in liquid phase. The mass of element elution was in the order of 40 °C drying > −20 °C drying ≥ continuous wetting. Results indicate that the element leachability is increased through drying events and the leachate concentration is associated with the dissolution reaction of sulfur-bearing minerals. Frequent occurrence of prolonged droughts along with high temperatures over the mine waste disposal site, can enhance the leaching potential of toxic metallic elements.