ARTICLE | doi:10.20944/preprints201702.0086.v1
Online: 23 February 2017 (10:37:50 CET)
This work shows the physicochemical and mineralogical characterization of diatomites form the Hidalgo and Jalisco States, Mexico. In the case of the mineral from Hidalgo State, this has the following chemical composition; 70.0 % wt. SiO2, 11.63 wt. % Al2O3, 1.95 wt. % FeO, 1.79 wt. % MgO, 2.41 wt. % K2O, 0.85 wt. % CaO and 6.10 wt. % Na2O. On the other hand, the mineral from Jalisco has the following chemical composition; 93.58 wt. % SiO2, 3.03 wt. % Al2O3, 1.81 wt. % FeO, 0.40 wt. % MgO, 0.92 wt. % K2O, 0.11 wt. % CaO and 0.24 wt. % Na2O. For recovery of metals, both minerals got arsenic, silver, lead and nickel recoveries upper to 95 % and lower to 10 % for chromium. According to efficiency of interchange, the mineral from Hidalgo is slightly higher in the case of arsenic, lead and silver; while for nickel and particularly chromium (VI) the efficiency is higher for the mineral from Jalisco.
ARTICLE | doi:10.20944/preprints202110.0331.v1
Online: 22 October 2021 (13:10:46 CEST)
Oil pollution of extraction areas is an undesirable phenomenon, but very present, es-pecially in old farms. In the context in which the depollution of these areas, in Roma-nia, is carried out from public funds, this fact is more and more difficult to achieve. That is why the effect of pollutants on the environment is being analyzed more and more, it often remains that the depollution is done naturally. This material analyzes the effect of metals present in crude oil (Cu, Pb, Zn, Ag, Ni, Mn, As, Cd, V, Cr, S), on the soil affected by a historical accidental pollution in the Moinesti area, Romania. This article presents the results of analyzes performed by metal detection techniques, namely optical emission spectrophotometry with inductive coupled plasma and atomic absorption spectrophotometry. The metals determined in the polluted soil were statis-tically analyzed regarding the dispersion, standard deviation and coefficient of varia-tion compared to the control sample and compared with the results from two areas in Romania. The risk of exploitation of polluted areas was also analyzed, namely the method of pollution indices and the method of combining the effects of pollutants
ARTICLE | doi:10.20944/preprints202101.0576.v1
Subject: Earth Sciences, Atmospheric Science Keywords: metals; arsenic; leachates; pollution; Mexico
Online: 27 January 2021 (21:32:27 CET)
The soil and water contamination by metals from hazardous waste confined with urban solid wastes, highlights the importance of enhance the monitoring of disposal sites once closed. It is common to fail to comply with the regulations on their location, operation and post-closure, and located in areas that affect the environment and the health of the population. In the closed dump of Morelia, contamination of the soil and groundwater by leachates with heavy metals in the water from supply wells has been reported. The objective of this study was to determine the presence of heavy metals and arsenic in the confined wastes of the Morelia closed dump, in order to diagnose the affectation from the contaminants. Composition, degradation status and the presence of heavy metals were analyzed in samples of confined solid wastes from eight wells with different age of confinement. The results of this study ratify the contamination of the leachates of the site and are associated with the contamination of the water for human consumption in the area. The actual regulation does not apply in the case of urban solid waste, so it is crucial to regulate monitoring and management for correct decision-making during post-closure management.
ARTICLE | doi:10.20944/preprints202101.0343.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Metals; Arsenic; Leachates; Pollution; Mexico
Online: 18 January 2021 (14:19:34 CET)
The soil and water contamination by metals from hazardous waste confined with urban solid wastes, highlights the importance of enhance the monitoring of disposal sites once closed. It is common to fail to comply with the regulations on their location, operation and post-closure, and located in areas that affect the environment and the health of the population. In the closed dump of Morelia, contamination of the soil and groundwater by leachates with heavy metals in the water from supply wells has been reported. The objective of this study was to determine the presence of heavy metals and arsenic in the confined wastes of the Morelia closed dump, in order to diagnose the affectation from the contaminants. Composition, degradation status and the presence of heavy metals were analyzed in samples of confined solid wastes from eight wells with different age of confinement. The results of this study ratify the contamination of the leachates of the site and are associated with the contamination of the water for human consumption in the area. The actual regulation does not apply in the case of urban solid waste, so it is crucial to regulate monitoring and management for correct decision-making during post-closure management.
ARTICLE | doi:10.20944/preprints202010.0139.v1
Online: 6 October 2020 (16:01:57 CEST)
Spin crossover (SCO) complexes are in the forefront of image, memory and sensing devices, with applications already established since for thirty years. In order to reach magnetic multistability conditions, the high-spin (HS) and low-spin (LS) states have to be carefully balanced by ligand field stabilization and spin pairing energies. Both of these effects could be effectively modelled by electronic structure theory, if the description would be accurate enough to describe these concurrent influences to within a few kJ/mol. Such a milestone would allow for the in silico-driven development of SCO complexes. However, so far, the ab initio simulation of such systems has been dominated by general gradient approximation density functional calculations. The latter can only provide the right answer for the wrong reasons, given that the LS states are grossly stabilized. In this contribution, we explore different venues for the parameterisation of hybrid functionals. A fitting set is provided on the basis of explicitly correlated coupled cluster calculations, with single- and multi-dimensional fitting approaches being tested to selected classes of hybrid functionals (hybrid, range separated and local hybrid). Promising agreement to benchmark data is found for a rescaled PBE0 hybrid functional and a local version thereof, with a discussion of different atomic exchange factors.
ARTICLE | doi:10.20944/preprints202007.0554.v1
Subject: Earth Sciences, Environmental Sciences Keywords: metals, seasonal variability, pollution, industries
Online: 23 July 2020 (11:59:27 CEST)
Wetlands are carriers of metals and organic pollutants from natural and anthropogenic sources. Studies have shown that sediments are sinks for these pollutants as they carry more than 99% of the total amount of metals which are released as soluble metals into the Lagoon. The University of Lagos, located at Akoka North eastern part of Yaba in Lagos Mainland runs along a highly industrialized and residential area. This paper reports the total metal concentrations in wetland and sediment and their seasonal variations. Wetland and sediment samples were collected for two seasons in 8 sampling sites. Results showed wetland data having lower concentrations of metals as compared to sediments. Wet season had higher concentrations of metals as compared to other season. Total concentrations in wetlands were Cd (1.0-6.0), Cu (1.0-11.0), Cr (0.3-82.7), Zn (2.7-65.0) and Pb (0.3-16.0) all in μg L-1 respectively. Statistical analysis showed that there was a significant difference between the wet and dry seasons for sediments. Cd was the only metal at acceptable levels while Cr, Cu, Pb and Zn concentrations all exceeded levels deemed acceptable by the SABS and the EPA. Therefore, the wetland is in poor health.
ARTICLE | doi:10.20944/preprints202205.0019.v1
Subject: Mathematics & Computer Science, Applied Mathematics Keywords: seepage velocity; heavy metals; reservoirs pollution
Online: 5 May 2022 (03:19:54 CEST)
Increasing rate of seepage velocity from several formation characteristics, such as permeability and porosity, in water aquifer environment greatly prompt pollution of water reservoirs within a short period of time. Considerably, migration rate of dissolved heavy metals from Solid Waste Dumpsites (SWD), such as municipal dumpsites and landfills, through heterogeneous aquifer environment, and finally into nearby water reservoirs are mainly influenced by variation of seepage velocity within the soil and water environment. This presents a dynamic system for water pollution that was studied using a formulated mathematical model to describe the transport process of dissolved heavy metals, mainly characterized by seepage velocities, within the water aquiferous environment. Permeability, porosity, fluid pressure and concentration of heavy metals in aquiferous environment were used as principal parameters that influence seepage velocity of the metals, in dissolved state, through the structural formation of water aquifers. The derived mathematical equations that constitute the model of this study were generated through Darcy’s law and the equation of continuity. The model was validated on structural river aquifer sediments, and it was solved using graphical method through matlab open-source software. The initial and boundary conditions were obtained by discretizing the geological setting of flow region so as to transform the gradient of the head, into the time domain.
Subject: Materials Science, Metallurgy Keywords: oxygen depletion; heritage metals; corrosion testing
Online: 10 August 2021 (09:46:39 CEST)
The altered nature of archaeological metals means they deteriorate at conditions where metals would be stable. The study of deterioration for such materials is hampered by their complexity, variability and difficulties in measuring deterioration. Placing an object in a sealed container, controlling the RH and pollutant gases and measuring any decrease in oxygen concentration is an accessible method to measure deterioration rate. It has been used for research into suitable environmental conditions to manage deterioration rates of such artefacts including differences in response for artefacts from different excavation sites. Some objects need careful control of RH to low values, this is expensive to maintain and poses risks to other artefacts displayed together. Many objects are actually stable up to quite high RH values and oxygen depletion testing has been used to identify those that can be safely displayed with minimal environmental control. The accelerated corrosion, ‘Oddy’ test is frequently used to sift out unsuitable display materials. The visual assessment is widely recognized to be subjective. The test container has been modified and oxygen depletion appears to give good quantitative measurements of corrosion that correspond with both visual comparison and corrosion quantification for copper, lead and steel, but not for silver.
ARTICLE | doi:10.20944/preprints202209.0066.v1
Online: 5 September 2022 (13:44:44 CEST)
Silicon is an essential trace nutrient for plant growth and is frequently employed to remediate soils contaminated with heavy metals in agriculture. However, silicon’s role and mechanism in reducing heavy metal toxicity have not been well understood, especially for multi-heavy metals. In this study, the effects of silicon-rich materials (silicate, rice husk biochar (RHB), and bentonite) on growth trait, antioxidant response, and heavy metal accumulation and distribution of wheat grown in two soils polluted by multiple heavy metals (Cd, Zn, Pb, and As) were investigated. The results revealed that the addition of silicon-rich materials enhanced plant growth, improved the photosynthetic attributes in leaf tissues, and decreased the contents of Cd, Zn, Pb, and As in wheat shoots and grains. The examination of the subcellular distribution of heavy metals in plants implied that silicon-rich materials transferred heavy metals as intracellular soluble fractions to the cell walls, indicating the reduction of mobility and toxicity of heavy metals in the plants. In addition, the application of the silicon-rich materials reduced oxidative damage in plants by downregulating plant antioxidant response systems and decreasing the production of malondialdehyde (MDA), ascorbic acid (AsA), and glutathione (GSH). Moreover, fractionation analysis of soil heavy metals showed that silicon-rich amendments could convert bioavailable heavy metals into immobilized forms. The results indicated that silicon-rich materials could remediate multi-heavy metal-polluted soils and promote wheat production.
REVIEW | doi:10.20944/preprints202104.0637.v1
Subject: Biology, Anatomy & Morphology Keywords: metal toxicity, phytomelatonin, heavy metals, ROS, NO
Online: 23 April 2021 (12:36:12 CEST)
Metal toxicity in soils, along with water runoff, are increasing environmental problems that affect agriculture directly and, in turn, human health. In light of finding a suitable and urgent solution, research on plant treatments with specific compounds that can help mitigate these effects has increased, and thus the exogenous application of melatonin (MET) and its role in alleviating the negative effects of metal toxicity in plants, have become more important in the last few years. MET is an important plant-related response molecule involved in growth, development, and reproduction, and in the induction of different stress-related key factors in plants. It has been shown that MET plays a protective role against the toxic effects induced by different metals (Pb, Cd, Cu, Zn, B, Al, V, Ni, La, As, and Cr) by regulating both the enzymatic and non-enzymatic antioxidant plant defense systems. In addition, MET interacts with many other signaling molecules, such as reactive oxygen species (ROS) and nitric oxide (NO), and participates in a wide variety of physiological reactions. Furthermore, MET treatment enhances osmoregulation and photosynthetic efficiency and increases the concentration of other important antioxidants such as phenolic compounds, flavonoids, polyamines (PAs), and carotenoid compounds. Some recent studies have shown that MET appeared to be involved in the regulation of metal transport in plants, and lastly, various studies have confirmed that MET significantly upregulated stress tolerance-related genes. Despite all the knowledge acquired over the years, there is still more to know about how MET is involved in the metal toxicity tolerance of plants.
ARTICLE | doi:10.20944/preprints202103.0428.v1
Online: 16 March 2021 (14:29:44 CET)
Vigina radiata (Mung bean) is an important legume species belongs to the family Fabaceae, cultivated in varies region of Ethiopia for its nutritional values. The nutritional composition of the crop affected by different biotic and environmental stress which depends on growth environment. The aim of the present study was to determine the concentrations of selected heavy metals (Pb, Cu and Cr) in seed of mung bean collected from Shewarobit, Northcentral Ethiopia using inductively coupled plasma optical emission spectroscopy (ICP-OES). Acid digestion with HCl, HNO3 and HClO4 for 1hr at temperature of 90oC to 95oC by hot plate digester. The level of the heavy metals in the samples were 2.51 mg/L, Pb; 6.53 mg/L, Cu; and 0.38 mg/L, Cr respectively. The concentration of copper (Cu) in the seed of mung bean was higher than the other target metals (Pb and Cr) whereas, Cr occurred in least concentration. The overall accuracy of the method obtained from spiking experiment (recovery) was within the range 80 to 120%, which accounts 115.75%, 97.5%, 101.17% for Pb Cr and Cu respectively. Notably, these results indicating the reliability and applicability of the procedure for extraction of studied metals. The concentration of heavy metals in edible seed of mungbean is low as compared to WHO/FAO recommendation and absolutely safe for consumption in the study area. Thus, producer should follow similar agroecological managements of the crop production to maintain heavy metal concentration of such in the crop.
ARTICLE | doi:10.20944/preprints202012.0550.v1
Subject: Life Sciences, Biochemistry Keywords: Metals; Isoprostane; Biomarkers; Oxidative stress; Puerto Rico.
Online: 22 December 2020 (10:33:04 CET)
Metal exposure has been associated with a wide range of adverse birth outcomes and oxidative stress is a leading hypothesis of the mechanism of action of metal toxicity. We assessed the relationship between maternal exposure to essential and non-essential metals and metalloids in pregnancy and oxidative stress markers, and sought to identify windows of vulnerability and effect modification by fetal sex. In our analysis of 215 women from the PROTECT birth cohort study, we measured 14 essential and non-essential metals in urine samples at three time points during pregnancy. The oxidative stress marker 8-iso-prostaglandin F2α (8-iso-PGF2α) and its metabolite 2,3-dinor-5,6-dihydro-15-15-F2t-IsoP, as well as prostaglandin F2α (PGF2α), were also measured in the same urine samples. Using linear mixed models, we examined the main effects of metals on markers of oxidative stress as well as the visit-specific and fetal sex-specific effects. After adjustment for covariates, we found that a few urinary metal concentrations, most notably cesium (Cs) and copper (Cu), were associated with higher 8-iso-PGF2α with effect estimates ranging from 7.3 to 14.9 % for each interquartile range, increase in the metal concentration. The effect estimates were generally in the same direction at the three visits and a few were significant only among women carrying a male fetus. Our data show that higher urinary metal concentrations were associated with elevated biomarkers of oxidative stress. Our results also indicate a potential vulnerability of women carrying a male fetus.
ARTICLE | doi:10.20944/preprints202012.0321.v1
Subject: Earth Sciences, Atmospheric Science Keywords: quantile regression; groundwater; environmental; multivariate; metals; health
Online: 14 December 2020 (10:13:09 CET)
One of the most important defining characteristics of groundwater quality is pH as it fundamentally controls the amount and chemical form of many organic and inorganic solutes in groundwater. Groundwater data are frequently characterized by a wide degree of variability of the factors which possibly influence pH distribution. For this reason, it is challenging to link the spatio-temporal dynamics of pH to a single environmental factor by the ordinary least squares regression technique of the conditional mean. In this study, quantile regression was used to estimate the response of pH to nine environmental factors (As, Cd, Fe, Mn, Pb, turbidity, electrical conductivity, total dissolved solids and nitrates). Results of 25%, 50%, 75% quantile regression and ordinary least squares (OLS) regression were compared. The standard regression of the conditional means (OLS) underestimated the rates of change of pH due to the selected factors in comparison with the regression quantiles. The effect of arsenic increased for sampling locations with higher pH values (higher quantiles) likewise the influence of Pb and Mn. However, the effects of Cd and Fe decreased for sampling locations in higher quantiles. It can be concluded that these detected heterogeneities would be missed if this study had focused exclusively on the conditional means of the pH values. Consequently, quantile regression provides a more comprehensive account of possible spatio-temporal relationships between environmental covariates in groundwater. This study is one of the first to apply this technique on groundwater systems in sub-Saharan Africa. The approach is useful and interesting and has broad application for other mining environments especially tropical low-income countries where climatic conditions can drive rapid cycling or transformations of pollutants. It is also pertinent to geopolitical contexts where regulatory; monitoring and management capacities are weak and where mining pollution of groundwater largely occur.
