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Articoli di riviste sul tema "Arsenic"

1

LUNDH, DAN, DENNIS LARSSON, NOOR NAHAR e ABUL MANDAL. "ARSENIC ACCUMULATION IN PLANTS – OUTLINING STRATEGIES FOR DEVELOPING IMPROVED VARIETY OF CROPS FOR AVOIDING ARSENIC TOXICITY IN FOODS". Journal of Biological Systems 18, n. 01 (marzo 2010): 223–41. http://dx.doi.org/10.1142/s0218339010003214.

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Contamination of food with arsenics is a potential health risk for both humans and animals in many regions of the world, especially in Asia. Arsenics can be accumulated in humans, animals and plants for a longer period and a long-term exposure of humans to arsenics results in severe damage of kidney, lever, heart etc. and many other vascular diseases. Arsenic contamination in human may also lead to development of cancer. In this paper we report our results on data mining approach (an in silico analysis based on searching of the existing genomic databases) for identification and characterization of genes that might be responsible for uptake, accumulation or metabolism of arsenics. For these in silico analyses we have involved the model plant Arabidopsis thaliana in our investigation. By employing a system biology model (a kinetic model) we have studied the molecular mechanisms of these processes in this plant. This model contains equations for uptake, metabolism and sequestration of different types of arsenic; As(V), As(III), MMAA and DMAA. The model was then implemented in the software XPP. The model was also validated against the data existing in the literatures. Based on the results of these in silico studies we have developed some strategies that can be used for reducing arsenic contents in different parts of the plant. Data mining experiments resulted in identification of two candidate genes (ACR2, arsenate reductase 2 and PCS1, phytochelatin synthase 1) that are involved either in uptake, transport or cellular localization of arsenic in A. thaliana. However, our system biology model revealed that by increasing the level of arsenate reductase together with an increased rate of arsenite sequestration in the vacuoles (by involving an arsenite efflux pump MRP1/2), it is possible to reduce the amount of arsenics in the shoots of A. thaliana to 11–12%.
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Volynkin, Sergey S., Svetlana B. Bortnikova, Nataliya V. Yurkevich, Olga V. Shuvaeva e Sofia P. Kohanova. "Determination of Arsenic Species Distribution in Arsenide Tailings and Leakage Using Geochemical and Geophysical Methods". Applied Sciences 13, n. 2 (12 gennaio 2023): 1067. http://dx.doi.org/10.3390/app13021067.

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This study describes the distribution of arsenic mobile species in the tailings of Cu–Co–Ni–arsenide using the sequential extraction and determining the contents of arsenate (AsV) and arsenite (AsIII). The object of this study is the tailings ponds of the Tuvakobalt plant, which contains waste from the hydrometallurgical arsenide ore processing of the Khovu-Aksy deposit (Republic of Tuva, Russia). A procedure of sequential extraction for arsenic was applied, and it includes the extraction of the following forms: water-soluble, potentially water-soluble and exchangeable, easily sorbed on the surface of carbonates, associated with Fe/Mn oxides/hydroxides, associated with easily oxidized minerals, and accounted for by non-oxidized arsenic minerals. This procedure, which takes into account the peculiarities of the physical and chemical composition of the waste, was supplemented by the analytical determination of the arsenite and arsenate content by using the methods of inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with the hydride generation technique (HG-ICP-AES). The content of the most mobile forms of arsenic, which are water-soluble, potentially water-soluble, and exchangeable species, is equal to 56% of the total arsenic content, 23% and 33% of which are arsenite and arsenate, respectively. Unlike arsenic, the mobile forms of metals have been determined in small quantities. The largest proportion of water-soluble and exchangeable forms is formed by Mg, Ca, and Sr at 11, 9.4, and 20%, respectively (residual and redeposited carbonates). The proportion of water-soluble forms of other metals (Cu, Zn, Co, and Ni) is < 1% or 0. The main part of the metals is adsorbed on the surface of Fe and Mn hydroxides, enclosed in easily and hardly oxidized minerals. In addition to geochemical studies, the presence of leaks from the tailing ponds into ground waters was determined by using electrical resistivity tomography. The data obtained indicate a high environmental hazard of tailings and the possibility of water-soluble and highly toxic arsenic compounds entering ground waters and aquifers.
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Castriota, Felicia, Peter-James H. Zushin, Sylvia S. Sanchez, Rachael V. Phillips, Alan Hubbard, Andreas Stahl, Martyn T. Smith, Jen-Chywan Wang e Michele A. La Merrill. "Chronic arsenic exposure impairs adaptive thermogenesis in male C57BL/6J mice". American Journal of Physiology-Endocrinology and Metabolism 318, n. 5 (1 maggio 2020): E667—E677. http://dx.doi.org/10.1152/ajpendo.00282.2019.

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The global prevalence of type 2 diabetes (T2D) has doubled since 1980. Human epidemiological studies support arsenic exposure as a risk factor for T2D, although the precise mechanism is unclear. We hypothesized that chronic arsenic ingestion alters glucose homeostasis by impairing adaptive thermogenesis, i.e., body heat production in cold environments. Arsenic is a pervasive environmental contaminant, with more than 200 million people worldwide currently exposed to arsenic-contaminated drinking water. Male C57BL/6J mice exposed to sodium arsenite in drinking water at 300 μg/L for 9 wk experienced significantly decreased metabolic heat production when acclimated to chronic cold tolerance testing, as evidenced by indirect calorimetry, despite no change in physical activity. Arsenic exposure increased total fat mass and subcutaneous inguinal white adipose tissue (iWAT) mass. RNA sequencing analysis of iWAT indicated that arsenic dysregulated mitochondrial processes, including fatty acid metabolism. Western blotting in WAT confirmed that arsenic significantly decreased TOMM20, a correlate of mitochondrial abundance; PGC1A, a master regulator of mitochondrial biogenesis; and, CPT1B, the rate-limiting step of fatty acid oxidation (FAO). Our findings show that chronic arsenic exposure impacts the mitochondrial proteins of thermogenic tissues involved in energy expenditure and substrate regulation, providing novel mechanistic evidence for arsenic’s role in T2D development.
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Dong, Owen, Michael Powers, Zijuan Liu e Masafumi Yoshinaga. "Arsenic Metabolism, Toxicity and Accumulation in the White Button Mushroom Agaricus bisporus". Toxics 10, n. 10 (22 settembre 2022): 554. http://dx.doi.org/10.3390/toxics10100554.