ARTICLE | doi:10.20944/preprints202007.0553.v1
Subject: Keywords: bioavailability, heavy metals, BCR extraction, lagoon, sediments
Online: 23 July 2020 (11:47:24 CEST)
Heavy metals have been implicated as Lagoon pollutants from sources such as agriculture, mining and manufacturing industries and waste water treatment works. A study was carried out in the University of Lagos lagoon to investigate the seasonal bioavailability of the heavy metal contaminants Cd, Cr, Cu, Pb and Zn. The physical parameters pH, redox potential, temperature, TDS and conductivity were measured on site. Dried sediment samples were extracted using the Community Bureau of Reference (BCR) sequential procedure and analysed by ICP-OES. A certified reference material (CRM), BCR 701 (lake sediment) was used for quality assurance with recoveries ranging between 80-120%. Statistical analysis (ANOVA) showed that there was a significant difference between metal distribution in the dry and wet seasons. Cu, Pb and Zn were in the available fractions (carbonate, Fe/Mn oxide and organic). Cu was highest in the Fe/Mn oxide and organic fractions. This indicated that an increase in organic matter and reducing agents will avail the Cu. Zn was distributed in all fractions while Pb was found in the Fe/Mn oxide fraction (3.93- 21.3 %). Results showed that the bioavailability of Cu, Pb and Zn was high. Metal bioavailability by BCR indicates a potential risk of pollution in lagoon sediments as the available metals exceeded the permissible Sediment Quality Assessment Guidelines (SQAG’s) from Environmental Protection Agency (EPA).
ARTICLE | doi:10.20944/preprints202007.0339.v1
Subject: Earth Sciences, Environmental Sciences Keywords: cocoa seed; cocoa beans; heavy metals; Cadmium
Online: 16 July 2020 (04:09:54 CEST)
The presence of heavy metals in cocoa crops is currently a serious problem for farmers and producers in various regions of Peru. Exports of cocoa and its derivatives to European markets are threatened by possible indications of contamination of heavy metals such as Cadmium (Cd) in cocoa beans for export, some at levels higher than those allowed by food regulations established by European Community, which are oriented to consumer protection. The possible sources of cadmium contamination in cocoa crops can be due to natural activities, such as volcanic activities, erosion processes and sedimentation in rocks that contain minerals with a high content of heavy metals (Greenockite, Burnsite, Hawleite, among others), and by anthropogenic activities such as: mining of associated deposits, agriculture (use of fertilizers), smelting of minerals and burning of fossil fuels. Currently, there is no information about contents of heavy metals in areas located in The Campo Verde-Honoria-Tournavista corridor (Ucayali Region and Huanuco Region), due to this, in this work we make a study of this region. A methodology will be used to take cocoa samples from the seed and soil in these areas, and then through chemical analysis, determine the concentrations of heavy metals, using an atomic absorption spectrophotometer. As a consequence of this study, we determined and concluded that the concentrations of cadmium obtained in soils are slightly higher than European standards allowed. Therefore, with this information we prepare a geochemical cadmium map in soils for the study area, which will help cocoa producers to identify areas that exceed the allowed cadmium values, in order to comply with standards that European Community demands in relation of concentration levels of heavy metals (Cadmium) in chocolate. In this way, we can carry out in the future a mitigation plan for areas with cadmium problems, which allows to reduce their content in order to export the product without any problem. .
ARTICLE | doi:10.20944/preprints202003.0083.v1
Subject: Materials Science, General Materials Science Keywords: multiscale simulation; fatigue; metals; CRSS; endurance limit
Online: 5 March 2020 (11:33:05 CET)
The paper introduces a valuable new description of fatigue strength in relation to material properties and thus a new perspective on the overall understanding of the fatigue process. Namely, a relation between the endurance limits and the accompanying values of the critical resolved shear stress (CRSS) for various metallic materials has been discovered by means of a multiscale approach for fatigue simulation. Based on the uniqueness of the relation, there is a strong indication that it is feasible to relate the endurance limit to the CRSS, and not to the ultimate strength as often done in the past.
ARTICLE | doi:10.20944/preprints201912.0155.v1
Subject: Earth Sciences, Environmental Sciences Keywords: pollution sources; sediments; Palizada river; heavy metals
Online: 12 December 2019 (01:54:59 CET)
The fluvial-lagoon-deltaic system of the Palizada river in Campeche is an ecosystem of socioeconomic and ecological importance. It is justifiable to carry out studies in this system, due to its connection with another larger ecosystem called Términos lagoon. The objective of this investigation was to analyze the concentration of Pb and Cd in sediments of the fluvial-lagoon-deltaic system of the Palizada river and to determine, with this, the contamination index of these metals. Cd presented the highest concentration in sampling sites and climatic seasons with respect to Pb, with a maximum value of 53.926 ± 5.045, while Pb was 10.421 ± 0.218 μg g-1. The same tendency was presented with pollution and geoaccumulation indexes, where the Cd index stands out. The enrichment of heavy metals was identified through the accumulation of Cd and Pb, such process was evaluated through the geoacumulation index (Igeo). The results of this indicated that these elements are contaminating with an anthropogenic origin mainly. This element represents a toxic risk for the Palizada system, due to its high toxicity even at low concentrations, as well as to evaluate the sublethal effects in organisms that inhabit this system and it requires the implementation of an integral monitoring.
ARTICLE | doi:10.20944/preprints201806.0029.v1
Online: 4 June 2018 (10:13:25 CEST)
Family Fabaceae traditionally serves as food and herbal remedies source. Several plants are already used for menopausal symptoms treatment based on a presence of typical secondary metabolites, isoflavones. Beside soybean and clovers, isoflavones could be produced by other plants or in vitro cultures. This type of production can be further enhanced by elicitation that stimulates metabolites biosynthesis via stress reaction. Vanadium compounds have been already described as potential elicitors and the aim of this study was to determine an impact of NH4VO3 and VOSO4 solutions on isoflavones production in Genista tinctoria L. cell cultures. The significant increase of isoflavones content such as genistin, genistein or formononetin was measured in a nutrient medium or dry mass after NH4VO3 treatment for 24 or 48 hours. The possible transport mechanism of isoflavones was also evaluated. An incubation with different transport inhibitors prior elicitation took effect on isoflavones content in the medium. However, there was non-ended result for particular metabolites such as genistein and daidzein, where ABC or alternatively MATE proteins can participate. Possible elicitation by some inhibitors was also discussed as result of their pleiotropic effect. Despite this outcome, the determining of transport mechanism is important step for identification of specific transporter.
ARTICLE | doi:10.20944/preprints201805.0172.v1
Subject: Chemistry, General & Theoretical Chemistry Keywords: QTAIM; alkaline earth metals; theoretical electron densities.
Online: 10 May 2018 (16:32:42 CEST)
X-ray crystallographic and theoretical charge density data for a series of compounds [(Co(Ts3tren))M(Co(Ts3tren))] (M = Mg, Ca, Sr and Ba) is examined. The crystal structures are isostructural and the alkaline earth metal ions have the same arrangement of donor oxygen atoms despite the large variation in ionic radii. The isomorphism of these molecules is surprising and a theoretical examination of the electronic structures, with the different metal ions along the series, provides detailed insight into their stabilities. The theoretical and experimental data are consistent and agree well. The local properties of the Co(II) ion and its donor atoms are relatively independent of the alkali earth metal.
REVIEW | doi:10.20944/preprints201802.0051.v1
Subject: Life Sciences, Biotechnology Keywords: metals; dental regeneration; bioactivity; tissue regeneration; bone
Online: 6 February 2018 (05:25:46 CET)
The regeneration of bone tissue is a main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, while it should be resorbed even in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated and it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also on osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between the formation of new bone tissue and material degradation has not been found until now. The addition of different substances such as collagen or growth factors and also of different cell types have already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are differently used as basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designated for bone regeneration with the aim to give an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.
REVIEW | doi:10.20944/preprints202209.0048.v1
Subject: Chemistry, Chemical Engineering Keywords: removal; PAHs; heavy metals; marine sponges; bacterial consortium
Online: 5 September 2022 (07:43:34 CEST)
Toxic materials in waste generally contain several components of global trending pollutant categories, especially PAHs and heavy metals. Bioremediation technology for managing waste utilizing microorganisms (bacteria) has not been fully capable of breaking down these toxic materials simple and environmentally friendly chemical products. This study examines the potential application of a marine sponge symbiont consortium with high performance and efficiency in removing PAHs and heavy metal contaminants. The method is carried out through a review of some related research articles by the author and published by other re-searchers. The study results concluded that bioremediation technology development GTP, can be carried out to improve remediation efficiency. Several types of marine sponge symbiont bacteria, hydrocarbonoclastic (R-1), metalloclastic (R-2), and metallohydro-carbonoclastic (R-3), have the potential to be applied to improve the removal performance of waste. Bacterial screening be done to find and categorize R-1 bacteria, R-2; R-3 to remediate GTP. Develop of R-1 bacteria, R-2; R-3 forms of the mobile formulation are needed in the future. A crystalline consortium of bacteria preparations is needed so that they can be quickly mobilized to locations exposed to GTP. Marine sponge symbiont bacteria be traced mainly to marine sponges whose body surface is covered with mucus.
ARTICLE | doi:10.20944/preprints202208.0256.v1
Online: 15 August 2022 (11:22:35 CEST)
Studies suggest that elevated postnatal blood lead levels (BLLs) are negatively associated with child growth. This study aimed to investigate associations of childhood BLLs at age one-year and growth outcomes at age six-years (n=661) in a cohort of children in Allada, Benin. The growth outcomes studied are weight-for-age Z-score (WAZ), height-for-age Z-score (HAZ) and BMI-for-age Z-score (BMIZ), head circumference (HC), underweight, stunting, and wasting. Multivariable regression models examined associations between blood lead levels, growth outcomes with adjustment for potential confounders. The geometric mean BLLs was 59.3 μg/L and 82% of children had BLLs >35 μg/L at one year. After adjusting for confounding factors, no association was found between BLLs quartiles and HAZ, WAZ, BMIZ, and height and weight growth velocities. However, boys in the highest quartile had 1.02 cm lower HC (95% CI: [-1.81, -0. 24]) as compared to those in the lowest quartile with a dose-response trend across quartiles (Ptrend =0.02). Furthermore, an increased risk of being stunted was observed in children in the highest quartile of exposure compared to the first (OR: 2.43; 95% CI: [1.11 – 5.33]) with a dose-response trend (Ptrend =0.03). Blood lead was found to be associated with an increased risk of childhood stunting and lower head circumference in a resource-limited setting.
ARTICLE | doi:10.20944/preprints202206.0422.v1
Subject: Earth Sciences, Environmental Sciences Keywords: metals; trace elements; landscape; permafrost; river; watershed; boreal
Online: 30 June 2022 (08:44:41 CEST)
Towards a better understanding of vegetation, permafrost, climate, landscape and lithology control on major and trace element (including macro and micro-nutrients and toxicants) transport in riverine systems, we studied two medium size (100-150 thousand km² watershed area) pristine rivers (Taz and Ket) of boreal and subarctic zone, western Siberia. Choosing the river basins of very low population density (< 1 people km-²) in the absence of any industrial or agricultural activity allowed testing the sole effect of natural factors and long-range atmospheric transfer on hydrochemistry of riverine solutes during the open water period. In the permafrost-bearing Taz River (main stem and 17 tributaries), sizable control of vegetation on element concentration was revealed. In particular, light coniferous and broadleaf mixed forest controlled DOC, and some nutrients (N, Mn, Fe, Mo, Cd, Ba); deciduous needleleaf forest positively correlated with macronutrients (P, Si, Mg, P, Ca) and Sr, and dark needle-leaf forest impacted Ntot, Al and Rb. Organic C stock in the upper 30-100 cm soil positively correlated with Be, Mn, Co, Mo, Cd, Sb, and Bi. The lithological control was generally poorly pronounced, due to abundant peat deposits overlaying the mineral strata. However, cretaceous carbonate mineral-bearing sedimentary deposits positively impacted the pH and concentration of Si, Mg, Ca and Cs. In the Ket River basin (large right tributary of the Ob River), we revealed the correlations between the phytomass stock at the watershed and alkaline-earth metals and U concentration in the river water. This control was weakly pronounced during high-water period (spring flood) and mostly evidenced during summer low water period.
ARTICLE | doi:10.20944/preprints202105.0375.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Metals; Environmental monitoring; Bioassays; Amazon River; Amazon; mining
Online: 17 May 2021 (09:42:51 CEST)
As the number of legal and illegal mining sites increase, integrative methods to evaluate the effects of mining pollution on Andes-Amazonia freshwater ecosystems are paramount. Here, we sampled water and sediments in 11 sites potentially affected by mining activities in the Napo province (Ecuador). The environmental impacts were evaluated using four lines of evidence (LOEs): water physico-chemical parameters; metal exposure concentrations; macroinvertebrate community response (AAMBI); and toxicity by conducting bioassays with Lactuca sativa and Daphnia magna. Overall, dissolved oxygen and total suspended solids were, under (<80%) and above (>130 mg/Ls) quality standards. Ag, Al, As, Cd, Cu, Fe, Mn, Pb and Zn in water and V, B and Cr in sediments were detected above quality standards. Nine out of eleven sites were classified as having bad environmental quality based on the AAMBI. Ranges of L. sativa seed germination in both water (37% to 70%) and sediment (0% to 65%), indicate significant toxicity. In 5 sites, neonates of D. magna showed a 25% reduction in survival compared to the control. Our integrated LOEs index ranked sites regarding their environmental degradation. Given the importance of the Andes-Amazon region, we recommend environmental impact monitoring of the mining expansion using multiple LOEs.
ARTICLE | doi:10.20944/preprints202102.0608.v1
Subject: Chemistry, Analytical Chemistry Keywords: Cape Verde; cereals; metals; dietary intake; risk evaluation
Online: 26 February 2021 (11:05:17 CET)
Cereals and their derivatives are the basis of human nutrition. However, cereals also contribute to the dietary exposure to toxic metals that may pose a risk. Strengthening food security and nutrition information is a high priority challenge for the Cape Verde Government. The toxic metals content (Cr, Ni, Sr, Al, Cd, Pb) has been determined in 126 samples of cereals and derivatives (rice, corn gofio, corn flour, wheat flour, corn, wheat) consumed in Cape Verde. Wheat flour samples stand out for registering the highest Sr (1.60 mg/kg), Ni (0.25 mg/kg) and Cr (0.13 mg/kg). The results show relevant Al levels (1.17 – 13.4 mg/kg) with its highest levels in corn gofio. The mean Pb average content in the cereals is 0.03 – 0.08 mg/kg with the highest level observed in corn gofio. The Al and Pb levels are lower in cereals without husks. A consumption of 100 g/day of corn gofio provide an intake of 1.34 mg Al/day (13.7% of the tolerable weekly intake established at 1 mg/kg bw/week) and 8 µg Pb/day (20% of the BMDL set at 0.63 µg/kg bw/day for nephrotoxic effects). The minimization of the dietary exposure of the Cape Verdean population to toxic metals is through the importation of higher quality cereals.
REVIEW | doi:10.20944/preprints202102.0337.v1
Subject: Materials Science, Biomaterials Keywords: Nanomaterials; Rare earth metals; Wastewater treatment; CNT; Pollutants
Online: 16 February 2021 (14:12:17 CET)
Today major environmental issue facing the universe is Industrial wastewater. They are present in the form of various pollutants like organic/inorganic, heavy metals, and non-disintegrating materials at an enormous amount. As of now, eliminating these pollutants from wastewater from industries in a viable manner has become a significant issue. Productive refinement methodologies are required to eliminate those toxins before removal. Furthermore, nanomaterials are innovationally powerful to purification of water by utilizing inexpensive nanofiltration and nano adsorbent. Heavy metal ions removal in an efficient way from the environment is the first and foremost problem from a biological and ecological perspective, and numerous research practices have been dedicated to the removal of harmful metal particles, involved both in the underground and surface wastewater. This article mainly focuses on the nanomaterials utilization of various contaminating materials removal from industrial wastewater with an exceptional spotlight on rare earth components and nanofiber and nanocomposite films. The objective is to offer references an outline in the field of developing nanomaterials utilization for harmful pollutants removal from industrial wastewater for industrializers and analysts.
ARTICLE | doi:10.20944/preprints202012.0210.v1
Subject: Life Sciences, Biochemistry Keywords: antibiotic resistance; antibiotic alternatives; heavy metals; essential oils
Online: 9 December 2020 (09:44:37 CET)
Antimicrobial resistance (AMR) represents a growing crisis in both human and veterinary medicine. We evaluated the use of two categories of antibiotic alternatives – heavy metals and essential oils – in beef cattle, and their effects on gram-negative and gram-positive bacteria. In this randomized controlled field trial, we measured the impact of supplemental zinc and menthol on antimicrobial resistance among commensal enteric bacteria of feeder cattle. Fecal suspensions were plated onto plain- and antibiotic-supplemented MacConkey and m-Enterococcus agar for quantification of total and antimicrobial-resistant Escherichia coli and Enterococcus spp., respectively. Temporal effects on overall E. coli growth were significant (P< 0.05); however, there were no significant effects on antibiotic-supplemented agar. Zinc was associated with significant increases in growth on erythromycin-supplemented m-Enterococcus agar. Cattle fed zinc exhibited significantly higher macrolide resistance among fecal enterococci isolates.
REVIEW | doi:10.20944/preprints202011.0377.v1
Subject: Biology, Anatomy & Morphology Keywords: seagrass; trace metals; coastal ecosystems; Anthropogenic pollution; bioindicators
Online: 13 November 2020 (12:37:07 CET)
Seagrasses are considered as efficient bioindicators of coastal trace element contamination. This chapter provides an overview on the trace element accumulation, tolerance and biomonitoring capacity of the various seagrass species distributed along the coast of India. A total of 10 trace elements are reported in seagrasses, 11 in sediment and nine in the water column from India. From the 11 seagrass species studied, 60% of research have focused on Syringodium isoetifolium, Cymodocea serrulata, Cymodocea rotundata and Halophila ovalis. 78% of seagrass trace element research in India is from Palk bay and Gulf of Mannar (GOM), Tamil Nadu and 16% from Lakshadweep Islands. Out of the 10 trace elements, Cd, Cu, Pb and Zn are the most studied in seagrass, Fe, Mn, Ni and Pb in sediment and Cu, Fe, Mg, Ni and Zn in the water column. Accumulation capacity of various trace elements in seagrass were species-specific. S. isoetifolium have the highest concentration of Cd and Mg at Palk bay and Lakshadweep Islands respectively. The concentration of Cu was higher in C. serrulata at GOM. Halodule uninervis and Halophila decipens have the highest concentration of Co, and Cr, Ni, Pb and Zn from Lakshadweep Islands. The highest concentration of Fe and Mn were highest in Halophila beccarii and H. ovalis from the coast of Goa and Palk bay respectively. Threshold levels (>10 mg L-1) of Cd, Cu, Pb and Zn were observed for C. serrulata, H. ovalis, H. uninervis and T. hemprichii, that can affect the Photo System -II of these seagrasses and exert cellular stress leading to seagrass loss and die-off. High concentration of these elements can exert negative impacts on seagrass associated trophic assemblages and ecosystem functioning. Seagrasses of India can be utilized as bioindicators of coastal trace element contamination but the associated toxicity and human health risks needs further investigation.
ARTICLE | doi:10.20944/preprints202009.0731.v1
Subject: Chemistry, Analytical Chemistry Keywords: Cosmetic, Heavy metals, Toxicity, Cadmium, Atomic Absorption Spectroscopy.
Online: 30 September 2020 (09:07:14 CEST)
Throughout the ages and times, the need to use everything that reflects women's beauty and helps them maintain their vision and health, and if the need to use the precious materials has been put in place, it is important that they produce the desired results without attention to the harmful chemicals and heavy metals that they contain. Over time, the toxicity of these heavy metals increases in our environment because of their long-term exposure to these pollutants, whether low or high-level in toxicity, animal-prednmost, environment, including air we breathe, water, food, etc. Cosmetics are one of these sources through which humans are exposed to heavy toxic metals. Heavy metals have been estimated in a number of previous studies, and in our study here, we aim to estimate the amount of cadmium metal and study it in various cosmetics such as Lipstick, Eye shadow, Face whitening cream. Two samples were taken from each of the locomoys and cadmium was estimated using the photometer of atomic absorption, one of the samples being expensive and the other low-cost, and purchased from the wholesale markets of Taiz City. Cadmium has been found prominently in these products and the highest rate found in the lowest cost-effective, Eye shadow, that the use of these cosmetic products exposes users to low- conc. heavy metals, which may pose a danger to their health. They are known to be clustered in their biological systems over time, resulting in an imbalance of body and environment. The results found that the low-priced color samples contained a higher concentration of cadmium than the high-price samples in low-priced samples, cadmium concentration was in order of eye shadow > lipstick = face whitening cream. The similar pattern are shown also for higher price product, which are lipstick > face whitening cream > eye shadow.
ARTICLE | doi:10.20944/preprints201908.0296.v1
Subject: Biology, Plant Sciences Keywords: oxidative stress; antioxidative system; Brassicaceae family; heavy metals
Online: 28 August 2019 (14:43:10 CEST)
Metal hyperaccumulating plants should have extremely efficient defence mechanisms, enabling growth and development in a polluted environment. Brassica species are known to display hyperaccumulation capability. Brassica juncea (Indiana mustard) v. Malopolska plants were exposed to trace elements, i.e., cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn), at a concentration of 50 M and were then harvested after 96 hours for analysis. We observed a high index of tolerance (IT), higher than 90%, for all B. juncea plants treated with the four metals, and we showed that Cd, Cu, Pb and Zn accumulation was higher in the above-ground parts than in the roots. We estimated the metal effects on the generation of reactive oxygen species (ROS) and the levels of protein oxidation as well as on the activity and gene expression of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). The obtained results indicate that organo-specific ROS generation was higher in plants exposed to essential metal elements (i.e., Cu and Zn), compared with non-essential ones (i.e., Cd and Pb), in conjunction with SOD, CAT and APX activity and expression at the level of encoding mRNAs and existing proteins. In addition to the potential usefulness of B. juncea in the phytoremediation process, the data provide important information concerning plant response to the presence of trace metals.
ARTICLE | doi:10.20944/preprints201908.0251.v1
Subject: Earth Sciences, Environmental Sciences Keywords: anthropogenic mineral; recycling; circular economy; metals; urban mining
Online: 25 August 2019 (15:15:47 CEST)
An increasingly large quantity of primary mineral resource is being converted into manufactured products and destined for solid waste disposal. This material can be reclassified as “anthropogenic mineral reserves” and be a potential source of metals for a range of manufacturing uses. China is implementing a range of policy interventions which can lead to such a classification that will raise the profile of recycling programs as a means of metal supply. China is not only a major producer of consumer products and importer of secondary metals, but also has a major urban infrastructure footprint. Here we consider three product groups, 30 products, and imports, and map the recycling potential of anthropogenic mineral and 23 types of the capsulated materials by targeting their evolution from 2010 to 2050. Total weight of anthropogenic mineral on average in China reached 39 Mt in 2010, but it will double in 2022 and quadruple in 2045. Stocks of precious metals and rare earths will increase faster than most base materials. The total economic potential in yearly-generated anthropogenic mineral is anticipated to grow markedly from 100 billion US$ in 2020 to 400 billion US$ in 2050. Anthropogenic mineral of around 20 materials will be able to meet projected consumption of three product groups by 2050, due to high availability of recycled content and gradual saturation of consumption. Durability of material usage and the concomitant stock of the anthropogenic mineral remain major challenges in determining the viability of this supply in the second half of the coming century.
ARTICLE | doi:10.20944/preprints201807.0599.v1
Subject: Chemistry, Applied Chemistry Keywords: 4-Methylacetophenone; Refractory metals; Solvent extraction; Selective recovery
Online: 30 July 2018 (22:03:33 CEST)
A study has been carried out on Ta and Nb recovery by liquid-liquid extraction process using 4-methylacetophenone (4-MAcPh) as organic phase. The 4-MAcPh was compared to methylisobutylketone (MIBK) with respect to extraction efficiencies (kD values) at different concentrations of H2SO4 in the aqueous phase. The results showed a similar extraction of Nb for both solvents. However, for Ta extraction efficiency is increased by a factor of 1.3 for 4-MAcPh. In addition, the MIBK solubilized completely after 6 mol L-1 of H2SO4 against only a loss of 0.14 to 4% for 4-MAcPh between 6 and 9 mol L-1 of H2SO4. The potential of 4-MAcPh has also been studied to selectively recover Ta from a model capacitor waste solution. The results showed a selectivity for Ta in the presence of impurities such as Fe, Ni, Mn. The 4-MAcPh also presents the advantage of having physicochemical properties adapted to its use in liquid-liquid extraction technologies such as mixer-settlers.
ARTICLE | doi:10.20944/preprints201805.0311.v1
Subject: Life Sciences, Other Keywords: phytochemical; heavy metals; flavoured alcoholic beverages; herbal extract
Online: 23 May 2018 (05:15:55 CEST)
There is proliferation of alcoholic beverages flavoured with herbal-extracts perceived to have medicinal values. Information on the phytochemical and heavy metal contents of these products is scarce. This study assessed the phytochemical properties and heavy metal contents of herbal-extract flavoured alcoholic beverages in major motor parks in Ibadan, Nigeria. The phytochemical properties of the beverages were determined in triplicate using standard methods while the heavy metal contents were assessed using atomic absorption spectrophotometry. Data were analyzed using descriptive statistics and means were compared using ANOVA at p<0.05. The pH range of the beverages was 3.28-6.57 and the alcohol content was 34.0-51.5%. Detected major phytochemicals and concentration ranges were phytic acid (0.72-2.37 mg/g), alkaloids (0.42-4.11 mg/g), flavonoids (0.22-3.64 mg rutin equivalents/g), total phenols (1.13-3.66 mg gallic acid equivalents/g), anthraquinones ((0.74-1.93 mg/g) and triterpenoids (0.74-1.93 mg/g). The phytochemical contents were within the acceptable limits while the heavy metals were: Pb (2.13-4.70 mg/L), Cd (0.06-0.07 mg/L), Co (0.12-0.23 mg/L), Zn (0.14-0.40 mg/L) and Fe (0.72-4.22 mg/L); all except Pb and Cd were within permissible limits. The herbal-extract flavoured alcoholic beverages contain beneficial phytochemicals and traces of heavy metals. Safety awareness of these products for improved consumers’ health would be of public health importance.
ARTICLE | doi:10.20944/preprints201709.0012.v1
Subject: Earth Sciences, Environmental Sciences Keywords: dams; trace metals; contaminated sediments; siltation; sedimentation rate
Online: 5 September 2017 (04:13:17 CEST)
Reservoirs are characterized by accumulation of sediments where micropollutants may concentrate, with potential toxic effects on downstream river ecosystems. However, sediment management such as flushing is needed to maintain storage capacity. Climate change is expected to increase sediment loads, but potential effects on their quality are scarcely known. In this context, sediment contamination by trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) and organics (PAHs, PCBs, C>12) was analyzed in 20 reservoirs located in Italian Central Alps. A strong As and a moderate Cd, Hg and Pb enrichment was emphasized by Igeo, with potential ecotoxicological risk according to PEC quotients. Siltation, granulometry, total organic carbon (TOC) and altitude resulted as the main drivers governing pollutant concentrations in sediments. According to climate change models, expected increase of rainfall erosivity will enhance soil erosion and consequently the sediment flow to reservoirs, potentially increasing coarse grain fractions and thus potentially diluting pollutants. Conversely, increased weathering may enhance metal fluxes to reservoirs. Increased vegetation cover will potentially result in higher TOC concentrations, which may contrast contaminant bioavailability and thus toxicity. Our results may provide elements for a proper management of contaminated sediments in a climate change scenario aiming at preserving water quality and ecosystem functioning.
REVIEW | doi:10.20944/preprints202212.0043.v1
Subject: Chemistry, Other Keywords: adsorption; GBV; heavy metals; secondary pollution; spent adsorbent reuse
Online: 2 December 2022 (08:43:18 CET)
Water contamination has intensified over the year as the world's population and industrial activities have grown. Heavy metals (HMs) are amongst the environmental contaminants commonly found in water and wastewater. These include Lead, Manganese, Chromium, Mercury, etc. Various techniques have been used to remediate this environmental challenge and adsorption has proven to be more effective because it is simple to use, excellent efficiency, low cost, possibility to operate in several experimental conditions. Regrettably, this method yields waste materials, which represents a scaling restriction. Furthermore, after the HM has been removed and loaded onto the adsorbent, there is still a question of the fate of the metal-loaded adsorbent. Most of the time these metal loaded adsorbents are discarded in the environment and constitute a secondary pollution. New applications for heavy metals laden have been investigated. This review article presents the various applications that had been investigated to reuse the loaded metal adsorbent. A case study on developing tools for combatting gender-based violence (GBV) has also been discussed.
ARTICLE | doi:10.20944/preprints202204.0205.v1
Subject: Chemistry, Other Keywords: pollutants; microplastics; heavy metals; PAH; pesticide residues; medical waste
Online: 21 April 2022 (10:53:10 CEST)
A quality marine ecosystem if it is free from GTP contaminants. Accuracy and caution are needed in the exploitation of marine resources as marine tourism destinations so that in the future, there will be no ecological hazards that cause chain effects, not only on aquatic ecosystems but also on humans. This article identifies exposure to GTP (MP, PAH, PR, HM, MW) in marine ecosystems in the MTA area and BCI waters. The combination of qualitative and quantitative analysis methods uses a combination of analytical instruments and mathematical formulas. The search results show the average total abundance of MP in seawater and fish samples (5.47 units/m3) and (7.03 units/m3), respectively, while in sediment and sponge samples (8.18 units/m3) and (8.32 units/m3). Based on the analysis of the polymer structure, it was identified that the dominant light group MP (PE, PP and PS), followed by PA and PC. Several PAH pollutants were identified in the samples, especially NL types found in all samples, followed by PN and AZ. BCI sea waters are suspected to be exposed to MW and PR. Pollutants of Pb+2 and Cu+2 around BCI were successfully calculated with average concentrations in seawater 0.164 mg/L and 0.294 mg/L, respectively, while in fish, 1.8110 µg/g and 2,452 µg/g, respectively. Based on these findings, the BCI area is not recommended as a marine tourism destination.
ARTICLE | doi:10.20944/preprints202204.0186.v1
Subject: Earth Sciences, Environmental Sciences Keywords: arid regions; Kazakhstan; irrigated soils; soil salinity; heavy metals
Online: 20 April 2022 (08:53:15 CEST)
A single paragraph of about 200 words maximum. For research articles, abstracts should give a pertinent overview of the work. We strongly encourage authors to use the following style of structured abstracts, but without headings: (1) Background: Place the question addressed in a broad context and highlight the purpose of the study; (2) Methods: briefly describe the main methods or treatments applied; (3) Results: summarize the article's main findings; (4) Conclusions: indicate the main conclusions or interpretations. The abstract should be an objective representation of the article and it must not contain results that are not presented and substantiated in the main text and should not exaggerate the main conclusions.
REVIEW | doi:10.20944/preprints202201.0233.v2
Subject: Chemistry, Electrochemistry Keywords: water electrolysis; nickel; earth-abundant metals; electrocatalysis; HER; OER
Online: 24 January 2022 (14:30:26 CET)
Current hydrogen production is based on the reforming process leading to the emission of pollutants; therefore, a substitute production method is imminently required. Water electrolysis is an ideal alternative for large-scale hydrogen production, as it does not produce any carbon-based pollutant byproducts. Production of green hydrogen from water electrolysis using intermittent sources (e.g., solar, eolic) would facilitate clean energy storage. However, the electrocatalysts currently required for water electrolysis are noble metals, making this potential option expensive and inaccessible for industrial applications. Therefore, there is a need to develop electrocatalysts based on earth-abundant and low-cost metals. Nickel-based electrocatalysts are a fitting alternative because they are economically accessible. Extensive research has focused on developing nickel-based electrocatalysts for hydrogen and oxygen evolution. Theoretical and experimental work have addressed the elucidation of these electrochemical processes and the role of heteroatoms, structure, and morphology. Even though some works tend to be contradictory, they have lit up the path for efficient nickel-based electrocatalysts. For these reasons, herein, a review of recent progress is presented.
ARTICLE | doi:10.20944/preprints202104.0434.v1
Subject: Medicine & Pharmacology, Allergology Keywords: environmental exposures; heavy metals; idiopathic dilated cardiomyopathy; Katanga Copperbelt
Online: 16 April 2021 (10:43:32 CEST)
Blood and/or urine levels of 27 heavy metals were determined by ICPMS in 41 patients with dilated cardiomyopathy (DCM) and 29 presumably healthy subjects from the Katanga Copperbelt (KC), in the Democratic Republic of Congo (DRC). After adjusting for age, gender, education level, and renal function, DCM probability was almost maximal for blood concentrations above 0.75 and 150 µg/dl for arsenic and copper, respectively. Urinary concentrations above 1 for chromium, 20 for copper, 600 for zinc, 30 for selenium, 2 for cadmium, 0.2 for antimony, 0.5 for thallium and 0.05 for uranium, all in μg/g of creatinine, were also associated with increased DCM probability. Concurrent and multiple exposures to heavy metals, well beyond permissible levels, are associated with increased probability for DCM. Study findings warrant screening for metal toxicity in case of DCM and prompt public health measures to reduce exposures in the KC, DRC.
ARTICLE | doi:10.20944/preprints202101.0004.v1
Subject: Life Sciences, Biochemistry Keywords: shipyard welders; PM2.5 metal components; urinary metals; insulin resistance
Online: 4 January 2021 (08:38:23 CET)
Certain studies have reported various insulin resistance responses to ambient heavy metal pollution, but few have reported such responses to occupational heavy metal pollution. Even fewer have demonstrated a relationship between mixture effects of heavy metals and insulin resistance in welding workers. Overall, we recruited 53 welders and 48 administrative staff from a shipyard located in northern Taiwan. Personal exposure to heavy metals was monitored for PM2.5 and urine. Blood samples from each participant were collected from the antecubital vein after fasting. Urine samples from each participant were collected in the same period as blood samples. The geometric mean levels for chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd) in the PM2.5 of the personal breathing zone and urinary Mn of welders were significantly higher than those in administrative staffs. Ambient Cr, Co, Ni, and Cu levels in the PM2.5 and urinary Cd were positively related to HOMA2-IR after adjusting for personal covariates (PM2.5-Cr: β=0.036, 95%C.I.: 0.002 to 0.070; PM2.5-Co: β=0.040, 95%C.I.: 0.002 to 0.077; PM2.5-Ni: β=0.054, 95%C.I.: 0.013 to 0.094; PM2.5-Cu: β=0.049, 95%C.I.: 0.010 to 0.088; U-Cd: β=0.209, 95%C.I.: 0.052 to 0.366, respectively). Our findings indicated the PM2.5 metal components and urinary metals were associated with increased insulin resistance in shipyard welders.