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Mushrooms have unique properties in arsenic metabolism. In many commercial and wild-grown mushrooms, arsenobetaine (AsB), a non-toxic arsenical, was found as the dominant arsenic species. The AsB biosynthesis remains unknown, so we designed experiments to study conditions for AsB formation in the white button mushroom, Agaricus bisporus. The mushrooms were treated with various arsenic species including arsenite (As(III)), arsenate (As(V)), methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and trimethylarsine oxide (TMAsO), and their accumulation and metabolism were determined using inductively coupled mass spectrometer (ICP-MS) and high-pressure liquid chromatography coupled with ICP-MS (HPLC-ICP-MS), respectively. Our results showed that mycelia have a higher accumulation for inorganic arsenicals while fruiting bodies showed higher accumulation for methylated arsenic species. Two major arsenic metabolites were produced in fruiting bodies: DMAs(V) and AsB. Among tested arsenicals, only MAs(V) was methylated to DMAs(V). Surprisingly, AsB was only detected as the major arsenic product when TMAsO was supplied. Additionally, AsB was only detected in the fruiting body, but not mycelium, suggesting that methylated products were transported to the fruiting body for arsenobetaine formation. Overall, our results support that methylation and AsB formation are two connected pathways where trimethylated arsenic is the optimal precursor for AsB formation.
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Kim, Hyojin, Yangwon Jeon, Woonwoo Lee, Geupil Jang e Youngdae Yoon. "Shifting the Specificity of E. coli Biosensor from Inorganic Arsenic to Phenylarsine Oxide through Genetic Engineering". Sensors 20, n. 11 (30 maggio 2020): 3093. http://dx.doi.org/10.3390/s20113093.

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It has recently been discovered that organic and inorganic arsenics could be detrimental to human health. Although organic arsenic is less toxic than inorganic arsenic, it could form inorganic arsenic through chemical and biological processes in environmental systems. In this regard, the availability of tools for detecting organic arsenic species would be beneficial. Because As-sensing biosensors employing arsenic responsive genetic systems are regulated by ArsR which detects arsenics, the target selectivity of biosensors could be obtained by modulating the selectivity of ArsR. In this study, we demonstrated a shift in the specificity of E. coli cell-based biosensors from the detection of inorganic arsenic to that of organic arsenic, specifically phenylarsine oxide (PAO), through the genetic engineering of ArsR. By modulating the number and location of cysteines forming coordinate covalent bonds with arsenic species, an E. coli cell-based biosensor that was specific to PAO was obtained. Despite its restriction to PAO at the moment, it offers invaluable evidence of the potential to generate new biosensors for sensing organic arsenic species through the genetic engineering of ArsR.
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Percy, Andrew J., e Jürgen Gailer. "Methylated Trivalent Arsenic-Glutathione Complexes are More Stable than their Arsenite Analog". Bioinorganic Chemistry and Applications 2008 (2008): 1–8. http://dx.doi.org/10.1155/2008/539082.

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The trivalent arsenic glutathione complexes arsenic triglutathione, methylarsonous diglutathione, and dimethylarsinous glutathione are key intermediates in the mammalian metabolism of arsenite and possibly represent the arsenic species that are transported from the liver to the kidney for urinary excretion. Despite this, the comparative stability of the arsenic-sulfur bonds in these complexes has not been investigated under physiological conditions resembling hepatocyte cytosol. Using size-exclusion chromatography and a glutathione-containing phosphate buffered saline mobile phase (5 or 10 mM glutathione, pH 7.4) in conjunction with an arsenic-specific detector, we chromatographed arsenite, monomethylarsonous acid, and dimethylarsinous acid. The on-column formation of the corresponding arsenic-glutathione complexes between 4 and37°C revealed that methylated arsenic-glutathione complexes are more stable than arsenic triglutathione. The relevance of these results with regard to the metabolic fate of arsenite in mammals is discussed.
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Hoque, M. M., S. Rahman, M. E. Hoque, M. J. Ara e M. R. Jamal. "Arsenic pollution and its impact on agricultural production, including the ecosystem services delivered by biodiversity". Journal of Science Technology and Environment Informatics 13, n. 01 (15 febbraio 2024): 827–39. http://dx.doi.org/10.18801/jstei.130124.83.

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Abstract (sommario):
Arsenic (As), a noxious metal(loid) widely available in the biosphere, originates mainly from geogenic and anthropogenic origin. Massive global development and industrialization, using pesticides carrying arsenic, arsenical animal feeds, medicine, mining, aquifer sediments, coal burning, and microbial and natural processes continuously release this obnoxious bane to the natural environment and pollute soil and water. Inorganic (iAs) species, mainly arsenate and arsenite, are comparatively more lethal than methylated species. However, pentavalent [As (V)] organic species are nearly non-toxic. An elevated level of arsenic has been found in various crops and feeds consumed by humans and animals. This notable carcinogen threatens human health by drinking arsenic-polluted freshwater and/or ingesting arsenic-adulterated food like cereals, fruits and vegetables grown in arsenic-polluted soil or grown using arsenic-rich irrigation water. Arsenic pollution exerts an irreversible harmful effect on the aquatic and terrestrial ecosystem as well. Much research has been carried out in the last couple of centuries on arsenic pollution and reported its ability to influence the agro-ecosystem to a great extent, including plant accumulation, phytotoxicity, and land degradation. However, underground water is considered the principal source of arsenic pollution, Iron plaque, sulphur oxides, organic matter, microbiome activities and many other factors responsible for speciation, bioavailability and toxicity of As to the environment. This review attempts to comprehend the global arsenic pollution occurrence, its forms, bioavailability and toxicity to humans and microbiota, translocation and accumulation in plants and impact on crop yield. Besides providing the insights, the ultimate targets of this desktop study are to ascertain probable knowledge gaps linked to crop productivity and ecosystem benefit losses that need further investigation.
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Chang, Jin-Soo, Hyun-Jung Kim, Won-Seok Kim e Seyong Lee. "Ars Genotype of Arsenic Oxidizing Bacteria and Detoxification". Journal of Korean Society of Environmental Engineers 46, n. 5 (31 maggio 2024): 185–94. http://dx.doi.org/10.4491/ksee.2024.46.5.185.