ARTICLE | doi:10.20944/preprints202007.0236.v1
Subject: Chemistry, Other Keywords: trace metals; mine drainage remediation; zinc; red media; biochar
Online: 11 July 2020 (09:36:40 CEST)
The river Teign in Devon has come under scrutiny for failing to meet Environmental Quality Standards for ecotoxic metals due to past mining operations. A disused mine known as Bridford Barytes mine, has been found to contribute a significant source of Zn, Cd and Pb to the river. Recently, studies have been focused on the remediation of such mine sites using low-cost treatment methods to help reduce metal loads to the river downstream. Red mud is a waste product from the aluminium industry, the utilization of this resource has proven an attractive low-cost treatment method for adsorbing toxic metals. Adsorption kinetics and capacity experiments reveal metal removal efficiencies of up to 70% within the first 2 hours when red mud is applied in pelletized form. Biochar is another effective adsorbent with the potential to remove >90% Zn using agricultural feedstock. Compliance of the Teign has been investigated by analysing dissolved metal concentrations and bioavailable fractions of Zn to assess if levels are of environmental concern. By applying a Real-World Application Model, this study reveals that compressed pellets and agricultural biochar offer an effective, low-cost option to reducing metal concentrations and thus improving the quality of the river Teign.
ARTICLE | doi:10.20944/preprints201908.0074.v1
Subject: Biology, Ecology Keywords: Heavy metals; Mining; Balochistan gerbil; liver injury; Kidney damage.
Online: 6 August 2019 (12:14:09 CEST)
Mining can impact the environment, biodiversity and human health through direct and indirect practices. This study investigated the effects of gold mining on Gerbillus nanus, pointing to organ dysfunction and redox imbalance. Soil samples, Lycium shawii and G. nanus were collected from a site near a mining planet and a control site. Soil and L. shawii samples from the mining site showed a significant increase cadmium (Cd), cupper (Cu), mercury (Hg), arsenic (As), zinc (Zn), lead (Pb) and vanadium (V). Hepatic, renal and pulmonary Cd, Pb, Hg, Zn, Cu, Fe, As and V concentrations were increased significantly in G. nanus at the mining site. Markers of liver and kidney function were elevated in serum, and several histological manifestations were demonstrated in liver, kidney and lung of G. nanus at the mining site. Malondialdehyde and nitric oxide were increased, and glutathione and antioxidant enzyme were declined in the liver and kidney of G. nanus. In conclusion, mining practices triggered tissue damage and oxidative stress in G. nanus living close to the mining site. These findings can represent the scientific basis for evaluating the environmental and health impact of mining in the on the nearby communities.
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: heavy metals; oligodendrocytes; myelination; lipid formation; intracellular calcium regulation
Online: 1 August 2019 (04:47:18 CEST)
Evidence has been accumulated demonstrating that heavy metals may accumulate in various organs leading to tissue damage and toxic effects in mammals. In particular, the Central Nervous System (CNS) seems to be particularly vulnerable to cumulative concentrations of heavy metals, though the pathophysiological mechanisms is still to be clarified. In particular the potential role of oligodendrocyte dysfunction and myelin production after exposure to subtoxic concentration of heavy metals is to be better assessed. Here we investigated on the effect of sub-toxic concentration of several essential (Cu2 +, Cr3+, Ni2+, Co2+) and non-essential (Pb2+, Cd2+, Al3+) heavy metals on MO3.13 and SHSY5Y human oligodendrocyte and neuronal cell lines (grown individually or in co-culture). In particular, exposure of both cell lines to heavy metals produced a reduced cell viability of co-cultured cell lines compared to cells grown separately. This effect was more pronounced in neurons which were more sensitive to metals than oligodendrocytes when the cells were grown in co-culture. On the other hand, a significant reduction of lipid component in cells occurred after their exposure to heavy metals, an effect accompanied by substantial reduction of the main protein that makes up myelin (MBP) in co-cultured cells. Finally, the effect of heavy metals in oligodendrocytes were associated to imbalanced intracellular calcium ion concentration as measured through the fluorescent Rhod-2 probe, thus confirming that heavy metals, even used at subtoxic concentrations, lead to dysfunctional oligodendrocytes. In conclusion, our data show, for the first time, that sub-toxic concentrations of several heavy metals lead to dysfunctional oligodendrocytes, an effect highlighted when these cells are co-cultured with neurons. The pathophysiological mechanism(s) underlying this effect is to be better clarified. However, imbalanced intracellular calcium ion regulation, altered lipid formation and, finally, imbalanced myelin formation seem to play a major role in early stages of heavy metal-related oligodendrocyte dysfunction.
ARTICLE | doi:10.20944/preprints201801.0076.v1
Subject: Earth Sciences, Geology Keywords: cations; groundwater; heavy metals; pollution; anions; surface water; microbes
Online: 9 January 2018 (07:39:44 CET)
Analysis of water resources of this area was carried out in order to assessing the water quality by determining the concentrations of Cations, Anions, Heavy metals, Trace elements, PH, Alkalinity, Total Dissolved Solids and microbial loads in water samples. Ten (10) water samples were collected from the study area - samples each of rain water, two pond waters - 1 and 2, stream water, four (4) hand-dug wells, hand pump water and a motorized borehole. The results obtained were compared with WHO standards and it showed that all the cations in water samples are within the limits. The water samples at locations B, E, F, G, H, I, and J have high alkalinity and HC0-3 content. The heavy metals (Pb, Ni and Cd) and trace elements (Fe and Cu) are dominantly high in the surface waters. Microbiological substances in the water samples from the study area revealed indicator organisms higher than the WHO standard for drinking water. Samples obtained from location G, I and J recorded an absence of E. coli and are fit for human consumptions but needed to be treated due to high MPN (Most Probable Number) index of viable microorganisms as against WHO standard. This research showed that the water resources of the study area are gradually polluted and in the near future may not be good for drinking.
ARTICLE | doi:10.20944/preprints201712.0038.v1
Subject: Earth Sciences, Environmental Sciences Keywords: sewage sludge recycling; soil organic fertility; heavy metals bioavailability
Online: 7 December 2017 (05:41:57 CET)
The biomass fraction of processed municipal and industrial wastes added to soil can maintain, and in some case improve, the soil’s organic fertility. One of the main constraints in the agricultural use of the sewage sludge is its content of heavy metals. In the long term, soil administration of sewage sludge in agriculture could result in a risk of environmental impact. The aim of this research was to evaluate the effects of medium-term fertilization with sewage sludge diversely processed on the soil’s organic carbon content and humification – mineralization soil’s processes and on the physical and mechanical properties of soil. Furthermore, the heavy metals accumulation in soil, in their total and available form, has been investigated. After eight years of administration to soil, the use of sewage sludge as an agricultural soil amendment has contributed to maintaining the soil’s organic fertility. An increase in concentrations of total Ni and Zn was detected in soil. For bioavailable form (DTPA-extractable) this trend was evidenced for all heavy metals analysed. However, the concentrations of total and available heavy metals in the soil did not exceed the legal threshold established by Italian law for unpolluted soils.
ARTICLE | doi:10.20944/preprints201710.0109.v1
Subject: Earth Sciences, Environmental Sciences Keywords: dust; bioavailability; particle sizes; heavy metals; health risk; exposure
Online: 17 October 2017 (03:59:40 CEST)
In this study, we attempted to verify the hypothesis that total metals bound to dust of different particle sizes may reflect pollution levels, but cannot predict its bioavailability and risks in human health assessments. Dust samples were collected using active sampling method; during the dry season months of November, 2014 to March, 2015 at different locations in Akure (7˚10ʹN and 5˚15ʹE). The samples were sorted into different particle sizes (< 10µm, 10 – 50 µm, >50µm), analyzed for some physicochemical properties and assessed for metals bioavailability using two-step physiological extraction method. The amount of metals (Cd, Cu, Cr, Ni, Pb, Zn and Mn) released in each particle sizes were determined using Perkin-Elmer 6000 Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES) analysis. The results showed that bioavailability of some metals (Cd, Ni, Pb, and Zn) decreases with increasing particle sizes, however, the reverse trend was observed for Mn, Cu and Fe concentrations. This may be attributed to some combination of physicochemical characteristics of the dust and metal speciation. Hence, it was concluded that metal bioaccessibility in dust can best be described by the knowledge of physicochemical characteristics. The exposure dose of the metals showed that cancer risks due to inhalation were very high when compared to other exposure routes (ingestion and dermal contact). The calculated non-cancer (HQ) and cancer risk (HI) for humans in the area showed values higher than unity, indicating possibility of the metals’ body burden.
ARTICLE | doi:10.20944/preprints201710.0026.v1
Subject: Materials Science, Nanotechnology Keywords: carbon materials; heavy metals; optical sensors; spectroscopy; photoluminescence; quenching
Online: 4 October 2017 (16:55:37 CEST)
A novel type of graphene-like quantum dots, synthesized by oxidation and cage-opening of C60 buckminsterfullerene, has been studied as a fluorescent and absorptive probe for heavy-metal ions. The lattice structure of such unfolded fullerene quantum dots (UFQDs) is distinct from that of graphene since it includes both carbon hexagons and pentagons. The basic optical properties, however, are similar to those of regular graphene oxide quantum dots. On the other hand, UFQDs behave quite differently in the presence of heavy-metal ions, in that multiple sensitivity to Cu2+, Pb2+ and As(III) was observed through comparable quenching of the fluorescent emission and different variations of the transmittance spectrum. By dynamic light scattering measurements we confirmed, for the first time in metal sensing, that this response is due to multiple complexation and subsequent aggregation of UFQDs. Nonetheless, the explanation of the distinct behaviour of transmittance in the presence of As(III) and the formation of precipitate with Pb2+ require further studies. These differences, however, also make it possible to discriminate between the three metal ions in view of the implementation of a selective multiple sensor.
ARTICLE | doi:10.20944/preprints202207.0092.v1
Subject: Behavioral Sciences, Other Keywords: Heavy metals; Risk assessment; Source analysis; Surface sediment; Qinjiang River
Online: 6 July 2022 (08:57:28 CEST)
Heavy metals are toxic, persistent and non-degradable. After sedimentation and adsorption, they accumulate in water sediments. The aim of this study was to understand the heavy metal pollution of Qinjiang River sediments on the ecological environment and apportioning sources. The mean total concentrations of Mn, Zn, Cr, Cu, and Pb are 3.14, 2.33, 1.39, 5.79, and 1.33 times higher than the background values, respectively, except for the Co, Ni, and Cd, which are lower than the background values; Fe, Co, Ni, Cd, Cr, Cu, and Pb are all primarily in the residual state, while Mn and Zn are primarily in the acid-soluble and oxidizable states, respectively. Igeo, RI, SQGs and RAC together indicate that the pollution status and ecological risk of heavy metals in Qinjiang River sediments are generally moderate; among them, Fe, Co, Ni, Cd, Cr, and Pb are not harmful to the ecological environment of the Qinjiang River. Cu is not readily released because of its higher residual composition, depicting that Cu is less harmful to the ecological environment. Mn and Zn, as the primary pollution factors of the Qinjiang River, are harmful to the ecological environment. This heavy metal pollution in surface sediments of the Qinjiang River primarily comes from manganese and zinc ore mining. Manganese carbonate and its weathered secondary manganese oxide are frequently associated with a significant amount of residual copper and Cd, as a higher pH is suitable for the deposition and enrichment of these heavy metals. Lead-zinc ore and its weathering products form organic compounds with residual Fe, Co, Cr, and Ni, and their content is related to salinity. The risk assessment results of heavy metals in sediments provide an important theoretical basis for the prevention and control of heavy metal pollution in Qinjiang River.
ARTICLE | doi:10.20944/preprints202111.0577.v1
Subject: Life Sciences, Other Keywords: Ciona robusta; tunicate; metals; typical 2-Cys peroxiredoxins; antioxidant enzymes.
Online: 30 November 2021 (17:58:47 CET)
Typical 2-Cys peroxiredoxins (2-Cys Prdxs) are proteins with antioxidant properties belonging to the thioredoxin peroxidase family. With their peroxidase activity, they contribute to the homeostatic control of reactive oxygen species (ROS) and, therefore, participate in various physiological functions such as cell proliferation, differentiation, and apoptosis. Although Prdxs have been shown to be potential biomarkers for monitoring the aquatic environments, minimal scientific attention has been devoted to describing their molecular architecture and function in marine invertebrates. Our study aims to clarify the protective role against stress induced by exposure to metals (Cu, Zn, and Cd) of three Prdxs (Prdx2, Prdx3, and Prdx4) in the solitary ascidian Ciona robusta, an invertebrate chordate. Here we report a detailed pre- and post-translational regulation of the three Prdx isoforms. Data on intestinal mRNA expression, provided by qRT-PCR analyses, show a generalized increase for Prdx2, 3, and 4, which is correlated to metal accumulation. Furthermore, the increase in tissue enzyme activity observed after Zn exposure is slower than that observed with Cu and Cd. The obtained results increase our knowledge of the evolution of anti-stress proteins in invertebrates and emphasize the importance of the synthesis of Prdxs as an efficient way to face adverse environmental conditions.
ARTICLE | doi:10.20944/preprints202109.0308.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: coltan; niobium; tantalum; critical raw materials; technological metals; mineral processing.
Online: 17 September 2021 (12:02:04 CEST)
Demand for niobium and tantalum is increasing exponentially as these are essential ingredients for the manufacture of, among others, capacitors in technological devices and ferroniobium. Mine tailings rich in such elements could constitute an important source of Nb and Ta in the future and so alleviate potential supply risks. This paper evaluates the possibility of recovering niobium and tantalum from the slags generated during the tin beneficiation process of mine tailings from the old Penouta mine, located in Spain. To do so, a simulation of the processes that would be required to beneficiate and refine both elements is carried out. After tin carbothermic reduction, the slags are sent to a hydrometallurgical process where at the end niobium oxide and tantalum oxide are obtained. Reagents, water and energy consumption, in addition to emissions, effluents and product yields are assessed. Certain factors were identified as critical, and recirculation was encouraged in the model to maximize production and minimize reagents use and wastes. With this simulation, considering 3000 production hours per year, the metal output from the tailings of the old mine could cover around 1% and 7.4% of the world annual Nb and Ta demand, respectively.
ARTICLE | doi:10.20944/preprints202108.0412.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: additive manufacturing; scaffolds; bioabsorbable metals; lattice structures; stiffness properties; biodegradation
Online: 20 August 2021 (11:57:25 CEST)
For orthopaedic applications, additive manufactured (AM) porous scaffolds made of absorbable metals like magnesium, zinc or iron are of particular interest. They do not only offer the potential to design and fabricate bio-mimetic or rather bone equivalent mechanical properties, they also do not need to be removed in further surgery. Located in a physiological environment, scaffolds made of absorbable metals show a decreasing Young’s modulus over time, due to product dissolution. For WE43 scaffolds, during the first days an increase of the smeared Young's modulus can be observed, which is mainly attributed to a forming substrate layer of degradation products on the struts surfaces. In this study the influence of degradation products on the stiffness properties of metallic scaffolds is investigated. For this, analytical calculations and finite element simulations are performed to study the influence of the substrate layer thickness and Young's modulus for single struts and for a new scaffold geometry with adapted polar f2cc,z unit cells. The finite element model is further validated by compression tests on AM scaffolds made from Zn1Mg. The results show, that even low thicknesses and Young's moduli of the substrate layer increases significantly the smeared Young's modulus under axial compression.
ARTICLE | doi:10.20944/preprints202106.0451.v1
Subject: Chemistry, Analytical Chemistry Keywords: Clinoptilolites; Acid modification; heavy metals; toxic substances; purification; lead removal.
Online: 17 June 2021 (09:14:51 CEST)
Four naturally occurring zeolites AZLB-Ca and AZLB-Na (Bowie, Arizona), NM-Ca (Winston, New Mexico), and NV-Na (Ash Meadows, Nevada) were studied to evaluate structural modifications after treatment with HCl acid. AZLB-Ca and AZLB-Na are chabazite-like species and become amorphous when boiled in concentrated HCl acid as confirmed by powder X-ray diffraction. In contrast, NM-Ca and NV-Na which are clinoptilolite-like species withstood boiling in concentrated HCl acid. This treatment removes calcium, magnesium, sodium, potassium, aluminum, and iron atoms or ions from the framework while leaving the silicon framework intact as confirmed via X-ray fluorescence and diffraction. SEM images on calcined and HCl treated NV-Na were obtained. BET surface area analysis confirmed an increase in surface area for the two zeolites after treatment, NM-Ca (20.0(1) to 111(4) m2/g) and NV-Na (19.0(4) to 158(7) m2/g). 29Si and 27Al MAS NMR were performed on the natural and treated NV-Na zeolite and the data for the natural NV-Na zeolite suggested a Si:Al ratio of 4.33 similar to that determined by X-Ray fluorescence of 4.55. Removal of lead ions from solution decreased from the native (NM-Ca, 0.27(14), NV-Na, 1.50(17) meq/g) compared to the modified zeolites (30 min HCl treated NM-Ca 0.06(9) and NV-Na, 0.41(23) meq/g) and also decreased upon K+ ion pretreatment in the HCl modified zeolites.
ARTICLE | doi:10.20944/preprints202102.0060.v1
Subject: Biology, Anatomy & Morphology Keywords: Escherichia coli; magnetite nanoparticles; metals; antibiotics; genomics; pleiotropy; cell morphology
Online: 1 February 2021 (15:58:10 CET)
Experimental evolution was utilized to produce 5 magnetite nanoparticle-resistant (FeNP1-5) populations of Escherichia coli. The control populations were not exposed to magnetite nanoparticles. The 24-hour growth of these replicates was evaluated in the presence of increasing concentrations magnetite NPs as well as other ionic metals (gallium III, iron II, iron III, silver I) and antibiotics (ampicillin, chloramphenicol, rifampicin, sulfanilamide, tetracycline). Scanning electron microscope was utilized to determine cell size and shape in response to magnetite nanoparticle selection. Whole genome sequencing was carried out to determine if any genomic changes that resulted from magnetite nanoparticle resistance. After 25 days of selection magnetite resistance was evident in the FeNP treatment. The FeNP populations also showed a highly significantly (p < 0.0001) greater 24-growth as measured by optical density in metals (Fe (II), Fe (III), Ga (III), Ag and Cu II); as well as antibiotics (ampicillin, chloramphenicol, rifampicin, sulfanilamide, and tetracycline). The FeNP resistant populations also showed a significantly greater cell length compared to controls (p < 0.001). Genomic analysis of FeNP identified both polymorphisms and hard selective sweeps in the RNA polymerase genes rpoA, rpoB, and rpoC. Collectively, our results show that E. coli can rapidly evolve resistance to magnetite nanoparticles and that this result is correlated resistances to other metals and antibiotics. There were also changes in cell morphology resulting from adaptation to magnetite NPs. Thus, the various applications of magnetite nanoparticles could result in unanticipated changes in resistance to both metal and antibiotics.
REVIEW | doi:10.20944/preprints202010.0593.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Oligodendrocytes; Myelination; Endoplasmic Reticulum; Unfolded Protein Response; Heavy metals; alcohol
Online: 28 October 2020 (14:08:14 CET)
Oligodendrocytes are myelinating cells of the central nervous system, which are generated by progenitor oligodendrocytes as a result of maturation processes. The main function of mature oligodendrocytes is to produce myelin, a lipid-rich multi-lamellar membrane that wraps tightly around neuronal axons, isolating them and facilitating nerve conduction through saltatory propagation. The myelination process requires the consumption of a lot of energy and a high metabolic turnover. Mitochondria are essential organelles which regulate many cellular functions including the energy production through oxidative phosphorylation. Any mitochondrial dysfunction impacts cellular metabolism and negatively affects the health of the organism. If the functioning of the mitochondria is unbalanced the myelination process is impaired. At the end of myelination, oligodendrocytes synthesize about 40% of the total lipids present in the brain. Since lipid synthesis occurs in the cellular endoplasmic reticulum, the alteration of this organelle can lead to partial or deficient myelination, triggering numerous neurodegenerative diseases. In this review the main dysfunctions of oligodendrocytes caused by exogenous or endogenous stimuli will be investigated. Furthermore, the oligodendrocyte reactions to excessive mitochondrial oxidative stress and an altered regulation of the functioning of the endoplasmic reticulum will be discussed.
ARTICLE | doi:10.20944/preprints201911.0015.v1
Subject: Engineering, Civil Engineering Keywords: phase change materials (pcms); metals; container; latent heat storage; corrosion
Online: 3 November 2019 (15:06:53 CET)
Phase Change Materials (PCMs) are latent heat storage media with high potential of integration in building structures and technical systems. Their solid-liquid transition is commonly utilized for thermal energy storage in building applications. It also means that some kind of encapsulation is necessary. This is often solved with metal containers that also have high thermal conductivity and resistance to mechanical damage enhancing the performance these so called latent heat thermal energy storage (LHTES) systems. However selection of suitable metal is rather challenging. It depends, among other things, on the elimination of undesirable interaction between storage medium and surrounding metal. Heat storage medium must be reliably sealed in metal container especially when the storage system is integrated in systems like domestic hot water storage tanks, where PCM leaks can negatively affect human health. The aim of this study was evaluation of interaction between selected commercially available organic and inorganic PCMs and metals. The evaluation is based on the calculation of corrosion rate and use gravimetric method for determination of the weigh variations of the metal samples. Results show that aluminium is the most suitable container material with lowest mass loss and suffered only minimal visual changes on the surface after prolonged exposure to PCMs.
ARTICLE | doi:10.20944/preprints201906.0263.v1
Subject: Engineering, Other Keywords: acid mine drainage; contaminated areas; environmental; heavy metals; public health
Online: 26 June 2019 (07:41:12 CEST)
The mining industry is known for the intense environmental impacts it triggers, especially when it is developed in an open environment. Pit lakes are formed in depleted deposits and may be promising opportunities for use by society as well as troubling environmental liabilities. While these artificial basins are increasing numerically in many parts of the world, they are still little known researchers in the Environmental Sciences, which makes their environmental management challenging. The main objective of this study was to evaluate the environmental quality of sediments from three deactivated open-pit gold mines, located in the Mara Rosa, Brazil, through chemical, ecotoxicological and genotoxicology analyses. For this purpose, we collected samples in the dry season boom, and subsequently, we analysed metals. In sequence, acute ecotoxicological and a genotoxicology test (comet assay) were developed with Danio rerio fishes, in concentrations of 3.12%; 6.25%; 12.5%; 25%; 50% and 100%, in addition to the control group. The results indicated that the three lakes are environmentally compromised, especially Lago Azul, whose waters and sediments are undergoing an intense process of geological conditioning. Our results did not verify the ecotoxicity of the sediments of any of the lakes, only behavioural alterations in the test organisms exposed to the concentrations of 25%, 50% and 100% of the samples obtained in the Lago Azul. About the sediments, DNA damage at Danio rerio was detected in the three investigated environments, although fishes kept in the water sampled at Lago Azul presented the most extension of DNA damages.
ARTICLE | doi:10.20944/preprints201901.0075.v1
Subject: Earth Sciences, Environmental Sciences Keywords: arsenic; health risk assessment; hazard quotient; hazard index; trace metals
Online: 8 January 2019 (15:32:41 CET)
Groundwater plays a pivotal role as the largest potable water sources in Bangladesh. However, the quality of the groundwater faces challenges due to xenobiotic compounds in it. Excess amount of arsenic (As) has already been found in groundwater in many parts of Bangladesh. Thus, this study was conducted to assess the water quality and associated human health risk in central Bangladesh. A total of 99 groundwater samples from the central part of Bangladesh were analyzed to assess human health risk due to high level of nitrate (NO3-) and other trace elements i.e. arsenic (As), iron (Fe), and manganese (Mn). It was found that NO3- concentration (253.17 mg/L) in the groundwater samples exceeds the recommended guideline value by the WHO (50 mg/L). Moreover, this study area also characterized with elevated concentration of As (19.44 µg/L), Fe (811.35 µg/L), and Mn (455.18 µg/L) in the groundwater. Non-carcinogenic human health risk was calculated by justifying HQ (Hazard Quotient) and HI (Hazard Index) and attributed potential conjunctive human health risks due to NO3-, As, Fe and Mn in the study area. Moreover, high carcinogenic risk was found due to As contamination in the groundwater samples in the study area.
ARTICLE | doi:10.20944/preprints201701.0099.v1
Subject: Engineering, General Engineering Keywords: Zhundong coal; char; CO2 gasification; alkali and alkaline earth metals
Online: 23 January 2017 (09:27:35 CET)
Coal gasification with carbon dioxide is a process for generating clean gaseous fuels and relieving greenhouse effect. Zhundong coal has high alkali and alkali earth metals (AAEMs) content, medium volatile and low ash in nature. Isothermal CO2 gasification of char derived from Zhundong coal (R-char) and char from acid washing R-char (AR-char) are performed in thermo-gravimetric analyzer (TGA). The effect of AAEMs is investigated on the gasification behavior in the range of temperatures 1073 K to 1273 K. The carbon conversion increases rapidly with increasing reaction temperature and CO2 concentration. R-char has high gasification rate and carbon conversion compared with AR-char. The accuracy of the free-model approach for calculating activation energy at different conversions is validated by compared with different kinetic models (volume reaction model, distributed activation energy model). Moreover, R-char gasification with CO2 shows a compensation effect as the Arrhenius parameters (EA and k0) increase or decrease simultaneously.
REVIEW | doi:10.20944/preprints202105.0574.v1
Subject: Chemistry, Analytical Chemistry Keywords: ionic liquids; surface active ionic liquids (SAILs); room temperature ionic liquids (RTILs); alkyl ethylene glycol ether carboxylates; rare earth metals, transition metals, colloids, green chemistry
Online: 24 May 2021 (13:43:28 CEST)
Most of the commonly used Ionic Liquids (ILs) contain bulky organic cations with suitable anions. With our COMPLET (Concept of Melting Point Lowering due to Ethoxylation), we follow a different approach. We use simple, low-toxic, cheap and commercially available anions of the type Cx(EO)yCH2COO– to liquefy presumably any simple metal ion, independently of its charge. In the simplest case, the cation can be sodium or lithium, but synthesis of Ionic Liquids is also possible with cations of higher valences such as transition or rare earth metals. Anions with longer alkyl chains are surface active and form surface active ionic liquids (SAILs), which combine properties of ionic and nonionic surfactants at room temperature. They show significant structuring even in their pure state, i.e. in the absence of water or any other added solvent.
ARTICLE | doi:10.20944/preprints202210.0288.v1
Subject: Materials Science, Nanotechnology Keywords: Proteomics; 2D SDS-PAGE; Nanoscale and ionic metals; Quantum dots; Hyperaccumulator
Online: 19 October 2022 (13:14:25 CEST)
Hyperaccumulator plant species growing on metal-rich soils can accumulate high quantity of metals and metalloids in aerial tissues and several proteomic studies on the molecular mechanisms at the basis of metals resistance and hyperaccumulation have been published. Hyperaccumulator are also at the basis of phytoremediation strategy to remove more efficiently metals from polluted soils or water. Arabidopsis halleri and Noccea caerulescens are both hyperaccumulators of metals and nano-metals. In this study it was assessed the change in some proteins in A. halleri and N. caer-ulescens after the growth in soil with cadmium and zinc, provided as sulphate salts (CdSO4 and ZnSO4) or sulfide quantum dots (CdS QDs and ZnS QDs). The protein extracts obtained from plants after 30 days of growth were analyzed by 2D-gel electrophoresis (2D SDS-PAGE) and identified by MALDI-TOF/TOF mass spectrometry. A bioinformatics analysis was carried out on quantitative protein differences between control and treated plants. In total, 43 proteins resulted significatively modulated in A. halleri, while 61 resulted modulated in N. caerulescens. Though these two plants are hyperaccumulator of both metals and nano-metals, at protein levels the mechanisms involved do not proceed in the same way but at the end bring to a similar physiological result.
REVIEW | doi:10.20944/preprints202206.0253.v1
Subject: Life Sciences, Biophysics Keywords: Bioinorganic chemistry; metal-binding; structural biology; zinc; iron; copper; transition metals
Online: 17 June 2022 (09:30:07 CEST)
All living organisms require some metal ions for their energy production as well as metabolic and biosynthetic processes. Within cells, metal ions are involved in the formation of adducts interact with metabolites and macromolecules (proteins and nucleic acids). The proteins that require binding to one or more metal ions to be able to carry out their physiological function are called metalloproteins. About one third of all protein structures in the Protein Data Bank involve metalloproteins. Over the past few years there has been a tremendous progress in the number of computational tools and techniques making use of 3D structural information to support the investigation of metalloproteins. This trend has been boosted also by the successful applications of neural networks and deep learning approaches in molecular and structural biology at large. In this review, we discuss recent advances in the development and availability of resources dealing with metalloproteins from a structure-based perspective. We start by addressing tools for the prediction of metal-binding sites (MBSs) using structural information on apo-proteins. Then, we provide an overview of methods for and lessons learned from the structural comparison of MBSs in a fold-independent manner. We then move to describing databases of metalloprotein/MBS structures. Finally, we summarize recent DL applications enhancing the functional interpretation of metalloprotein structures.
REVIEW | doi:10.20944/preprints202206.0113.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Euglena; toxicity; pollution; heavy metals; PAHs; pesticides; UV radiation; Fv/Fm
Online: 8 June 2022 (04:13:01 CEST)
Euglenoids are a common component of primary producers in high acidic and organic shallow freshwater systems. They are free-living photosynthetic motile flagellates exhibiting rapid responses to various external stimuli including chemical pollution. The unique combination of diverse physiological processes of Euglena such as photosynthesis, movement, and orientation offers a range of sensitive criteria that respond to aquatic pollutants. This has led to the development of several acute and chronic assay methods to monitor the adverse impacts of potent toxicants in aquatic ecosystems. Euglenoids also reflect the consequences of physical stress factors such as UV radiation. This review summarizes the ecotoxicity studies using euglenoid flagellates as model species and their potential to contribute toward rapid screening of ecological impacts of pollution in the aquatic environment. Factors determining the reliability of Euglena tests are outlined.
ARTICLE | doi:10.20944/preprints202106.0470.v1
Subject: Earth Sciences, Atmospheric Science Keywords: heavy metals; surface sediment; Manila Bay; pollution; multivariate analysis; ecological risk
Online: 18 June 2021 (08:32:18 CEST)
Recent work on heavy metal pollution in Manila Bay suggests elevated concentration in the surface sediments. It is critical to identify the sources of these heavy metals to effectively rehabilitate the bay. Our study investigated the sources of the heavy metal pollution that ended up in Manila Bay and the risks associated with these toxic metals based on a recent survey conducted. Surface sediment samples with higher heavy metal concentrations were found in the upper to middle parts of the bay while lower concentrations were in the southeast areas. Multivariate analyses such as hierarchical cluster analysis (HCA), principal component analysis (PCA), and Pearson correlation analysis were used to identify the sources of the heavy metals. The heavy metal pollution in Manila Bay is attributed to several rivers draining northeast of Manila Bay, particularly the Marilao-Meycauayan-Obando River System (MMORS) which is cited as one of the 30 dirtiest river systems in the world. The ecological risks associated with heavy metals in the sediments found higher incidences of toxicity in north and middle parts of Manila Bay. Cu and Cr posed the highest risks of toxicities than any other heavy metals. Based on our analysis, the counterclockwise water gyre of the bay can explain the distribution and ecological risks associated with the heavy metals as supported by the findings of the PCA. Given the high priority by the Philippine government to rehabilitate the bay, our study strongly shows that efforts to restore the ecological status of Manila Bay will only succeed if the pollution from major rivers draining to it will be properly addressed.
ARTICLE | doi:10.20944/preprints202106.0378.v1
Subject: Keywords: Trace metals; COVID-19; Lagoon ecosystem; Anthropogenic pollution; Water quality; India
Online: 14 June 2021 (15:56:06 CEST)
A complete halt on all anthropogenic activities and human movement due to COVID-19 lockdown has provided a great opportunity to assess the impact of human activities on coastal marine ecosystems. The current study assessed the concentration of the metals in water samples of the largest brackish water lagoon of Asia; the Chilika lagoon in the state of Odisha, India between pre-COVID-19 and post-COVID-19 lockdown scenarios. Monthly water samples (n=30 stations) from 0.3 m depth were collected from three sectors of the lagoon seasonally; pre-monsoon, monsoon, and post-monsoon. In addition to various physical parameters [pH, salinity, alkalinity, (DO) dissolved oxygen, (TDS) total dissolved solids, and (EC) electrical conductivity] the collected water samples were analysed for 18 trace metals (Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr, Th, Tl, U, V). Most of the physical parameters showed a significant variation between pre-and post-COVID-19 scenarios, except for pH and DO. The concentration of five metals (Be, Cd, Co, Ni, and Pb) remained below detection limits in all water samples. The impact of COVID-19 lockdown on the concentration of the metal in the water samples was noticed along with the three sectors of the lagoon. However, eight metals (Al, As, Cr, Fe, Mn, Th, U, and V) were significantly different between the COVID-19 scenarios and the remaining five metals were not statistically significant. The mean concentration of Al, As, Fe, Th, and V were higher in the pre-COVID-19 scenarios, whereas only Cr and Mn were higher in the post-COVID-19 scenarios. The mean concentration of U was similar among both COVID-19 scenarios, even though there were seasonal and sectoral differences. The seasonal influence of riverine influx was more evident on metal concentration during the monsoon season, whereas the difference between sectors was more prominent during the post-monsoon season. An increased number of correlations between physical parameters and metal concentration were observed in the post-monsoon season and post-COVID-19 scenario. This study provides evidence that the imposition of COVID-19 lockdown reduced metal influx in the water column and improved the water quality of the Chilika lagoon. Our results can be used as baseline for metal concentration in surface waters of the lagoon.