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Objectives:The objectives of this study is bioremediation and detoxification of arsenite using arsenic resistance system (ars) genotypes of Arsenic Oxidizing Bacteria (AOB) isolated from highly As-contaminated mine.Methods:Bacterial strains that are resistant to arsenic were isolated from the Samkwang mine. The identification of AOB was conducted by analyzing the 16S rRNA gene using universal primers. To determine the genotypes of the arsenic resistance system (ars), specific primers were used for each gene. The extent of arsenic resistance was measured, and the efficiency of arsenite oxidation was assessed through a batch test. Arsenic concentration was measured using ICP-MS.Results and Discussion:The arsenic concentrations at site 1 of the Samkwang mine were found to be 1,322 mg/kg. This concentration is 26.4 times higher than the standard for soil pollution concerns (50 mg/kg) and 8.8 times higher than the standard for soil pollution measures (150 mg/kg). The appropriate remediation is studied such as bacterial remediation. The three efficient AOBs were identified as Agrobacterium tumefaciens EBC-SK1 (MF928870), Ochrobactrum anthrophi EBC-SK4 (MF928873), Ochrobactrum anthrophi EBC-SK12 (MF928881), respectively. The arsenic resistance system (ars) genotype were detected, which is the leader genes of the arsenic oxidation system (arsR and arsD), and the membrane gene (arsB). The arsB is involved in the encoding of the efflux/influx pumping system and moves arsenite into the bacterial cells. Arsenite-oxidizing (aox) genes are activated to oxidize arsenite into arsenate. The AOBs biotransform arsenite to arsenate with the regulation of ars genes, which detoxify highly As-contaminated mine.Conclusion:The AOBs from Samkwang mine are known for their resistance to highly toxic arsenic environments. They play a crucial role in the bioremediation of abandoned mines by transforming As(III) into As(V) through biotransformation.
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Isokpehi, Raphael D., Udensi K. Udensi, Shaneka S. Simmons, Antoinesha L. Hollman, Antia E. Cain, Samson A. Olofinsae, Oluwabukola A. Hassan et al. "Evaluative Profiling of Arsenic Sensing and Regulatory Systems in the Human Microbiome Project Genomes". Microbiology Insights 7 (gennaio 2014): MBI.S18076. http://dx.doi.org/10.4137/mbi.s18076.

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The influence of environmental chemicals including arsenic, a type 1 carcinogen, on the composition and function of the human-associated microbiota is of significance in human health and disease. We have developed a suite of bioinformatics and visual analytics methods to evaluate the availability (presence or absence) and abundance of functional annotations in a microbial genome for seven Pfam protein families: As(III)-responsive transcriptional repressor (ArsR), anion-transporting ATPase (ArsA), arsenical pump membrane protein (ArsB), arsenate reductase (ArsC), arsenical resistance operon transacting repressor (ArsD), water/glycerol transport protein (aquaporins), and universal stress protein (USP). These genes encode function for sensing and/or regulating arsenic content in the bacterial cell. The evaluative profiling strategy was applied to 3,274 genomes from which 62 genomes from 18 genera were identified to contain genes for the seven protein families. Our list included 12 genomes in the Human Microbiome Project (HMP) from the following genera: Citrobacter, Escherichia, Lactobacillus, Providencia, Rhodococcus, and Staphylococcus. Gene neighborhood analysis of the arsenic resistance operon in the genome of Bacteroides thetaiotaomicron VPI-5482, a human gut symbiont, revealed the adjacent arrangement of genes for arsenite binding/transfer (ArsD) and cytochrome c biosynthesis (DsbD_2). Visual analytics facilitated evaluation of protein annotations in 367 genomes in the phylum Bacteroidetes identified multiple genomes in which genes for ArsD and DsbD_2 were adjacently arranged. Cytochrome c, produced by a posttranslational process, consists of heme-containing proteins important for cellular energy production and signaling. Further research is desired to elucidate arsenic resistance and arsenic-mediated cellular energy production in the Bacteroidetes.
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Miyashita, Shin-ichi, Chisato Murota, Keisuke Kondo, Shoko Fujiwara e Mikio Tsuzuki. "Arsenic metabolism in cyanobacteria". Environmental Chemistry 13, n. 4 (2016): 577. http://dx.doi.org/10.1071/en15071.