ARTICLE | doi:10.20944/preprints202010.0119.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Lead poisoning; environmental health; toxic metals; sub-Saharan Africa; environmental exposure
Online: 6 October 2020 (10:55:42 CEST)
Lead exposure is associated with poor cognitive development in children. Very few studies in sub-Saharan Africa (SSA) have studied blood lead levels (BLLs) and non-gasoline sources of exposure in children. Data from a birth cohort in Benin (2011-2013) suggested that 58% of one-year-old children had BLLs > 50 ug/L. We aimed to investigate the prevalence of elevated BLLs (>50 µg/L and >100 µg /L) among 425 of these children at six-years-of-age in 2016-18 and to compare BLLs between age one-year and six-years and study sources of lead at six years. BLLs were analyzed by inductively coupled plasma mass spectrometry. Multiple linear regression and quantile regressions were used to study potential sources of lead. The prevalence of BLLs >50 µg/L in children was 59.5% [Geometric Mean (GM) 56.4 µg/L, 95% CI: 54.1 - 58.7] at six years of age compared to 54.8% [GM 56.5 µg/L, 95% CI: 53.4-59.6] at one year of age. The prevalence of children with BLLs >100 µg/L decreased from 14.4% at one year of age to 8.2% at six years of age. After adjustment for all other covariates, consumption of peanut more than once per month was significantly associated with a 22.0% (95% CI: 4.6, 42.5) increment in BLLs at six years compared with no consumption. Consumption of bushmeat killed by lead bullets at six years was associated with an increase in the higher percentiles of BLLs (P75) compared with the absence of this source. Other potential sources of lead associated with BLLs with marginal significance were consumption of rice, paternal occupational exposure, and the presence of activity with the potential use of lead. This prospective cohort confirms the persistently high prevalence of elevated BLLs in children residing in a rural region in the south of Benin as well as the presence of multiple and continuous sources of lead. These results highlight the need for prevention programs to reduce and eliminate lead exposure in children.
ARTICLE | doi:10.20944/preprints202009.0070.v1
Subject: Chemistry, Analytical Chemistry Keywords: inactivation column test; silanol; trace metals; in silico; bonded-phase silica
Online: 3 September 2020 (11:41:25 CEST)
The silanol activity and trace metal detection methods for chemically bonded silica gels were evaluated in silico. Test compounds with large molecular sizes may demonstrate negative results because of the possibility of indirect hydrogen bonding via short alkyl groups or siloxane of the silica gels. This hypothesis was based on the observation of weak hydrogen bonding energy values similar to those observed in the study of the alkyl group effect on the hydrogen bonding of alkanols. Consequently, smaller molecules may be a better choice for the analysis of bonded-phase quality.
REVIEW | doi:10.20944/preprints201908.0012.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: zebrafish diet; heavy metals; contaminant; toxin; development; behavior; persistent organic pollutant
Online: 1 August 2019 (10:28:59 CEST)
Dietary contaminants are often an over-looked factor in the health of zebrafish. Typically, water is considered to be the source for most contaminants, especially within an aquatic environment. For this reason, source water for zebrafish recirculating systems is highly regulated and monitored daily. Most facilities use reverse osmosis or de-ionized water filtration systems to purify incoming water to ensure that contaminants, as well as pathogens, do not enter their zebrafish housing units. However, diets are rarely tested for contaminants and, in the case of manufactured zebrafish feeds, since the product is marketed for aquaculture or aquarium use it is assumed that the feed is acceptable for animals used for research. The following provides examples as to how contaminants could lead to negative effects on development and behavior of developing zebrafish.
ARTICLE | doi:10.20944/preprints201907.0109.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: brass; Cu-Zn-Pb; raids layers; metals; electrode; ozone; plasma reactor
Online: 8 July 2019 (06:13:40 CEST)
Researchers from around the world are looking for better and cheaper ozone production. One of the methods increasing the efficiency of ozone production is the use to a rotating electrode presented in this paper. Experiments were carried out which shows that the most important parameters are the materials used on the electrodes and the condition of its surface. The metallographic investigations of the electrodes after continuous monthly work was made, which show how the raids layers are formed. As a result of working in a highly oxidizing environment, the electrode is oxidized in the process of chemical corrosion. It is obvious that the layer of corrosion products created during the work of the plasma reactor isolates the surface of the electrode, which reduces the intensity of the electric field, causing a decrease in the amount of plasma generated, which is a direct cause of lowering the concentration of ozone during this process. The dynamics of plasma generation process and the type of electrode material working in changing process conditions are the decisive factors influencing the concentration of ozone produced. The influence of the medium, which is the electrode material, depends mainly on its resistance to corrosion in the environment of dynamically changing conditions, e.g. electrode rotation, oxygen flow through the rotating electric field and the long monthly working time of the plasma reactor.
ARTICLE | doi:10.20944/preprints201905.0051.v1
Subject: Medicine & Pharmacology, Pediatrics Keywords: infant formulae; infant foods; minerals; toxic metals; hydroxymethylfurfural; storage conditions; safety
Online: 6 May 2019 (10:38:25 CEST)
Infant foods and formulae may contain toxic substances and elements which can be neo-formed contaminants or derived from raw materials or processing. The content of minerals, toxic elements and hydroxymethylfurfural in infant foods and formulae were evaluated. The effect of storage temperature on HMF formation in infant formulae and its potential as a quality parameter was also evaluated. Prune-based foods contained the highest HMF content. HMF significantly increased when storage temperature was elevated to 30 ℃ for 21 days. All trace elements were present in adequate amounts while the concentration of nickel was higher when compared to those of other studies. The study indicates that HMF can be used as quality indicator for product shelf-life and that the concentrations of minerals and toxic elements vary greatly due to the diverse compositions of foods and formulae. Such contaminants need to be monitored as infants represent a vulnerable group compared to adults.
ARTICLE | doi:10.20944/preprints201806.0260.v1
Subject: Chemistry, Physical Chemistry Keywords: ATRP; chitosan grafted poly acrylic acid; heavy metals; adsorption; water treatment.
Online: 15 June 2018 (14:50:41 CEST)
In this work, we synthesized chitosan grafted-poly acrylic acid (CS-g-PA) through surface-initiated atom transfer radical polymerization (SI-ATRP). We also studied the adsorption process of copper and lead ions onto CS-g-PA surface. Adsorption equilibrium studies indicated pH 4.0 as the best pH for the adsorption process, while the maximum adsorption capacity for Pb2+ ions was 98 mg*g-1 and for Cu2+ was 164 mg*g-1, higher adsorption capacities than chitosan alone (CS), where Pb2+ was only 14.8 mg*g-1and Cu2+ was 140 mg*g-1, respectively. Furthermore, the adsorption studies indicated that Langmuir model describes all the experimental data. All these results suggest that the new CS-g-PA polymers had potential as adsorbent for hazardous and toxic metal ions produced by different industries.
ARTICLE | doi:10.20944/preprints201804.0098.v1
Subject: Chemistry, Applied Chemistry Keywords: oilfield produced water; wastewater; heavy metals; irrigation; bioaccumulation; soil health; California
Online: 9 April 2018 (07:48:31 CEST)
Oilfield produced water (OPW) is used to boost freshwater sources for crop irrigation in California's agriculturally important Central Valley. OPW is known to contain salts, metals, hydrocarbons, alkylphenols, naturally radioactive materials, biocides, and other compounds from drilling and production processes. Less is known about the potential uptake and accumulation of these compounds in crops and soil irrigated with OPW. In this study 23 potted mandarin orange plants were irrigated 2-3 times weekly (depending on season) with water containing three different concentrations of the known OPW heavy metals barium, chromium, lead, and silver. Seven sets of samples of soil and leaves and all fruits were collected and processed using microwave-assisted digestion (EPA Method 3051A). Processed samples were analyzed using ICP-OES. ANOVA, ANCOVA, and Tukey’s honest significant difference test were used to examine the effects of metal concentrations in the irrigation water, sample number, and number of watering days on the metal concentrations in the soil, leaf, and fruit samples. Accumulation of barium in soil and leaves was strongly positively associated with sample and number of watering days, increasing nearly 2,000-fold. Lead also showed an upward trend, increasing up to 560-fold over baseline level. Chromium showed an increase in the soil that tapered off, but less consistent results in the leaves and fruit. The silver results were more volatile, but also indicated at least some level of accumulation in the tested media. The smallest absolute accumulation was observed for chromium. Concentrations in the fruit were highest in the peel, followed by pith and juice. Accumulation of all heavy metals was generally highest in the soil and plants that received the highest irrigation water concentration. Considering the potential for adverse human health effects associated with ingesting soluble barium contained in food and drinking water, and to a lesser extent chromium and lead, the study signals that it is important to conduct further research into whether OPW contaminants can enter the food chain and pose risks to consumers.
ARTICLE | doi:10.20944/preprints201711.0185.v1
Subject: Behavioral Sciences, Other Keywords: Atoyac River; water pollution; heavy metals; coliforms; Emilio Portes Gil; Puebla
Online: 29 November 2017 (07:43:21 CET)
The Atoyac River crosses the metropolitan area of Puebla, Mexico, and presents a condition of severe degradation that has been poorly studied. The research was conducted in the year 2016 and analyzed the space-time dynamics of the water quality of the river, the increase in pollution in the period 2011–2016, and the water quality of the Atoyac River used for agricultural irrigation and human consumption in the population of Emilio Portes Gil, Ocoyucan, based on official Mexican standards (NOMs). The anoxic state of the river was demonstrated (~1.47 mgO2/L) and the high organic pollution, particularly in drought, as well as the presence of large populations of coliform bacteria, and 11 enterobacteries of pathogenic importance. The pollution recorded an average increase of 49% in the period 2011-2016, and the values of Fe, Al, Pb, and Cd in variable percentages. It was evidenced that water for irrigation and wells is contaminated with fecal bacteria (104–549 NMP/100 mL), including pathogenic. In wells, the concentration of heavy metals was 5 times higher in drought. These results represent a serious threat for the population of Emilio Portes Gil and the environment in the metropolitan area of Puebla.
ARTICLE | doi:10.20944/preprints202012.0816.v1
Subject: Engineering, Automotive Engineering Keywords: heavy metals; industrial wastewater; natural wetlands; phytoremediation; Wadi Zomer restoration; water quality
Online: 31 December 2020 (13:46:33 CET)
This paper investigated the effectiveness of natural wetlands (Phragmites australis) along Wadi Zomer in reducing the organic and inorganic pollution loads from diverse industrial discharges including occasional emergency discharges from Nablus West Sewage Treatment Plant (NWSTP), Palestine. We monitored physical and chemical parameters at four selective sampling stations (S1-S4) along Wadi Zomer with a length of 5 km downstream of NWSTP to assess the purification capacity of Wadi Zomer treatment wetlands (water, sediment, and vegetation) with Phragmites australis in pollution loads reduction. The results showed that S2 (0+0.5 km) and S3 (0+3.0 km) reflected an increase in pollution loads due to illicit industrial discharge and sewer overflow discharge from NWSTP during emergency conditions. BOD values varied significantly along the sampling sites from 6.64 mg/l (S1) to 437.10 mg/l (S3). The BOD at S1 and S2 in water samples were below the Palestinian Water Standard (PWS) compared to S3 and S4 with 437.1 and 333.9 mg/l, respectively. Water samples from all sites (S1-S4) showed a decreasing tendency in heavy metals concentrations (Fe>Cu>Zn>Cr >Ni) and were below the PWS limits, sediment samples followed the same decrease pattern for Zn, Cr, and Ni content with Wadi Zomer flow course. The concentration of Fe (6687 mg/kg) and Cu (1384.7 mg/kg) were highest in the sediment samples (S1-S4); this might be due to non-point sources of pollution. The research demonstrated that phytoremediation is a sustainable nature-based technology for the restoration of heavily polluted surface water bodies in Palestine.
Subject: Medicine & Pharmacology, Cardiology Keywords: cardiovascular disease; heavy metals; cooper; zinc; manganese; cobalt; iron; health risk assessment
Online: 9 June 2020 (03:25:06 CEST)
Cardiovascular diseases (CVDs) constitute the first cause of death among the population of developing and developed countries. Atherosclerosis, which is a disorder with multifactorial etiopathogenesis, underlies most CVDs. The available literature includes ample research studies on the influence of classic cardiovascular (CV) risk factors. However, environmental exposure to heavy metals, among other substances, is still an unappreciated risk factor of CVDs. This study aimed to assess the concentration of some heavy metals (copper (Cu), zinc (Zn), manganese (Mn), cobalt (Co), and iron (Fe)) in the blood serum of postmyocardial infarction (post-MI) patients and patients free from myocardial infarction (MI) as well as estimate the relationship between the occurrence of MI and increased concentration of heavy metals. The concentration of heavy metals (Cu, Zn, Mn, Co, and Fe) was assessed using the inductively coupled plasma mass spectrometry technique in a group of 146 respondents divided into two groups: post-MI group (study group (SG), n = 74) and group without cardiovascular event (CVE) having a low CV risk (control group (CG), n = 72). The concentration of the analyzed heavy metals was higher in SG. All the heavy metals showed a significant diagnostic value (p < 0.001). The highest value of area under the curve (AUC) was observed for manganese (Mn) (0.955; 95% confidence interval (CI) = 0.922–0.988), while the lowest value was found for zinc (Zn) (0.691; 95% CI = 0.599–0.782). In one-dimensional models, high concentrations of each of the analyzed heavy metals significantly increased the chances of having MI from 7-fold (Cu) to 128-fold (Mn). All the models containing a particular metal showed a significant and high discrimination value for MI occurrence (AUC 0.72–0.92). Higher concentrations of Cu, Zn, Mn, Co, and Fe were found to considerably increase the chances of having MI. Considering the increasingly higher environmental exposure to heavy metals in recent times, their concentrations can be distinguished as a potential risk factor of CVDs.
ARTICLE | doi:10.20944/preprints201907.0012.v1
Subject: Biology, Plant Sciences Keywords: Calendula officinalis; elicitation; hairy roots; heavy metals; sterols; triterpenoids; ultrasound; UV-radiation
Online: 1 July 2019 (11:56:33 CEST)
The aim of the study was the evaluation of the efficiency of selected abiotic elicitors, i.e. silver and cadmium ions, ultrasound, and UV-C irradiation, in the stimulation of triterpenoid biosynthesis, accumulation, and saponin secretion in Calendula officinalis hairy root cultures. Apart from the possible enhancement of triterpenoid production, the relationship between primary and secondary metabolism (represented respectively by sterols and pentacyclic triterpenes), modifications of the sterol compositional profile, and fluctuations in the total triterpenoid content were monitored in the performed experiments. The main phenomenon observed as a response to heavy metal treatment was the stimulation (up to 12-fold) of the secretion of saponins, accompanied by significant changes in sterol composition. Ultrasound stimulated the secretion of saponins (up to 11-fold); however, it exerted diverse influences on the triterpenoid content in hairy root tissue (stimulating or decreasing) depending on the duration of the exposure to the elicitor. UV-C radiation caused a slight increase in the content of both sterols and saponins in hairy root tissue, and stimulated saponin secretion up to 8.5-fold. The expected symptoms of the competition between the biosynthetic pathways of sterols and pentacyclic triterpenoids were less evident in reactions to abiotic stressors than those reported previously for biotic elicitors
ARTICLE | doi:10.20944/preprints201905.0019.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: biochar; phytoextraction; corn; uptake; mine soils; heavy metals; root biomass; shoot biomass
Online: 5 May 2019 (12:11:59 CEST)
Mining activities could produce a large volume of spoils, waste rocks, and tailings, which are usually deposited at the surface and become sources of metal pollution. Phytostabilization of the mine spoils could limit the spread of these heavy metals. Phytostabilization can be enhanced by using soil amendments like manure-based biochar capable of immobilizing metal(loid)s when combined with plant species that are tolerant of high levels of contaminants while simultaneously improving properties of mine soils. However, the use of manure-based biochar and other organic amendments for mine spoil remediation are still unclear. In this greenhouse study, we evaluated the interactive effect of biochar application and compost on shoots biomass yield (SBY), roots biomass yield (RBY), uptake, and bioconcentration factor (BCF) of Zn and Cd in corn (Zea mays L.) grown in mine soil. Biochar sources (BS) consisted of beef cattle manure (BCM); poultry litter (PL); and lodge pole pine (LPP) were applied at 0, 2.5, and 5.0% (w/w) in combination with different rates (0, 2.5, and 5.0%, w/w) of cattle manure compost (CMC), respectively. Shoots and roots uptake of Cd and Zn were significantly affected by BS, CMC, and the interaction of BS and CMC. Corn plants that received 2.5% PL and 2.5% BCM had the greatest Cd and Zn shoot uptake, respectively. Corn plants with 5% BCM had the greatest Cd and Zn root uptake. When averaged across BS, the greatest BCF for Cd in the shoot of 92.3 was from the application BCM and the least BCF was from the application of PL (72.8). Our results suggest that incorporation of biochar enhanced phytostabilization of Cd and Zn with concentrations of water-soluble Cd and Zn lowest in soils amended with both manure-based biochars while improving biomass productivity of corn. Overall, phytostabilization technique and biochar application have the potential to be combined in the remediation of heavy metals polluted soils.
TECHNICAL NOTE | doi:10.20944/preprints201904.0282.v1
Subject: Earth Sciences, Environmental Sciences Keywords: fly ash, process mineralogy, minerals, rare and precious metals, separation and enrichment
Online: 25 April 2019 (11:24:23 CEST)
The separation and enrichment can be targeted to enrich the rare and precious metals in fly ash and reduce the cost of leaching and recovering of fly ash. Regarding their different properties, the single-component separation was used to obtain uncompleted burned carbon, glass microbeads, minerals, and other characteristic components from the ash. Also, the mineral composition of each component was analyzed by electron microscopy. The metal minerals were mainly concentrated in the mineral components. Besides, the electron probe micro-analysis shows that the Pt content in the minerals of fly ash was significantly correlated with the metal contents of Ni and Cu. After the obtainment of the characteristics of fly ash metal enrichment, the heavy minerals with Cu, Ni, Pt, Pd, and other target metal elements were enriched by gravity separation and flotation. The enrichment coefficients of Cu, Ni, Pt, and Pd were 1.45, 1.33, 1.90 and 1.60, respectively, and the recovery rates were 77%, 81%, 97% and 88% respectively. Since the yield of heavy minerals obtained by separation was 62.24%, it indicated the physical separation method could significantly reduce the cost of leaching and recovering of fly ash metal resources.
ARTICLE | doi:10.20944/preprints201808.0185.v1
Subject: Engineering, Civil Engineering Keywords: porous asphalt pavement system; stormwater; stormwater runoff; heavy metals removal; geotextile membrane
Online: 9 August 2018 (10:07:29 CEST)
Porous asphalt (PA) pavement systems with and without a geotextile layer were investigated in laboratory experiments to determine the impacts of the geotextile layer on processes leading to lead ion (Pb2+) removal from stormwater runoff. Two types of geotextile membranes placed separately at upper and lower levels within the PA systems were tested in an artificial rainfall experiment using synthetic rainwater. The effect of storage capacity within the system on Pb2+ removal was also investigated. Results indicated that the use of a geotextile layer resulted in a longer delay to the onset of effluent. The non-woven geotextile membrane placed below the reservoir course improved the Pb2+ removal rate by 20% over removal efficiency of the system using a woven geotextile placed just below the surface but before the choker course. Pb2+ ions were reduced by over 98% in the effluent after being held for 24 hours in reservoir storage. Results suggest that temporary storage of stormwater in the reservoir course of a PA system is essential to improving Pb2+ ion removal capability.
ARTICLE | doi:10.20944/preprints201807.0322.v1
Subject: Earth Sciences, Environmental Sciences Keywords: stormwater; monitoring; gross pollutant generation rates; suspended solids; nitrogen; phosphorus; heavy metals
Online: 18 July 2018 (09:07:46 CEST)
Urban stormwater runoff from a medium-density residential development in southeast Queensland has been monitored in the field since November 2013. A treatment train installed on the site includes rainwater tanks collecting roofwater, 200-micron mesh baskets installed in grated gully pits and two 850 mm high media filtration cartridges installed in an underground 4 m3 vault. A monitoring protocol developed by research partners, Queensland University of Technology (QUT), guided the monitoring process over a 4.5-year period. Heavy metals were included in the list of analytes during the monitoring period as the catchment is within 1 km of the environmentally-sensitive Moreton Bay, Queensland. Removal efficiencies observed at this site for the regulated pollutants; total suspended solids (TSS), total phosphorus (TP) and total nitrogen (TN) for the pit baskets were 61%, 28% and 45% respectively. The cartridge filters removed 78% TSS, 59% TP, 42% TN, 40% total copper and 51% total zinc. As the measured influent concentrations to the cartridge filters were low when compared to industry guidelines, the dataset was merged with international field results for TSS (n=39) and TP (n=32) but truncated within anticipated guideline levels. The combined dataset for the media filter demonstrates performance at 89% TSS, 66% TP and 42% TN. The total gross pollutant generation rate from the medium-density residential catchment was observed to be 0.24 m3/Ha/year, with a corresponding air-dried mass of 142.5 kg/Ha/year. Less than 2% of the gross pollutant mass was anthropogenic. The findings of this research suggest that the treatment train, and in particular the media filter, holds promise for the removal of total copper and total zinc, in addition to TSS, TP and TN, from urban stormwater runoff. Based on a maximum, low risk trigger TN concentration of 1.5 mg/L, the field test data from 4.5 years of operation and standard maintenance, suggests a 5.5-year replacement interval for the media filters.
ARTICLE | doi:10.20944/preprints201807.0154.v1
Subject: Biology, Plant Sciences Keywords: bread wheat; correlations, gamma, grain nutrients concentrations; mutation, phytic acid; metals bioavailability
Online: 9 July 2018 (15:39:51 CEST)
Metal, primarily Fe and Zn, deficiencies affect over half of the world's population. Human diets with prevalent cereal products cause micronutrient malnutrition. Biofortification is one of the most effective approaches to alleviate malnutrition. Spring wheat genetically stable (M7) mutant lines developed with 100 and 200 Gy gamma treatments to broaden genetic variation and search for new resources were analyzed for nutritionally important minerals (Ca, Mg, K, Fe, and Zn), their bioavailability, and grain protein content (GPC). The variation was 172.3–883.0 mg/kg for Ca, 472.9–1088 mg/kg for Mg, 3128.6–5487.5 mg/kg for K, 40.9–89.0 mg/kg for Fe, and 22.2–89.6 mg/kg for Zn. In mutant lines, among the investigated minerals, the highest increases in concentrations were observed in Fe, Zn, and Ca when compared to the parent. Some mutant lines, mostly in the 100 Gy-derived germplasm, had two to three times higher Fe, Zn, and Ca concentrations, lower phytic acid concentration (1.4–2.1 times), and 6.5–7% higher GPC compare to the parent. Variation was detected for the Ca:Phy, Mg :Phy, Phy:K, Phy:Fe, and Phy:Zn molar ratios, (1.27–10.41, 5.05–18.68, 1.66–4.87, 1.40–5.32 and 1.78–11.78, respectively). The results showed how the genetic variation could be generated through radiation and be useful to develop biofortification by micronutrient varieties with their appropriate bioavailability to overcome malnutrition.
COMMUNICATION | doi:10.20944/preprints201801.0153.v1
Subject: Biology, Ecology Keywords: lead pollution; alpine environments; Alticola argentatus; Microtus gregalis; atmospheric deposition; heavy metals
Online: 17 January 2018 (11:37:36 CET)
High mountain areas are an appropriate indicator of anthropogenic lead (Pb), which can reach the remote mountain ranges through long distance atmospheric transport. We compared the content of Pb in ecologically equivalent rodent species from Tian-Shan with European mountain ranges Tatra, Vitosha and Rila mountains. We used bone tissues from terminal tail vertebrae of small rodents for detection of Pb levels by using electrothermal atomic absorption spectroscopy (AAS). The tail bones of Tian-Shan rodents had significantly lower Pb levels than snow voles from Tatra mountains, but there was no significant difference in comparison with Vitosha and Rila mountains. We can conclude that Tian-Shan shows lower pollution by Pb than Tatra mountains, what may be a reason of longer lasting industrialization of north-western Europe and strongly prevailing west winds in Tatra mountains.
REVIEW | doi:10.20944/preprints201612.0097.v2
Subject: Life Sciences, Microbiology Keywords: pathogens; Legionella; amoeba; protozoa; biofilm; antibacterial; antimicrobial; cooling towers; biocides; polyvalent metals
Online: 20 December 2016 (10:26:22 CET)
Application of toxic antibacterial agents is considered necessary to control prevalent fresh water microorganisms in evaporative cooling water systems, but these agents can adversely affect the environment and human health. Alternatively, natural antibacterial water chemistry has been applied in industrial cooling water systems for over 10 years with excellent results. The tower water chemistry method concentrates natural salts in highly-softened water to produce elevated pH and dissolved solids, with low calcium and magnesium. This practice conserves water while generating only a small volume of non-toxic natural salt concentrate for cost efficient separation and disposal if required. This review presents a novel perspective of natural antimicrobial chemistry for inhibiting parasitic microbiome functional relationships within the bio-triad of Legionella outbreaks, "Trojan Protozoans" and biofilms. The review further examines practical application and function of polyvalent metal ions in the inhibition of biofilms. Reducing global dependence on toxic antibacterial agents discharged to the environment is an emerging concern due to their impact on the natural microbiome, plants, animals and humans. Discharge of antibacterial agents also contributes to development of pathogen resistance. Use of natural antibacterial chemistry can play a key role in managing the cooling water environment in a more ecologically sustainable manner.
ARTICLE | doi:10.20944/preprints202008.0142.v1
Subject: Physical Sciences, Atomic & Molecular Physics Keywords: graphene; fullerenes; atomic metals; doubly-charged anions; tunable catalysts; water oxidation; electron scattering
Online: 6 August 2020 (10:04:21 CEST)
The fundamental mechanism underlying negative-ion catalysis involves bond-strength breaking in the transition state (TS). Doubly-charged atomic/molecular anions are proposed as novel dynamic tunable catalysts and demonstrated in water oxidation to peroxide. Density Functional Theory TS calculations have found tunable energy activation barrier reduction ranging from 0.030 eV to 2.070eV, with Si2ˉ, Pu2ˉ, Pa2ˉ and Sn2ˉ the best catalysts; the radioactive elements usher in new application opportunities. C602ˉ reduces significantly the standard C60ˉ TS energy barrier while graphene increases it, behaving like cationic systems. Rank-ordered catalysts according to their reaction barrier reduction efficiency, variation across charge states and systems reveal their tunable and wide applications, ranging from water purification to biocompatible anti-viral and anti-bacterial sanitation systems.
ARTICLE | doi:10.20944/preprints201804.0024.v1
Subject: Earth Sciences, Environmental Sciences Keywords: pollutant transport modelling; metals transport modelling; free surface water bodies; toxics-reaction equation
Online: 2 April 2018 (11:27:40 CEST)
This paper describes the development of a two-dimensional water quality model that solves hydrodynamic equations tied to transport equations with reactions mechanisms inherent in the processes. This enable us to perform an accurate assessment of the pollution in a coastal ecosystem. The model was developed with data drawn from the ecosystem found in Mexico's southeast state of Tabasco. The coastal ecosystem consists of the interaction of El Yucateco lagoon with the Chicozapote and Tonalá rivers, that connect the lagoon with the Gulf of Mexico. We present the results of pollutants transport simulation in the coastal ecosystem, focusing on toxic parameters for two hydrodynamic scenarios: wet and dry seasons. As it of interest in the zone, we study the transport of four metals: Cadmium, Chromium, Nickel and Lead. In order to address our objectives we solved numerically a self-posed mathematical problem,which is based on the measured data. The performed simulations show to characterise metal transport within the acceptable range of accuracy and in accordance with the measured data. The performed simulations show to characterise metals transport with an acceptable accuracy, agreeing well with measured data in total concentrations in four control points along the water body. Although for the accurate implementation of the hydrodynamic-based water quality model herein presented, boundary (geometry, tides, wind, etc.) and initial (concentrations measurements) conditions are required, it poses as an excellent option when the distribution of solutes with high accuracy is required, easing environmental, economic and social management of coastal ecosystems.
ARTICLE | doi:10.20944/preprints201803.0171.v1
Subject: Earth Sciences, Atmospheric Science Keywords: firework displays; toxic metals; principal component analysis; risk assessment; hazard quotient; hazard index
Online: 20 March 2018 (07:19:53 CET)
Bonfire night is a worldwide phenomenon given to numerous annual celebrations characterised by bonfires and fireworks. Since Thailand has no national ambient air quality standards for metal particulates, it is important to investigate the impacts of particulate injections on elevations of air pollutants and ecological health impacts resulting from firework displays. In this investigation, Pb and Ba were considered potential firework tracers because their concentrations were significantly higher during the episode and lower than/comparable with minimum detection limits during other periods, indicating that their elevated concentrations were principally due to pyrotechnic displays. Pb/Ca, Pb/Al, Pb/Mg, and Pb/Cu can be used to pin-point emissions from firework displays. Air mass backward trajectories (72 h) from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model indicated that areas east and north-east of the study site were the main sources for the air transportation. Although the combined risk associated with levels of Pb, Cr, Co, Ni, Zn, As, Cd, V, and Mn was far below the standards mentioned in international guidelines, the lifetime cancer risks associated with As and Cr levels exceeded US-EPA guidelines, and may expose inhabitants of surrounding areas of Bangkok to elevated cancer risk.
ARTICLE | doi:10.20944/preprints201711.0152.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Urban road dust, Functional areas, Heavy metals, Pollution assessment, Health risk assessment, Jeddah
Online: 23 November 2017 (10:20:50 CET)
Data dealing with the assessment of heavy metal pollution in road dusts in Jeddah, Saudi Arabia and its implication to human health risk of human exposure to heavy metals, are scarce. Road dusts were collected from five different functional areas (traffic areas TA, parking areas PA, residential areas RA, mixed residential commercial areas MCRA and suburban areas SA) in Jeddah and one in rural area (RUA) in Hada Al Sham. We aimed to measure the pollution levels of heavy metals and estimate their health risk of human exposure applying risk assessment models described by USEPA. Using geo-accumulation index (Igeo), the pollution level of heavy metals in urban road dusts was in the following order Cd > As > Pb > Zn > Cu > Ni > Cr > V > Mn > Co > Fe. Urban road dust was found to be moderately to heavily contaminated with As, Pb and Zn, and heavily to extremely contaminated with Cd. Calculation of enrichment factor (EF) revealed that heavy metals in TA had the highest values compared to that of the other functional areas. Cd, As, Pb, Zn and Cu were severely enriched, while Mn, V, Co, Ni and Cr were moderately enriched. Fe was consider as a natural element and consequently excluded. The concentrations of heavy metals in road dusts of functional areas were in the following order: TA > PA > MCRA > SA > RA > RUA. The study revealed that both children and adults in all studied areas having health quotient (HQ) < 1 are at negligible non-carcinogenic risk. The only exception was for children exposed to As in TA. They had an ingestion health quotient (HQing) 1.18 and a health index (HI) 1.19. The most prominent exposure route was ingestion. The cancer risk for children and adults from exposure to Pb, Cd, Co, Ni, and Cr was found to be negligible (< 1 x 10-6).
ARTICLE | doi:10.20944/preprints202003.0056.v1
Subject: Life Sciences, Other Keywords: Hermetia illucens prepupae; Black soldier fly; coffee silverskin; microalgae; toxic metals; bioaccumulation; chemical hazard
Online: 4 March 2020 (09:48:16 CET)
Among other species, Black Soldier Fly (Hermetia illucens, HI, Diptera, Stratiomydae) has the great potential as food and feed ingredient in the EU, particularly thanks to its preference for organic waste as growth substrate. The production of insects as livestock feed or as food ingredient requires a strict monitoring of heavy metal content in the growth substrate in order to secure its safe. This study aims to investigate the presence of toxic metals cadmium, lead, mercury, arsenic, and nickel in HI prepupae and their growth substrates based on coffee roasting by-product and microlagae Schizochytrium sp. and Isochrysis sp. Analyses were carried out via graphite furnace atomic absorption spectrophotometry for Cd, Pb, Ni, and As, and via Direct Mercury Analyzer for Hg. All metal concentrations found in growth substrates were below the legal limit of undesirable substances in animal feed (2002/32/EC). Metals concentrations in HI prepupae were in the range (mg kg-1 wet weight): Cd 0.072–0.084, Pb 0.018–0.026, Hg 0.010–0.032, As 0.036–0.047, Ni 0.18–0.76. HI prepupae accumulate Cd, Pb and Hg, but our results indicate that the risk of exposure to metals from consumption of HI prepupae is relatively low and in compliance with European Union regulations.
ARTICLE | doi:10.20944/preprints202208.0401.v1
Subject: Materials Science, Metallurgy Keywords: e-waste; e-waste mechanical pretreatment; disintegration; e-waste milling; printed circuit boards; precious metals
Online: 23 August 2022 (17:24:51 CEST)
Various metals and semiconductors containing Printed Circuit Boards (PCBs) are abundant in any electronic device equipped with controlling and computing features. These devices inevitably constitute E-waste after the end of service life. The typical construction of PCBs includes mechanically and chemically resistive materials, which significantly reduce the reaction rate or even avoid accessing chemical reagents (dissolvents) to target metals. Additionally, the presence of relatively reactive polymers and compounds from PCBs requires high energy consumption and reactive supply due to the formation of undesirable and sometimes environmentally hazardous reaction products. Preliminarily milling PCBs into powder is a promising method for increasing the reaction rate and avoiding liquid and gaseous emissions. Unfortunately, current state-of-the-art milling methods also lead to the presence of significantly more reactive polymers still adhered to milled target metal particles. This paper aims to find a novel single and two-stage disintegration-milling approach that can provide the formation of metal-rich particle size fractions. The morphology, particle fraction sizes, bulk density, and metal content in produced particles were measured and compared. Research results show the highest bulk density (up to 6.8 g·cm-3) and total metal content (up to 95.2 wt. %) in finest sieved fractions after the single-step milling of PCBs. Therefore, the concentrations of about half tested metallic elements are higher in the single milled specimen and with lower adhered plastics concentrations, as compared to double milled specimens.