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Environmental context Cyanobacteria are ecologically important, photosynthetic organisms that are widely distributed throughout the environment. They play a central role in arsenic transformations in terms of both mineralisation and formation of organoarsenic species as the primary producers in aquatic ecosystems. In this review, arsenic resistance, transport and biotransformation in cyanobacteria are reviewed and compared with those in other organisms. Abstract Arsenic is a toxic element that is widely distributed in the lithosphere, hydrosphere and biosphere. Some species of cyanobacteria can grow in high concentrations of arsenate (pentavalent inorganic arsenic compound) (100mM) and in low-millimolar concentrations of arsenite (trivalent inorganic arsenic compound). Arsenate, which is a molecular analogue of phosphate, is taken up by cells through phosphate transporters, and inhibits oxidative phosphorylation and photophosphorylation. Arsenite, which enters the cell through a concentration gradient, shows higher toxicity than arsenate by binding to sulfhydryl groups and impairing the functions of many proteins. Detoxification mechanisms for arsenic in cyanobacterial cells include efflux of intracellular inorganic arsenic compounds, and biosynthesis of methylarsonic acid and dimethylarsinic acid through methylation of intracellular inorganic arsenic compounds. In some cyanobacteria, ars genes coding for an arsenate reductase (arsC), a membrane-bound protein involved in arsenic efflux (arsB) and an arsenite S-adenosylmethionine methyltransferase (arsM) have been found. Furthermore, cyanobacteria can produce more complex arsenic species such as arsenosugars. In this review, arsenic metabolism in cyanobacteria is reviewed, compared with that in other organisms. Knowledge gaps remain regarding both arsenic transport (e.g. uptake of methylated arsenicals and excretion of arsenate) and biotransformation (especially production of lipid-soluble arsenicals). Further studies in these areas are required, not only for a better understanding of the role of cyanobacteria in the circulation of arsenic in aquatic environments, but also for their application to arsenic bioremediation.
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Tesi sul tema "Arsenic"

1

Rosner, Mitchell Harris. "ARSENIC METABOLITE ANALYSIS AFTER GALLIUM-ARSENIDE AND ARSENIC OXIDE ADMINISTRATION (DISTRIBUTION, EXCRETION, SOLUBILITY, HAMSTER)". Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275409.

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Roberge, Jason Linscot. "Binational Arsenic Exposure Survey: Modeling Arsenic and Selenium Intake on Urinary Arsenic Biomarkers". Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/255165.

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Introduction: It has been reported that the principal source of exposure for humans to inorganic arsenic (As) comes from drinking water. It is known that selenium (Se) competes with the reductive metabolism and methylation of As and Se compete for the availability of glutathione. The overarching goal of this dissertation research is to assess relationships between arsenic intake from water and other fluids with urinary arsenic output and then to assess how urinary arsenic output is modified by selenium exposure. Methods: Households in the Binational Arsenic Exposure Survey (BAsES) were selected for their varying groundwater arsenic concentrations. A first morning urine void and water samples from all household drinking sources were collected for As quantification. Relationships were examined between various urinary arsenic biomarkers and estimated arsenic exposures. The association between urinary arsenic biomarkers and dietary intake and urinary output of selenium was also evaluated. Results: Arizonans reported consuming 18.5 mL/kg-day of water and 34.3 mL/kg-day from all fluids. In contrast, participants from Mexico reported 3.5 mL/kg-day of water and 12.3 mL/kg-day from all fluids. Median urinary inorganic As concentration among Arizona participants (ranging from 1.2 to 2.0 µg/L) was lower than among participants from Mexico (range 2.5 to 6.2 µg/L). Estimated arsenic intake from drinking water was associated with urinary total arsenic concentration (p<0.001), urinary inorganic arsenic concentration (p<0.001), and urinary sum of species (p<0.001). Urinary arsenic concentrations increased between 7% and 12% for each one percent increase in arsenic consumed from drinking water. No statistically significant relationships were seen between urinary methylated arsenic biomarkers with either dietary intake of selenium or the urinary selenium concentration. Conclusion: Water was the primary contributor to total fluid intake among Arizonans while Mexico participants primarily consumed carbonated beverages. Arsenic intake from water was significantly associated with urinary arsenic output; however, the concentration of arsenic consumed explained a small fraction of urinary arsenic levels. While selenium can biologically interact with arsenic in the liver, no relationship between urinary arsenic biomarkers were identified with either dietary intake of selenium or urinary output of selenium.
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Sadee, Bashdar. "Total arsenic and arsenic speciation in indigenous food stuffs". Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/4583.

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The properties of an element are highly dependent on its chemical form, it’s called elemental speciation. This study evaluates the arsenic species found in a range of food stuffs together with growing environments and toxicity issues. Total arsenic concentrations in fish tissue and vegetable crops were determined by ICP-MS following microwave-assisted acid digestion using nitric acid/hydrogen peroxide, trypsin and cellulase enzymatic extraction procedures. The extracted arsenic species were then quantified using HPLC-ICP-MS. A dilute nitric acid (1 % (v/v)) digestion procedure was also used to extract arsenic species from rice and the different parts (root, skin, stem, leaf and grain) of a range of plant crops. The study was extended to include the aqua-regia extractable arsenic content of the soils collected from the area where the plants had been cultivated in the Kurdistan region of Iraq. Irrigation water was also investigated, but found to contain low levels of arsenic. An anion-exchange HPLC-ICP-MS method was developed, using sulphate and phosphate, for the separation and quantification of AsB, MMA, DMA, InAsIII and InAsV. The results obtained for fish samples were in the range of 3.53-98.80 µg g-1 (dry weight) with non-toxic AsB being the predominant species. The InAsV concentration was in the range of 0.1-1.19 µg g-1 for all fish species except for the John Dory which was below the limit of detection (0.027 µg g-1). Total arsenic, arsenic species, and total multi-elements (including Ag, Al, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Si, Ti, V and Zn) were determined in rice samples from Kurdistan, Iraq and other regions of geographical origin. The transport of arsenic from the soil and irrigation water into roots, stem, leaf and subsequently into the grain or bean of the plants is important when assessing the potential health risks from food crops. For the soil sample, InAsV was found to be the major species with smaller quantities of InAsIII . After applying a full BCR sequential extraction procedure to the soils, it was found that 7.87 - 21.14 % of the total arsenic was present in an easily acid-soluble extractable form. Finally, a novel method was developed to measure total arsenic and arsenic species associated with vegetative DNA. In rice plant, it was found that InAsV incorporated within the DNA molecule in which it could replace phosphate. It was also found that the concentration of InAsV associated with DNA molecule decreased with decreasing total arsenic in the rice plant from the root to the leaf.
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Whitacre, Shane D. "Soil Controls on Arsenic Bioaccessibility: Arsenic Fractions and Soil Properties". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244036619.

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Whitacre, Shane Dever. "Soil controls on arsenic bioaccessibility arsenic fractions and soil properties /". Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1244036619.

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Sun, Wenjie. "Microbial Oxidation of Arsenite in Anoxic Environments: Impacts on Arsenic Mobility". Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/194899.

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AbstractArsenic (As) contamination of groundwater and surface water is a worldwide problem. Exposure to arsenic in drinking water is an important current public health issue. Arsenic is well known for its carcinogenic and teratogenic effects. The U.S. Environmental Protection Agency (USEPA) has recently enacted a stricter drinking water standard for arsenic that lowers the maximum contaminant level (MCL) from 50 to 10 ug l-1.Localized elevated As concentrations in groundwater or surface water have been attributed to the natural release of As from the weathering of As bearing minerals. Microbial reduction of arsenate (As(V)) to arsenite (As(III)) and ferric (hydr)oxides to Fe(II) is hypothesized to be the dominant mechanisms of As mobilization in subsurface environments. If oxidizing conditions can be restored, As can be immobilized by the formation of As(V) and ferric (hydr)oxides. As(V) is more strongly adsorbed than As(III) at circumneutral conditions by common non-iron metal oxides in sediments such as those of aluminum. Ferric (hydr)oxides have strong affinity for both As(III) and As(V) in circumneutral environments. Oxygen can be introduced into the anaerobic zone by injection of gaseous O2 to promote oxidation reactions of As(III) and Fe(II), but O2 is poorly soluble and chemically reactive and thus difficult to distribute in the subsurface. Nitrate or chlorate can be considered as alternative oxidants with advantages over elemental oxygen due to their high aqueous solubility and lower chemical reactivity which together enable them to be better dispersed in the saturated subsurface.The objective of this study is to evaluate the importance of anoxic oxidation of As(III) to As(V) by anaerobic microorganisms such as chemolithotrophic denitrifying bacteria and chlorate respiring bacteria in the biogeochemical cycle of arsenic. This study also investigated a arsenic potential bioremediation strategy based on injecting nitrate or chlorate into contaminated groundwater and surface water under anaerobic conditions.In this study, denitrification or chlorate reduction linked to the oxidation of As(III) to As(V) was shown to be a widespread microbial activity in anaerobic sludge and sediment samples that were not previously exposed to arsenic contamination. The biological oxidation of As(III) utilizing nitrate or chlorate as sole electron acceptor was feasible and stable over prolonged periods of operation in continuous-flow anaerobic bioreactors. Evidence for the complete denitrification was demonstrated by direct measurement of N2 formation dependent on As(III) addition. Also complete chlorate reduction to chloride was attributable to the oxidation of As(III). A 16S rRNA gene clone library characterization of enrichment cultures indicated that the predominant phylotypes responsible for As(III) oxidation linked to denitrification were from the genus Azoarcus and the family Comamonadaceae. A bioremediation strategy was explored that is based on injecting nitrate to support the microbial oxidation of Fe(II) and As(III) in the subsurface as a means to immobilize arsenic. Two models were utilized to illustrate the mechanisms of As removal.1) Sediment columns packed with activated alumina were utilized to demonstrate the role of nitrate in supporting microbial As(III) oxidation and arsenic mobility in anoxic sediments containing mostly non-iron oxides;2) Sand-packed columns were used to simulate natural anaerobic groundwater and sediment systems with co-occurring As(III) and Fe(II) in the presence or absence of nitrate. Microbial oxidation by denitrifying microorganisms lead to the formation of ferric (hydroxides) which adsorbed As(V) formed from As(III)-oxidation.The studies presented here demonstrate that anoxic microbial oxidation of As(III) and Fe(II) linked to denitrification significantly enhance the immobilization of As in the anaerobic subsurface environments.
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Senn, David B. (David Bryan) 1970. "Coupled arsenic, iron, and nitrogen cycling in arsenic-contaminated Upper Mystic Lake". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8750.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.
Includes bibliographical references (p. 253-265).
This dissertation addresses the mechanisms controlling arsenic (As) remobilization and cycling in the hypolimnion of As-contaminated Upper Mystic Lake (UML; Winchester, MA). We conducted field and laboratory studies, and applied mass balance, surface complexation, and thermodynamic modeling to explore As cycling and its links to other elemental cycles (Fe, N, 02) in UML. Nitrate appears to control iron (Fe) and As cycling in the hypolimion of urban, eutrophic UML. In doing so, nitrate assumes the role typically taken by oxygen in the cycling of redoxactive metal(loid)s. High nitrate and ammonium inputs, combined with authigenic nitrate production in the water column (nitrification, consuming 40% of hypolimnetic oxygen), result in several months per year of anoxic, yet nitrate-rich conditions in the hypolimnion. As expected, the onset of anoxia triggers Fe and As remobilization from UML's contaminated sediments. However, despite anoxia, remobilized Fe and As accumulate in the water column primarily in their oxidized forms (Fe(IlI)-oxides and As(V)). Mass balance estimates indicate that nitrate is responsible for oxidizing the majority of the iron, which must initially have been remobilized by reductive dissolution as Fe(II). Microcosm studies confirmed this reaction's feasibility: anaerobic, biologically mediated Fe(II) oxidation occurred in nitrate-spiked microcosms with sample obtained from the sediment-water interface. Shifts in As and Fe redox chemistry toward their reduced forms (Fe(II) and As(III)) were correlated temporally and spatially with nitrate depletion. Nitrate's presence therefore appears to favor arsenic's accumulation as particle-reactive As(V) , either by directly oxidizing remobilized As(III) or indirectly by serving as a more energy-rich electron acceptor and forestalling As(V) reduction to As(III). During nitrate-rich periods, greater than 85% of remobilized arsenic was found to be particle complexed (deff > 0.05 [mu]m) at representative hypolimnetic depths by in situ filtration. Surface complexation modeling of As on Fe(III)-oxides accurately predicts As distribution between particle-complexed and dissolved phases. Thus Fe(III)-oxides appear to scavenge the vast majority of remobilized As. Through the anaerobic production of particulate Fe(III)-oxides, and by indirectly or directly causing As to accumulate as particle-reactive As(V), nitrate dominates remobilized As chemistry, and provides a continued As sink (via settling) during a large portion of anoxic periods.
by David B. Senn.
Ph.D.
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Castlehouse, Hayley. "The Biogeochemical controls on arsenic mobilisation in a geogenic arsenic rich soil". Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515417.