ARTICLE | doi:10.20944/preprints202203.0205.v1
Subject: Earth Sciences, Environmental Sciences Keywords: heavy metals; abandoned mine; soil pollution; potential ecological risk; multivariate analysis; health index; soil; sediments
Online: 15 March 2022 (10:58:46 CET)
A recent survey that determined heavy metal concentrations in an abandoned Hg mine in Palawan, Philippines, found the occurrence of Hg with As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl, V, and Zn. While the Hg originated from the mine waste calcines as supported by previous studies, the critical knowledge about the origin of the other heavy metals remains to be unknown. Our study investigated the sources of heavy metal pollution surrounding the abandoned Hg mine; and assessed the soil and sediment quality, ecological risks, and health risks associated with these toxic metals. Multivariate analyses, such as hierarchical cluster analysis (HCA), principal component analysis (PCA), and Pearson correlation analysis, were used to identify the heavy metal sources from the results of a previous paper. Our results showed that Fe, Ni, Cr, Co, and Mn are associated with the ultramafic geology of the study, whereas As, Ba, Cd, Cu, Pb, Sb, Tl, V, and Zn are likely due to historical mining and processing of cinnabar from 1953-1976. The mine waste calcines were used as construction material for the wharf and as land filler for the adjacent communities. The modified contamination factor (mCdeg) showed that the coast of Honda Bay is highly contaminated, while the inland areas, including the rivers, are very- to ultra-highly contaminated. There is a considerable ecological risk associated with the heavy metals, wherein Ni, Hg, Cr, and Mn contribute an average of 46.3 %, 26.3 %, 11.2 %, and 9.3 % to the potential ecological risk index (RI), respectively. The overall mean hazard index (HI) for both adults (1.4) and children (12.1) exceeded 1, implying the probability of non-carcinogenic adverse effects. The mean total cancer risk over a lifetime (LCR) for both adults (1.19×10-3) and children (2.89×10-3) exceeded the tolerable threshold of 10-4, suggesting a potentially high risk for developing cancer mainly by Ni, Co, and Cr exposure.
ARTICLE | doi:10.20944/preprints202106.0439.v1
Subject: Earth Sciences, Atmospheric Science Keywords: heavy metals; MMORS, Meycauayan River; soil pollution; multivariate analysis; Sediment Quality Guidelines; Single Pollution Index
Online: 16 June 2021 (10:34:20 CEST)
The City of Meycauayan is considered as one of the most polluted cities in the developing world on the account of industrial discharges of toxic materials to the environment. This work investigated the sources of the heavy metal pollution by analyzing soil and sediment samples for heavy metals (Cr, Hg, Ni, and Pb) together with selected environmental indicators (TN, TOM, and TP) located along the Meycauayan River. Hierarchical cluster analysis (HCA), principal components analysis (PCA), and Pearson correlation analysis (CA) were used to identify the sources of the metals. Results showed delineated locations of severe levels of heavy metal pollution downstream because of the concentration of industrial activities. Cr contributed more than any other heavy metals analyzed due to proliferation of tanneries discharging untreated wastewaters to the river. Significant inputs of Pb and Hg from Pb-acid battery recycling and gold smelting industries were also found. Risk assessments indicated severe levels of heavy metal pollution where industrial activities are concentrated. The mean Cr, Pb, Ni, and Hg in the sampling locations have mean incidences of toxicity of 91.7 %, 53.6 %, 27.7 %, and 70.0 %, respectively. Our study showed a serious need to address heavy metal pollution in Meycauayan.
ARTICLE | doi:10.20944/preprints201811.0492.v1
Subject: Chemistry, Electrochemistry Keywords: single atom catalysis; carbon-supported catalysts; platinum-group metals; aberration-corrected scanning transmission electron microscopy
Online: 20 November 2018 (09:19:06 CET)
Nanoparticles of platinum-group metals (PGM) on carbon supports are widely used as catalysts for a number of chemical and electrochemical conversions on laboratory and industrial scale. The newly emerging field of single atom catalysis focuses on the ultimate level of metal dispersion, i.e. atomically dispersed metal species anchored on the substrate surface. However, the presence of single atoms in traditional nanoparticle-based catalysts remains largely overlooked. In this work we use aberration-corrected scanning transmission electron microscope to investigate four commercially available nanoparticle-based PGM/C catalysts (PGM = Ru, Rh, Pd, Pt). We show that in addition to nanoparticles, single atoms are also present on the surface of carbon substrates. These observations raise questions about the role that single atoms play in conventional nanoparticle PGM/C catalysts. We critically discuss the observations with regard to the quickly developing field of single atom catalysis.
ARTICLE | doi:10.20944/preprints202003.0153.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: unrecorded alcohol; home-produced fruit spirits; metals; lead; cadmium; ethanol; health risk; risk assessment; margin of exposure
Online: 10 March 2020 (02:44:16 CET)
Unrecorded alcohol comprises all types of alcohol that is not registered in the jurisdiction where it is consumed. In some countries in Central and Eastern parts of Europe as well as the Balkan, the major amount of unrecorded alcohol consumption may derive from homeproduction of fruit spirits. Some studies found a high prevalence of lead and cadmium in such spirits. This article provides a quantitative comparative risk assessment using the margin of exposure (MOE) methodology for lead and cadmium, compared to ethanol, for unrecorded fruit spirits. For average concentration levels, the lowest MOE (0.8) was calculated for ethanol (alcohol itself). For lead, the MOE was 13 for moderate daily drinking and 0.9 for the worst case. For cadmium, the MOE was 1982 for moderate daily drinking and 113 for the worst case. The results of this study are consistent with previous comparative risk assessments that ethanol itself comprises by far the highest risk of all compounds in alcoholic beverages. Regarding the metal contaminants, the risk of cadmium appears negligible, however, lead may pose an additional health risk in heavy drinking circumstances. Strategies to avoid metal contamination in settings of artisanal homeproduction of spirits need to be developed.
REVIEW | doi:10.20944/preprints201908.0261.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: review; additive manufacuring; thin films; noble metals; catalysis; conductive; hydrogen technology; sensors; fuel cells; 3-D printing
Online: 26 August 2019 (04:55:11 CEST)
The noble metals palladium and silver find use in many high performance applications, and their alloys (PdAg), known for more than sixty years, are industrially important, finding use in many fields including hydrogen purification and separation, numerous facets of catalysis, and in fuel cells. In recent years, interest in these materials has grown significantly, particularly in energy generating applications and due to their performance as solid-state chemical sensors for a range of small molecules. PdAg thin films can be prepared using traditional physical methods such as cold rolling, or more modern and controllable chemical or physical deposition techniques such as electrodeposition or chemical vapour deposition. Despite the wide-reaching uses of PdAg, several recent advancements in materials preparation, such as additive manufacturing, better known as 3-D printing, remain unexplored for this material due to the differing chemistries of the two elements. In this review, we explore the manufacturing methods commonly employed for the preparation of PdAg thin films, the common and niche applications of these materials, and opportunities for the future development of these two aspects, with an emphasis on how preparation of thin films can utilise additive manufacturing approaches.
ARTICLE | doi:10.20944/preprints202111.0289.v1
Subject: Earth Sciences, Environmental Sciences Keywords: vegetation decline; multitemporal satellite; time series; remote sensing; Landsat; Theil-Sen estimator; Mann-Kendall test; pollution; heavy metals
Online: 16 November 2021 (11:39:44 CET)
The work consisted in identifying possible effects from heavy metals (HMs) pollution due to waste disposal activities in three potentially polluted sites located in Basilicata (Italy), where a release of pollutants with values over the thresholds allowed by the Italian legislation was detected. The potential variations in the physiological efficiency of vegetation have been analyzed through the multitemporal processing of satellite images. In detail, Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager (OLI) images were used to calculate the Normalized Difference Vegetation Index (NDVI) trend over the years. Then, the multitemporal trends were analyzed using the median of Theil-Sen, a non-parametric estimator particularly suitable for the treatment of remote sensing data, being able to minimize the outlier effects due to exogenous factors. Finally, the subsequent application of the Mann-Kendall test on the trends identified by Theil-Sen slope allowed the evaluation of trends significance and, therefore, the areas characterized by the effects of contamination on vegetation. The application of the procedure to the three survey sites led to the exclusion of the presence of significant effects of HMs contamination on the vegetation surrounding the sites during the years of waste disposal activities.
Subject: Physical Sciences, Acoustics Keywords: Sulfur dioxide reduction; doubly-charged anions; triple-hybrid catalyst; super-benzene; fullerene; atomic metals; tunable catalysts; carbon nanotube
Online: 9 June 2021 (11:52:57 CEST)
Sulfur dioxide (SO2) reduction remains an area of global necessity further enhanced by the current international focus on pandemic diseases mitigation, elimination of air pollution, and promotion of renewable green energy. The dynamics of chemical bond-strength breaking and reformation in the transition state (TS) is a fundamental process in the reduction of SO2 by CO. Density Functional Theory (DFT) has been used to determine optimal TS reaction pathway via a novel triple-hybrid catalyst utilizing doubly-charged negative atomic V, Mn, and Au. The triple-hybrid catalyst is furthermore tailored to the subsequent minimization of each individual step of the 3-Step SO2 reduction by CO chemical reaction. Each optimized step 1, 2, and 3 is minimized with doubly-charged V, Mn, and Au, respectively, with TS barrier reductions ranging from 1.18 eV to 0.002 eV. Super-benzene, armchair (6, 6) single wall carbon nanotube, and fullerene TS reaction pathways have also been calculated to compare the nanoscale catalytic effectiveness with that of the atomic scale transition metals.
ARTICLE | doi:10.20944/preprints202012.0263.v1
Subject: Physical Sciences, Acoustics Keywords: Liquid-vapour phase transition; metals; thermodynamic perturbation theory; coupling-parameter expansion; critical point parameters; universal aspects; scaled variables.
Online: 10 December 2020 (13:40:39 CET)
The first objective of this paper is to investigate the scaling behavior of liquid-vapor phase transition in FCC and BCC metals starting from the zero-temperature four-parameter formula for cohesive energy. The effective potentials between the atoms in the solid are determined using lattice inversion techniques as a function of scaling variables in the above formula. These potentials are split into repulsive and attractive parts as per the Weeks-Chandler-Anderson prescription, and used in the coupling-parameter expansion for solving the Ornstein-Zernike equation supplemented with an accurate closure. Thermodynamic quantities obtained via the correlation functions are used to obtain critical point parameters and liquid-vapor phase diagrams. Their dependence on the scaling variables in the cohesive energy formula are also determined. Equally important second objective of the paper is to revisit coupling parameter expansion for solving the Ornstein-Zernike equation. The Newton-Armijo non-linear solver and Krylov-space based linear solvers are employed in this regard. These methods generate a robust algorithm that can be used to span the entire fluid region, except very low temperatures. Accuracy of the method is established by comparing the phase diagrams with those obtained via computer simulation. Avoidance of the 'no-solution-region' of Ornstein-Zernike equation in coupling-parameter expansion is also discussed. Details of the method and the complete algorithm provided here would make this technique more accessible to researchers investigating thermodynamic properties of one component fluids.
Subject: Chemistry, Analytical Chemistry Keywords: screen printed electrodes; Ag nanoparticles; drop-casting; spin-coating; nanoprisms; heavy metals; Differential pulse anodic stripping voltammetric; electrocatalysis
Online: 5 August 2019 (04:55:05 CEST)
The screen-printed carbon nanofibers electrodes (SPCNFE) represent an alternative with great acceptance due to their results, as well as their low impact for the environment. In order to improve their performance, in the present work they were modified with silver nanoparticles (Ag-NPs) and electrochemically characterized by using anodic stripping voltammetry. From the Ag-NPs synthesis, silver seeds (Ag-NS) and silver nanoprisms (Ag-NPr) were obtained. The Ag-NPs formation was confirmed by micrographs where Ag-NPs with diameters of 12.20±0.04 nm for Ag-NS, and 20.40±0.09 nm for Ag-NPr were observed. The electrodes were modified by using three different deposition methods: drop-casting, spin-coating and in-situ approaches. It was observed that the last methodology showed a low amount of Ag-NS deposited on the electrode surface and a deep alteration of this surface. Those facts suggested that the in situ synthesis methodology were not appropriate for the determination of heavy metals and it was discarded. The incorporation of the nanoparticles by spin-coating and drop-casting strategies showed different spatial distribution on the electrode surface as proved by scanning electron microscopy. The electrodes modified by these strategies, were evaluated for the cadmium(II) and lead(II) detection using differential pulse anodic stripping voltammetry, obtaining detection limit values of 2.1 and 2.8 µg L-1, respectively. The overall results showed that the incorporation route does not change directly the electrocatalytic effect of the nanoparticles, but the shape of these nanoparticles (spherical for seeds and triangular for prisms) has a preferential electrocatalytical enhancement over Cd(II) or Pb(II).
ARTICLE | doi:10.20944/preprints201806.0478.v1
Subject: Earth Sciences, Environmental Sciences Keywords: allophane; adsorption; precipitation; interface processes; environment; heavy metals; nano-structure; short-range order aluminosilicate; wastewater treatment; aqueous geochemistry
Online: 28 June 2018 (15:39:12 CEST)
The capacity and the mechanism of the adsorption of aqueous barium (Ba), cobalt (Co), strontium (Sr) and zinc (Zn) by Ecuadorian (NatAllo) and synthetic (SynAllo-1 and SynAllo-2) allophanes were studied as a function of contact time, pH and metal ion concentration using kinetic and equilibrium experiments. The mineralogy, nano-structure and chemical composition of the allophanes were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and specific surface area analyses. The evolution of adsorption fitted to a pseudo-first-order reaction kinetics, where equilibrium between aqueous metal ions and allophane was reached within < 10 min. The metal ion removal efficiencies varied from 0.7 to 99.7 % at pH 4.0 to 8.5. At equilibrium, the adsorption behavior is better described by the Langmuir model than by the Dubinin-Radushkevich model, yielding sorption capacities of 10.6, 17.2 and 38.6 mg/g for Ba^(2+), 12.4, 19.3 and 29.0 mg/g for HCoO_2^-, 7.2, 15.9 and 34.4 mg/g for Sr^(2+) and 20.9, 26.9 and 36.9 mg/g for Zn^(2+), respectively, by NatAllo, SynAllo-2 and SynAllo-1. The uptake mechanism is based on a physical adsorption process. Allophane holds great potential to remove aqueous metal ions and could be used instead of zeolites, montmorillonite, carbonates and phosphates for wastewater treatment.
ARTICLE | doi:10.20944/preprints201705.0068.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Source separation system; Greywater treatment; Water reuse; Hydroponic system; Green wall; Heavy metals bioaccumulation; QMRA; Health risk assessment
Online: 8 May 2017 (17:39:16 CEST)
The scarcity and pollution of freshwater are extremely crucial issues today and the expansion of water reuse have been considered as an option to reduce its impact. This study aims to assess the efficiency of an integrated greywater treatment system and hydroponic lettuce production as a part of a green wall structure and to evaluate the health risk associated with the production and consumption of lettuce through quantitative microbial risk assessment (QMRA) and chemical health risk assessment. The study was conducted based on the unique configuration of source separation system; on-site greywater treatment system; green wall structure as a polishing step; and hydroponic lettuce production in the green wall structure. The final effluent from the system was used to grow three lettuce varieties by adding urine as a nutrient solution. Both water samples and plant biomass were collected and tested for E. coli and heavy metals contamination. The system has gained a cumulative 5.1 log10 reduction of E. coli in the final effluent and no E. coli found in the plant biomass. QMRA results indicated that the system attained the health-based targets, 10–6 DALYs per person per year. Similarly, health risk index (HRI) and targeted hazard quotient (THQ) results did not exceed the permissible level, thus the chemical health risk concern was insignificant.
ARTICLE | doi:10.20944/preprints202009.0171.v1
Subject: Biology, Physiology Keywords: protein-protein interaction network; GPx; glutathione peroxidases genes; ciliate protists; copper; metals; antioxidant system; free-radicals; ROS; reactive oxygen species
Online: 8 September 2020 (04:59:18 CEST)
Glutathione peroxidases (GPxs) form a broad family of antioxidant proteins essential for maintaining redox homeostasis in eukaryotic cells. In this study, we used an integrative approach that combines bioinformatics, molecular biology, and biochemistry to investigate the role of GPxs in reactive oxygen species detoxification in the unicellular eukaryotic model organism Tetrahymena thermophila. Both phylogenetic and mechanistic empirical model analyses provided indications about the evolutionary relationships among the GPXs of Tetrahymena and the orthologous enzymes of phylogenetically related species. In-silico gene characterization and text mining were used to predict the functional relationships between GPxs and other physiologically-relevant processes. The GPx genes contain conserved transcriptional regulatory elements in the promoter region, which suggest that transcription is under tight control of specialized signaling pathways. The bioinformatic findings were next experimentally validated by studying the time course of copper (Cu)-dependent regulation of gene transcription and enzymatic activity. Results emphasize the role of GPxs in the detoxification pathways that, by complex regulation of Cu-dependent GPx gene expression, enables Tetrahymena to survive in high Cu concentrations and the associated redox environment.