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Valentine, Vecorena Rominna E. "Arsenic Analysis: Comparative Arsenic Groundwater Concentration in Relation to Soil and Vegetation". CSUSB ScholarWorks, 2016. https://scholarworks.lib.csusb.edu/etd/279.

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Abstract (sommario):
Arsenic (As) is a toxic semi-metallic element found in groundwater, soils, and plants. Natural and anthropogenic sources contribute to the distribution of arsenic in the environment. Arsenic’s toxic and mobile behavior is associated with its speciation ability. There are two types of arsenic available to the environment, inorganic and organic arsenic. Of the two, inorganic arsenic is more toxic to humans and more mobile in the environment. Two inorganic compounds responsible for arsenic contamination are trivalent arsenite, As (III), and pentavalent arsenate, As (V). Trivalent arsenate is considered to be more soluble, toxic, and mobile than pentavalent arsenate. Arsenic’s absorptive properties in plant cells and ability to attach to minerals causing secondary contamination are due to environmental factors such as pH, redox potential, and solubility. The current maximum contaminant level for arsenic in water is 10 µg/L (or ppb). Research on arsenic involving high concentrations already present in groundwater (>300ppb) are compared either with crops irrigated with such water or a human indicator (such as; hair, nails, blood, or urine) in order to determine exposure limits. In this current research, relationships between the area in the studies and the contaminated media (water, soil, vegetation) were tested to determine if arsenic in water was correlated with arsenic concentrations present in soil and vegetation. Commercially obtained ITS Quick Rapid Arsenic Test Kits were used to measure arsenic concentrations for the media tested. A method for analysis of arsenic in vegetation was developed, with an estimated 80% recovery. The pH and conductivity were also taken for water and soil samples as a means of correlative comparison. The development of faster and portable methods for arsenic concentration may provide means for predicting the relationship between all contaminated media. The purpose of the study was to determine the correlation between arsenic water concentration and pH for water, soil, or vegetation and whether it plays an overall role in the amount of arsenic present. As a result, water and soil pH played a significant role in the presence of arsenic in the water and vegetation, respectively. A moderate negative correlation between arsenic in water and water pH was discovered to have a Spearman’s rho value of -0.708 with a p ≤ 0.05. In addition, a significant negative correlation between soil pH and arsenic in vegetation was also discovered to have a Spearman’s rho of -0.628 at a p ≤ 0.05. Even though, pH was significantly correlated with arsenic concentrations in different media, there is evidence that pH plays a role also in the amount of arsenic available in the soil and vegetation. Further studies are recommended.
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Ouypornkochagorn, Sairoong. "Uptake and biotransformation of arsenic species in various biological forms". Available from the University of Aberdeen Library and Historic Collections Digital Resources. Restricted: contains 3rd party material and therfore cannot be made available electronically, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=65766.

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Abstract (sommario):
Thesis (Ph.D.)--Aberdeen University, 2009.
With: Monitoring the arsenic and iodine exposure of seaweed-eating North Ronaldsay sheep from the gestational and sucking periods to adulthood by using horns as a dietary archive / Guilhem Caumette ... et al. Environmental Science and technology 2007: 41, 8, 2673-2679. Includes bibliographical references.
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Libri sul tema "Arsenic"

1

Abernathy, Charles O., Rebecca L. Calderon e Willard R. Chappell, a cura di. Arsenic. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5864-0.

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Henke, Kevin, a cura di. Arsenic. Chichester, UK: John Wiley & Sons, Ltd, 2009. http://dx.doi.org/10.1002/9780470741122.

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States, J. Christopher, a cura di. Arsenic. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.

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Roza, Greg. Arsenic. New York, NY: Rosen Pub. Group, 2009.

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Vuluka, Valérie Kabeya. Arsenic. Kananga, Congo?]: Editions de la Pléiade congolaise, 2005.

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Hanna, Kahelin, a cura di. Arseeni porakaivovesissä: Poistomenetelmien vertailututkimus = Summary, Arsenic in drilled wells, comparison of arsenic removal methods. Espoo: Geologian tutkimuskeskus, 1998.

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Kosnett, Michael. Arsenic toxicity. Atlanta, GA: U.S. Dept. of Health & Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, 1990.

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Kathleen, Kreiss, United States. Agency for Toxic Substances and Disease Registry e DeLima Associates, a cura di. Arsenic toxicity. Atlanta, GA: U.S. Department of Health & Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, 1990.

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Badruzzaman, A. B. M. Leaching of arsenic from wastes of arsenic removal systems. Dhaka: International Training Network Centre, BUET, 2008.

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Edwards, Martin. The arsenic labyrinth. Scottsdale, AZ: Poisoned Pen Press, 2007.

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Capitoli di libri sul tema "Arsenic"

1

Hughes, Michael F. "History of Arsenic as a Poison and a Medicinal Agent". In Arsenic, 1–22. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch1.

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Stýblo, Miroslav, e Christelle Douillet. "Diabetes Mellitus". In Arsenic, 221–47. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch10.

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Arteel, Gavin E. "Hepatotoxicity". In Arsenic, 249–65. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch11.

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Banerjee, Mayukh, e Ashok K. Giri. "Genetic Epidemiology of Susceptibility to Arsenic-Induced Diseases". In Arsenic, 267–88. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch12.

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Hudson, Laurie G., Karen L. Cooper, Susan R. Atlas, Brenee S. King e Ke Jian Liu. "Arsenic Interaction with Zinc Finger Motifs". In Arsenic, 289–314. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch13.

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Mann, Koren K., e Maryse Lemaire. "Role in Chemotherapy". In Arsenic, 315–45. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch14.

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Salazar, Ana María, e Patricia Ostrosky-Wegman. "Genotoxicity". In Arsenic, 347–67. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch15.

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Druwe, Ingrid L., e Richard R. Vaillancourt. "Arsenic and Signal Transduction". In Arsenic, 369–96. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch16.

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Xu, Yuanyuan, Erik J. Tokar e Michael P. Waalkes. "Stem Cell Targeting and Alteration by Arsenic". In Arsenic, 397–420. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch17.

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Paul, Somnath, e Pritha Bhattacharjee. "Epigenetics and Arsenic Toxicity". In Arsenic, 421–37. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118876992.ch18.

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Atti di convegni sul tema "Arsenic"

1

Jasudkar, Dipali P., Aditi L. Tulankar e S. R. Satone. "Arsenic and arsenic health effects". In INTERNATIONAL CONFERENCE ON “MULTIDIMENSIONAL ROLE OF BASIC SCIENCE IN ADVANCED TECHNOLOGY” ICMBAT 2018. Author(s), 2019. http://dx.doi.org/10.1063/1.5100415.

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Chu, Ting L., Shirley S. Chu, Richard F. Green e C. L. A. Cerny. "Epitaxial growth of gallium arsenide from elemental arsenic". In Physical Concepts of Materials for Novel Optoelectronic Device Applications, a cura di Manijeh Razeghi. SPIE, 1991. http://dx.doi.org/10.1117/12.24416.

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Benjamin, S. D., e P. W. Smith. "Ultrafast nonlinear optical properties of arsenic-rich gallium arsenide". In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/oam.1993.muu.9.

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Semenov, Igor Vitalievich, e Irina Viktorovna Iakovleva. "Chemical element Arsenic". In International Research and Practical Conference for Pupils. TSNS Interaktiv Plus, 2019. http://dx.doi.org/10.21661/r-508599.

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Serfes, Michael, Steve Spayd e Greg Herman. "ARSENIC MOBILIZATION AND DISPERSION FROM AN ARSENIC-SULFIDE ENRICHED BIOTITE GNEISS". In 51st Annual Northeastern GSA Section Meeting. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016ne-272910.

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Frantz, Jesse A., Jason D. Myers, Robel Y. Bekele, Anthony Clabeau, Vinh Q. Nguyen, Collin C. McClain, Natalia Litchinitser e Jasbinder S. Sanghera. "Arsenic selenide dielectric metasurfaces". In Optical Components and Materials XVI, a cura di Michel J. Digonnet e Shibin Jiang. SPIE, 2019. http://dx.doi.org/10.1117/12.2507894.

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Geary, Kaitlin, e Hongbing Sun. "ARSENIC LEVEL IN RICE OF THE US, ITS POSSIBLE LINKS TO SOIL ARSENIC AND HIGHER BLOOD ARSENIC LEVEL IN ASIAN AMERICANS". In Joint 69th Annual Southeastern / 55th Annual Northeastern GSA Section Meeting - 2020. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020se-344388.

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Yerby, Cooper J., Maxime Blatter, Kenneth H. Nealson, Christos Comninellis e Fabian Fischer. "USING LOW CURRENT DENSITY ARSENIC ELECTROCOAGULATION KINETICS TO MODEL MICROBIALLY MEDIATED ARSENIC ELECTROCOAGULATION". In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-321384.

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OLOPADE, Christopher, Faruque Parvez, M. Eunus, T. Islam, A. Ahmed, R. Hassan e Habibul Ahsan. "Arsenic Impairs Lung Function: Findings From The Health Effects Of Arsenic Longitudinal Study". In American Thoracic Society 2011 International Conference, May 13-18, 2011 • Denver Colorado. American Thoracic Society, 2011. http://dx.doi.org/10.1164/ajrccm-conference.2011.183.1_meetingabstracts.a2676.

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Islamiati, Dian, e Dini Arista Putri. "Environmental Health Risk Assessment Carcinogen and Non-Carcinogen Analysis: Arsenic in Rice". In 4th International Conference on Public Health and Well-being. iConferences (Pvt) Ltd, 2023. http://dx.doi.org/10.32789/publichealth.2022.1008.

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Abstract (sommario):
Rice is the staple food of most Indonesian people. The process of planting rice using pesticides can cause contamination, one of which is arsenic contamination. Arsenic is a heavy metal that can cause various health problems such as disorders of the nervous system, respiratory system, digestive system, cardiovascular and kidney. This study aims to assess the health risks of both carcinogenic and non-carcinogenic risks due to consumption of rice containing arsenic. This research uses environmental health risk analysis method. The sample in this study amounted to 9 samples of rice which were analyzed by the Inductively Coupled Plasma (ICP) method. The sample of respondents was 96 people who were taken by purposive sampling method. Through this study, it was found that the average concentration of arsenic was 0.01 mg/kg, the respondent's body weight was 45.74 kg, the frequency of exposure was 365 days, the intake rate of 200 grams and the duration of exposure adjusted for each respondent's exposure. The final result of the calculation of the carcinogenic analysis (ECR) was 1.02 X 10-4 and the non-carcinogenic analysis (RQ) was 0.29. The results of these two analyzes indicate that the consumption of rice containing arsenic is still within safe limits. Continuous efforts should be made to keep arsenic concentrations within safe limits. Keywords: Pesticides, rice, Arsenic, EHRA
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Rapporti di organizzazioni sul tema "Arsenic"

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Siegel, Malcolm Dean. Arsenic in water treatment. Office of Scientific and Technical Information (OSTI), dicembre 2004. http://dx.doi.org/10.2172/975247.

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Goodwin, T. A. Arsenic in Nova Scotia. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2011. http://dx.doi.org/10.4095/287968.

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Meagher, Richard B. A Phytoremediation Strategy for Arsenic. Office of Scientific and Technical Information (OSTI), giugno 2005. http://dx.doi.org/10.2172/893582.

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Kawano, Toshihiko. New Arsenic Cross Section Calculations. Office of Scientific and Technical Information (OSTI), marzo 2015. http://dx.doi.org/10.2172/1172207.

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Russell, R. G., e M. G. Otey. Arsenic removal from gaseous streams. Office of Scientific and Technical Information (OSTI), novembre 1989. http://dx.doi.org/10.2172/5136273.

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Shan, Yina, Praem Mehta, Duminda Perera e Yurissa Yarela. Cost and Efficiency of Arsenic Removal from Groundwater: A Review. United Nations University Institute for Water, Environment and Health, febbraio 2019. http://dx.doi.org/10.53328/kmwt2129.

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Abstract (sommario):
Hundreds of millions of people worldwide are exposed to arsenic-contaminated drinking water, leading to significant health complications, and social and economic losses. Currently, a wide range of technologies exists to remove arsenic from water. However, despite ongoing research on such technologies, their widespread application remains limited. To bridge this gap, this review aims to compare the effectiveness and costs of various arsenic remediation technologies while considering their practical applicability. A search conducted using the Medline and Embase databases yielded 31 relevant articles published from 1996 to 2018, which were categorized into laboratory and field studies. Data on the effectiveness of technologies in removing arsenic and associated costs were extracted and standardized for comparison as much as was possible, given the diversity of ways that studies report their key results. The twenty-three (23) technologies tested in laboratory settings demonstrated efficiencies ranging from 50% to ~100%, with the majority reaching relatively high removal efficiencies (>90%). Approximately half achieved the WHO standard of 10 µg/L. Laboratory studies used groundwater samples from nine (9) different countries – Argentina, Bangladesh, Cambodia, China, Guatemala, India, Thailand, the United States, and Vietnam. The fourteen (14) technologies tested in the field achieved removal efficiency levels ranging between 60% and ~99%, with ten (10) attaining above 90% removal efficiency. Of these, only five (5) reached established the WHO standard. Some of the technologies under-performed when their influent water contained excessive concentrations of arsenic. Only six (6) countries (Argentina, Bangladesh, Chile, China, India, and Nicaragua) were represented among the studies that implemented and tested technologies in the field, either at household or community level. For technologies tested in the laboratory, the cost of treating one cubic meter of water ranged from near-zero to ~USD 93, except for one technology which cost USD 299/m³. For studies conducted in the field, the cost of treating one cubic meter of water ranged from near-zero to ~USD 70. Key factors influencing the removal efficiencies and their costs include the arsenic concentration of the influent water, pH of the influent water, materials used, the energy required, absorption capacity, labour used, regeneration period and geographical location. Technologies that demonstrate high removal efficiencies when treating moderately arsenic-contaminated water may not be as efficient when treating highly contaminated water. Also, the lifetime of the removal agents is a significant factor in determining their efficiency. It is suggested that remediation technologies that demonstrate high arsenic removal efficiencies in a laboratory setting need to be further assessed for their suitability for larger-scale application, considering their high production and operational costs. Costs can be reduced by using locally available materials and natural adsorbents, which provide near zero-cost options and can have high arsenic removal efficiencies. A notable feature of many arsenic removal approaches is that some countries with resource constraints or certain environmental circumstances – like typically high arsenic concentrations in groundwater –aim to reach resultant arsenic concentrations that are much higher than WHO’s recommended standard of 10 µg/L. This report maintains that – while this may be a pragmatic approach that helps progressively mitigate the arsenic-related health risks – it is unfortunately not a sustainable solution. Continuing exposure to higher levels of arsenic ingestion remains harmful for humans. Hence arsenic-removal technology should only be seen efficient if it can bring the water to the WHO standard. A less radical approach effectively shifts the attention from the origin of the problem in addressing the impacts and postpones achieving the best possible outcome for populations. The quantitative summary of costs and effectiveness of arsenic remediation technologies reviewed in this report can serve as a preliminary guideline for selecting the most cost-effective option. It may also be used as an initial guideline (minimum standard) for summarising the results of future studies describing arsenic remediation approaches. Looking ahead, this study identifies four priority areas that may assist in commercializing wide-scale implementation of arsenic removal technologies. These include: i) focusing efforts on determining market viability of technologies, ii) overcoming practical limitations of technologies, iii) determining technology contextual appropriateness and iv) concerted effort to increase knowledge sharing in and across regions to accelerate the implementation of research on the ground. Overall, the current science and knowledge on arsenic remediation technologies may be mature enough already to help significantly reduce the global numbers of affected populations. The missing link for today’s arsenic removal challenge is the ability to translate research evidence and laboratory-level successes into quantifiable and sustainable impacts on the ground. Achieving this requires a concerted and sustained effort from policymakers, engineers, healthcare providers, donors, and community leaders.
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Everett, Randy L., Malcolm Dean Siegel, Paul E. McConnell e Carolyn Kirby. Evaluation of innovative arsenic treatment technologies :the arsenic water technology partnership vendors forums summary report. Office of Scientific and Technical Information (OSTI), settembre 2006. http://dx.doi.org/10.2172/893130.

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Athey, J. E., R. D. Daanen e K. A. Hendricks. Naturally occurring arsenic in Alaska groundwater. Alaska Division of Geological & Geophysical Surveys, 2018. http://dx.doi.org/10.14509/30060.

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Pruet, J., D. McNabb e W. Ormand. Cross Section Evaluations for Arsenic Isotopes. Office of Scientific and Technical Information (OSTI), marzo 2005. http://dx.doi.org/10.2172/15015183.

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Percival, J. B., C. G. Dumaresq, Y. T. J. Kwong, K. B. Hendry e F A Michel. Arsenic in surface waters, Cobalt, Ontario. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1996. http://dx.doi.org/10.4095/207451.

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